OSICON-15 - Ocean Society of Indiaoceansociety.in/osicon/osicon2015/osicon2015_abstracts.pdf · OSICON-15 OCEANIC PROCESSES ALONG THE COASTS OF INDIA 22-24 March 2015 ... Vasant Kunj

CSIR-National Institute of Oceanography Dona Paula, Goa - 403 004

INDIA

4th National Conference of

Ocean Society of India

OSICON-15

OCEANIC PROCESSES ALONG THE COASTS OF INDIA

22-24 March 2015

CHAIRMAN Dr. S. W. A. NAQVI CONVENER Dr. V. RAMASWAMY CO-CONVENER Dr. JAYA KUMAR SEELAM TREASURER Dr. A. S. UNNIKRISHNAN

4th National Conference of Ocean Society of India OSICON-15

22-24 March 2015

CSIR-National Institute of Oceanography, Goa, INDIA

OSI is grateful to follwoing valued sponsors for their generous

support for OSICON-15

Ministry of Earth Sciences

Government of India

Ministry of Earth Sciences Prithvi Bhavan, Lodhi Road, New Delhi - 110003

Naval Research Board Defense R&D Organization Ministry of Defense Government of India Rajaji marg, New Delhi 110011

Department of Science, Technology &

Environment, Govt. of Goa

Department of Science, Technology & Environment, Govt. of Goa. Opp. Saligao Seminary, Saligao, Bardez, Goa - 403511.

Science and Engineering Research Board

(SERB) Department of Science and Technology (DST)

Government of India

Science and Engineering Research Board, DST, Govt. of India 5 & 5A, Lower Ground Floor Vasant Square Mall Sector-B, Pocket-5 Vasant Kunj New Delhi – 110 070

National Centre For Antarctic And Ocean Research Ministry of Earth Sciences, Government of India, Headland Sada, Vasco-da-Gama, Goa 403 804,

Indian National Centre for Ocean Information Services , "Ocean Valley", Pragathi Nagar (BO), Nizampet (SO), Hyderabad-500090

Adani Ports and Special Economic Zone Limited. 1st floor, APSEZL house, Navrangpura , Ahmedabad 380 009, Gujarat


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CONTENTS

SPONSORS ii

ABOUT OCEAN SOCIETY OF INDIAN iv

ABOUT OSICON-15 v

ABOUT CSIR-NIO vi

COMMITTEES ix

LIST OF ABSTRACTS xi

ABSTRACTS xxii

SESSION-01 1

SESSION-02 45

SESSION-03 113

SESSION-04 143

SESSION-05 177

SESSION-06 237

ADVERTISEMENTS 293

AUTHOR INDEX 295


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ABOUT OCEAN SOCIETY OF INDIA Ocean Society of India (OSI) is a registered professional society registered in Kochi,

launched on March 19, 2006, with primary objective to strive for the advancement and dissemination of knowledge in science, technology, engineering and allied fields related to oceans. OSI endeavors to provide a forum for sharing the knowledge and experience of individuals, scientific institutions and industrial organization for promoting the said objectives and act as a link among academic and R&D institutions, national policy making bodies, operational organizations and ocean industries by organizing programs such as courses, lectures, workshops, symposia and topical reviews. OSI is a non-profit organization devoted to excellence in science, engineering, technology and allied fields related to Ocean.

OSI is 9 years old and has a total of 450 members with its Life Members being more than 325, 120 student members and about 5 annual members. OSI membership has grown strongly during the recent years and is gaining strength with the active support received from the ocean science, technology and engineering community. OSI has life members located in all parts of India. So far three conferences i.e., OSICON-09; OSICON-11 and OSICON-13 were held in Visakhapatnam, Chennai and Pune respectively. The OSICON-15 is the fourth edition of the OSI conferences.

The OSI has is governed by the Governing Council (GC) elected by Members of the OSI. The current GC consists of the following members:

Dr. S.W.A. Naqvi, Director, CSIR-NIO President Dr. M. Baba, Former Director, CESS Vice-President Dr. C. Gnanaseelan, IITM, Pune Vice-President Dr. V. Ramaswamy, CSIR-NIO, Goa Gen. Secretary Dr. K.V.S.R. Prasad, Andhra Univ. Joint Secretary Dr. B.K. Jena, NIOT, Chennai Joint Secretary Dr. A.S. Unnikrishnan, CSIR-NIO, Goa Treasurer Dr. M.R. Ramesh Kumar, CSIR-NIO, Goa Member Dr. Jaya kumar Seelam, CSIR-NIO, Goa Member Dr. Milind Mujumdar, IITM, Pune Member Dr. Roxy Mathew Koll, IITM, Pune Member Dr. C.V.K. Prasada Rao, Ex-NPOL, Kochi Member Dr. P. Anand, NPOL, Kochi Member Dr. K.V. Jayachandran, KUFOS(FRM&HT), Kochi Member Dr. A.D. Rao, IIT-Delhi Member Dr. P.V. Joseph, Former Director IMD Ex-officio Member Dr. C. Revichandran, CSIR-NIO-RC, Kochi Ex-officio Member


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ABOUT OSICON-15

The 4th national conference of the OSI (OSICON-15) is scheduled to be held at National Institute of Oceanography, Goa during 22-24 March 2015. The main thrust for this conference would be “Oceanic Processes along the Coasts of India”. OSICON-15 provides a forum to bring together scientists, academicians, researchers, engineers, technologists and all other personnel in the marine related fields to share their knowledge for the benefit of mankind. As it was done in the case of previous OSICONs, research contributions were solicited as abstracts for OSICON-15 through e-mail. OSICON-15 invited active participation from all branches of marine sciences, engineering and technologies and received overwhelming response.

Keeping the focus on “Oceanic Processes along the Coasts of India”, abstracts were invited on topics of interest to Ocean Scientists / Academicians /Engineers and Technologists in the following areas:

Session No. Topic Session Conveners 01 Ocean Biogeochemistry Dr. S. Prasanna Kumar, CSIR-NIO

Dr. VVSS Sarma, CSIR-NIO Dr. TM Balakrishnan Nair, INCOIS

02 Indian Ocean Variability and Indian monsoon

Dr. Gnanaseelan, IITM Dr. Milind Mujumdar, IITM Dr. PV Hareesh Kumar, NPOL Dr. MR Ramesh Kumar, CSIR-NIO

03 Ocean Technology and acoustics

Mr. R Madhan, CSIR -NIO Mr. P Maurya CSIR-NIO Dr. R Venkatesan, NIOT Dr. CVK Prasada Rao, Former NPOL

04 Marine Geosciences Dr. B Nagender Nath, CSIR -NIO Dr. A Mazumdar CSIR-NIO Dr. AK Chaubey, CSIR-NIO Dr Kamesh Raju, CSIR-NIO

05 Coastal Processes Dr. M Baba, Former Director CESS Dr. AS Unnikrishnan CSIR-NIO Dr. Jaya Kumar Seelam, CSIR-NIO Dr. BK Jena, NIOT

06 Marine Biology Dr. N Ramaiah, CSIR-NIO Dr. AC Anil, CSIR-NIO Dr KV Jayachandran, KUFOS, Kochi

A total of 225 abstracts were selected from about 230+ abstracts received and out of these select abstracts were considered for oral presentation and remaining for Poster presentation. About 140 poster and 85 oral presentations are scheduled during this OSICON-15.


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CSIR-NATIONAL INSTITUTE OF OCEANOGRAPHY DONA PAULA, GOA, INDIA

(A constituent laboratory of Council of Scientific and Industrial Research)

CSIR- National Institute of Oceanography (NIO) with its headquarters at Dona Paula, Goa, and regional centres at Kochi, Mumbai and Visakhapatnam, is one of the 37 constituent laboratories of the Council of Scientific & Industrial Research (CSIR). NIO was established on 1 January 1966 following the International Indian Ocean Expedition (IIOE) that was undertaken from 1962 to 1965. The mission of CSIR-NIO is: “To continuously improve our understanding of the seas around us and to translate this knowledge to benefit all”. Research and development The major research areas include the four traditional branches of oceanography - biology, chemistry, physics and geology &geophysics, besides ocean engineering, marine instrumentation and archaeology. The major thrust areas for research are:

Ocean Science towards Forecasting Indian Marine Living Resource Potential

Geological Processes in the Indian Ocean – Understanding the Input Fluxes, Sinks and Paleoceanography

Geo-scientific Investigations for Deciphering the Earth’s Internal Processes and Exploration of Energy Resources

Indian Aquatic Ecosystems: Impact of Deoxygenation, Eutrophication and Acidification

Analyses and Harnessing of Marine Biodiversity for Bioremediation of Aquaculture and Other Industrial Effluents

Impact of Natural and Anthropogenic Stresses on the Coastal Environment of India

Geological and Geophysical Studies of Coastal Zone of India

Development of Autonomous Platform/s for Ocean Applications

Marine Ecological Assessment and Studies for Sustainable Development in the Coastal and Shelf Areas alongWest Coast of India

Ecobiogeography and Biotechnology of Estuaries and Coastal Waters of India

Coastal Processes and Tectonics of Eastern Continental Margin of India


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Industry and society CSIR-NIO provides services to industry and society through projects related to ports & harbours, oil & gas companies, power plants, chemical & pharmaceutical companies that use the water front for their marine facilities, which necessitate systematic study of the coastal environment. NIO provides services in the following areas: • Bathymetry, shallow seismic and side scan

sonar surveys • Collection of shallow core samples • Geo-technical investigations • Studies related to coastal zone Management • Delineation of Coastal Regulation Zone • Environmental Impact Assessment • Environmental monitoring • Simulation of Met & Oceanographic parameters

based on numerical modelling • Oil spill prediction and risk analysis and

preparation of contingency plan • Identification of suitable sites for marine facilities • Feasibility studies for marine facilities • Oceanographic design parameters for marine facilities • Testing of oil spill dispersants • Underwater inspection

Research facilities: CSIR-NIO uses 2 of its own research vessels – Sindhu Sankalp and Sindhu Sadhana besides other research vessels for scientific expeditions. CSIR-NIO offers state of the art analytical instruments The library of CSIR-NIO is recognized as the National Information Centre for Marine Sciences Research achievements: CSIR-NIO contributes more than 200 scientific publications annually in reputed national and international journals many of which have high impact factor. CSIR-NIO scientists have filed several patents on inventions based on research carried out at the Institute. Outreach activities: Training programs – CSIR-NIO conducts training programs for national and international agencies catering to students, researchers, professionals and government officials. Student programs – students from India and overseas can enrol in several programs (visit: www.nio.org)


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LOCAL ORGANISING COMMITTEES

Core-Committee: Protocol committee: S.W.A Naqvi - Chairman Rajiv Nigam - Chairman M.R. Ramesh Kumar P.S.Parameswaran P.S. Rao M. R. Ramesh Kumar B. Nagender Nath P. Vethamony A.C. Anil N. Ramaiah S. Prasanna Kumar A. K. Saran N. Ramaiah A. C. Anil A.S. Unnikrishnan Rahul Sharma - Convener C. Revichandran A.K. Chaubey Venue & Sessions Committee: Rahul Sharma Rahul Sharma - Chairman P.M. Muraleedharan D.M. Shenoy V. Sanil Kumar A.P. Selvam Jaya Kumar Seelam Sharon Tracy Gomes V. Ramaswamy - Convener Sundaresh Areef Sardar V. Khedekar Sponsorship & Finance: Ryan Luis V. Ramaswamy - Chairman Hema Naik P. C. Rao R.L. Chavan P. S. Rao Mahesh Mochemadkar V. Sanil Kumar Chandrakant Shirvoikar Jaya Kumar Seelam Uday K Javali C.Prakash Babu Vinod Kumar A. S. Unnikrishnan - Convener Pundalik Gawas Jai Singh Abstracts & Souvenir: Manoranjan Singh B. Nagender Nath - Chairman Jaya Kumar Seelam V. Ramaswamy V. Ramaswamy S. Akrekar Pratima Kessarkar - Convener Sujal Bandodkar Food: Jaya Kumar Seelam - Convener P. M. Muraleedharan - Chairman A. Mahale R. Madhan - Convener


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Transport: Registration: R A Sreepada - Chairman M.R. Ramesh Kumar - Chairman P S Pednekar P.M. Muraleedharan Uday Mandrekar D. Ilangovan H. Dalvi Prakash Mehra Prakash Babu - Convener Maria Desa Catherine S. Manohar Accommodation: Liditha K Dattesh Desai - Chairman Jaya Kumar Seelam - Convener Rajeev Saraswat Rajaram Patil Toraskar - Convener


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LIST OF ABSTRACTS Paper

No. Title Page

No.

101 MODELING THE BIOGEOCHEMICAL CYCLE OF MICROBES ALONG THE COASTAL ZONES by Kiran Gurung* and Geetha N

2

102 PHYTOPLANKTON BLOOM EVENTS FROM SEAWIFS DATA ACTIVATED BY MULTIPLE FORCINGS IN BAY OF BENGAL by R. Roy Chowdhury*, A. Chakraborty

3

103 APPLICATION OF BAYESIAN INVERSION TO OPTIMIZE THE PHYSICAL AND BIOGEOCHEMICAL PARAMETERS IN OCEAN BIOGECHEMICAL MODELS by Vinu K. Valsala*, N. Pavan Kumar, S. Maksyutov, R. Murtugudde

5

104 RECENT INSIGHT ON BIOGEOCHEMICAL CONSTITUENTS IN THE COCHIN ESTUARINE SYSTEM (CES) by K.Sriram, Soja Louis, C.H. Sujatha*

6

105 METAL FRACTIONATION PROFILE OF CORE SEDIMENTS IN THE SPECIFIC ZONES OF COCHIN ESTUARINE SYSTEM by Nair Manju P and C.H Sujatha*

7

106 CHLOROPHYLL-A DYNAMICS IN NEAR COASTAL WATERS OF WESTERN BAY OF BENGAL USING IN SITU AND LONG-TERM SATELLITE DATA by Aneesh A. Lotliker*, Sanjiba Kumar Baliarsingh, K. C. Sahu, T. Srinivasa Kumar

8

107 ESTIMATION OF AEROSOL AND NUTRIENT DEPOSITION IN THE COASTAL BAY OF BENGAL OFF VISAKHAPATNAM by K. Yadav*, V.V.S.S. Sarma, M. Dileep Kumar

10

108 SPATIAL VARIATIONS IN TROPHIC LEVEL OF PRIMARY CONSUMERS ALONG THE GODAVARI ESTUARY by J. Mukherjee*, V. V. S. S. Sarma

11

109 A MODELLING STUDY OF BIOLOGICAL FEEDBACKS ON SEA SURFACE TEMPERATURE by Kunal Chakraborty*, Arya Paul, Satya Prakash

12

110 EFFECTS OF MACRONUTRIENTS ON COASTAL DIATOM GROWTH DYNAMICS AT VISAKHAPATNAM, NW COAST OF BAY OF BENGAL, INDIA: AN EXPERIMENTAL APPROACH by Debasmita Bandyopadhyaya* and Haimanti Biswas

13

111 VARIATIONS IN EFFICIENCY OF BIOLOGICAL PUMP IN THE BAY OF BENGAL USING STABLE ISOTOPIC COMPOSITION OF NITROGEN IN THE SUSPENDED MATTER by C.K. Sherin* and V.V.S.S. Sarma

14

112 INTRA-ANNUAL VARIABILITY IN ORGANIC CARBON SINKING FLUXES OFF A TROPICAL MAJOR RIVER, GODAVARI: SEDIMENT TRAP RESULTS by Sreenu Lenka*, M. S. Krishna and V.V.S.S. Sarma

15

113 SOURCES AND DISTRIBUTION OF PARTICULATE ORGANIC MATTER IN THE WESTERN COASTAL BAY OF BENGAL DURING SW MONSOON: INFLUENCE OF RIVER DISCHARGE by M.S. Krishna*, L. Gawade, S.A. Naidu, V.V.S.S. Sarma, N.P.C. Reddy

16

114 SENSITIVITY OF COASTAL PHYTOPLANKTON TO VARIABLE COPPER CONCENTRATIONS FROM THE VISAKHAPATNAM COAST (SW COAST OF BAY OF BENGAL, INDIA) by Haimanti Biswas* and Debasmita Bandyopadhyay

17

115 BIO-PHYSICAL COUPLING AND UPPER OCEAN BIOLOGICAL PRODUCTIVITY IN THE NORTHERN INDIAN OCEAN by S. Prasanna Kumar* and Jayu Narvekar

18

116 EFFECTS OF ZINC ON COASTAL PHYTOPLANKTON GROWTH AND PRIMARY PRODUCTION UNDER LOW AND HIGH CO2 LEVELS FROM VISAKHAPATNAM by Aziz Ur Rahman Shaik1*, Debasmita Bandyopadhyay2 and Haimanti Biswas3

19


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Paper No.

Title Page No.

117 DISTRIBUTION OF BIOCHEMICAL COMPOUNDS IN INDIAN MONSOONAL ESTUARIES DURING SW MONSOON by B.S.K. Kumar*, V.V.S.S. Sarma, M.S.R. Krishna and N.P.C. Reddy

20

118 OBSERVED INTRA-SEASONAL VARIABILITY OF CHLOROPHYLL-A USING ARGO PROFILING FLOAT IN THE EASTERN EQUATORIAL INDIAN OCEAN by V. P. Thangaprakash*, M. S. Girishkumar, T.V.S. Udaya Bhaskar, M. Ravichandran

21

119 VARIABILITY OF PHYTOPLANKTON PIGMENT CONCENTRATION IN INDIAN ESTUARIES DURING PEAK RIVER DISCHARGE PERIOD by D. B. Rao*, V.V.S.S. Sarma, M.S. Krishna and N.P.C. Reddy

22

120 INTERANNUAL TO LONG-TERM VARIABILITY OF OXYCLINE ALONG THE WEST COAST OF INDIA: UNDERSTANDING ANOXIC EVENTS THROUGH MODELING APPROACH by V. Parvathi*, I. Suresh, S. Neetu, M. Lengaigne, M. Levy, L. Resplandy, C. Ethé, J. Vialard, O. Aumont, H. Naik, SWA. Naqvi

23

121 VERTICAL VARIATION OF PRIMARY PRODUCTIVITY IN PRESENCE OF ULTRAVIOLET RADIATIONS, CENTRAL WEST COAST OF INDIA by Prachi A. Naik*, M. Gauns

24

122 INFLUENCE OF ANTHROPOGENIC ACTIVITIES ON ABUNDANCE OF HETEROTROPHIC AND PATHOGENIC BACTERIA ALONG THE COAST OF ANDAMAN ISLANDS by P. Sudharani*, Y. Sathibabu, T. N. R. Srinivas

26

123 BENTHIC REMINERALIZATION AND NUTRIENTS EXCHANGE ALONG THE SALINITY GRADIENT OF A TROPICAL ESTUARY, CENTRAL WEST COAST OF INDIA by A. K. Pratihary*, J. Araujo, K.F. Bepari, R. Naik, S. Morajkar, P. Satardekar, D.M. Shenoy, S.W.A. Naqvi

27

124 BIOGEOCHEMICAL CYCLING IN MANDOVI AND ZUARI ESTUARIES, WEST COAST OF INDIA by Hema Naik, D. M. Shenoy, S. Kurian, S. W. A. Naqvi

29

125 VARIATION OF DIMETHYLSULPHIDE AND ASSOCIATED COMPOUNDS IN THE MANDOVI AND ZUARI ESTUARY by Kausar Fatima M. Bepari, Damodar M. Shenoy*, M. Gauns, H. Naik and S.W.A. Naqvi

31

126 IMPACT OF SEWAGE DISCHARGE ON THE WATER QUALITY OF VERSOVA CREEK by Anirudh Ram*, B. R. Thorat, M. A. Rokade, D. Majithiya, A. Yadav, S. Salvi, V. Joshilkar, N. Shinde, Jiyalal Ram. M. Jaiswar, S. N. Gajbhiye

32

127 METHANE EMISSIONS FROM THE SHELF WATERS OF SOUTHEASTERN ARABIAN SEA by V.Sudheesh, G.V.M.Gupta* and M.Sudhakar

34

128 BEHAVIOUR AND FATE OF TRACE ORGANIC CONTAMINANTS IN THE COCHIN ESTUARINE SYSTEM (CES), INDIA: AN OVERVIEW by P.S. Akhil, C.H. Sujatha*

35

129 INTER-SEASONAL OBSERVATIONS IN DMS (P) VARIABILITY IN TROPICAL INTERTIDAL ESTUARINE ECOSYSTEM by Pandey Sunita Surendra, P. A. LokaBharathi*

36

130 MEASUREMENT OF NITROGEN FIXATION RATES ALONG THE SOUTHWEST COAST OF INDIA by Ayaz Ahmed*, Mangesh Gauns, Pratirupa Bardhan, Damodar Shenoy, Hema Naik, Siby Kurian, Anil Kiran Pratihary and SWA Naqvi.

38

131 CONCENTRATION OF TRACE METALS AND THEIR COVARIANCE WITH CARBON, NITROGEN AND SULPHUR IN ANOXIC ENVIRONMENT OF VERAVAL HARBOUR by Divya Majithiya, Ajay Yadav, Anirudh Ram*, Shailesh Salvi, Archana Kamble

39

132 PHYTOPLANKTON–ZOOPLANKTON DYNAMICS IN COASTAL WATERS OF CENTRAL WEST COAST OF INDIA by Mangesh Gauns, Anil Pratihary, D M Shenoy, Siby Kurian, H Naik and S.W.A. Naqvi

41

133 GLOBAL SEAWATER DMS CLIMATOLOGY: COMPARISON & UPDATE by Smrati Gupta*, Anoop S. Mahajan

42


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Paper No.

Title Page No.

134 CARBON DIOXIDE EMISSIONS FROM A TROPICAL ESTUARY LOCATED ALONG THE WEST COAST OF INDIA- ZUARI ESTUARY by Rashith P*, H. Naik, D. M. Shenoy and S.W. A. Naqvi

44

201 ROLE OF NINGALOO NINO/NINA IN ALTERING THE BIOLOGICAL ACTIVITY IN SOUTHERN SUB TROPICAL INDIAN OCEAN by Sandeep.N, K. Ashok, Swapna.P*, Aparna.K

47

205 ROLE OF INDIAN OCEAN SST IN MODULATING ONSET AND PROGRESSION OF ISM IN THE SUCCESSIVE YEARS OF 2013 AND 2014 by Ramesh Kumar Yadav* and Bhupendra Bahadur Singh

48

206 OBSERVATIONAL EVIDENCE OF MIXED ROSSBY GRAVITY WAVES AT THE CENTRAL EQUATORIAL INDIAN OCEAN by P.M. Muraleedharan*, S. Prasanna Kumar, K. Mohanakumar, S. Sijikumar, K.U.Sivakumar, Teesha Mathew

49

207 PRECIPITATION EXTREMES DURING SOUTHWEST MONSOON AND ITS CONNECTION WITH INDIAN OCEAN DIPOLE by J.V. Revadekar*, H. Varikoden

50

208 TROPICAL INDIAN OCEAN SIMULATION USING NEMO-AGRIF by Umesh Kumar Singh*, Suneet Dwivedi, Lokesh Kumar Pandey

51

209 IMAPCT OF INDIAN OCEAN VARIABILTY ON INDIAN SUMMER MONSOON RAINFALL DURING RECENT YEARS by Sanjo Jose V*, E. K. Kurien, Athira P. Ratnakaran, Binsiya T. K.

52

210 POSSIBLE ROLE OF INDIAN OCEAN IN THE BIENNIAL TRANSITION OF INDIAN SUMMER MONSOON IN OBSERVATION AND CMIP5 SIMULATIONS by Prasanth A Pillai*, A. K Sahai

53

211 ROLE OF INDIAN OCEANS IN CLIMATE OF WEST COAST OF INDIA by P.K. Murumkar, H. Varikoden, S.A. Ahmed, J.V. Revadekar*

54

212 NEAR-SURFACE STRATIFICATION AND SUBMESOSCALE FRONTS IN THE NORTH BAY OF BENGAL IN AUGUST-SEPTEMBER 2014 by J. Sree Lekha*, S. Shiva Prasad, M. Ravichandran, D. Sengupta

55

213 INFLUENCE OF INDO-PACIFIC SEA SURFACE TEMPERATURE ON THE PRECIPITATION OVER NORTHWEST HIMALAYAS by V. M. Shakuntala, J. V. Revadekar, S. A. Ahmed and H. Varikoden*

57

214 CLIMATOLOGICAL VARIATION OF CIRCULATION FEATURES OF THE NORTH INDIAN OCEAN AND ITS INTERANNUAL VARIABILITY FROM TOPEX/POSIDEN ALTIMETRY by R. Sen*, A. Chakraborty

58

215 RETRIEVING OF TEMPERATURE AND SALINITY OF THE INTERIOR OCEAN FROM HIGH RESOLUTION SATELLITE SEA SURFACE TEMPERATURE by D. Sarkar*, A. Chakraborty, Raj Kumar, Rashmi Sharma

60

216 SUBSURFACE TEMPERATURE BIAS IN THE EQUATORIAL INDIAN OCEAN IN NCEP CLIMATE FORECASTING SYSTEM by G. Srinivas*, J. S. Chowdary, Rashmi Kakatkar, Anant Parekh and C. Gnanaseelan

62

217 A REVIEW OF LATE HOLOCENE CLIMATE CHANGE FROM WESTERN INDIA: HUNTING ARCHIVES FOR RECONSTRUCTING HIGH RESOLUTION CLIMATE DYNAMICS by Nisarg Makwana*, S.P. Prizomwala, N.P. Bhatt, B.K. Rastogi

63

218 NUDGING OF THERMODYNAMIC PROFILES: IMPACT ON REPRESENTATION OF INDIAN SUMMER MONSOON by Raju Attada, Anant Parekh*, C. Gnanaseelan and J. S. Chowdary

64

219 INTERCOMPARISON OF NIOT WAVE BUOY DATA WITH DATAWELL WAVERIDER BUOY by J. Vimala*, K. Ramesh, G. Latha and R. Venkatesan

65

220 SOIL MOISTURE DURING SOUTHWEST MONSOON PERIOD AND ITS RELATION WITH INDIAN OCEAN SEA SURFACE TEMPERATURE by H. Varikoden*and J. V. Revadekar,

66

221 RESPONSE OF BAY OF BENGAL TO CYCLONE PHAILIN FROM MOORED AND SATELLITE DATA by Chaudhuri. D*, Vekatesan. R, Ravichandran. M, Sengupta. D

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Paper No.

Title Page No.

222 INDIAN SUMMER MONSOON AND THE OCEAN HEAT BUDGET SIMULATED IN CFSV2 MODEL by Gibies George*, D. Nagarjuna Rao, C.T. Sabeerali, A. Suryachandra Rao

69

223 PREDICTION AND ERROR GROWTH IN THE DAILY FORECAST OF PRECIPITATION FROM THE NCEP CFSV2 OVER THE SUBDIVISIONS OF INDIAN CONTINENT by Shailendra Rai, *, Dhruva Kumar Pandey, A. K. Sahai and S. Abhilash

71

224 MODELING THE HYDROGRAPHY AND CIRCULATION OF THE BAY OF BENGAL USING A HIGH-RESOLUTION OCEAN CIRCULATION MODEL by Atul Srivastava*, Suneet Dwivedi and Alok Kumar Mishra

73

225 USING THE TELESCOPICALLY VARYING HORIZONTAL AND VERTICAL GRIDS FOR MODELING THE INDIAN OCEAN VARIABILITY by Anupam Kumar Dixit* and Suneet Dwivedi

74

226 POSSIBLE INTERACTIONS BETWEEN SUBSURFACE OCEAN BIASES AND THE SURFACE INTERANNUAL VARIABILITY IN COUPLED MODELS. by Shikha Singh*, Vinu Valsala

75

227 NORTH-SOUTH HEMISPHERIC THERMAL CONTRAST AND INDIAN SUMMER MONSOON RAINFALL VARIABILITY by Lekshmi Mudra. B* and H. N. Singh

76

228 STUDY OF INDONESIAN THROUGHFLOW USING HYBRID COORDINATE OCEAN MODEL by Vivek Kumar Pandey*, Sudhir Kumar Singh, Satyam Srivastava

77

229 ROLE OF UPPER OCEAN STRATIFICATION IN THE INTENSIFICATION OF THE SEVERE CYCLONE “HUDHUD” by K.Maneesha*, Y.Sadhuram and V.S.N.Murty

78

230 SEASONAL CHANGE IN THE TROPICAL CYCLONE CHARACTERISTICS BETWEEN PRE- AND POST-MONSOON SEASONS IN THE BAY OF BENGAL: RESPECTIVE INFLUENCE OF THE OCEAN AND ATMOSPHERE by M. Teesha, S. Neetu , M. Lengaigne , J. Vialard , G. Samson

80

231 REMOTE AND REGIONAL OCEANIC INFLUENCE DURING SOUTH-WEST SUMMER MONSOON 2014. by Milind Mujumdar*, Swapna P., M. K. Roxy, Sabin T.P., C. Gnanaseelan, and R. Krishnan

81

232 ON THE POSSIBLE CAUSE OF DISTINCT EL NIÑO TYPES IN THE RECENT DECADES by Jyoti J, Swapna* P, Shamal Marathe and K. Ashok

82

233 INTRASEASONAL TO INTERANNUAL VARIABILITY OF SURFACE LAYER TEMPERATURE INVERSION IN THE BAY OF BENGAL by Pankajakshan Thadathil, I. Suresh, S. Gautham*,S. Prasanna Kumar , Matthieu Lengaigne, R.R.Rao, S. Neetu and Y.K. Somayajulu

83

234 EFFECT OF RIVER DISCHARGE IN SIMULATION OF SEA SURFACE SALINITY USING ROMS MODEL by K. K. Sandeep*, Vimlesh Pant, A. D. Rao, Arulalan T

84

235 ROLE OF IOD AND ENSO ON THE INTER-ANNUAL VARIABILITY OF TROPICAL INDIAN OCEAN by Anju S*, P. Swapna, K.Ashok,, Sandeep and Jyoti

85

236 RELATIVE ROLE OF EL-NINO SOUTHERN OSCILLATION AND IOD EVENTS ON MONSOON ACTIVITY OVER INDIA by S. Gopika*, M. R. Ramesh kumar

86

237 PROCESSES ASSOCIATED WITH THE ARABIAN SEA MINI WARM POOL FORMATION AND THEIR EPOCHAL CHANGES by Aniket Barphe, ,*, C. Gnanaseelan and P. Pradeep Kumar

87

238 INDIAN OCEAN WARMING – ITS EXTENT, AND IMPACT ON THE MONSOON AND MARINE PRODUCTIVITY by Roxy M. K.*, K. Ritika, A. Modi, P. Terray, R. Murtugudde, K. Ashok, B. N. Goswami, S. Masson, V. Valsala, P. Swapna, S. Prasanna Kumar and M. Ravichandran

88

239 FLAVOURS IN THE DECAY PHASE OF EL NIÑO AND THE ASSOCIATED RESPONSE ON MONSOON CIRCULATION AND RAINFALL by H. Sree Harsha*, J. S. Chowdary, C. Gnanaseelan, C.V. Naidu, G. Srinivas, A Parekh and Prasanth Pillai

89


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240 SUB-SURFACE TEMPERATURE TRENDS IN THE NORTH INDIAN OCEAN AND OCEAN VERTICAL PROCESSES by Anand babu Amere, *, Anant Parekh, Fousiya T.S, G.Bharathi, C.Gnanaseelan and J.S.Chowdary

90

241 THE STRUCTURE OF INDIAN OCEAN MERIDIONAL OVERTURNING IN OCEAN REANALYSIS DATASETS AND AN OGCM by S Rahul, C Gnanaseelan

91

242 MESO-SCALE EDDIES IN THE NORTH INDIAN OCEAN AND THEIR PROPAGATION PATHWAYS by T.N. Shyni and P.V. Hareesh Kumar

92

243 PHYSICAL PROCESSES CONTROLLING MIXED LAYER VARIABILITY IN THE NORTHERN INDIAN OCEAN by Jayu Narvekar* and S. Prasanna Kumar

93

244 VARIABILITY AND TRENDS IN THE TROPICAL INDIAN OCEAN SEA SURFACE SALINITY, IN A CHANGING CLIMATE by Vivek Shilimkar *, M. K. Roxy

94

245 IMPACT OF AQUARIUS SEA SURFACE SALINITY ASSIMILATION IN IMPROVING THE OCEAN STATE by Vivek .S*, P. Sreenivas, C. Gnanaseelan and K. V. S. R. Prasad

95

246 DYNAMICAL LINK BETWEEN TROPICAL INDIAN OCEAN AND CYCLONES by P. Sreenivas*, C. Gnanaseelan, J.S. Chowdary and K.V.S.R. Prasad

96

247 ASSIMILATION OF ALTIMETRY DERIVED TEMPERATURE AND SALINITY IN GODAS AND ITS IMPACT ON MONSOON PREDICTION by P. Sreenivas, N. Pavan Kumar, R. Kakatkar and C. Gnanaseelan

97

248 EQUATORIAL INDIAN OCEAN SUBSURFACE CURRENT VARIABILITY IN AN OCEAN GENERAL CIRCULATION MODEL AND ITS IMPACT ON REGIONAL CLIMATE. by Aditi Deshpande* and C. Gnanaseelan

98

249 INTER-ANNUAL VARIABILITY OF UPPER OCEAN STRATIFICATION IN BAY OF BENGAL: OBSERVATIONAL AND MODELING ASPECTS by T.S. Fousiya*, Anant Parekh and C. Gnanaseelan

99

250 A NEW MODE OF VARIABILITY IN THE TROPICAL INDIAN OCEAN SUBSURFACE TEMPERATURE AND ITS CLIMATIC IMPACTS by C. Gnanaseelan* and Sayantani Ojha

100

251 INTER COMPARISON OF DIFFERENT OCEAN MODELS OVER THE TROPICAL INDIAN OCEAN by Ananya Karmakar*, Anant Parekh, Jasti Chowdary, and C. Gnanaseelan

101

252 IMPACT OF PROLONGED ENSO EVENTS ON TROPICAL INDIAN OCEAN IN THE COUPLED MODEL CFSV2 AND OBSERVATIONS by P. Singh, J.S. Chowdary and C. Gnanaseelan

102

253 PHYSICO-CHEMICAL PROPERTIES AND STABLE OXYGEN ISOTOPIC (Δ18O) VARIATIONS OF SEAWATER, ALONG THE CONTINENTAL SHELF DURING POST NE AND SW MONSOON PERIODS, SOUTH EAST COAST, INDIA. by Nisha.V* and H. Achyuthan

103

254 DECADAL VARIABILITY IN THE TROPICAL INDO PACIFIC OCEAN AND ITS IMPACT ON INDIAN SUMMER MONSOON by Abhishek Savita, *, C. Gnanaseelan, S. Rahul

104

255 DYNAMICS OF SUMMER MONSOON OCEANIC EDDIES IN BAY OF BENGAL AND ITS EFFECT ON ATMOSPHERE by Saurabh Rathore*, Anant Parekh, Mihir Kumar Dash

105

256 VARIABILITY OF ATMOSPHERIC REFRACTIVE INDEX STRUCTURE PARAMETER (CN2) – A CASE STUDY AND IT’S PREDICTION USING METEOROLOGICAL DATA by G Nageswara Rao* and Amit Pratap

107

257 EPOCHAL CHANGES IN THE DOMINANT SUBSURFACE MODE OF TROPICAL INDIAN OCEAN by Ojha Sayantani* and C. Gnanaseelan

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258 VALIDATION OF GEKCO AND OSCAR PRODUCTS FOR THE INDIAN OCEAN REGION USING IN – SITU OBSERVATIONS FROM MOORINGS by A Phanindra Reddy*, Simi Mathew, G. Latha and R. Venkatesan

109

259 IMPACT OF CLIMATE MODES ON THE INTER-ANNUAL VARIABILITY OF ZONAL CURRENTS IN THE EQUATORIAL INDIAN OCEAN. by Chinnu Sachidanandan* and P.M. Muraleedharan

110

260 SPATIO-TEMPORAL VARIATIONS IN SALINITY PROFILES OVER THE BAY OF BENGAL by Kumar Ravi Prakash*, Vimlesh Pant

111

261 SUPPLEMENTING XBT OBSERVATIONS WITH SALINITY IN THE BAY OF BENGAL by Venugopal Reddy.T, Ali.M.M*, Gopala Krishna.V.V

112

301 GPS/GSM BASED SEAMLESS IN-SITU PROFILER FOR ATMOSPHERIC BOUNDARY LAYER by Femy Paulose*, Feby Paulose, Gibies George

114

302 ESTABLISHMENT OF SHIPBOARD AWS ON INDIAN RESEARCH VESSEL SINDHU SADHANA by K. Vijay Kumar, Prakash Mehra, Yogesh Agarvadekar, Govind Ranade, G.P Naik, Ryan Luis, Bharat Harmalkar, Devika V. Ghatge, Narayan Satelkar, and Pramath Keny

116

303 SPATIAL DISTRIBUTION OF SOFAR CHANNEL PARAMETERS OVER BAY OF BENGAL by K.Ashalatha, T.V.R.Murty, K.V.S.R.Prasad

117

304 DEVELOPMENT OF MICROBIAL FUEL CELL BASED ENERGY HARVESTING SYSTEM USING MARINE SEDIMENT FOR UNDERWATER APPLICATIONS by P. Janani*, S. Sakthivel Murugan, N. Archana

118

305 RAIN FALL ANALYSIS USING NOISE MEASUREMENTS IN SHALLOW WATERS OFF ANDHRA COAST by M. Ashokan*, G. Latha, K. Nithyanandam

119

306 CONVERTED WAVE AVO ANALYSIS FOR RESERVOIR CHARACTERISATION by Prabhakar Nayak, A. K. Rai

120

307 DEVELOPMENT OF DUAL MODE COMMUNICATION A NOVEL TECHNIQUE FOR REAL TIME TSUNAMI BUOY SYSTEMS by R.Sundar, M.Arulmuthiah, S.Elango, D.Gowtham, R.Venkatesan, M.A.Atmanand

121

308 AMBIENT NOISE VARIABILITY ALONG THE CENTRAL WEST COAST OF INDIA – OFF GOA by R. Kannan*, G. Latha, G. Raguraman

122

309 FISH CHORUS RECORDED IN THE SOUTHEASTERN ARABIAN SEA: A COMPARISON STUDY WITH OTHER SHALLOW WATER ENVIRONMENTS by M. M. Mahanty*, G. Latha and A.Thirunavukkarasu

123

310 NOISE LEVEL VARIABILITY AND SPECTRAL CHARACTERISTICS OF SHALLOW WATER AMBIENT NOISE AT VIZAG by K.K Noufal*, M.C Sanjana, G. Latha

124

311 HINDUSTAN UNIVERSITY AUTONOMOUS UNDERWATER VEHICLE: DESIGN AND IMPLEMENTATION OF THE POSEIDON AUV by S.Suryakumar*, Gokulavasan, Indrajeet Ghosh, A.Muthuvel, N.Prakash, K.Kamalakkannan

125

312 MAPPING SLOPE MORPHOLOGY OFF GOA, WESTERN CONTINENTAL MARGINS OF INDIA by Andrew Menezes*, S. M. Karisiddaiah, Bishwajit Chakraborty, K. Haris, William Fernandes

127

313 A METHOD FOR IMPROVING MULTIBEAM BATHYMETRY DATA QUALITY AFFECTED BY ERRONEOUS SOUND SPEED by William A. Fernandes*, Bishwajit Chakraborty

128

314 RECENT ADVANCES IN THE DESIGN OF SONAR HUMAN MACHINE INTERFACE by *Anjaly C Gopi, G K Nagarajan, Sumi A Samad and V S Shenoi

130


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315 REFINEMENT OF SHALLOW WATER DEPTH ESTIMATION ALGORITHM USING WEIGHTED LINEAR REGRESSION APROACH by Vinayaraj Poliyapram, Venkatesh Raghavan, Glejin Johnson and V.V. Sanil Kumar

131

316 A VLSI BASED INTEGRATED DATA ACQUISITION SYSTEM FOR POLAR OBSERVATORY by Lydia Kiruba R*, M.Arul Muthiah, R. Venkatesan, A. Sivagami

133

317 COLLECTION OF OCEANOGRAPHIC DATA IN MACRO TIDAL REGIME- GULF OF KHAMBHAT EXPERIENCE. by M.Sankar, K.M.Sivakholundu, B.K.Jena, Vijaya Ravichandran, V.Suseentharan, Karunakar Kintada

134

318 DEVELOPMENT OF DRIFTER BUOY FOR MEASURING CURRENTS IN SURF ZONE by V Suseentharan*, K M Sivakholundu, Basanta Kumar Jena, M Ravinder, R Balaji

135

319 HIGH STRENGTH TERMINATION TECHNIQUE FOR VECTRAN FIBRE ARMOURED UNDERWATER TOW CABLES by Kiran Govind V*, Anshath Hussain, Thulasidas K R, Sabu Sebastian M

136

320 INTER-COMPARISON OF COLLOCATED CUP TYPE AND SONIC ANEMOMETER ON THE MOORED COASTAL BUOY by Jagadeesh Kadiyam, G. Vengatesan, M Arul Muthiah, J. Vimala and Dr. R Venkatesan

138

321 A REVIEW ON THE INDIRECT ESTIMATION OF GEO-ACOUSTIC PROPERTIES OF SEABED by V.K. Unny*, C.P. Uthaman, Nitheesh Thomas

139

323 COOPERATIVE MOTION CONTROL OF MULTIPLE AUVS – CHALLENGES IN IMPLEMENTATION by Manish Singh*, Nupur Thakker, Pramod Maurya, Gajanan Navelkar, Antonio Mascarenhas

140

324 VALIDATION OF INDIAN TSUNAMETER IN LABORATORY ENVIRONMENT by Tata Sudhakar* and G.A. Ramadass

141

401 UNDERSTANDING EARTHQUAKES AND TSUNAMI HAZARD IN BAY OF BENGAL by Saroj K. Dash, A. K. Rai*

144

402 ROLE OF MARINE TRANSGRESSION IN THE FORMATION OF KACHCHH BAUXITE, GUJARAT, INDIA by P.S.Choudhury, G.N.Jadhav and D.U.Vyas

145

403 EVALUATION OF NUMERICAL MODELS FOR PALAEOTSUNAMI/PALAEOSTORM DEPOSITS FROM SAURASHTRA COAST, WESTERN INDIA by Drasti Gandhi, *, S.P.Prizomwala, N.Y.Bhatt, Kapil Mohan, B.K. Rastogi

146

404 DEMARCATION OF NEAR SUBBOTTOM SEDIMENT STRATA OF SHALLOW WATERS USING IMAGE PROCESSING by Satyanarayana Yegireddi

147

405 DISTRIBUTION OF REE IN SEDIMENT CORES FROM THE THANE CREEK, MUMBAI by Lina L. Fernandes *, Pratima M. Kessarkar, V. Purnachandra Rao

149

406 GEOCHEMISTRY OF THE SURFACE SEDIMENTS WITHIN AND BELOW OXYGEN MINIMUM ZONE FROM THE SOUTHWESTERN CONTINENTAL MARGIN OF INDIA by Pratima M. Kessarkar*, G. Parthiban, J.N. Pattan, Lina L. Fernandes, Supriya G. Karapurkar, Siby Kurian, V. Purnachandra Rao

150

407 DELIVERY OF PARTICULATE ORGANIC CARBON DURING THE GREAT FLOOD OF KRISHNA RIVER IN OCTOBER 2009 by C. Prakash Babu*, V. Ramaswamy, P.S. Rao

151

408 MINERALOGY AND RARE EARTH ELEMENTS IN SEDIMENT CORES FROM THE MANDOVI ESTUARY, WESTERN INDIA: INFERENCES ON SOURCES OF THE SEDIMENTS by Prajith, A., Rao, V. P.* and Pratima M. Kessarkar

152


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409 STABLE ISOTOPIC INVESTIGATION OF PORITES CORAL FROM MINICOY ISLAND by A. A. Fousiya, S. Chakraborty*, H. Achyuthan, Naveen Gandhi, Nitesh Sinha, Amey Datye

153

410 ANTHROPOGENIC IMPRINTS ON A SEDIMENT CORE OFF GOA FROM THE ARABIAN SEA – A ROCK MAGNETIC & GEOCHEMICAL APPROACH by Tyson Sebastian*, Sangeeta Naik, B.Nagender Nath, D.V.Borole

155

411 WET DEPOSITION OF MIDDLE-EAST DUST OVER THE INDIAN PENINSULA by V. Ramaswamy*, Prakash Babu

156

412 PRELIMINARY OBSERVATIONS OF GEOMORPHOLOGICAL, SEDIMENTOLOGICAL AND MINERALOGICAL CHARACTERISTICS OF THE ARNALA BEACH AND ARNALAPADA ISLAND, THANE DISTRICT, MAHARASHTRA, INDIA by S. D. Iyer, A. R. Gujar, D. K. Naik, S. S. Gaonkar, R. A. A. Luis, F. K. Badesab

157

413 PARTITIONING OF METALS IN DIFFERENT BINDING PHASES OF MARINE SEDIMENTS: IMPORTANCE OF METAL CHEMISTRY by P. Chakraborty

159

414 ISOTOPIC FINGERPRINTING OF ATMOSPHERIC DUST OVER ARABIAN SEA by A. Kumar*, K. Suresh, P. P. Padalkar, C. Prakashbabu, V. Ramaswamy

160

415 DISTRIBUTION AND SPECIATION OF PB IN COASTAL SEDIMENTS AROUND INDIA by Sucharita Chakraborty*, Parthasarathi Chakraborty and B. Nagender Nath

162

416 HIGH RESOLURION HOLOCENE PALEOMAGNETIC SECULAR VARIATION RECORDS FROM BAY OF BENGAL by A. Usapkar, P. Dewangan*, F.K. Badesab, A. Mazumdar, T. Ramprasad, K.S. Krishna, N. Basavaiah

163

417 INITIATION OF OCEAN BOTTOM SEISMOMETER EXPERIMENT IN THE ANDAMAN BACK ARC BASIN by K.A. Kamesh Raju*, Pawan Dewangan, Aswini, K.K., Yatheesh, V., Pabitra Singha, Kiranmayi S

164

418 SULFUR AND IRON SYSTEMATICS OF A CORE (MD161-15) FROM THE KRISHNA-GODAVARI BASIN, BAY OF BENGAL by M. Carvalho, A. Mazumdar*

165

419 INFLUENCE OF LAND USE PATTERN ON DISTRIBUTION OF ORGANIC MATTER IN A TROPICAL LAGOON by Arindam Sarkar*, B.Nagender Nath

166

420 NATURE OF SULFIDIZATION WITHIN A SEDIMENT COLUMN OFF MAHANADI BASIN, BAY OF BENGAL, INDIA by Brahmanand Sawant, A. Mazumdar*, Maqbool Yousuf, Aditya Peketi

167

421 DEPOSITIONAL ENVIRONMENT OF THE SURFACE SEDIMENTS IN CENTRAL INDIAN BASIN (CIB), INDIAN OCEAN BASED ON THEIR MAJOR ELEMENT COMPOSITION by Simontini Sensarma, Ranadip Banerjee* and Subir Mukhopadhyay

168

422 TERRESTRIAL AND MARINE PRODUCTIVITY: SOME COMMON THREADS by R. DaSilva, A. Mazumdar*, R.K. Joshi, A. Shaji, P. Mahalakshmi, B.G. Naik

169

423 THE EFFECT OF HOLOCENE TEMPERATURE CHANGES ON HUMAN SETTLEMENTS IN ASIA by Rajeev Saraswat

170

424 SEDIMENT DISPERSAL AND TRANSPORT ON THE CONTINENTAL SHELF OF MYANMAR, NORTHEAST INDIAN OCEAN by P.S. Rao and V.Ramaswamy

171

425 IDENTIFICATION OF SOURCES AND FREQUENCY OF MINERAL DUST OVER THE MIDDLE-EAST AND SOUTHWEST ASIA BY USING SATELLITE DATA. by K.Suresh*, V.Ramaswamy, C.Prakashbabu

173

426 PHOSPHATE UPTAKE BY MICROBIAL COMMUNITES IN THE CONTINENTAL MARGIN SEDIMENTS by S. S. Mamatha*, P.P.Sujith, S. Benjamin, D. Vaigankar, T. Singh, T.R.A. Thomas, B. Nagender Nath, P.A. Loka Bharathi

174


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501 SURFZONE CURRENTS AT MIRAMAR BEACH OF GOA, INDIA: A COMPARISON OF OBSERVATION AND THEORY by Yadhunath E.M, Jaya Kumar Seelam*, Jishad, M, Gowthaman R, Pednekar P.S

178

502 CHANGE DETECTION STUDIES ALONG VENGURLA COAST, INDIA THROUGH REMOTE SENSING AND GIS by R. Gowthaman*, Y.G. Harikrishna Sharma and V. Sanilkumar

180

503 UPWELLING FEATURES OFF SOMALIA AND OMAN COASTS FROM MODEL SIMULATIONS by Tanuja Nigam*, Vimlesh Pant

182

504 EVALUATION OF MITIGATION OPTIONS FOR SUSTAINABLE SHORELINE MANAGEMENT FOR POOMPUHAR COAST by Abhishek Tavva*, S Sankar, Vijaya Ravichandran, KM Sivakholundu

183

505 EFFECT OF WIND DRIVEN CIRCULATION ON INTERNAL WAVES: A CASE STUDY by Sachiko Mohanty*, Himansu K Pradhan, A D Rao

184

506 VALIDATION OF STORM SURGES USING A COUPLED SURGE-TIDE-WAVE MODEL: A CASE STUDY FOR TAMIL NADU COAST by Smita Pandey*, Jismy Poulse , A D Rao

185

507 EVIDENCES OF HIGH ENERGY MARINE EVENTS FROM THE GUJARAT COAST, WESTERN INDIA: STORM OR TSUNAMI DEPOSITS? by S.P.Prizomwala*, Drasti Gandhi, , N.P. Bhatt, B.K. Rastogi

186

508 PERFORMANCE OF DELFT3D-WAVE MODULE IN THE NEAR-SHORE WAVE TRANSFORMATION OFF RATNAGIRI, WEST COAST OF INDIA by Glejin Johnson and V. Sanil Kumar*

187

509 MODELLING THE BIOLOGICAL ACTIVE LAYER CIRCULATION IN THE SOUTH-EASTERN ARABIAN SEA by Vijay Kumar

188

510 TIDAL INLET CLASSIFICATION ALONG THE COASTS OF GOA AND KARNATAKA by M. Vikas, Jaya Kumar Seelam*, Subbarao

189

511 A STUDY ON SEASONAL MORPHOLOGICAL CHANGES AND CLASSIFICATION OF TIDAL INLETS ALONG GUJARAT AND KERALA COASTS by N. Amarnath Reddy*, M. Vikas, Jaya Kumar Seelam, Subbarao

191

512 MORPHOLOGICAL CHANGES DUE TO DEVELOPMENTAL ACTIVITIES AT PARADIP PORT by S.G. Manjunatha*, K.B. Bobade, M.D. Kudale

193

513 PREDICTION OF SHORELINE DYNAMICS USING GEOSPATIAL TECHNOLOGY: A CASE STUDY OF ENNORE COAST, TAMIL NADU, INDIA by S. Saravanan*, R. Manjula, S. Sivaranjani

195

514 TIDE MODULATION OF SURFZONE WAVES OFF MAHARASHTRA COAST ON THE CENTRAL WEST COAST OF INDIA by M. Jishad*, Jaya Kumar Seelam

196

515 SPRING-NEAP VARIABILITY IN RESIDUAL FLUXES THROUGH COCHIN INLET by Vinita J*, Revichandran C., Muraleedharan K.R., Lallu K.R., Jineesh V.K.

197

516 VARIABILITY OF SUSPENDED SEDIMENT CONCENTRATION AND ITS TIDAL INFLUENCE IN THE GULF OF KACHCHH, INDIA by R. Ratheesh*, A.S. Rajawat, R. Smitha

199

517 AN EVALUATION OF FACTORS CONTROLLING DECADAL-SCALE SEA LEVEL RISE IN THE MACRO-TIDAL GULF OF KACHCHH by Onkar S. Chauhan

202

518 PRELIMINARY RESULTS OF RADIANT HEATING RATE OF THE COASTAL AND ESTUARINE WATERS OF GOA by Priya Rauth*, T Suresh, Prakash Chauhan, Arvind Sahay

203

519 NEARSHORE CURRENTS OF AN UPWELLING REGION, SOUTHWEST COAST OF INDIA by V.K. Jineesh*, C. Revichandran, K.R. Muraleedharan, K.R. Naveen Kumar

205


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520 PRELIMINARY OBSERVATIONS ON OCCURRENCE, SPATIAL DISTRIBUTION AND IDENTIFICATION OF PLASTIC RESIN PELLETS IN SEDIMENTS AROUND AGATTI ISLAND, LAKSHADWEEP ARCHIPELAGO by S. Veerasingam*, M. Mugilarasan, R. Venkatachalapathy, P. Vethamony

207

521 SEDIMENT TRANSPORT DURING NILAM CYCLONE AT KADALUR PERIYAKUPPAM COAST, TAMIL NADU by A. S. Kiran*, B. K. Jena and K.M. Sivakholundu

208

522 OPTIMIZATION OF ENTRANCE CHANNEL IN A TIDAL INLET FOR FISH LANDING JETTY by L.R.Ranganath*, A.K.Singh, M.Karthikeyan and M.D.Kudale

209

523 ROLE OF CURRENTS ON THE INTRUSION OF THE BAY OF BENGAL WATER MASS TO SOUTHEASTERN ARABIAN SEA by Rajith, K., Rao, A. R. and Anil Kumar, K.

210

524 CHANGING DEPOSITIONAL ENVIRONMENT ALONG NORTH MAHARASHTRA COAST: REASONS AND POSSIBLE IMPLICATIONS by Volvoikar S. P*, Nayak G. N, Mazumdar A, Peketi A

211

525 DISTRIBUTION OF SUSPENDED PARTICULATE MATTER IN THE MANDOVI AND ZUARI ESTUARIES: INFERENCES ON THE ESTUARINE TURBIDITY MAXIMA by Suja S , Pratima M. Kessarkar*, R. Shynu, V. Purnachandra Rao

212

526 IMPACT OF THE VERY SEVERE CYCLONIC STORMS – THE PHAILIN AND HUDHUD – ON THE BEACH PROCESSES ALONG THE VISAKHAPATNAM COAST by Hani, T.*, Ganesan, P. and Murty, V.S.N.

213

527 SEASONAL AND INTER-ANNUAL VARIABILITY OF COASTAL CURRENTS AND CIRCULATION OFF VISAKHAPATNAM DURING 2010-2014 by V.S.N.Murty, D.Gayatri Vani*, Y.Steeven Paul, V.Fernando, T.A.Prakash, Almeida Anselmo and A.Suryanarayana

214

528 ROLE OF LITHOLOGY AND STRUCTURE ON THE COASTAL LANDFORMS OF GOA, INDIA by G. Q. Fernandes*, S. D. Iyer, K. Mahender

215

529 INTERNAL TIDES ON THE CONTINENTAL SHELF AND SLOPE OFF THE EAST COAST OF INDIA by A.K. Jithin*, A.S. Unnikrishnan, Fernando Vijayan, M.P. Subeesh, R. Fernandes, S. Khalap, S. Narayan, Y. Agarvadekar, M. Gaonkar, P. Tari, A. Kankonkar, S. Vernekar

217

530 NEARSHORE PROCESSES AND LITTORAL SEDIMENT TRANSPORT AT AN OPEN BEACH ALONG THE NORTH TAMIL NADU COAST by D. Sathish Kumar, Basanta Kumar Jena*, Usha Natesan and K.M.Sivakholundu

218

531 HYDRODYNAMIC AND WATER QUALITY SIMULATION OF SEWAGE DISCHARGES IN WEST COAST, MUMBAI: PRESENT AND FUTURE SCENARIO by Trupti Mardikar, Ritesh Vijay* and Satish R. Wate

219

532 IDENTIFICATION OF INLET AND OUTLET FOR COOL SEAWATER DISCHARGE FROM AN LNG FACILITY: A SIMULATION APPROACH by Vikash K. Kushwaha, Ankit Gupta, Ritesh Vijay* and Satish R. Wate

220

533 VARIABILITY OF INTERNAL TIDES ON THE CONTINENTAL SLOPE OFF JAIGARH, WEST COAST OF INDIA by M.P Subeesh*, A.S Unnikrishnan

221

534 A CASE STUDY OF SST DISTRIBUTION OVER BAY OF BENGAL DURING HUDHUD CYCLONE by T.S.D.Bhavani*, G.Bharathi, P.Amarendra and P. Hariprasad

222

535 THE ROLE OF WAVE CLIMATE ON COASTAL SEDIMENTATION - A CASE STUDY by R. Anjali, K.Jossia Joseph*, B. K. Jena, K.M. Sivakholundu and Ravibabu Mandla

223

536 IMPACT OF CYCLONE ON THE COASTAL AREA THROUGH EMPIRICAL RELATIONS AND NUMERICAL MODEL by P. Vyshnavi, B. K. Jena*, K. Jossia Joseph, J. Rajkumar and Ravibabu Mandla

224


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537 AN OBSERVATIONAL STUDY ON WAVE CHARACTERISTICS DURING HUDHUD CYCLONE OFF GANGAVARAM by P. Amarendra*, K.Gopala Reddy, G. Bharathi, P. Bhanumurthy and T.M. Balakrishnan Nair

225

538 TIDAL STREAM ENERGY POTENTIAL AT MANDOVI AND ZUARI RIVERS, GOA by Jaya Kumar Seelam, Manasa Ranjan Behera, R. Mani Murali, Aqleema Shah, D. Ilangovan, P. Mehra, R. Madhan

226

539 OBSERVED TEMPORAL AND SPATIAL VARIATION OF STRATIFICATION IN THE ZUARI ESTUARY, WEST COAST OF INDIA by D. Sundar, A.S. Unnikrishnan, G.S. Michael, A. Kankonkar

228

540 EFFECT OF CLIMATE CHANGE ON ESTIMATION OF DESIGN WAVE HEIGHT by V. R. Remsiya and Manasa Ranjan Behera

229

541 CHANGES IN SEA LEVEL EXTREMES ALONG THE EAST COAST OF INDIA AND AT THE HEAD OF THE BAY OF BENGAL by A.S. Unnikrishnan, Charls Antony and Philip L. Woodworth

231

542 UNDERSTANDING SEASONAL CHANGES OF GOA BEACHES USING EMPIRICAL ORTHOGONAL FUNCTION METHOD by Yadhunath E.M* and Jaya Kumar Seelam

232

543 TIDAL CURRENT ENERGY ASSESSMENT IN THE GULF OF KHAMBHAT by Aqleema Shah and Manasa Ranjan Behera

233

544 PRELIMINARY RESULTS OF UNDERWATER VERTICAL AND HORIZONTAL VISIBILITY OF THE COASTAL WATERS OF GOA by Shreya S. Joshi*, T Suresh, Anil Kumar

235

601 BIODIVERSITY AND STATUS OF CORAL REEF IN MALVAN MARINE SANCTUARY, CENTRAL WEST COAST OF INDIA by Kalyan De , Sambhaji Mote, Lobsang Tsering, Perisamy, R., Vishal Patil, Rahul Nagesh , Afreen Hussain, Sabyasachi Sautya, Baban Ingole*

239

602 BENTHIC FLAGELLATE COMMUNITY DISTRIBUTION IN RELATION TO ABIOTIC AND BIOTIC VARIABLES ALONG THE NORTH EAST COAST OF INDIA, BAY OF BENGAL by Sangeeta Mishra*, Rakhesh Madhusoodhanan,, Kalavati Chaganti, Raman V Akkur

240

603 MACROBENTHIC COMMUNITY STRUCTURE IN RELATION TO STRESSORS IN A FISHING HARBOR OF PARADIP, ODISHA, EAST COAST OF INDIA by Dipti Raut*, Himadri Tanaya Panda, Aswini Nayak, Biswaprajna Mohanty, Lipika Patnaik

242

604 STUDY OF CESTODE INFECTION IN SCOLIODON IN MUMBAI REGION, INDIA by V. V. Andhare*, P. Hatkar and S. Soni

243

605 STRESS RESPONSE TO VARIATIONS IN TEMPERATURE IN FRESHWATER FOOD FISH PANGASIANODON HYPOPHTHALMUS by S. Soni* and V. V Andhare

245

606 STUDY OF BENTHIC FAUNA IN THE NEAR SHORE WATERS OFF GULF OF KUTCH, NORTH WEST COAST OF INDIA. by Shivanagouda .N. Sanagoudra*, U. G. Bhat

247

607 SPATIAL AND TEMPORAL VARIATIONS OF COLORED DISSOLVED ORGANIC MATTER IN THE ESTUARINE AND COASTAL WATERS OF GOA. by Albertina Dias*, T. Suresh, Manguesh Gauns, Arvind Sahay, Prakash Chauhan

248

608 STUDY OF EPIPHYTIC DIATOMS ON SEAWEEDS AND ASSESSING THEIR POTENTIAL AS POLLUTION INDICATORS by V. A. Kulkarni*, S. P. Jagdale

250

609 SPATIAL AND TEMPORAL COMMUNITY CHARACTERISTICS OF ASSOCIATED ORGANISMS IN SARGASSUM CINCTUM by Wasim Ezaz*, Temjensangba Imchen

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610 ARABIAN SEA LONG TERM PRODUCTIVITY TREND by Prince Prakash* and Satya Prakash 253


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611 ASSESSING THE ECOLOGICAL STATUS OF COASTAL WATERS OF INDIA USING AMBI (AZTI’S MARINE BIOTIC INDEX). by SK Sivadas*, R. Nagesh, B.S. Ingole, GVM Gupta

255

612 DIVERSITY OF MACROBENTHOS AND MACROPHYTE RELATIONSHIP ON THE ROCKY SHORE by Uday Gaonkar, Periasamy R., S.K. Sivadas, Vishal Patil, B.S. Ingole*

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613 EFFECT OF UPWELLING-DRIVEN HYPOXIA ON MACROBENTHIC COMMUNITY OF SOUTH WEST COAST OF INDIA by Sanitha K. Sivadas*, G.V.M. Gupta, BS Ingole

258

614 MARINE MICROALGA TETRASPORA SP: ABUNDANCE, NUTRIENT AVAILABILITY AND INDICATION OF INTRACELLULAR LIPID AT VERAVAL FISHING HARBOUR, GUJARAT, INDIA by A. B. Fulke*, M. Dey, A. Ram, R. Hardikar and S.N. Gajbhiye

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615 ARE BORING SPONGES AN INCREASING THREAT FOR CORAL GROWTH IN MALVAN MARINE SANCTUARY? by Sambhaji Mote, Kalyan De, Vishal Patil, Perisamy R, Rahul Nagesh, Sabyasachi Sautya, Baban S. Ingole*

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616 QUANTIFICATION OF PHYTOPLANKTON PHOTO-PHYSIOLOGICAL STATUS IN A MONSOONAL ESTUARY by J. S. Patil*, A. C. Anil

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617 SPATIO-TEMPORAL VARIATION IN ASSOCIATED FAUNA OF THE SPONGE CINACHYRELLA CAVERNOSA by A. Singh, D.V. Desai, N. L. Thakur*

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618 RESPONSES OF PICOPHYTOPLANKTON COMMUNITY TO ENVIRONMENTAL CONDITIONS IN DIFFERENT ECOSYSTEMS by S. Mitbavkar*, A. C. Anil

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619 DISTRIBUTION OF CYST PRODUCING DINOFLAGELLATES FROM A MONSOON INFLUENCED TROPICAL EUTROPHICATED ENVIRONMENT by R. V. Rodrigues*, J. S. Patil, K. Sathish, A. C. Anil

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620 BIODIVERSITY PATTERNS OF MEIOBENTHOS FROM THE INDIAN OCEAN by IVY PEREIRA, B. S. INGOLE*

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621 BACTERIOLOGICAL STUDY OF A COMMERCIAL AQUACULTURE POND OF LITOPENAEUS VANNAMEI ALONG SOUTH WEST COAST, INDIA. by Elaine A. Sabu*, Maria Judith Gonsalves, Sreepada A. R, Naseera K., Archana Naik and Ramaiah N.

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622 PICOPHYTOPLANKTON CONTRIBUTION TO THE PHYTOPLANKTON BIOMASS IN A MONSOON INFLUENCED TROPICAL ESTUARY by K. M. Rajaneesh*, S. Mitbavkar, A. C. Anil

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623 SALINITY INDUCED PHYTOPLANKTON DOMINANCE ALONG TAPI ESTUARINE ECO- SYSTEM by Prince Prakash Jeba Kumar. J* , Ragumaran.S, Sundararajan.S, Karupasamy.M,

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624 DIVERSITY AND COMMUNITY STRUCTURE OF MACROBENTHOS ALONG THE SALINITY GRADIENT OF AN ANTHROPOGENICALLY STRESSED ESTUARY by J.T. Mulik, S. Sukumaran*, T.V. Vijapure, S.M. Salvi

271

625 MACROBENTHIC ASSEMBLAGES OF TWO MARINE PROTECTED AREAS ALONG NORTHWEST COAST OF INDIA: DIVERSITY AND DISTRIBUTION by T.V. Vijapure, S. Sukumaran*, J.T. Mulik, V.R. Joshilkar, S. N. Gajbhiye

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626 STUDY OF MACROBENTHIC ASSEMBLAGES ON SUBTIDAL NEARSHORE WATERS IN THE VICINITY OF ADANI POWER LTD MUNDRA, GUJARAT, INDIA by Santosh Kumar Singh, Anil Soni and Shivanagouda N. Sanagoudra*

275

627 SPATIAL VARIATION OF PHYTOPLANKTON PIGMENTS ALONG THE EASTERN ARABIAN SEA DURING THE ONSET OF SOUTH WEST MONSOON by Ayaz Ahmed*, Chandrasekhara Rao, Siby Kurian, Manguesh Gauns, Amara BM, Bhagyashri N, Hema Naik and S.W.A Naqvi

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628 SEASONAL INFLUENCE ON METHANOTROPHIC ABUNDANCE, ITS ACTIVITY AND METHANE PRODUCTION IN A TROPICAL MANGROVE ECOSYSTEM by Delcy R. Nazareth*, M-Judith Gonsalves

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629 TEMPORAL AND SPATIAL VARIATION IN THE ZOOPLANKTON DISTRIBUTION AND ABUNDANCE IN THE ZUARI ESTUARY, WEST COAST OF INDIA by Dattesh V Desai*, Dayakaran P, Monteiro MC, Anil, A.C.

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630 VARIATION IN THE CULTURABLE VIBRIO CHOLERAE ABUNDANCE ALONG THE COAST OF INDIA by Lidita Khandeparker*, Gardade L, Kuchi N, Eswaran R, Hede N, Mapari, K.E., Anil, A.C.

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631 DISTRIBUTION AND ABUNDANCE OF MACROBENTHOS FROM MANGALORE PORT by Dattesh V Desai*, Atchuthan P, Noyel V, Anil, A.C.

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632 RESPONSE OF VIBRIO SPP. TO VARIATIONS IN SALINITY AND TEMPERATURE: ELUCIDATION THROUGH PROTEIN PROFILING by Lidita Khandeparker*, Barnes N, Anil, A.C.

281

633 MOLECULAR DIVERSITY OF CHROMOPHYTIC PHYTOPLANKTON ASSEMBLAGES FROM SUNDARBANS MANGROVE ECOREGION BASED ON RBCL GENE SEQUENCING by Brajogopal Samanta and Punyasloke Bhadury*

282

634 INFLUENCE OF UPWELLING ON THE DISTRIBUTION OF BACTERIA AND ARCHAEA IN PERSISTENT MUDBANK REGIONS OF ALLEPPEY, SOUTHWEST COAST OF INDIA by Appukuttan V. Sheeba, Saumya Nair, Diana Mathew, Gireesh TR, Abdulaziz Anas*

283

635 RESPONSE OF PHYTOPLANKTON COMMUNITY TO MONSOON INDUCED HYDROLOGICAL VARIATIONS IN THE ALLEPPEY MUDBANK REGION, SOUTHWEST COAST OF INDIA by Madhu.N.V*, Ullas. N, Ashwini.R, Jyothibabu. R, Muraleedharan. K.R, Balachandran. K. K

285

636 SULFUR OXIDIZING POTENTIAL IN THE MANGROVE CLAM POLYMESODA EROSA by T.R.A. Thomas, P. A. Lokabharathi*

286

637 MULTIPLE ANTIBIOTIC RESISTANCES AMONG VIBRIO CHOLERA ISOLATED FROM COCHIN ESTUARY, SOUTHWEST COAST OF INDIA by Vijitha Vijayan, Abdulaziz Anas*, Sneha K.G , Anila Chandran, Jasmin C, Shanta Nair

288

638 DYNAMICS AND DISTRIBUTION OF BACTERIA AND VIRUS IN KRISHNA GODAVARI BASIN, BAY OF BENGAL by Aswathy Vijaya Krishna, Anwesha Sarkar, Jasna Vijayan and Parvathi A*

290

639 MULTIPLE ANTIBIOTIC RESISTANT VIBRIO HARVEYI ISOLATED FROM PENAEUS MONODON LARVAL REARING SYSTEMS OF SOUTH INDIA by Somnath S. Pai, R. Preetha,, N.S. Jayaprakash ,, A. Anas,, I.S. Bright Singh*

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640 ADENOSINE TRIPHOSPHATE IN THE WATERS OF WEST COAST OF INDIA-AN INDICATOR OF LIVING MICROBIAL BIOMASS by Anindita Das, Christabelle EGF-C, Sheryl OF, Sunita Pandey Dhillan Vellip and LokaBharathi PA*

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ABSTRACTS

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OCEAN BIOGEOCHEMISTRY SESSION - 01

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MODELING THE BIOGEOCHEMICAL CYCLE OF MICROBES ALONG THE COASTAL ZONES

Kiran Gurung* and Geetha N

Dept. of Studies in Biotechnology, University of Mysore, Mysore 570006; [email protected]

Microbial communities play a pivotal role in biogeochemical cycling of nutrients. Microorganisms along the coastal zones have taken part in nutrient cycles too. Due to global warming there has been a change in the distribution of species of microbes. But there might have been a possibility too, that microbes may have adapted to the change in atmospheric warming by altering their metabolic pathways. So the change in a particular flora may have an effect on another microbial group and so on. Creating an artificial environment for studying the community structure and ecology will not yield the desired results in comparison to when studied in the natural environment. We may say that the construction of the whole community in the coastal zone is in itself a complex task. Our approach is to analyze each and every aspect by studying these components and the effect one has on the other. This also includes studying the cycling of nutrients especially nitrogen, then trying to construct the whole community structure on the basis of obtained observations. Successful completion of biogeochemical modelling will further make it possible to determine the rate in change of species distribution along this zone.

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PHYTOPLANKTON BLOOM EVENTS FROM SEAWIFS DATA ACTIVATED BY MULTIPLE FORCINGS IN BAY OF BENGAL

R. Roy Chowdhury*, A. Chakraborty

1Centre for Oceans, Rivers, Atmosphere and Land Sciences, Indian Institute of Technology Kharagpur;

[email protected]

Ocean colour is a key parameter for understanding oceanic, biological and physical processes. It is known that the biological processes in the ocean are largely controlled by the presence of phytoplankton, which are the primary producers and responsible for CO2

fixation in the ocean. The Bay of Bengal is located in the eastern part of the Northern Indian Ocean due to monsoonal variation, large amount of river discharge, mixing of high-saline water from its western counterpart and the circulation pattern makes the bay significant and less productive than its western counterpart. Coastal upwelling and Ekman pumping have significant role in nutrient abundance in the bay and are responsible for increasing the phytoplankton biomass. Oceanic and atmospheric differences sufficiently alter the circulation patterns and thermal structure of the region to produce variability in phytoplankton biomass. Near real-time data from seawifs was used to detect phytoplankton bloom in Bay of Bengal from 1998 January to December 2010. Three phytoplankton bloom events were shown in January, 1998; December, 2000 and December, 2005 in south-eastern part of the Bay. The bloom was possibly analysed by sea surface temperature, wind stress, sea surface height and geostrophic current data. It was found that strong cyclonic eddies transported cold nutrient rich water from subsurface layer to the surface layer which was responsible for the growth of the phytoplankton causing bloom events. In addition, bloom occurred in the Indian Ocean Dipole years. In this paper, it has been shown that other forcing parameters such as sea surface temperature, sea surface height, oceanic currents and wind stress are also responsible for phytoplankton blooming. Thirteen years (1998-2010) climatology data were prepared and from there monthly mean anomaly was calculated. The study area has been divided into three boxes (A,B,C) on the abundance of phytoplankton bloom where chlorophyll-a concentrations are comparatively high bloom ranges from 0.5-1.0 mg/m3 but patches exceeds 1.5-2.0 mg/m3 The domain within which both the oceanographic and meteorological data were extracted were for the regions 5°N-25°N latitude and 76°E-100°E longitude.

Fig.1. Monthly mean chlorophyll-a anomaly showing bloom events in Box A (5-10゜N, 90-

95゜E) , Box B (7-9゜ N, 80-85゜E) and Box C (9-16゜ N, 82-85゜E) are found in January 1998 December 2000, December 2005 and respectively.

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Fig.2. Timeseries of monthly chlorophyll-a anomal of (a ) BoxA (b) BoxB (c) BoxC respectively. Timeseries of anomalies of Sea surface height, sea surface temperature and

chlorophyll-a of (d ) BoxA(e) BoxB(f) BoxC respectively. (g) Timeseries of chlorophyll-a of Box A, BoxB, BoxC and Dipole mode index.

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APPLICATION OF BAYESIAN INVERSION TO OPTIMIZE THE PHYSICAL AND BIOGEOCHEMICAL PARAMETERS IN OCEAN BIOGECHEMICAL MODELS

Vinu K. Valsala1*, N. Pavan Kumar1, S. Maksyutov2, R. Murtugudde3 1Senior Scientist, Indian Institute of Tropical Meteorology; [email protected]

2National Institute for Environmental Studies, Tsukuba, Japan 3ESSIC, University of Maryland College Park, Maryland, USA

Bayesian inversion is a linear state estimator used in several of the earth science related applications (Enting, 2005). Here, the possibility of the Bayesian inversion in estimating a set of optimal values of selected physical and biogeochemical parameters in the model for minimizing the data-model misfit is explored. At first, the parameterizations of the surface ocean vertical mixing are optimally estimated in a linear offline tracer transport model (OTTM) of Valsala et al., 2008. Exploiting the linear nature of the offline modelling system, the vertical mixing profiles of selected global oceanic zones are optimally corrected by minimizing the data-model misfit by utilizing the salinity as a control variable and Bayesian inversion as a state estimator. The method yields optimal profiles of vertical mixing coefficients, which, upon tailoring into the offline model yields significant error reduction in the simulated salinity and thereby guarantying the error reductions in the simulated model transports of any biogeochemical tracers. The study further explores the application of the same in the optimization of biological parameters in an ecosystem model that is coupled to OTTM by utilizing the oceanic pCO2 and phosphate profiles as the control variables. Such optimization techniques are important in the global ocean carbon cycle simulation and robust estimations of contemporary uptake of atmospheric CO2 by the oceans.

References: Enting, I. G., (2005), Inverse modeling in the atmospheric chemistry constituent transport, Cambridge Atmospheric and Space Science Series, ISBN: 9780521018081 Valsala V., S. Maksyutov and M. Ikeda, (2008): Design and validation of an offline Oceanic Tracer Transport Model for Carbon Cycle Study, J. Climate , Vol. 21, 2752-2769.

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RECENT INSIGHT ON BIOGEOCHEMICAL CONSTITUENTS IN THE COCHIN ESTUARINE SYSTEM (CES)

K.Sriram1, Soja Louis2, C.H. Sujatha1* 1Cochin University of Science and Technology, Cochin-16, Kerala; [email protected]

2St. Therasa College, Department of Zoology, Cochin˗35, Kerala

Cochin Estuary is a unique complex system situated at the west coast of India, and is environmentally more sensitive than the east coast primarily because it is bordering one of the most sensitive ecosystems in the world, the Arabian Sea. The symptoms are there to show considerable impact of deterioration of estuarine waters on the coastal ecosystem, based on the emerging industrial establishments and human settlements along the west coast of India. A number of investigations in recent years have shed light on the varied nature of biogeochemical characteristics of the estuarine and mangrove sediments in and around Cochin estuary. The present study intends to reveal recent trends in the biogeochemical constituents in the sedimentary environment of the CES and also infers the quality of the biogeochemical constituents of the studied site. For this assignment, surface sediments (top 0-5 cm) and water samples were collected from six prominent locations of CES during December 2014 for performing the various biogeochemical analysis (Nutrients, Organic matter, Pigments and Trace metals). Biogeochemical evaluation of the study region revealed that organic matter in the sediments from CES are aged and the role of protein contribution as a potentially limiting factor for benthic consumers. Overall, C/N ratio supports the allochthonous character of the sediments in the aquatic system and it clearly indicates the terrestrial OM could be the dominant contributor in the study region and make profound influence in the biogeochemical processes. The results are relevant and serve as a measuring tool for pollution control in the Cochin Estuarine System.

Key words: Biogeochemistry, Sediment, Cochin Estuarine System.

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METAL FRACTIONATION PROFILE OF CORE SEDIMENTS IN THE SPECIFIC ZONES OF COCHIN ESTUARINE SYSTEM

Nair Manju P and C.H Sujatha*

Cochin University of Science and Technology, Cochin-16, Kerala; [email protected]

The geochemical distribution of sequentially leached metal fractions (Cd, Cu, Pb, Fe, Mn and Ni) in the core sediments sampled from three contrasting zones in the CES. These chemical fractionation of metals are exchangeable (EXC), bound to carbonate (CA), organic matter bound (oxidisable) (OM), iron and manganese bound (reducible) (FMO) and residual (RES) fraction. In this study, the northern zone of the estuary was enriched with EXC fraction for most of the metal studied. An intensification of CA fraction of metal was found for southern and northern part of the estuary which accounts the increased agricultural and industrial runoff in the study area. Among the metal analysed Pb, Mn and Fe are found to be high value for FMO in this study. Cu, Fe, Pb and Mn are dominant in OM fraction in this study under investigation. Fe and Ni are intensified in the residual fraction of the study area indicating the lithogenic origin.

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CHLOROPHYLL-A DYNAMICS IN NEAR COASTAL WATERS OF WESTERN BAY OF BENGAL USING IN SITU AND LONG-TERM SATELLITE DATA

Aneesh A. Lotliker1*, Sanjiba Kumar Baliarsingh1, K. C. Sahu2, T. Srinivasa Kumar1 1Indian National Centre for Ocean Information Services (INCOIS), Hyderabad 500 090; [email protected]

2Department of Marine Sciences, Berhampur University, Odisha 7600076

The distribution of optically active substances (OAS), accuracy assessment of satellite derived Chlorophyll-a (Chl-a) and long term trend in distribution of satellite Chl-a was carried out at a coastal site of SATellite Coastal and Oceanographic REsearch (SATCORE) programme. The in situ data of OAS such as Chl-a, Total Suspended Matter (TSM) and absorption due to Coloured Dissolved Organic Matter at 440 nm (aCDOM440) along with its spectral slope were analyzed for the period of three years (Fig. 1). The temporal distribution of Chl-a, TSM and aCDOM440 showed one common peak during southwest monsoon season (August-October). Apart from this Chl-a also showed a prominent peak during pre-southwest monsoon (March-April). The spatial variability in TSM and aCDOM440 was maximum during southwest monsoon whereas in the case of Chl-a it was during pre-southwest monsoon. The relationship between aCDOM440 and slope parameter indicate conservative mixing between CDOM arising from river and coastal waters (e.g., Mishra et al., 2003).

Fig. 1: Spatially averaged monthly distribution of Chl a, b) TSM and aCDOM440 in the study area. The vertical bars indicates the standard deviation.

The accuracy assessment of Chl-a, retrieved from Moderate Resolution Imaging Spectroradiometer onboard the Aqua satellite (MODISA), Ocean Colour Monitor onboard Oceansat-2 (OCM-2) and Visible Infrared Imager Radiometer Suit (VIIRS) onboard Soumi National Polar-orbiting Partnership (NPP), showed overestimation in nearshore waters (depth < 30m). The error in satellite estimation of Chla was in the range of 33 to 51% and the overestimation was predominantly due to the covariance of TSM with Chla (Tilstone et al., 2013). The Chl-a retrieved from MODISA using OC3M algorithm was most accurate with better slope (1.001), regression coefficient (R2=0.67) and Log10RMSE (0.18 mg-m-3). The Chl-a retrieved from VIIRS using OC3V algorithm performed equally well (Fig. 2).

Ten years of Chl-a retrieved from MODISA was analyzed with an aim to understand its trend in the view of bio-physical forcing (Fig. 3). The Chl-a trend in MODISA and VIIRS matched well. Hence, VIIRS Chla can be efficiently utilized to continue time-series studies. The bi-modal distribution of Chl-a was also clearly evident. The peak in Chl-a during pre-southwest monsoon was due to phytoplankton bloom having recurring occurrence at an annual scale (Sasamal et al., 2005).

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Fig. 2: Scatter plot showing the relation between in situ measured Chl-a and that derived from a) MODISA, b) VIIRS and c) OCM-2 using sensor default algorithm. The dotted line

indicates 1:1, solid straight line shows the regression and solid curved lined shows the 95% confidence limit.

Fig. 3: Time series distribution of spatially averaged Chl-a retrieved from sensors MODISA, OCM-2 and VIIRS. The inset shows inside view of the rectangular box.

The source of this bloom was from the Rushikuliya estuary and surf waters and the extent was restricted to the inshore waters having depth < 30m. The process restricting offshore spread of high Chl-a, during pre-southwest monsoon, can be attributed to the northward moving East India Coastal Current (EICC) which acts as a boundary between inshore and offshore waters. The second peak in Chl-a during end of southwest monsoon was due to upwelling and pumping of nutrients due to eddies. The shift in peak Chl-a towards end of the monsoon might be due to the limitation in availability of sunlight due to cloud cover and less penetration of sunlight due to high sediment from river influx (Prasanna Kumar et al., 2010).

References: Mishra, R.K., Shaw, B.P., Das, S.K., Rao, K.S., Choudhury, S.B., Rao, K.H., (2003) Spatio-temporal variation of optically active substances in the coastal waters off Orissa from Rushikulya to Dhamra (east coast of India). Indian Journal of Marine Sciences 32 (2), 133-140. Prasannakumar, S., Nuncio, M., Narvekar, J., Ramaiah, N., Sardessai, S., Gauns, M., Fernandes, V., Paul, J.T., Jyothibabu, R., Jayaraj, A., (2010) Seasonal cycle of physical forcing and biological response in the Bay of Bengal. Indian Journal of Marine Sciences 39(3), 388-405. Sasamal, S.K., Panigrahy, R.C., Misra, S., (2005) Asterionella blooms in the northwestern Bay of Bengal during 2004. International Journal of Remote Sensing 26(17), 3853-3858. Tilstone, G.H., Lotliker, A.A., Miller, P.I., Ashraf, P.M., Kumar,T.S, Suresh, T., Ragavan, B.R., Menon, H.B., (2013). Assessment of MODIS-Aqua chlorophyll-a algorithms in coastal and shelf waters of the eastern Arabian Sea. Continental Shelf Research 65, 14-26.

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ESTIMATION OF AEROSOL AND NUTRIENT DEPOSITION IN THE COASTAL BAY OF BENGAL OFF VISAKHAPATNAM

K. Yadav1*, V.V.S.S. Sarma1, M. Dileep Kumar2 1CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam-530017; [email protected]

2CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004

Oceanic regions adjacent to Indian subcontinent are greatly influenced by the continental sources with both natural and anthropogenic emissions. The sources, characteristics and potential health effects of PM10 (<10μm) and PM2.5 (<2.5μm) are different. Currently the regulatory standards for PM10 and nitrate in ambient environments in India are 100 and 40 μg/m3 respectively. Urban areas release more suspended particles due to heavy vehicular emissions and industries than rural regions. The studies on evaluating the contributions of PM10 and PM2.5 to the Indian coastal regions are rather scarce. The objective of this study is to estimate the contribution and characteristics of these two size classes of aerosols to and in a coastal urban region (Visakhapatnam) and estimate its impact on coastal ecosystem. We would like to test the hypothesis that most of the coarser particles settle in the coastal regions while finer particles are transported far from the source.

The total suspended particle (TSP) ratio of PM2.5/PM10 in the study region was 1.37 to 2.27 in the study region and it is significantly higher than reported elsewhere in the world (0.39 to 0.86). The PM2.5 contributed to ~65% of the TSP. Higher PM2.5 particles in the study region have their source in several industries such as thermal power and steel plants, ore transport through open belt system etc. in Visakhapatnam. The concentrations of nitrate and sulphates are 2 to 3 times higher in the PM2.5 than in PM10 suggesting that former size particles can significantly influence coastal ecosystem than the latter. Since coarser particles are expected to settle close to the coast, due to its higher density, an experiment was conducted by collecting simultaneously TSP of PM10 on land (The Institute building, China Waltair) closer to the coast and at ~10 km offshore (Bay of Bengal) when wind blew from land to sea. Aerosols of PM10 were collected using a Respirable Dust Sampler during March 14 and December13. And later with the help of Ion Chromatography their ionic concentration were measured.

Relatively higher concentrations of TSP (PM10) were observed both over land and sea during March (76 and 60 μg/m3) compared to that in December (51 and 33 μg/m3). This suggests that about 15 to 45% of TSP is settled in the coastal region within 10 km from the coast and the remaining might have transported further offshore. The concentration of nitrate was low during March both over land and sea (1.56±0.83 and 0.16±0.26 μg/m3) than in December (2.56±1.52 and 0.64±0.30 μg/m3). Our study suggests that up to half of the pollutants released into the atmosphere would influence the near coastal ecosystem than hitherto hypothesized.

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SPATIAL VARIATIONS IN TROPHIC LEVEL OF PRIMARY CONSUMERS ALONG THE GODAVARI ESTUARY

J. Mukherjee*, V. V. S. S. Sarma 1CSIR-National Institute of Oceanography, Regional Center, Visakhapatnam 530 017; [email protected]

Estuaries are highly dynamic environments with large spatial variations in physico-chemical properties and its impact on food web dynamics is unclear. Stable isotopic composition of carbon (δ13C) and nitrogen (δ15N) are used as a tracer to study base of the food web supporting primary consumers and estimating the trophic level (TL) of the primary and secondary consumers in the aquatic ecosystems. The objective of this study is to test the hypothesis that TL of the primary consumers along the estuary need not be uniform. To examine the same, studies have been conducted along the largest monsoonal estuary in India, Godavari, during dry period.

Water samples for nutrients, chlorophyll-a (Chl-a), particulate organic matter (POM), phytoplankton and mesozooplankton were collected from upper, middle and lower regions of Godavari estuary during January 2013. Nutrients and Chl-a were measured following standard protocols. About 50-100 specimens of different groups of phyto and zoopalankton were picked using microscope and their isotopic composition were measured using elemental analyzer coupled with isotope ratio mass spectrometer.

Relatively higher POM, and lower Chl-a were observed in the upper and vice versa

was found towards lower estuary. The δ13C and 15N of POM (-30.0‰, 5.5‰) suggest that significant contribution of detritus from freshwater algae and C3 plants. In contrast, enriched isotopic composition was observed in the lower estuary (-24‰) suggesting

significant contribution from in-situ phytoplankton. The mean 13C of mesozooplanktons (-20.4‰) was relatively depleted compared to phytoplankton (-11.0‰) suggesting that the former were not depended on the latter for feeding. Higher DOC concentrations in the upper than lower estuary suggests that microbial loop may be operational resulting in higher TL (2.1, 2.6) for meso and benthic plankton in the former region. In contrast, the mean isotopic composition of mesozooplankton was close to that of both POM and phytoplankton suggesting that either live or dead phytoplankton was used as a diet. The TL for the zooplanktons and the benthic organisms was higher (2.3) in the upper estuary. Similar to middle estuary, fresh in-situ phytoplankton contributed to POM pool and has been used as diet by primary consumers. The TL for zooplanktons and benthic organisms was the lowest (1.6) in the entire estuary. This study suggests that TL of zooplankton and benthic organisms decreased from upper to lower estuary indicating that existence of longer food chain at the former while shorter and classical food chain is operational at the latter region.

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A MODELLING STUDY OF BIOLOGICAL FEEDBACKS ON SEA SURFACE TEMPERATURE

Kunal Chakraborty*, Arya Paul, Satya Prakash

Indian National Centre for Ocean Information Services (INCOIS), Hyderabad-500090; [email protected]

This paper describes the results of a coupled 3-D bio-physical model, ocean general circulation model ROMS with an ecosystem model, which has been employed to study biogeochemical variability in the Indian Ocean. The interannual run of the coupled set-up has been forced using Quick-SCAT wind during the period of 01 January 2000–18 November 2009. We have applied EOFs to the weekly SST data over the Arabian Sea. EOFs do not change structure in time, they only change sign and overall amplitude to represent the state of the ocean. The first two EOFs explain respectively 60.21% and 26.24% of the total variance whereas the first two EOFs of observation (AVHRR) explain respectively 60.62% and 26.12% of the total variance. However, the first two EOFs of the model without biology explain respectively 55.76% and 29.81% of the total variance. It is clearly observed from first two modes that biological feedback significantly improve SST in the Arabian Sea, Based on a qualitative look of the temporal function, it is to be noted that EOF-1 and EOF-2 are respectively associated with the semi-interannual and interannnual signal in the Arabian Sea. It may be noted that the model with bio-geo-chemistry is able to capture the observed variability in SST better (particularly in the western Arabian sea, where the biological activity is significant) than the model setup without BGC module.

References: Nakamoto, S. et al., (2000), Chlorophyll Modulation of Sea Surface Temperature in the Arabian Sea in a Mixed-Layer Isopycnal General Circulation Model, Geophysical Research Letters, 27, 6, 747-750. Rao, S. A, et al., (2002), Interannual subsurface variability in the tropical Indian Ocean with a special emphasis on the Indian Ocean Dipole. Deep-Sea Research Part II-Topical Studies in Oceanography, 49, 1549-1572.

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13

EFFECTS OF MACRONUTRIENTS ON COASTAL DIATOM GROWTH DYNAMICS AT VISAKHAPATNAM, NW COAST OF BAY OF BENGAL, INDIA: AN

EXPERIMENTAL APPROACH

Debasmita Bandyopadhyaya* and Haimanti Biswas

CSIR National institute of Oceanography, Regional Centre, Visakhapatnam; [email protected]

Regardless of their insignificant size, marine diatoms contribute significantly to oceanic primary production Coastal waters are usually enriched with nutrients and are usually dominated by diatoms. Western Coastal Bay of Bengal receives significant amount of all major nutrients through river discharge and land runoff, hence can promote diatom growth in this area and has been reported by many earlier studies. However supply of the major nutrients (nitrate, silicate and phosphate) to the coastal waters may not be uniform and their differential loading can potentially alter growth and biomass production in coastal diatom communities. Unlike other microalgae found in the coastal waters, diatoms demand a significant amount of silicate along with nitrate and phosphate owing to their siliceous frustules. Production of biogenic silica can be dependent not only on silicate concentrations, but also on nitrate and phosphate. We have conducted a series of microcosm experiments using natural diatom communities from the Visakhapatnam coast to understand, growth rate, utilization rate of silicate and biogenic production in presence of variable nitrate and phosphate concentrations. Our experimental results revealed that when nitrate and silicate were present in 1:3 concentration, the maximum growth rate (0.78μ d-1) was less than when it was given in 1:1 concentration (0.85 μ d-1). This is in well agreement with the classical Redfield ratios. Biogenic silica production also followed a similar trend. Additionally, increasing phosphate concentration also helped to enhance biomass, silicate uptake and biogenic silica production till a certain level (4 - 4.5µmol L-1), however, did not affect thereafter. Increasing silicate concentration in the presence of excess nitrate only showed an enhancement in BSi:Chla ratios, however did not show any change in Chla concentrations in the treatments. We infer that coastal diatoms can only utilize the supplied nutrients efficiently when other nutrients are present in optimum concentrations and hence periodical loading of a particular nutrient may not promote growth, biomass and biogenic silica production in the study area and can remain unutilized.

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14

VARIATIONS IN EFFICIENCY OF BIOLOGICAL PUMP IN THE BAY OF BENGAL USING STABLE ISOTOPIC COMPOSITION OF NITROGEN IN THE SUSPENDED

MATTER

C.K. Sherin* and V.V.S.S. Sarma

CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam, 530 017; [email protected]

The Bay of Bengal is known as low productive basin compared to its western counterpart, the Arabian Sea, due to strong stratification imposed by high river discharge lead to inhibition of vertical nutrients input. Despite such low production, sinking carbon fluxes to the deep ocean were almost similar in both the basins and were attributed to the ballast effect in the Bay of Bengal. Here we aim to examine the efficiency of biological pump in terms of f-ratio (the fraction of production supported by new nitrogen to the total production) and its spatial variability in the Bay of Bengal during post monsoon (November-December 2013), using stable isotopic composition of suspended particulate nitrogen (PN) in the upper ocean.

The surface water samples were collected along the cruise track at one degree interval and ~20-30 L of water filtered through pre-combusted grass fibre (GF/F) filter under low vacuum. The concentration and isotopic composition of carbon and nitrogen in the suspended matter (SPM) was measured using Elemental Analyser coupled with Isotopic Ratio Mass Spectrometer (Delta V Plus, Thermo Electron, Germany) and vertical distribution of nitrate concentration was measured using sensor.

The nitrogen isotopic composition of PN (δ15Nsus) ranged from 1.8 to 6.3‰ with higher values in the southern and western than northern and central Bay and has strong inverse relation with depth of nitracline indicating that subsurface nitrate is supporting the production in the Bay of Bengal during study period. The mean C/N ratios (6.9±0.8) and

(-25.3±0.5‰) indicating that SPM was mainly derived from in situ sources. Based on the δ15Nsus and the slope of the relation between δ15Nsus and nitracline depth, the f-ratio was computed using the mass balance approach. Since δ13Csus of SPM is close to that of marine origin, we assumed that the isotopic composition of SPM represents phytoplankton and δ15Nsus NO3 of deep water as 5‰, which is a global mean deep water NO3 value. The computed f-ratios varied from 0.29 to 0.72 with relatively higher ratios in the south (0.56±0.12) than northern Bay (0.39±0.1). This suggests that higher fraction of the primary production is leaving the photic depth in the southern than northern Bay. The higher f-ratio in the southern bay is associated with shallow nitracline suggesting that higher sinking fluxes in the Bay of Bengal were mainly driven by in situ production supported by physical processes. This study suggests that higher sinking organic carbon fluxes in the Bay of Bengal were supported by in situ processes than hitherto hypothesized.

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15

INTRA-ANNUAL VARIABILITY IN ORGANIC CARBON SINKING FLUXES OFF A TROPICAL MAJOR RIVER, GODAVARI: SEDIMENT TRAP RESULTS

Sreenu Lenka*, M. S. Krishna and V.V.S.S. Sarma

CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam, India – 530017; [email protected]

Export of organic matter (OM) to the seafloor and its subsequent burial in ocean sediments is a sink for atmospheric carbon dioxide (CO2) on geological time scales. However, in-situ biological production of OM, terrestrial OM input through river discharge, rate of sedimentation and preservation conditions largely controls the OM sinking fluxes in coastal regions. Here, we present the results of sinking particulate matter collected for one year from two sediment traps deployed at 350m and 1000m below the surface at off the major monsoonal river, Godavari, central east coast of India. Content and stable isotope ratios of carbon and nitrogen were determined to understand possible sources and transformation of OM in the water column and to estimate sinking fluxes of OM to the seafloor from this region. Annual mean mass fluxes were found to be 2.46±2.2 (range: 0.23 - 9.62 g m-2 d-1) and 1.76±1.33 g m-2 d-1 (0.24 - 5.00 g m-2 d-1) in the shallow and deep traps, respectively. These fluxes are relatively higher than those fluxes reported from similar depths in the northern and central Bay of Bengal. Mean mass fluxes were found to be higher by ~10-folds in both shallow (mean: 4.83±2.6 g m-2 d-1) and the deep (3.14±1.36 g m-2 d-1) traps during discharge (June - September) period than during no discharge period. It is attributed to the influence of freshwater discharge from the major monsoonal river, Godavari which supplies ~170x106 tons yr-1 of suspended sediment and 2.81x106 tons yr-1 of POM to the Bay of Bengal through discharge. Estimated sinking fluxes of OC ranged from 0.3 - 237 and 0.3 - 71 mg m-2 d-1 in the shallow and deep traps, respectively, with a higher fluxes of 100-fold during discharge and 30-fold during no-discharge periods. The range of δ13C, δ15N and elemental OC:TN ratios in the shallow (-22.1 to -19.4‰, 4.6-8.5‰, 8-14, respectively) and deep (-21.6 to -19.3‰, 3.2-6.1‰, 8-12) traps indicate that the POM is a mixture of OM derived from both allochthonous and autochthonous sources

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16

SOURCES AND DISTRIBUTION OF PARTICULATE ORGANIC MATTER IN THE WESTERN COASTAL BAY OF BENGAL DURING SW MONSOON: INFLUENCE OF

RIVER DISCHARGE

M.S. Krishna*, L. Gawade, S.A. Naidu, V.V.S.S. Sarma, N.P.C. Reddy

CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam, 530017; [email protected]

In order to understand the influence on the composition of particulate organic matter (POM) of river discharge, a study was conducted along the western coastal Bay of Bengal during SW monsoon (discharge period). Elemental and stable isotope ratios of carbon and nitrogen showed that POM is a mixture of OM derived from autochthonous and allochthonous sources, with a predominance of the former in the north western (NW) and latter in the south western (SW) parts of the coastal Bay of Bengal during study period. Dual isotope mixing model ‘SIAR’ revealed that OM derived from terrestrial C3 plants contributes predominantly (~75%) than the contribution from marine phytoplankton derived OM (~20%) to POM in the SW region. On the other hand, phytoplankton derived OM dominates (~60%) the POM, with a minor contribution from terrestrial C3 (~20%) and C4 plants (~20%) in the NW region. A predominance of the allochthonous POM in the SW region is attributed to transport through discharge of terrestrial vascular plant material by the major rivers Godavari and Krishna during SW monsoon. In addition, relatively high suspended load (20.6±8.6 mg l-1) limits the light availability to phytoplankton resulting in relatively low biological production (Chl-a: 1.3±0.9 mg m-3) in the SW region. By contrast, major contribution from autochthonous sources in the NW region could be due to enhanced biological production (Chl-a: 3.2±2.7 mg m-3) supported by conducive conditions for phytoplankton to grow. Relatively low suspended load (12.0±5.8 mg l-1) in the NW region increases in-situ biological production by allowing light availability to deeper depths for phytoplankton. Therefore, freshwater discharge along with nutrients and suspended matter has a significant influence on the composition of POM in the western coastal Bay of Bengal during SW monsoon.

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17

SENSITIVITY OF COASTAL PHYTOPLANKTON TO VARIABLE COPPER CONCENTRATIONS FROM THE VISAKHAPATNAM COAST (SW COAST OF BAY

OF BENGAL, INDIA)

Haimanti Biswas* and Debasmita Bandyopadhyay

CSIR National Institute of Oceanography, Regional Centre, Visakhapatnam; [email protected]

Copper (Cu) a redox-active transition metal plays dual role in phytoplankton physiology depending on its concentrations; at lower concentrations Cu plays numerous roles in oxidation-reduction reactions of many physiological processes like photosynthesis and respiration; conversely, at higher concentrations, Cu has mostly been considered as toxic for being able to make strong complexes with biomolecules and numerous studies showed various types of deleterious effects on marine phytoplankton. Coastal waters receive significant amount of copper from different anthropogenic sources and can be deleterious to coastal phytoplankton. However, when living permanently in a metal enriched environment, coastal phytoplankton also may develop some adaptability to tolerate metals levels and to overcome the stress, marine phytoplankton was found to control their internal Cu pool well below the toxic level and this capability was species/genera specific. Visakhapatnam coast is under direct anthropogenic pressure due to the vicinity of port, naval base and many industries which may release significant amounts of toxic metals including Cu in the adjacent coastal waters. In our earlier studies we have shown that Cu may play a vital beneficial role in coastal phytoplankton physiology, however, our knowledge about the sensitivity of coastal phytoplankton communities to different Cu concentrations on a spatial scale is almost scarce. The impact of variable Cu concentrations (till 1000nM) was investigated on coastal phytoplankton communities from different distances (0km, 1km and 10km) from the Visakhapatnam coast. Our results revealed that the coastal phytoplankton which are just found adjacent to the coast are highly tolerant to Cu level up to > 100nM which is consistent with our earlier studies. Moreover, at 1000nM Cu level, phytoplankton growth was severely inhibited (3.5 times). Diatoxanthin index was also increased with increasing Cu concentrations which indicates the presence of oxidative stress by this redox metal at higher concentrations. When the phytoplankton communities

from 1km far from the coast were grown with variable Cu levels, a slight enhancement in growth up to 25nM were observed and was almost diminished at 50nM Cu level.

Interestingly, when moving further from the coast ( 10km), phytoplankton biomass decreased significantly at 10nM Cu level and 20-50% reduction in biomass was observed. Our results indicate that coastal waters in the study area are enriched with metals like Cu, however, the coastal species are quite adaptive to higher Cu concentrations and further increase many largely impede their growth. Nonetheless, those species inhabiting far from the coast are still highly vulnerable to higher Cu level and further metal enrichment may cause significant damage to them. This can have a large biogeochemical significance in the coastal waters.

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18

BIO-PHYSICAL COUPLING AND UPPER OCEAN BIOLOGICAL PRODUCTIVITY IN THE NORTHERN INDIAN OCEAN

S. Prasanna Kumar* and Jayu Narvekar

CSIR-National Institute of Oceanography, Dona Paula, Goa-403 004; [email protected]

Bio-physical coupling is an important aspect in the production of organic carbon in the euphotic zone. In a top-down system the primary production and subsequent chlorophyll biomass in the upper ocean is controlled by the availability of sunlight, macronutrients such as nitrate, phosphate and silicate, and micro nutrients such as iron. In addition to this, grazing by zooplankton also is an important factor in the build-up of chlorophyll biomass. Through this presentation we synthesize the information on the former using 2 decades of collocated data on physical and biogeochemical parameters collected onboard Indian research ships following stringent protocol during Joint global ocean flux studies in the Arabian Sea (JGOFS, 1992-1997), Bay of Bengal Process Study (BOBPS, 2001-2006) and equatorial Indian Ocean Process Study (EIOPS, 2005- 2012). The salient features that emerged out of these studies are the role of winter convection driving the winter bloom, while a combination of coastal upwelling, advection, wind-mixing and upward-Ekman pumping supporting the high summer chlorophyll biomass in the Arabian Sea. The column integrated chlorophyll as well as primary production, based on in situ measurements, depicted the signatures of winter and summer blooms, which was also discernible from satellite derived chlorophyll pigment concentration. In contrast, in the Bay of Bengal, the satellite derived chlorophyll pigment concentration showed very low level of chlorophyll biomass, with very weak seasonality. However, the integrated chlorophyll as well as primary productivity, though low compared to Arabian Sea, showed sustained levels of biomass and production with winter values slightly higher than summer values with no defined seasonality. These results along with the results from sediment trap data on sinking organic carbon flux at mid-depth (~1000m) suggest role of meso-scale eddies in enhancing and sustaining elevated chlorophyll biomass and primary production. The strong stratification during summer monsoon makes the Bay a less productive basin due to lack of strong upwelling as well as wind-mixing. In addition to meso-scale eddies, the tropical cyclones that occur regularly during spring and fall intermonsoons contribute to the production of organic carbon during these seasons. In the equatorial region, however, the satellite derived chlorophyll pigment concentration showed higher values only in the western and central region during summer monsoon, which is associated with upwelling. During the rest of the year the upper ocean waters in the equatorial region is oligotrophic making it an oceanic desert. This situation alters during Indian Ocean Dipole (IOD) years when eastern equatorial Indian Ocean becomes productive with chlorophyll blooms, which advect westward impacting even the central parts as well. In the equatorial Indian Ocean apart from IOD, propagating waves also impacts the upper ocean nutrients and chlorophyll.

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19

EFFECTS OF ZINC ON COASTAL PHYTOPLANKTON GROWTH AND PRIMARY

PRODUCTION UNDER LOW AND HIGH CO2 LEVELS FROM VISAKHAPATNAM

COAST

Aziz Ur Rahman Shaik1*, Debasmita Bandyopadhyay2 and Haimanti Biswas3 1CSIR National Institute of Oceanography, Regional Centre, Visakhapatnam, India; [email protected]

Zn is one of those bioactive trace metals that play significant role in plant physiology and biochemistry. However, like other metals, Zn is also toxic at higher level and can create several damages to coastal and marine phytoplankton. Zn is present as a cofactor in one of the most important enzymes involved in carbon metabolism, carbonic anhydrase (CA). Additionally, Zn is involved in synthesizing numerous plant proteins, a process of chlorophyll synthesis, DNA base pair repairing, photosynthetic-D1 protein repairing and hence variability in Zn availability may significantly affect plant physiology. Coastal waters are believed to be metal enriched, however, also can be limiting sometimes due to high variability in its input rate from riverine, land runoff and atmospheric sources. Incubation experiments were conducted using natural phytoplankton communities which are mostly diatom dominated from the Visakhapatnam coast in order to understand the responses of coastal phytoplankton to added Zn under low and high CO2 levels. Our results revealed that under both low

(200µatm) and high (1500µatm) CO2 levels, Zn showed significant effect on coastal phytoplankton physiology. Chla normalized photosynthetic oxygen evolution rate showed almost 27% higher values in the low CO2 treatment where Zn is added relative to the control (without Zn addition). High CO2 treated samples without Zn showed very high values (almost 200%) of photosynthetic oxygen evolution relative to the controls. However, in the treatments with high CO2 and Zn, the same rate was reduced. Particulate organic carbon and nitrogen including total protein also revealed a similar trend. Interestingly the highest concentrations of total protein and chlorophyll and the lowest concentration of biogenic silica (BSi) were detected at high CO2 and Zn added treatments. Biogenic silica to organic carbon ratios (BSi:POC) were 2.42 % higher at low CO2 and Zn treated samples than that of Zn untreated samples; whereas 2.95% lower at high CO2 plus Zn treated samples relative to the high CO2 alone. Total protein concentration was maximum and BSi was minimum at high CO2 and Zn added treatments. Thus, these results indicate that at low CO2 levels, Zn addition enhances photosynthetic oxygen evolution and it could be due to the involvement of the enzyme CA in inorganic carbon acquisition. Therefore, under low CO2 plus Zn treated treatments, no inhibitory impacts were observed. Under the high CO2 treatments, low pH (<7.6) of the water might increase the bioavailability of the metals and hence of Zn which could be beyond their requirements and hence showed lower photosynthetic rates. Moreover, excess Zn can largely inhibit silicate transport and hence might have hindered BSi production under high CO2 plus Zn added samples. Higher total protein and chlorophyll at this treatment indicates the involvement of Zn in both these processes. Thus we presume that Zn plays a significant role in coastal phytoplankton physiology, nonetheless, can also impede some other cellular processes at higher availability.

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20

DISTRIBUTION OF BIOCHEMICAL COMPOUNDS IN INDIAN MONSOONAL ESTUARIES DURING SW MONSOON

B.S.K. Kumar1*, V.V.S.S. Sarma2, M.S.R. Krishna2 and N.P.C. Reddy2

1Andhra University, Visakhapatnam-530003; [email protected]

2CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam, 530 017

Rivers are the major source of suspended matter (SPM), nutrients and organic matter (OM) to estuaries and coastal oceans, and establish a major link between land and ocean. However, the quality of the material depends on the drainage intensity and bed composition of the catchment. Here, we present the results of a systematic study conducted during SW monsoon in 27 major and medium Indian monsoonal estuaries. As the discharge from these rivers is dependent on the monsoon induced precipitation over the Indian subcontinent, which shows a large spatial variability, the discharge ranged from as low as 28 to 3500 m3 s-1. As the OM derived from in situ & terrestrial sources was reported to have distinctly different concentrations of proteins (TPRO) and carbohydrates (TCHO), the ratio of protein to carbohydrates can be used to identify the source of OM. Relatively lower TPRO:TCHO ratios were found in the northern estuaries (0.85±0.48), which receives relatively high river discharge along with high suspended matter, than the south east (SE) estuaries (1.56±1.21) indicating that degraded/ modified OM is predominant in the former, whereas freshly produced in situ OM in the latter. Relatively high concentration of Chl-a confirms the predominance of in situ OM in the SE estuaries. The ratio is in between 0.5 and 1.8 in the SW estuaries, suggesting that the OM is a mixture of in situ produced and terrestrial OM. It is estimated that the Indian estuaries transport 1.3x 109, 1.6x 108, 8.0x108

g C to Bay of Bengal, and 6.5x 108, 1.9x 107, 3.6x108 g C to Arabian Sea during discharge period in the form of TCHO, DFAA and TPRO respectively. This study demonstrates that the OM in the northern estuaries is mainly contributed by terrestrial sources, whereas it is a mixture of in situ and terrestrial OM in the southern estuaries.

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21

OBSERVED INTRA-SEASONAL VARIABILITY OF CHLOROPHYLL-A USING ARGO PROFILING FLOAT IN THE EASTERN EQUATORIAL INDIAN OCEAN

V. P. Thangaprakash*, M. S. Girishkumar, T.V.S. Udaya Bhaskar, M. Ravichandran

ESSO – Indian National Centre for Ocean Information Services, Hyderabad; [email protected]

Madden-Julian Oscillation (MJO) [Madden and Julian, 1994], a dominant intraseasonal mode in the tropical climate, can significantly modulate oceanic physical, dynamic and biogeochemical characteristics. Even though, earlier studies have examined the impact of MJO on physical and dynamical variability of ocean state, its impact on chlorophyll variability is limited due to lack of systematic measurements of in-situ observation [Jin et al, 2013]. The understanding of these processes is of importance not only for geophysical interest but also for the prediction of biological activities which is directly related to fishing industries. Analysis of two years (2013-2014) time-series of vertical profile of chlorophyll-a data obtained from a Argo profiling float (WMO ID - 2902088) in eastern equatorial Indian Ocean showed that modulation of near surface (< 30 m) chlorophyll (> 0.8 mg/m3) in sub-seasonal times scale. Our analysis shows that the existence of strong connection between MJO and enhancement of chlorophyll in the near surface layer. Further, presence of subsurface chlorophyll maxima, a well know characteristics of vertical structure of chlorophyll in the tropical climate, in depth range of 40-60 m has been noticed. Our analysis showed that, the deepening of mixed layer in to subsurface chlorophyll-a due to increasing wind field associated with MJO activity initiated the near surface bloom. However, all MJO events might not lead to near surface bloom. Further, the strong connection between the depth of subsurface chlorophyll maxima (in the presence of shallow thermocline) and enhancement of near surface bloom with MJO event has been noticed.

References: Jin, D., R. Murtugudde, and D. E. Waliser (2013), Intraseasonal atmospheric forcing effects on the mean state of ocean surface chlorophyll, J. Geophys. Res. Oceans, 118, 184–196, doi: 10.1029/2012JC008256. Madden, R. A., and P. R. Julian (1994), Observations of the 40–50-Day Tropical Oscillation—A Review, Mon. Weather Rev., 122(5), 814–837.

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22

VARIABILITY OF PHYTOPLANKTON PIGMENT CONCENTRATION IN INDIAN ESTUARIES DURING PEAK RIVER DISCHARGE PERIOD

D. B. Rao1*, V.V.S.S. Sarma2, M.S. Krishna2 and N.P.C. Reddy2 1CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam; [email protected]

2CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam

The intensity of monsoonal precipitation shows significant spatial variability over Indian subcontinent resulting in variable magnitude of discharge from Indian rivers/estuaries. Discharge brings significant amount of terrestrial nutrients to the estuary to support phytoplankton biomass. India ranks second in the world, in fertilizer usage with significant spatial variability and the excess fertilizers are expected to land in the rivers/estuaries. The artificial nutrients, such as fertilizers, not only increase concentrations but also ratios of nitrogen to phosphorus that would have significant impact on phytoplankton composition. The nitrogen isotopic composition of particulate nitrogen (δ15NPN) was lower (0.2 to 4‰) in the estuaries receiving high discharge and vice versa in low discharge estuaries (5.0 to 16.7‰) suggesting that artificial and regenerated nutrients are supporting primary producers.

To examine the impact of magnitude of river discharge and contribution of artificial nutrients on diversity of phytoplankton composition in the estuary; water samples were collected from 27 major and medium estuaries along Indian coast during the peak discharge period. About 0.5-1 L of water samples were filtered through Glass Fiber (GF/F) filters and the pigment retained on the filter was extracted with acetone and the composition was measured using HPLC (High performance liquid chromatography).

The rate of river discharge varied between 28 and 3505 m3s

-1 in the Indian estuaries and relatively higher discharge was observed in the estuaries located in the northern India. The concentrations of SPM was higher by an order of magnitude (223 ± 83mg/l) in the estuaries that received higher discharge (>500 m

3s

-1) than low discharge estuaries (29.7±12mg/l). The concentration of phytoplankton biomass (Chl-a) was higher (6.9μg/l) in the low discharge estuaries than high discharge estuaries (3.2μg/l) due to suppression of growth by less availability of light in the latter estuaries. The Fucoxanthin to Zeaxanthin (F/Z) ratio was low (0.4) in the high discharge estuaries than that (0.6) in low discharge estuaries suggesting that high turbidity did not promote diatoms as they require relatively higher light conditions. Lower F/Z ratio (0.2) was observed in the estuaries received

relatively higher fertilizer inputs, indicated by depleted 15NPN, than estuaries received regenerated nutrients (0.9) suggesting that artificial nutrients promoted picoplankton. In addition to this low N:P ratios (3) were observed in the estuaries received artificial nutrients than regenerated source (10) suggesting that modification of ratios further influenced phytoplankton composition in the Indian estuaries. Several dams have been constructed on many of the Indian rivers and the discharge is controlled by the dam authorities. Our study revealed that modification of discharge and concentrations of artificial nutrients modify phytoplankton composition in the Indian estuaries and may have significant impact of the food-web dynamics.

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23

INTERANNUAL TO LONG-TERM VARIABILITY OF OXYCLINE ALONG THE WEST COAST OF INDIA: UNDERSTANDING ANOXIC EVENTS THROUGH MODELING

APPROACH

V. Parvathi1*, I. Suresh1, S. Neetu1, M. Lengaigne1,2, M. Levy2, L. Resplandy3, C. Ethé2, J. Vialard2, O. Aumont2, H. Naik1, SWA. Naqvi1

1CSIR-National Institute of Oceanography, Goa, India; [email protected]

2Laboratoire d'Océanographie Expérimentation et Approches Numériques, Paris, France

3Scripps Institution of Oceanography, La Jolla, California, United States

Arabian Sea hosts one of the major open ocean oxygen minimum zones (OMZ) in the world's ocean. During the Indian summer monsoon, the continental shelf off the west coast of India experiences strong upwelling. The upwelling low-oxygen, high-nutrient waters lead to the formation of the world’s largest natural low-oxygen zone over the continental shelf off the Indian west coast during the post-southwest monsoon. During some years, these waters turn completely oxygen depleted, a condition called coastal anoxia. These anoxic events exhibit strong decadal and interannual variabilities and are reported to have been intensified by the turn of 20th century. However the mechanisms that cause oxygen variability along the west coast of India have not yet been understood. In the present study, we address this issue using an Indian Ocean regional configuration of NEMO/PISCES biogeochemical model. We show that the depth of oxycline along the western coast of India display considerable decadal fluctuations, along with interannual ones, with a shoaling from the late 70’s until 2000 and a deepening since then. These variations agree qualitatively well with the sparsely available oxygen measurements over the past 40 years. Our analysis indicates that these fluctuations are intimately tied to the decadal and interannual fluctuations of the thermocline depth, suggesting that the variability in the oxygen along the west coast of India are mainly controlled by physical mechanisms, largely related to natural variability.

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24

VERTICAL VARIATION OF PRIMARY PRODUCTIVITY IN PRESENCE OF ULTRAVIOLET RADIATIONS, CENTRAL WEST COAST OF INDIA

Prachi A. Naik1*, M. Gauns2 1 CSIR-National Institute of Oceanography, Goa; [email protected]

2CSIR-National Institute of Oceanography, Goa

West cost of India is strongly influenced by monsoonal cycle. High primary productivity in the region is observed during southwest monsoon (SWM) due to nutrient rich upwelled waters from intermediate depths (Naqvi et al., 2006). High oxygen demand for respiratory oxidation of the organic carbon produced during senescent phase of SWM ends-up in development of oxygen deficient zone (hypoxia), a few meters below the surface (Naqvi et al., 2000) thus becomes a global environmental problem. A resolute redressal to the problem lies in regulation of primary productivity of the region to optimal levels which is exhibited by dual nature of incoming solar Ultraviolet (UV) radiations observed along with Photosynthetically Active Radiation (PAR, 400-700 nm); as a consequence of atmospheric ozone depletion. The UV-B radiations (280-325 nm) are well known stressor (Häder, 2003) and reduce photosynthetic rates (Steemann Nielsen, 1964; Helbling et al., 2003). On the contrary, UV-A radiations (325-380 nm) have been reported to cause repair of UV-B-induced DNA damage (Buma et al., 2003) and enhance fixation of carbon dioxide (CO2) (Nilawati et al., 1997; Barbieri et al., 2002) by the phytoplankton community.

Our study addresses verification of the regulatory effect of solar UV radiations on primary productivity of coastal waters with reference to quantum efficiency of photosystem II (PS II) photochemistry expressed in terms of Fv/Fm ratio (Kolber and Falkowski, 1993) and phytoplankton biomass. The estimation of primary productivity was fluorescence-based; following the Kolber and Falkowski model 1993 (Suggett et al. 2001). Vertical profiles of solar irradiances of UV and PAR radiations and variable active fluorescence were obtained with commercial UV-PAR Radiometer and Fast Repetition Rate Fluorometer (FRRF) at a coastal station of eastern Arabian Sea (15°30.490’’N and 73°39.108’’E) during SWM of 2013 (September, October) and 2014 (July and October) as shown in Figure 1 A, B, C & D respectively. Upper 20m water column of the study region was euphotic and exposed to solar UV radiations along with PAR irradiance. The variation pattern of chlorophyll a (Chl a) concentration, Fv/Fm ratio in presence of UV and PAR irradiance to the variation of PP in the water column had highest coefficient of correlation observed for PP to UV-A & UV-B radiations followed by Fv/Fm, Chl a concentration and PAR irradiance (Table 1). The strength of irradiance of UV-B to UV-A except at Oct 2013 is lower wherein, at 10-15m column a 40% rise in Fv/Fm was seen to minimize the decrease in PP from 80% to 60% in presence of 20% rise of UV-B irradiance. The vertical decreased gradient in PP (Sep 2013) was similar to the reduced UV-A irradiance. In the year 2014 where the variation in UV-A and UV-B irradiance was consistent in the water column with UV-A greater than the UV-B irradiance (approximately twice), the variation in PP was simultaneous to the varying FV/Fm values. During the study period in waters off-Goa, the combined regulatory effect of UV-A and UV-B irradiance on primary productivity was seen but requires to be quantified.

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References: Barbieri, E. S., Villafañe V. E., Helbling E. W. (2002), Experimental assessment of UV effects on temperate marine phytoplankton when exposed to variable radiation regimes, Limnology and Oceanography, 47, 1648–1655. Buma, A. G. J., Boelen P., Jeffrey W. H. (2003), UVR-induced DNA damage in aquatic organisms, In UV Effects in Aquatic Organisms and Ecosystems, Helbling E. W., Zagarese H. E. (eds.), Royal Society of Chemistry, Cambridge, UK, 291–327. Häder, D. P. (2003), Effects of solar ultraviolet radiation on aquatic primary producers, In Handbook of Photochemistry and Photobiology, Nalwa H.S. (ed.), American Scientific Publishers, IV, Stevenson Ranch, CA, 329–35. Helbling, E. W., Gao K., Goncxalves R. J., Wu H., Villafañe V. E. (2003), Utilization of solar UV radiation by coastal phytoplankton assemblages off SE China when exposed to fast mixing, Marine Ecology Progress Series, (259), 59–66. Kolber, Z., Falkowski P. G. (1993), Use of active fluorescence to estimate phytoplankton photosynthesis in situ, Limnology and Oceanography, 38(8), 1646-1665. Nilawati, J., Greenberg B. M., Smith R. E. H. (1997), Influence of ultraviolet radiation on growth and photosynthesis of two cold ocean diatoms, Journal of Phycology, 33, 215–224. Naqvi, S. W. A., Jayakumar D. A., Narvekar P. V., Naik H., Sarma V. V. S. S., D’Souza W., Joseph S., George M.D. (2000), Increased marine production of N2O due to intensifying anoxia on the Indian continental shelf, Nature, 408, 346–349. Naqvi, S.W.A., Narvekar P.V., Desa E. (2006), Coastal biogeochemical processes in the North Indian Ocean (14, S-W), In The Sea, Vol. 14B, Robinson A.R., Brink K.H. (eds.), Harvard University Press: Cambridge, MA; 723–781. Steemann Nielsen E. (1964), On a complication in marine productivity work due to the influence of ultraviolet light, Journal du Conseil International pour l'Exploration de la Mer, 29, 130–135. Suggett D., Kraay G., Holligan P., Davey M., Aiken J., Geilder R. (2001), Limnology and Oceanography, 46(4), 802-810.

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INFLUENCE OF ANTHROPOGENIC ACTIVITIES ON ABUNDANCE OF HETEROTROPHIC AND PATHOGENIC BACTERIA ALONG THE COAST OF

ANDAMAN ISLANDS

P. Sudharani*, Y. Sathibabu, T. N. R. Srinivas

CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam; [email protected]

Anthropogenic activities bring land-derived material and fauna to the coastal regions, including heterotrophic and pathogenic bacteria, which may have significant impact on health of the coastal ecosystem. Heterogeneity in their distribution is expected due to variable characteristics of the discharge water from different rivers (from Myanmar) and anthropogenic activities in the islands which receive various degree of anthropogenic pressure. In order to examine the influence of anthropogenic activities on the coastal ecosystem along the coast of Andaman Islands, a study was conducted to examine abundance of heterotrophic and pathogenic bacteria (Aeromonas hydrophila, Escherichia coli, Enterococcus faecalis, Pseudomonas spp., Salmonella spp., Shigella spp. and Vibrio spp.) during monsoon season.

Samples were collected on board ORV Sindhu Sadhana (#SSD-001) during 1st August to 16th August 2014, from 24 stations (15 east side and 9 west side) around Andaman Islands. The bacteriological examinations were done onboard laboratory following standard protocols for the enumeration of total, heterotrophic and few pathogenic bacteria. Other physico-chemical parameters were studied following standard protocols.

The total microbial counts showed variation with reference to the particular organic carbon and Chlorophyll concentrations. The heterotrophic and pathogenic bacterial counts (Escherichia coli strain O157:H7 and Enterococcus faecalis) were high across 10o channel as it is a major shipping channel to Andaman Sea. Relatively higher counts of total, heterotrophic and pathogenic bacteria (Aeromonas hydrophila, Escherichia coli strain O157:H7 and Enterococcus faecalis), were observed in the coastal region compared to offshore may be due to release of domestic untreated sewage in the former zone. Pseudomonas spp., Salmonella spp., Shigella spp. were not detected in the study region while Vibrio spp. were sparsely detected. Relatively fewer counts were observed in the east coast of Andaman Islands comparative to western coast. The presence of Escherichia coli strain O157:H7 and Enterococcus faecalis counts at several stations indicate that untreated domestic sewage contaminated with human faeces was released into the coastal waters which is more intensified during monsoon season and its condition is unhygienic during this season, however its impact on the ecosystem needs more studies. But comparative to the east coast of Bay of Bengal (Visakhapatnam offshore data) the bacterial counts including pathogenic bacteria were an order of magnitude lower.

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BENTHIC REMINERALIZATION AND NUTRIENTS EXCHANGE ALONG THE SALINITY GRADIENT OF A TROPICAL ESTUARY, CENTRAL WEST COAST OF

INDIA

A. K. Pratihary*, J. Araujo, K.F. Bepari, R. Naik, S. Morajkar, P. Satardekar, D.M. Shenoy, S.W.A. Naqvi

CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004; [email protected]

Estuaries are transitional biogeochemical zones between two contrasting ecosystems i.e. terrestrial and oceanic, and receive significant amount of organic carbon and nutrients such as NO3

-, NH4+, PO4

3- and SiO44- through natural and/or anthropogenic sources. The health of the estuary is largely determined by the fact whether these extraneous carbon and nutrients undergo any biogeochemical processing in the estuary or are discharged to the coastal sea without undergoing any transformation.

The Mandovi estuary is a tropical, monsoonal and macrotidal estuary located along the central west coast of India. It experiences dramatic change in salinity and nutrients between the dry season (October-May) and the monsoon season (June-September). During the monsoon it becomes almost a fresh water body (Salinity = 0-4 psu) owing to heavy precipitation and land run-off. In contrast the estuary becomes tidal-dominated during the dry season and develops a prominent salinity gradient based on which the estuary could be divided broadly into three salinity zones i.e. marine (30-33 psu), brakish (20-25 psu) and freshwater (0-5 psu). To understand the geochemical control of salinity on the benthic remineralization and nutrient fluxes across sediment-water interface, a series of intact-core incubations were carried out along the salinity gradient. The cores were collected from Betim (32 psu), Amona (20 psu) and Ganjem (5 psu) during May-June 2014 and incubated both aerobically and anaerobically in the laboratory at controlled temperature under dark for 4-5 days Samples were collected at 6-12h interval for dissolved O2, N2O and nutrients. Separate sediment cores were also collected from these sites for organic carbon, porosity, and porewater nutrients and salinity.

Results showed that benthic respiration rates decreased linearly from 71 to 36 mmol m-2 d-1 from Betim to Ganjem resulting in a decrease in benthic mineralization rate from 68 to 31 mmol m-2 d-1 along the salinity gradient even as Corg increased from 1.7 to 8.5% upstream indicating dominance of refractory Corg towards upstream. Estuarine sediment behaved as a net source of DIN (dissolved inorganic nitrogen i.e. NO3

-+NO2-+NH4

+) to the overlying water though DIN efflux decreased from 2.59 to 0.67 mmol m-2 d-1 up the stream. Surprisingly though benthic denitrification rate (NO3

-+NO2- influx) varied from 0.08 to 0.41

mmol m-2 d-1 and did not show any trend along the salinity gradient, it showed a strong correlation with water column NO3

-+NO2- concentration. Though modest, build up of N2O

and its subsequent consumption observed in all the anaerobic incubations suggests benthic denitrification causing NO3

-+NO2- influx. NH4

+ comprised 91% of the DIN efflux at Betim which progressively decreased to 2% at Ganjem. In contrast, 8% of DIN released at Betim was in the form of NO3

-+NO2- which progressively increased to 97% at Ganjem. Differences

in anaerobic NH4+ and aerobic DIN flux suggest that at Betim 38% of upward diffusing NH4

+

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was lost in the coupled nitrification-denitrification within the sediment which reached a minimum at Amona (24%) and increased further to 69% at Ganjem. Benthic nitrification rate varied from 1.84 to 2.21 mmol m-2 d-1 from Betim to Ganjem with a minimum (0.98 mmol m-

2 d-1) at Amona and showed no correlation with salinity. Both NH4+ and PO4

3- effluxes showed inverse correlation with salinity indicating the geochemical control of salinity on their release. SiO44- was released at Betim and Amona at a rate of 2.4-3 mmol m-2 d-1 but showed downward flux at Ganjem. Higher benthic release of DIN and PO4

3- towards downstream implies that the estuary is more productive at the higher salinity end during the premonsoon. Decrease in porewater NH4

+ and PO43- towards Ganjem indicates the

effect of low salinity in controlling lower effluxes. Benthic denitrification can potentially remove 14-100% of the riverine DIN input and downward PO4

3- fluxes indicate that the adsorption and buffering capacity of the sediment can potentially remove 22-39% of the riverine DIP from Betim to Ganjem during the premonsoon.

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BIOGEOCHEMICAL CYCLING IN MANDOVI AND ZUARI ESTUARIES, WEST COAST OF INDIA

Hema Naik*, D. M. Shenoy, S. Kurian, S. W. A. Naqvi 1CSIR-National Institute of Oceanography, Dona Paula –Goa, 403 004; [email protected]

Under SIBER-India programme, we have been monitoring the estuarine systems – Mandovi and Zuari estuaries off Goa on a monthly basis since 2010. Both are well mixed coastal plain monsoonal estuarine systems situated between latitude 15°25’ – 15°31’N and longitude 73°45’ – 73°59’ E along the west coast of India. The physico-chemical conditions of the estuaries are influenced by the fresh water runoff during the monsoon (June-September) and the tidal influx of coastal waters during the non-monsoon (October to May). The maximum heating in the both surface and bottom waters takes place in the upstream reaches of the estuaries. During premonsoon (Feb-May), the intrusion of salt water in the estuaries is deep and is maximal in May upto a distance of 30 km from the mouth. During the monsoon, the estuary is almost dominated by freshwater. The freshwater dominance from upper reaches creates a strong stratification giving rise to salt wedges at the mouth upto a distance of 1-4 km in the Mandovi Estuary and upto 5 - 10km in the Zuari Estuary. The estuarine waters remain oxic and homogenous during most times of the year. The dissolved oxygen concentrations are slightly higher in upstream reaches (~ 5 ml/L) as compared to the mouth (4-4.5 ml/L) indicating freshwater influence at the former. The nutrient enrichment occurs at the upstream end as a result of riverine flow but at the mouth the concentrations decrease drastically due to the increased uptake rates and mixing with sea water which is oligotrophic during non-monsoon periods. With the onset of monsoon during June – September, the water column gets enriched with nutrients such that nitrate concentrations increase as much as 12 – 17µM and silicate concentrations reaching upto 100µM within the entire estuary. As the precipitation decreases in August, water column at the mouth of the estuary gets highly stratified with O2 - depletion (lowest concentrations observed in August ~3µM and 10µM in Mandovi and Zuari respectively) in bottom depths resulting from decomposition of organic matter.

The nutrient-rich estuary now shows reduced concentrations of nutrients at the mouth. This process could be a regional phenomenon or could be the flow of low oxygenated upwelled water mass from the inner shelf region that is entering the estuaries. There is evidence of upwelled waters intruding in Mandovi and Zuari in 1972 but the O2 values recorded were not as low as in our observations. Also we have not noticed the hydrogen sulphide at estuarine mouth as it happens at the inner shelf station of time-series site (CATS) located 10kms away from here. These waters show some accumulation of N2O (upto 100nM); build-up seen upto a distance of 10km from mouth of the estuary which could be supported by denitrification process. However, the low oxygenated water mass did not show accumulation of CH4 indicating that the water column do not turn anoxic. Based on available information it is known that the Indian estuaries along the east coast are also experiencing O2 depletion which gets severe during peak monsoon period but there is no

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evidence of denitrification in these waters implying the estuaries located along the two margins of India, eastern and western, experience different biogeochemical settings. The present study attempts to explain the biogeochemical variations within both the estuaries over a period of one full annual cycle.

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VARIATION OF DIMETHYLSULPHIDE AND ASSOCIATED COMPOUNDS IN THE MANDOVI AND ZUARI ESTUARY

Kausar Fatima M. Bepari, Damodar M. Shenoy*, M. Gauns, H. Naik and S.W.A. Naqvi

CSIR-National Institute of Oceanography, Goa, INDIA; [email protected]

Estuaries are complex systems which form an important link between the terrestrial

and the oceanic systems. The Mandovi-Zuari estuarine systems situated between 1515’N

to 1530’N and longitude 7345’E to 7406’E is one of the unique tropical estuarine systems along the west coast of India. Under the SIBER-India programme dimethylsulphide (DMS), total dimethylsulphoniopropionate (DMSP) and total dimethylsuphoxide (DMSO) were measured in the surface and bottom waters along these estuarine systems during January 2011 to December 2012 with an aim to study their spatial and temporal variability. In general higher concentrations of DMSP and DMS were observed near the mouth of the estuaries with the lowest observed in the upper reaches of the estuary. In contrast, DMSO concentrations in both the estuaries were observed even in the upper reaches of the estuary with higher concentrations observed during the southwest monsoon season and associated with low saline fresh water runoff suggesting a different source other than of phytoplankton origin. In the Mandovi estuary, the DMS concentrations varied between undetectable levels and 59.7 nM with the maximum observed at M3 station during the southwest monsoon period, whereas the DMSP concentrations varied between 0.4 nM and 75 nM with the maximum observed at M1 station during the pre-monsoon period. In the Zuari estuary, the DMS concentrations varied between undetectable levels and 57.8 nM with the maximum observed at Z1 station during the pre-monsoon period, whereas the DMSP concentrations varied between undetectable levels and 39.1 nM with the maximum observed at Z1 station during the onset of the southwest monsoon. Both estuaries observed higher concentrations of DMS and DMSP in 2012 in comparison to 2011. No correlation was observed between chlorophyll and DMSP or DMS in both the estuaries, however a linear relationship was observed with salinity supporting the osmoregulatory role of DMSP in phytoplankton cells.

References: Shenoy, D. M., & Patil, J. S. (2003). Temporal variations in dimethylsulphoniopropionate and dimethyl sulphide in the Zuari estuary, Goa (India). Marine Environmental Research, 56(3), 387-402. Shenoy, D. M., Sujith, K. B., Gauns, M. U., Patil, S., Sarkar, A., Naik, H., & Naqvi, S. W. A. (2012). Production of dimethylsulphide during the seasonal anoxia off Goa. Biogeochemistry, 110(1-3), 47-55. Shenoy, D. M., & Kumar, M. D. (2007). Variability in abundance and fluxes of dimethyl sulphide in the Indian Ocean. Biogeochemistry, 83(1-3), 277-292.

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IMPACT OF SEWAGE DISCHARGE ON THE WATER QUALITY OF VERSOVA CREEK

Anirudh Ram*, B. R. Thorat, M. A. Rokade, D. Majithiya, A. Yadav, S. Salvi, V. Joshilkar, N. Shinde, Jiyalal Ram. M. Jaiswar, S. N. Gajbhiye

CSIR-National Institute of Oceanography - Regional Centre, Mumbai; [email protected]

Versova Creek receives 4.40 x 105 m3/d sewage from point sources among which 2.0 x105 m3/d is released after aeration in the lagoon other 2.4 x105 m3 /d sewage is released directly after screening. Apart from known point sources the creek receives sewage as well industrial wastes from non-point sources of suburban Mumbai. The present study represents the spatial and temporal variation of water quality and plankton characteristics collected during 1991-2014 from Versova Creek to study the anthropogenic impacts on the water quality of Versova Creek. The creek remains anoxic (DO<0.2 mg/l) during low tide with high concentration of BOD (22 ±9.0 mg/l) and production of H2S (27.7± 8.6 µmol/l) even during monsoon period. As a result of organic matter oxidation PO4

3--P (21 ± 15 µmol/l) and NH4

+-N (43.4± 35 µmol/l) are released in the water of Versova Creek. Factor analysis indicated that ammonia and phosphate are having anthropogenic source into the creek. Low concentrations of NO3

--N and NO2--N and high concentrations of PO4

3--P, NH4+-N,

and BOD in this creek suggest sewage as the polluting source. Thus, though the sewage is treated in aerated lagoons at Versova post 1992, the water quality has not improved indicating that either the lagoons are inefficient in the removal of BOD or the sewage release is far in excess the assimilative capacity of the creek. With DO falling to zero sulphide is released, condition under which the fauna is severely impacted. DO replenish and concentration of H2S decreases with the ingress of coastal water to the creek during flood. Increased concentration of NO2

--N (4.9,±3.2µmol/l ) and NO3--N (29.2,±20.7µmol/l)

were recorded during high tide as a result of oxidation of NH4+-N to NO3

--N with NO2--N as

intermediate product. Appearance of bloom of toxic algae, Microcystis aeruginosa in recent years indicates alarming condition in the region. During 1994, 2000 and 2009 enhanced levels of average chl a of 10.4 mg m-3, 32.5 mg m-3 and 26.1 mg m-3 respectively may be due to the high anthropogenic nutrient inflow to the creek. The result of present study indicates that the condition of Versova Creek has not improved in recent years creating threat of spreading hypoxia in the coastal water.

Nutrient analyses were undertaken by following the method of Strickland and Parsons and concentration of pigments was determined following the Standard Methods (Strickland and Parsons 1972).

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Factor Analysis Low Tide

High Tide

Component 1 2

Component 1 2 3

Phosphate -0.17 0.85

Phosphate -0.30 0.81 0.22

Nitrite 0.62 -0.15

Nitrite -0.03 -0.29 -0.88

Nitrate 0.83 0.05

Nitrate 0.31 0.06 -0.84

Ammonia -0.52 0.43

Ammonia -0.02 0.90 0.01

DO 0.63 -0.29

DO 0.85 -0.11 0.00

Salinity 0.04 -0.83

Salinity 0.86 -0.11 -0.18

pH 0.71 -0.46

pH 0.65 -0.56 -0.30

Eigen value 3.07 1.11

Eigen value 3.23 1.19 1.17

Cumu. Variance

43.92 59.80

Cumulative Variance

46.28 63.34 80.11

Total Variance %

43.92 15.88

Total Variance %

46.28 17.06 16.76

References: 1. Strickland, J. D. H. and T. R. Parsons (1972): A Practical Handbook of Seawater Analysis. 2nd ed., Bull. Fish. Res. Bd. Can. No. 167, 310 pp.

0

5

10

15

20

25

30

Phosphate Nitrite Nitrate Ammonia

µM

Nutrients

HT LT

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

19

92

19

94

19

96

19

98

20

00

20

04

20

06

20

07

20

08

20

09

20

10

20

11

20

13

20

14

mg/

m3

Year

Chl a and Phaeo distribution 1992-2014

Chl a

Phaeo

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METHANE EMISSIONS FROM THE SHELF WATERS OF SOUTHEASTERN ARABIAN SEA

V.Sudheesh, G.V.M.Gupta* and M.Sudhakar

Centre for Marine Living Resources and Ecology, Ministry of Earth Sciences, Kendriya Bhavan, Kakkanad, Cochin-682037, India; [email protected]

Greenhouse gases (GHGs) from human activities are the most significant triggers of observed climate change since the mid-20th century. Among the most important GHGs, methane accounts for 20% of “enhanced greenhouse effect” and has a greenhouse gas potential of 25 times higher than that of carbon dioxide. Tropospheric methane has a variety of global sources, of which more than one half are anthropogenic. Coastal areas such as continental shelves, estuaries, deltas, fjords and lagoons can significantly contribute methane to the atmosphere. But highly limited data base from these coastal regions resulted in an uncertain magnitudes and variability of oceanic emissions of methane. In this study, we attempted to fill this gap from the shelf waters of Cochin (10°N), southeastern Arabian Sea through monthly observations made between April and December 2012. High methane concentrations were recorded in the nearshore region (7-152 nM, avg. 42±36 nM) which decreased towards mid-shelf (0-8.8 nM, avg. 2.4±2.3 nM) and outer shelf (0-8.2 nM, avg. 2.6±2.6 nM). Methane distribution in the shelf waters has not been shown to influenced by seasonal physical or biogeochemical forcings but affected largely by the discharges from the adjoining eutrophic Cochin estuary (CE) which recorded very high methane concentrations (309±233 nM) due to large scale anthropogenic perturbations. The methane flux from the Cochin shelf varied between 0 and 720 µmole m-2 d-1 with an average of 57±130 µmole m-2d-1. By extrapolating these fluxes linearly between southern tip of India to north of Cochin (7-11°N), the methane fluxes from the southwestern shelf region is computed at 0.007 Tg y-1. This represents 4-7% of the total Arabian Sea methane emission, is significant.

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BEHAVIOUR AND FATE OF TRACE ORGANIC CONTAMINANTS IN THE COCHIN ESTUARINE SYSTEM (CES), INDIA: AN OVERVIEW

P.S. Akhil, C.H. Sujatha*

Cochin University of Science and Technology, Cochin-16, Kerala, INDIA; [email protected]

The study on sediment biogeochemistry is being considered as record of impact, relying on the time integrative capacity of the sediment in the aquatic system. The sediments themselves are also the warehouse of the contaminants that can impact directly on the benthic ecosystem. Certain radionuclides and certain trace organic compounds (OCIs, PCBs, and PAHs etc) have both a geochemical and environmental half-life from which they can predict their persistence in the estuarine environment. Further, using a range of trace contaminants provides an important and verifiable approach to ecosystem health assessment. Therefore, their origin and fate in ecosystems cannot be understood without a fair knowledge on biogeochemical cycles. Estuarine sediments act both as a short or long term reservoir for many type of organic/inorganic contaminants (OCIs, PAHs, PCBs, trace metals etc). Diffusion, advection, mixing and resuspension of the sediment will affect the distribution of these trace contaminants in the estuarine niche. In this lacuna, a comprehensive idea on these disciplines will contribute a major role for the assessment of water quality and their management procedures in the aquatic system. Hence, the present research work elucidates the spatial and vertical trend pattern of Organochlorine Insecticide (OCI) residues in the sediments of CES. For this assignment, Fifteen persistent organochlorine compounds (OCs) were quantitatively analysed in the 6 sediment core samples and 17 surface sediment samples collected from specific sites of CES during November 2009 and 2011. Among these contaminants, residual levels of HCH, Cyclodienes and DDT were the dominant entities. According to the sediment quality guidelines (SQGs), the higher concentration of these persistent toxicants were found in the CES was enough to pose ecological risk to the bottom dwelling consumers. The main theme and objective of the study is to account the contaminant levels, distribution pattern and other contributing sources for assessing the environmental impact in the ecosystem. Moreover, the study intend to explain a brief explanation on how the biogeochemical studies of surface and sediment core profiles helps to describe the varying encapsulated biogenic compounds. Besides, the generated inference would provide useful information on the changes in the quality of the sediments from the past period.

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INTER-SEASONAL OBSERVATIONS IN DMS (P) VARIABILITY IN TROPICAL INTERTIDAL ESTUARINE ECOSYSTEM

Pandey Sunita Surendra, P. A. LokaBharathi*

CSIR - National Institute of Oceanography, Goa, India; [email protected]

Dimethylsulphide (DMS) and its precursor dimethylsulphoniopropionate (DMSP) are climatically and biologically relevant sulphur compounds produced in the marine ecosystem. Tropical estuaries are characterized by seasonal influence in hydrography and physico-chemical variables. In this study, we elucidated the factors influencing DMS variability in the intertidal zone of Dona Paula Bay with a hypothesis that tides wield their influence on DMSP dynamics irrespective of the season. To meet our objective, we carried out time series observations at 6 hour intervals synchronizing with tides during monsoon and non-monsoon season along with relevant environmental variables. A significant seasonal pattern in influence of tide on the abiotic and biotic factors involved in DMS (P) dynamics in tropical estuarine bay sediment was found during dry season. Average DMSP and DMS concentration was highest during monsoon ~ 252nM and 8 nM respectively, followed by ~60 nM and 4nM during post-monsoon. The lowest average was ~49 and 5 nM during pre-monsoon. During pre-monsoon season tides influenced both producers (17%) and utilizers (13%) of DMSP. Tidal height also exhibited positive correlation with DMS concentration (r = 0.478, p<0.01). This inference was further corroborated by Principal component analysis where tide featured as the most important variable in PC1 which yielded maximum influence. The precursor DMSP correlated well with the abundance and biomass of producers (phytoplankton and chl a), which in turn were influenced by nutrients during this season. During monsoon, physico-chemical variables like light, salinity, and phosphate were related to DMS. Abiotic factors like nitrate, silicate showed positive correlation with tidal amplitude. Also, the utilizers of DMSP (CFU) linked positively with the DMS content in the sediment. The association of DMSP with the phytoplankton continued during monsoon. During post-monsoon, the interactions were similar to those during monsoon where light, salinity, chl a and phosphate were linked to DMS. DMSP related only to chl a and not to phytoplankton. PCA also showed that chemical factors like pH, DO, and nitrate influenced the producers and utilizers during monsoon. Our results indicate that 1) intertidal sediments are significant sources of DMS (P), 2) direct tidal influence on the DMS (P) dynamics and source and sink of DMSP was masked by the combined influence of physico-chemical factors during monsoon in the intertidal sediments.

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Figure 1: Seasonal variability in DMS, DMSP in sediment of Dona Paula Bay

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MEASUREMENT OF NITROGEN FIXATION RATES ALONG THE SOUTHWEST COAST OF INDIA

Ayaz Ahmed*, Mangesh Gauns, Pratirupa Bardhan, Damodar Shenoy, Hema Naik, Siby Kurian, Anil Kiran Pratihary and SWA Naqvi.

CSIR-National Institute of oceanography; Dona Paula Goa-403004; [email protected]

Nitrogen (N2) fixation is an important process by which new nitrogen is introduced back to the oceanic system. We report here nitrogen fixation rates measured, south of 15oN (Fig. 1), during February 2013 in the upper euphotic water column from the eastern Arabian Sea using 15N2 tracer gas. The N2 fixation rates varied between 0.4 and 144 µmolN/m3/d. The higher rates were consistent with low δ15N of particulate organic matter reflecting N-fixation. The high rates (144.3 µMN/m3/d) found in the low nitrate region correspond to the early phase of Trichodesmium bloom where as the moderate rates (9.7µMN/m3/d) corresponded with the senescence phase. Lower N2 fixation rate (< 1 µmolN/m3/D) was observed at stations devoid of any Trichodesmium. Phosphate concentration seemed to drive the nitrogen fixation at lower levels of nitrate (<1 µM). Carbon fixation rates measured at a few stations using 14C technique showed rates between 0.07 and 12.8 mg C/m3/d. The present N2 fixation rates measured with modified technique is the first study of its kind from the region and has given important insight at the rate of nitrogen input to the total nitrogen pool of the area.

Fig.1 Map showing station locations in Arabian Sea

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CONCENTRATION OF TRACE METALS AND THEIR COVARIANCE WITH CARBON, NITROGEN AND SULPHUR IN ANOXIC ENVIRONMENT OF VERAVAL

HARBOUR

Divya Majithiya, Ajay Yadav, Anirudh Ram*, Shailesh Salvi, Archana Kamble

Regional Centre, CSIR-National Institute of Oceanography, Mumbai, India; [email protected]

Veraval located (20o53’N 70o26’E) on north-west coast of India is home to many textiles, chemicals and food processing industries and is the largest fishing harbour in Asia. The Veraval Harbour receives anthropogenic wastes from fish processing industries and sewage from Veraval City. The harbour has the stagnant water condition, due to the lack of turbulence, wind action and tidal effect in and around the jetty because of the abrupt designing of it, making dilution an impossible task for tides coming towards the jetty. Due to organic load discharge and restricted flushing, the water of Veraval Harbour remains anoxic irrespective of tides (NIO,TR, 2014) resulting the surface sediment also anoxic. The present work aims to study the effect of waste water discharge on the sediment quality ofharbour with special reference to the metal accumulation and their behaviour in the anoxic sediment. Two short sediment cores, (core 1, core 2) were collected and analysed for heavy metals such as Fe, Mn, Cr, Cu, Zn, Pb, Hg, and Cd from the Veraval Harbour. Sediment carbon and nitrogen ratio was examined to determine the source of organic matter.Analysis of sulphur was done to find out its control on heavy metals in anoxic sediment. Overlying bottom water of harbour was analysed for dissolved oxygen, hydrogen sulfide and dissolved metals to understand their role on sediment chemistry. A 63cm sediment core (Station-3) collected at the water depth of 30m from 10 km distance off Veraval Harbour was studied to find the baseline data and for calculating enrichment factor in harbour sediment.

Irrespective of tide, harbour water was found to be anoxic (DO <0.2 mg/l) with high concentration of ammonia (av. 459±21 µmol/l) and hydrogen sulphide (av. 73±2.5 µmol/l) at core 1 and core 2. In the harbour sediment core 1, geoaccumulation indices showed that Cd was extremely enriched (EF=147±49) followed by Hg (EF=5.3±1.4), Pb (EF=5.1±0.7), Cr (EF=5.0±0.96), Zn (EF=4.51±0.7) and Cu (EF=2.79±0.5). In core 2 enrichment was Cd (EF=13.2±7.5), Pb (EF=3.9±2.6), and Hg (EF=3.0±1.4). Fe and Mn concentrations were less than the background concentrations in the harbour sediment cores at both the stations. High concentration of Mn and Fe in overlying water indicates that under reduced conditions prevailing in the harbour, the sediment Fe-Mn oxides were reduced to Fe (II) and Mn (II) and diagenetically mobilized upwards in the sediment. The reduced Fe (II) and Mn (II) diffused upwards through interstitial water. As the overlying water was also anoxic, the mobilized Fe and Mn escaped in the water column instead of precipitating at the water sediment interface, increasing the concentration of dissolved Fe (41.0 ± 0.4 µg/l) &Mn (40.9 ±0.7 µg/l) in water. Low concentration of Cd (0.2 ± 0.01 µg/l), Pb (1.0 ± 0.05 µg/l) and Hg (0.2 ± 0.01 µg/l)in water and theirstrong positive correlation with total organic carbon (r=0.85, 0.91, 0.78 at p<0.001) and sulphur (r=0.69, 0.85 at p<0.001, r=0.51 at p<0.05) respectively in the sediment coresindicates that these metals are controlled by carbon and sulphur and not mobilized diagenetically even in the anoxic conditions [Sappal, et al., 2014]. Elements like

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Cu, Zn, Cd and Hg are higher in core 1 sediment compare to core 2. Similarly TOC and TN are also higher in core 1. Core 1 was taken from upper most part of the harbour, which is in the vicinity of discharge of industrial effluent. It is likely that the above elements accumulate near the source before moving to the downstream (Ram et al. 2009). The anoxic overlying bottom waters with high dissolved sulfides and strong positive correlation of Cu, Zn, Cd, Pb and Hg with total sulphur in the sediment cores indicated sulphur as the controlling factor scavenging the anthropogenic Cu, Zn, Cd, Pb and Hg.C/N ratio of harbour sediments at station-1 was (13±1.7) and at station-2 was (24±3) higher than the normal marine planktonic sediments [Bayraktarov and Wild, 2014] suggesting an increased contribution of terrestrial carbon in the harbour sediments.

Our study indicates that the sediment of Veraval Harbour is contaminated with metals such as Cu, Zn, Cd, Pb and Hg. Due to anoxic condition in the harbour, Fe, Mn and Zn are diagenetically mobilized and remain in high concentration in the dissolved form. The present study proves that concentration of metals such as Cd, Pb and Hgare mainly controlled by carbon and sulphur and not by Fe-Mn oxides even in the anoxic conditions.

References: Bayraktarov, E. and Wild, C. (2014) Spatio-temporal variability of sedimentary organic mattersupply and recycling processes in coral reefs of Tayrona National Natural Park, Colombian Caribbean. Biogeosciences, 11, 2977–2990, 2014. NIO,(2014) Marine EIA and Site Selection for the Seawater Intake and Outfall in Arabian Sea off Veraval for Reverse Osmosis (RO) Reject from Desalination Plant of Indian Rayon. NIO/SP-04/2014, pp. 1-127. Ram, A., Rokade, M. A., Zingde, M. D. And Boreole, D. V. (2009) Post-depositional memory record of mercury in sediment near the effluent disposal site of a chlor-alkali plant in Thane Creek-Mumbai Harbour, India. Environmental Technology 30, 765-783. Sappal, S. M.; Ramanathan, A. L.; Ranjan, R. K. and Singh, G.(2014) Sedimentary geochemistry of Chorao Island, Mandovi mangrove estuarine complex, Goa.Indian Journal of Geo-Marine Sciences, 43 (6), 1085-1094.

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PHYTOPLANKTON–ZOOPLANKTON DYNAMICS IN COASTAL WATERS OF CENTRAL WEST COAST OF INDIA

Mangesh Gauns, Anil Pratihary, D M Shenoy, Siby Kurian, H Naik and S.W.A. Naqvi

CSIR-National Institute of Oceanography, Dona Paula –Goa, 403 004; [email protected]

Biological productivity in the Arabian Sea is regulated mainly by nutrient inputs from subsurface waters via upwelling in summer and convective mixing in winter resulting in widespread phytoplankton blooms during both summer and winter. This, in turn, supports high export flux of organic matter to the deep sea, which contributes to the development of one of the thickest and most intense oxygen minimum zones of the world's oceans. In contrast to the perennial OMZs found in the open ocean areas of the northern Indian Ocean, severe oxygen deficiency also occurs during summer upwelling along the western continental shelf of India, covering an area of 180,000 km2. The onset of the southwest monsoon (SWM) in June marks the beginning of upwelling along the SW coast of India which propagates northward and persists until October. Upwelling brings up subsurface water having low dissolved oxygen content over the shelf. The upwelled water is, however capped by a thin low-salinity layer, which is formed as a result of intense rainfall runoff in the coastal zone. Degradation of organic matter in the relatively stagnated upwelled water quickly removes the residual oxygen below the shallow pycnocline.

Systematic studies carried out at the Candolim Time Series (CaTS) site located central west coast of India (off- Goa) have shown regular occurrence of hypoxia following the southwest monsoon (September-October period). The onset of oxygen-deficient conditions profoundly influences the dynamics of both phyto- and zooplankton. While microplakton (mostly diatoms but also dinoflagellates) constitute the major part of the phytoplankton biomass in oxic waters; pico-autotrophs, and to a smaller extent, pennate diatoms were found to be predominant in oxygen deficient waters. The zooplankton biomass was generally higher in oxic waters as compared to oxygen-deficient waters. Among various zooplankton, only a few forms observed to survive at low concentrations of oxygen (< 1 ml l-

1). The mechanism of survival in these organisms under very low oxygen environments is not known and needs to be investigated. This study also highlights long-term changes in zooplankton and phytoplankton abundance and floristic composition at the coastal time series site (CaTS).

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GLOBAL SEAWATER DMS CLIMATOLOGY: COMPARISON & UPDATE

Smrati Gupta*, Anoop S. Mahajan

Centre for Climate Change Research, IITM, Pune; [email protected]

Dimethyl sulfide (DMS), produced by oceanic phytoplankton, being the most abundant

source of natural sulfur over the marine environment plays an important role in influencing cloud microphysics, aerosol radiative forcing and hence the Earth’s radiation budget (as initially suggested by the CLAW hypothesis). Seawater DMS climatology is used by models to estimate the atmospheric DMS distribution and hence the resultant sulfur entities in atmosphere which affect cloud properties and radiation. Classical DMS climatology used in modelling studies is more than a decade old (Kettle and Andreae, 2000) referred to as K00, and was made with a few DMS data points. Since then, oceanic DMS measurements have increased and also measurement techniques have improved. A relatively newer DMS database is available in the shape of a recently published climatology (Lana et al., 2011) referred to as L10. The aim of this project work was to study the impacts of using the newer DMS climatology (L10) and validation of the model simulations with available observations. Model used is state-of-the-art GCM ECHAM-HAMMOZ aerosol chemistry model. Results showed the use of updated L10 climatology over prevailing K00 results in decrease in the total aerosol radiative forcing, which corresponds to the 20% cooling attributed to DMS climatology chosen (Figure 1). Comparison of model simulations with the available observations of atmospheric DMS and total sulfate also showed better correlation with the L10 climatology. Figure 2 shows the comparison between the observed atmospheric DMS climatology at Amsterdam Island, Southern Indian Ocean (1990-1999) and the modeled DMS at the surface using the K00 and L10 climatologies. Using the L10 climatology, the correlation coefficient value shows a strong improvement (R=0.83, P=0.001) as compared to the K00 climatology (R=0.45, P=0.15). For compiled discrete observations from all over the world, the L10 climatology shows a modest improvement in describing the atmospheric DMS as compared to the K00 climatology (Figure 3); R=0.48 for L10 as compared to 0.44 for K00. These results stress the necessity of using the latest updated climatology in modelling studies. Although better correlated with the observations, the L10 was found to overestimate DMS for the higher DMS concentrations. This was the motivation to update the L10 with recent data (Malaspina expedition 2010) as L10 was constructed using the seawater DMS data up to the year 2010. These helped lower the DMS concentrations to a certain extent and might help explain the positive bias in the model for atmospheric DMS. Furthermore, we observed some immediate changes in the annual DMS characteristics of few of the Longhurst’s biogeographic provinces attributed to the presence of increased number of data points in the regions influenced by DMS data obtained in Malaspina expedition. Further groundwork to develop subsequent climatologies at IITM through inclusion of a new high frequency data was also done, which is directed to create a new updated climatology taking into account the availability of high frequency data now-a-days. This work will lead to further updates, which should help reduce the present discrepancies between model simulations and observations.

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Aerosol Radiative Forcing at TOA (W m-2)

Figure 1 : Difference between the model output using two climatologies (L10-K00) for ARF

References: Charlson, R. J., Lovelock, J. E., Andreae, M. O., & Warren, S. G. (1987). Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate. Nature, 326(16), 655–661. Kettle, A. J., & Andreae, M. O. (2000). Flux of dimethylsulfide from the oceans : A comparison of updated datasets and flux models. Journal of Geophysical Research, 105(D22), 26793–26808. Kettle, A. J., Andreae, M. O., Amouroux, D., Bates, T. S., Berresheim, H., B, H., Uher, G. (1999). A global database of sea surface dimethylsulfide ( DMS ) measurements and a procedure to predict sea surface DMS as a function of latitude , longitude , and month. Global Biogeochemical Cycles, 13(2), 399–444. Lana, a., Bell, T. G., Simó, R., Vallina, S. M., Ballabrera-Poy, J., Kettle, a. J., Liss, P. S. (2011). An updated climatology of surface dimethlysulfide concentrations and emission fluxes in the global ocean. Global Biogeochemical Cycles, 25(1), n/a–n/a. doi:10.1029/2010GB003850

Figure 2: Comparison between the observed atmospheric DMS

climatology at Amsterdam Island, Indian Ocean (1990-99) and the

modeled DMS at the surface using the K00 and L10 climatologies

Figure 3: Correlation between the observed and modeled

DMS using the K00 and L10 seawater DMS climatologies.

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CARBON DIOXIDE EMISSIONS FROM A TROPICAL ESTUARY LOCATED ALONG THE WEST COAST OF INDIA- ZUARI ESTUARY

Rashith P*, H. Naik, D. M. Shenoy and S.W. A. Naqvi

CSIR-National Institute of Oceanography, Dona Paula –Goa, 403 004; [email protected]

The Carbon dioxide species such as TCO2 and Alkalinity were measured in Zuari estuary, a tropical estuary under the influence of strong monsoonal discharges. Water samples were collected from 7 stations during 2011. The partial pressure of carbon dioxide (pCO2) and pH were derived using measured TCO2 and alkalinity concentrations. While TCO2 and alkalinity concentrations were lower in the upper reaches of the estuary, averaging to 290.22 µmoles/kg and 407 µmoles/kg respectively, the concentrations were maximal at the seawater end, averaging to 1934.4 µmoles/kg and 2112 µmoles/kg respectively, indicating typical oceanic waters at the latter. The two CO2 species had strong correlation with salinity (0-35) and behaved conservatively during the estuarine mixing. The pCO2 displayed strong temporal and spatial variations within the estuary and showed inverse relationship with salinity. The highest pCO2 concentrations were recorded in the early estuarine mixing (> 2000 µatm at salinity ~18). The ~3 times higher concentration (average pCO2~1244 µatm) as compared to atmospheric (391.8 ppm) concentrations suggests that the estuary acts as a source of CO2 to the atmosphere. The quality of organic matter brought in by the river and rate of respiration could play a major role in sustaining these high values round the year. The higher pCO2 effluxes to the atmosphere, with higher fluxes recorded during monsoon which is influenced by stronger winds as compared to non-monsoon periods. The sea-air fluxes of CO2 from the estuary ranges between 4.19 – 8.85 mM C m-2d-1 (Av. F = 6.52 mM C m-2 d-1) which is found to be lower than that of the mean CO2 fluxes from the Indian estuaries (27 mM C m-2 d-1) , which is even lower than that of polluted European estuaries (Av. F= 170 mM C m-2d-1) suggesting lower flushing time of water in the estuary which provides lesser time for the microbial degradation of the supplied organic matter.

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INDIAN OCEAN VARIABILITY & INDIAN MONSOON

SESSION - 02

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ROLE OF NINGALOO NINO/NINA IN ALTERING THE BIOLOGICAL ACTIVITY IN SOUTHERN SUB TROPICAL INDIAN OCEAN

Sandeep.N1, K. Ashok1,2, Swapna.P1*, Aparna.K1 1Centre for Climate change Research (CCCR), IITM, Pune; [email protected]

2University of Hyderabad, Hyderabad, India

Using both Observations and Long Term Simulation of an ocean-biogeochemical coupled model, we investigate the biogeochemical response of both Ningaloo Nino (Nina) events, a climate mode associated with positive (negative) sea surface temperature (SST) anomalies off the west coast of Australia in southern subtropical Indian Ocean. This recently identified phenomenon effects precipitation over the western coast of Australia and thus the agriculture. The interannual variability of this phenomenon effects the productivity in this area. This paper provides an insight over the fluctuations in the productivity(using chlorophyll as proxy) during Ningaloo Nino (Nina). Our Model is able to reasonably simulate the characteristics of the biological variables in a way comparable to observations. During the developing period of Ningaloo Nino (Nina), an anomalous low (high) chlorophyll appears near the South West Australian Coast occuring concurrently with high (low) SST. The difference in the spatiotemporal response of chlorophyll for the two events is due to the southward advection of the meridional upper ocean current (Leeuwin current), which plays a major role in productivity along the Australian Coast.

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OSICON-15 22-24 March 2015


48

ROLE OF INDIAN OCEAN SST IN MODULATING ONSET AND PROGRESSION OF ISM IN THE SUCCESSIVE YEARS OF 2013 AND 2014

Ramesh Kumar Yadav* and Bhupendra Bahadur Singh

Indian Institute of Tropical Meteorology, Pashan, Pune; E-mail: [email protected]

It is well known that the Indian summer monsoons of 2013 and 2014 had contrasting onset and progression phases. The onset was timely and the progression of 2013 monsoon was the fastest in the last 70 years, whereas 2014 had a delayed onset and a very lethargic progression phase compared to 2013. The monthly rainfall of June, in 2013 being +34% whereas in 2014 it was -43% of its long-period average. In this study, we observed that the tropical Indian Ocean was much warmer and the warm-pool of Indonesia was much cooler in 2014 than in 2013 in the month of May, a month ahead of the commencement of ISM. The sub-tropical westerly jet (STJ) over south Indian Ocean was much stronger in 2013 than in 2014. The warm (cool) SST anomaly over warm-pool region had caused the positive (negative) 200-hPa geopotential anomaly over tropical Indian Ocean in the year 2013 (2014) which has strengthened (weakened) the STJ over south Indian Ocean due to the consequence of thermal wind balance. This created positive (negative) pressure anomaly over Mascarene High and hence early (delayed) onset and fast (lethargic) progression of ISM in the year 2013 (2014).

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OBSERVATIONAL EVIDENCE OF MIXED ROSSBY GRAVITY WAVES AT THE CENTRAL EQUATORIAL INDIAN OCEAN

P.M. Muraleedharan¹*, S. Prasanna Kumar¹, K. Mohanakumar2, S. Sijikumar3, K.U.Sivakumar¹, Teesha Mathew¹

¹CSIR-National Institute of Oceanography, Goa; [email protected] 2Department of Atmospheric Sciences, Cochin University of Science and Technology, Kochi, India

3Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India

Six hourly soundings (GPS sonde) were carried out at the central equatorial Indian Ocean (80º–83º E) during 25th September to 10th October 2011 under the CINDY2011 (Cooperative Indian Ocean Experiment on Intra-seasonal variability in Year 2011) field campaign. One degree interval soundings were also taken along a meridional section at 83º E from 5º N to 5º S during 12 - 20 October 2011 to supplement the time series data. Relative humidity (RH) and meridional wind component exhibit downward propagation of air mass in bands of high and low RH associated with northerly and southerly winds respectively. Low (20-100 day) and high (2-10 day) frequency band pass filtered OLR data (NOAA interpolated OLR) revealed the presence of Madden and Julian Oscillation (MJO) with 20-40 day periodicity, and weak mixed Rossby Gravity (MRG) waves with 4-5 day periodicity. Eastward (westward) propagating MJO (MRG wave) with wave numbers 3 – 4 (4 – 5), amplitudes of anomaly 1.1 to 1.2 Wm-2 (1.8 Wm-2) were observed. The asymmetric bifurcation of warm surface water by the subsurface cold water off Sumatra generate asymmetric convective regimes in the vicinity of the equator probably triggered convection with periodicity similar to MRG waves. The intermittent surface convection associated is believed to be responsible for the ascending moisture to the middle troposphere prior to the initiation of MJO. The moisture pumped to the middle troposphere makes the layer convectively more unstable leading to the state of deep convection, a situation conducive for the MJO initiation processes.

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PRECIPITATION EXTREMES DURING SOUTHWEST MONSOON AND ITS CONNECTION WITH INDIAN OCEAN DIPOLE

J.V. Revadekar1*, H. Varikoden1

1Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune ; [email protected]

The Indian Summer Monsoon rainfall (ISMR) has a profound impact on India’s socio-economic growth. It occurs over the Indian region for four months from June to September (JJAS). It significantly varies temporally and spatially over the region. Indian Summer Monsoon is a fully coupled land–atmosphere-ocean system and it is linked with the ocean variability. It is well known that the interannual variability (IAV) of ISMR is linked with El Nino-Southern Oscillation (ENSO). Past studies also identified influence of the IOD which is occurring in the tropical Indian Ocean on the IAV of the ISMR. However it is less known about their impact on regional precipitation extremes.

In view of the above, regional features of summer monsoon rainfall extremes are explored statistically in relation to IOD and ENSO. During positive IOD, increase in heavy precipitation extremes is found over Indian region. Decrease in frequency of precipitation extremes is found in negative phase and during increase in SSTs over Nino region.

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TROPICAL INDIAN OCEAN SIMULATION USING NEMO-AGRIF

Umesh Kumar Singh1*, Suneet Dwivedi2, Lokesh Kumar Pandey2 1K Banerjee Centre of Atmospheric and Ocean Studies, University of Allahabad, Allahabad;

[email protected] 2M N Saha Centre of Space Studies, University of Allahabad, Allahabad, UP 211002, INDIA

An ocean circulation model NEMO is customized to run globally with the sea-ice package at a horizontal resolution of 1 degree (362 x 292 grids) and with a nested (refined) version over tropical Indian Ocean [15°S-25°N; 65°E-100°E] with a horizontal eddy-permitting resolution of 1/4 degree (152 x 292 grids). The refinement is made using the AGRIF (Adaptive Grid Refinement In Fortran) two-way grid-nesting tool. Both the versions are integrated simultaneously with the previous one providing the boundary conditions for the later. The model uses the tripolar ORCA grid and involves hydrostatic and Boussinesq approximations. It uses 46 levels in the vertical with highest resolution of 5 m near the surface and then slowly increasing at depth. The model is forced with Coordinated Ocean Sea-Ice Reference Experiment version 2 (CORE II) air-sea forcings, namely, 6-hourly zonal and meridional wind, humidity, radiation, air temperature, daily precipitation, and monthly runoff. The model is integrated for 14 years (1994-2007) including 2 years of spin-up run. A comparison with the observation shows that the model is able to realistically simulate the surface as well as sub-surface structure of temperature, salinity, and velocity over the tropical Indian Ocean.

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IMAPCT OF INDIAN OCEAN VARIABILTY ON INDIAN SUMMER MONSOON RAINFALL DURING RECENT YEARS

Sanjo Jose V1*, E. K. Kurien2, Athira P. Ratnakaran1, Binsiya T. K.1

1Academy of Climate Change Education and Research (ACCER), K.A.U., Thrissur; [email protected]

2Special Officer, ACCER, K.A.U, Thrissur

Indian Ocean Dipole mode (IOD) impacts, many surrounding regions of the Indian Ocean. The western pole of the IOD has importance in modulating the rainfall over northwest regions of India also in weakening the relationship between ENSO and Indian summer monsoon rainfall (ISMR). The impact of IOD on ISMR during recent years (1977-2013) has been examined in this study.

The climatological distribution of ISMR shows maxima over western side of Western Ghats. There is also a considerable rainfall of about 17mm/day seen over north-eastern regions of India. The year to year variation of normalized monsoon rainfall anomalies and IOD Mode Index (IODMI) during June, July, August and September (JJAS) shows that the positive IOD years 1961, 1963, 1967, 1976, 1983, 1994, and 2007 are associated with surplus rainfall. The correlation between normalized IODMI and rainfall anomalies is negative during the two decades before 1990s and there is a positive correlation seen during two decades after 1990s.

The seasonal characteristics of climatological mean variables (SST, wind, and rainfall) were examined for January, May, July and October over southern Asia. The surface wind changes its direction and precipitation zone shifts with the corresponding changes in the warm SST region. This seasonal movement of these climatological variables has a significant impact on the IOD mode variability.

The spatial correlation of the IODMI and ISMR anomalies indicates that the IODMI positively influences the ISMR over the plains of monsoon trough region and also over some parts of the north-eastern India during the last four decades. It has a negative influence over the south-western parts of India.

Further study has been carried out to know the impact of IODMI on ISMR during the three decades (1980-1989, 1990-1999, and 2000-2009) individually. During 1980-1989, significant positive correlation shows over the plains of Bihar, West-Bengal and Orissa. The correlation is negative over North-west central India, Maharashtra and northern Karnataka. But when moving to 1990-1999 the positive correlation extends to north-west India and north-eastern India. During the last decade (2000-2009), positive correlation is seen over north-west central India and Maharashtra, but over North-eastern India, Bihar and West Bengal, there is a significant negative correlation.

References: Ashok, K. (2007), Nat Hazards, On the impacts of ENSO and Indian Ocean dipole events on sub-regional Indian summer monsoon rainfall, 42, 273-285. Krishnamurthy, V. (2003), Q. J. R. Meteorol. Soc., variability of the Indian Ocean: Relation to monsoon and ENSO, 129, pp, 1623-1646.

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POSSIBLE ROLE OF INDIAN OCEAN IN THE BIENNIAL TRANSITION OF INDIAN SUMMER MONSOON IN OBSERVATION AND CMIP5 SIMULATIONS

Prasanth A Pillai1*, A. K Sahai1 1Indian Institute of Tropical Meteorology; Pune, India; [email protected]

The biennial oscillation is a prominent component of interannual variation in the Indian summer monsoon (ISM). This biennial variability forms the part of tropospheric biennial oscillation (TBO) which includes both ISM and Australian summer monsoon (ASM) along with air-sea interaction over the tropical Indian and Pacific oceans. Observations indicate that the in-phase transition from ISM to ASM and out-of phase transition from ASM to ISM occurs in both the presence and absence of El Nino- Southern oscillation (ENSO) in the Pacific. The ENSO in the pacific maintains same phase through boreal summer and winter and controls the in-phase ISM to ASM transition. In absence of ENSO, the ISM leads the Indian Ocean SST anomalies and the SST anomalies can induce an in-phase ISM to ASM transition. Thus apart from ENSO, ISM-Indian Ocean interaction also can induce ISM-ASM in-phase transition. Meanwhile, the out-of- phase ASM-ISM transition in presence of ENSO will depend on the phase of ENSO. Direct ENSO forcing is important when ENSO changes its phase in boreal spring, which can cause out-of phase ASM-ISM transition. At the same time, if ENSO maintains its same phase to next summer, the air-sea interaction in the Indian Ocean plays major role on out-of phase transition. This air-sea interaction process in the Indian Ocean can contribute to biennial transition of the ISM in absence of ENS also. We have analyzed these observational evidences in century long ensemble simulations of selected coupled models from Coupled Model Inter comparison Project 5 (CMIP5). The most of the models show in phase ISM-to- ASM transition properly in presence of ENSO. At the same time the out-of phase transition from ASM-ISM is not captured by many of the models. Similarly the biennial transition in absence of ENSO is also not properly simulated by models. Thus the present study put forward possible causes for the failure of the models in capturing TBO transitions; (1) The models may be more depend on the ENSO for the inter-annual variability, (2) The long seasonal cycle of ENSO may be the reason for the absence of out-of phase ASM to ISM transition even after the successful in phase ISM-ASM transition. (3) The ISM- Indian Ocean SST interaction is not strong enough to cause biennial transition of ISM-ASM system. Thus the study underlines the need of accurate simulation of Indian Ocean along with ENSO cycle for the ISM-ASM transitions.

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ROLE OF INDIAN OCEANS IN CLIMATE OF WEST COAST OF INDIA

P.K. Murumkar1, H. Varikoden1, S.A. Ahmed2, J.V. Revadekar1*

1Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune-411008;

[email protected] 2Department of Geology, Central University of Karnataka, Gulbarga-585 311

The Western Ghats are a mountain range that runs almost parallel to the western coast of the Indian peninsula. During the summer monsoon season between June and September, the Western Ghats acts as a barrier to the moisture laden clouds. The heavy, eastward-moving rain-bearing clouds are forced to rise and in the process deposit most of their rain on the windward side. Rainfall in this region averages 3,000–4,000 mm with localised extremes. The eastern region of the Western Ghats lies in the rain shadow. Using daily station data, Revadekar et al., (2013) have shown that high altitude stations in peninsular India exhibit positive trends in surface temperature extremes.

In the tropical regions the interannual to decadal modes of climate variability are coupled ocean-atmosphere modes. In this study therefore, an attempt is made to analyse variability in temperature-rainfall over west coast and its relation with SSTs. Both summer and winter monsoon climate over west coast show link with Indian Ocean Dipole (IOD). Minimum temperature show strong link compared to maximum temperature.

References: Revadekar J.V., Hameed S., Collins D., Manton M., Sheikh M., Borgaonkar H. P., Kothawale D. R., Adnan M., Ahmed A. U., Ashraf J., Baidya S., Islam N., Jayasinghearachchi D., Manzoor N., Premalal K. H., Shreshta M.L.(2013), Impact of altitude and latitude on changes in temperature extremes over South Asia during 1971–2000, International Journal of Climatology, 33, 199-209

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NEAR-SURFACE STRATIFICATION AND SUBMESOSCALE FRONTS IN THE NORTH BAY OF BENGAL IN AUGUST-SEPTEMBER 2014

J. Sree Lekha1*, S. Shiva Prasad2, M. Ravichandran2, D. Sengupta1

1CAOS, Indian Institute of Science, Bangalore *[email protected]

2Indian National Center for Ocean Information Services (INCOIS), Hyderabad

A shallow layer of freshwater with a strong halocline underneath (Gopalakrishna 2002, Sengupta 2006) influences air-sea interaction (Sengupta 2008) and bio-geochemistry in the north Bay of Bengal. In this study, we use 1800 kilometers (Figure 1) of underway-Conductivity-Temperature-Depth (uCTD) data, collected from the ORV Sagar Nidhi during 22 August-4 September 2014, to understand the physical processes that maintain the shallow stratification. At ship speeds of 4-5 knots, the horizontal resolution is of order 1 km, and vertical resolution is 1m. These are the first observations from the Bay of Bengal with enough resolution to study submesoscale (1-20 km) salinity-dominated surface density fronts. Dynamical instability of submesoscale fronts can lead to slumping of heavier water under lighter water (Pollard and Regier 1992), i.e., fronts can enhance vertical stratification of the near-surface ocean, a process known as restratification. We identified 17 distinct submesoscale fronts along the ship track, out of which 14 fronts show a shallow mixed layer under the front (Figure 2), suggesting active restratification (Timmermans 2012). We propose that submesoscale fronts associated with pools/filaments of river and rain water maintain shallow stratification in the north Bay of Bengal. Under the Ocean Mixing and Monsoon (OMM) programme funded by MoES, we shall continue fine-scale observations to study the physics of the near-surface ocean in different seasons.

Figure 1: Ship track of cruise ORV Sagar Nidhi during 26 Aug-4 Sep 2014. Total length of track is 1800 km. Five density fronts analyzed are marked (red) with scales in kilometers.

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Figure 2: (a) Potential density (kg/m3) at 3 m depth as a funtion of distance. Front is marked (cyan) and scales are mentioned in kilometers. (b) Depth profiles of potential density to the

left (black), right of the front (blue) and under the front (red). Mixed layer depth (MLD) is marked in green dots. (c) Depth-sections of potential density as a function of along track

distance with density contours and MLD (white line). Contour interval is 0.1 kg/m3. Location of profiles marked in thick black, red and blue lines on the top. (d) Depth-sections of Brunt Vaisala frequency (N2; rad/s2) as a function of along track distance with density contours

and MLD (white line). Contour interval is 0.1 kg/m3.

References: Gopalakrishna, V. V., et al. "Upper ocean stratification and circulation in the northern Bay of Bengal during southwest monsoon of 1991." Continental shelf research 22.5 (2002): 791-802. Pollard, R. T., and L. A. Regier. "Vorticity and vertical circulation at an ocean front." Journal of Physical Oceanography 22.6 (1992): 609-625. Sengupta, Debasis, Bharath Raj Goddalehundi, and D. S. Anitha. "Cyclone‐induced mixing does not cool SST in the post‐monsoon North Bay of Bengal." Atmospheric Science Letters 9.1 (2008): 1-6. Sengupta, Debasis, G. N. Bharath Raj, and S. S. C. Shenoi. "Surface freshwater from Bay of Bengal runoff and Indonesian throughflow in the tropical Indian Ocean." Geophysical research letters 33.22 (2006). Timmermans, Mary-Louise, and Peter Winsor. "Scales of horizontal density structure in the Chukchi Sea surface layer." Continental Shelf Research 52 (2013): 39-45.

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INFLUENCE OF INDO-PACIFIC SEA SURFACE TEMPERATURE ON THE PRECIPITATION OVER NORTHWEST HIMALAYAS

V. M. Shakuntala1, J. V. Revadekar1, S. A. Ahmed2 and H. Varikoden1*

1Indian Institute of Tropical Meteorology, Pashan, Pune-08; *[email protected]

2Department of Geology, Central University of Karnataka, Gulbarga, Karnataka 585 311, India

Rainfall over the north-western Himalayas is vitally important due to recent unpredictable flash floods and other kind of extreme events. Climate change, its vagaries and short-lived extreme events are mainly controlled by regional topography and other mode of large scale circulation patterns. Using the rainfall and Sea Surface Temperature (SST) data, we tried to explore the influence of Indo-Pacific SSTs on rainfall over northwest Himalayas. The rainfall over the northwest Himalaya is not coherent spatially with other parts of Indian region. Therefore, the rainfall itself is unique in nature with extreme rainfall events. In recent decades the region experienced frequent floods during southwest monsoon period. From the correlation analysis, it is found that the rainfall is positively correlated with Indo-Pacific SST. The correlation coefficients are significant at 0.01% level over the northwest Pacific region; however, it is significant at 10% level over east equatorial Indian Ocean. It is also imperative to understand the mechanism of floods over the region and its relevance with the Indo-Pacific SSTs.

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CLIMATOLOGICAL VARIATION OF CIRCULATION FEATURES OF THE NORTH INDIAN OCEAN AND ITS INTERANNUAL VARIABILITY FROM TOPEX/POSIDEN

ALTIMETRY

R. Sen1*, A. Chakraborty2

1 Centre for Oceans, Rivers, Atmosphere and Land Sciences, Indian Institute of Technology Kharagpur, West

Bengal; [email protected] 2Centre for Oceans, Rivers, Atmosphere and Land Sciences, Indian Institute of Technology Kharagpur,

West Bengal

The north Indian Ocean (NIO) can be divided roughly into three major areas based on the circulation features and other meteorological characteristics: the equatorial belt stretching between 10 N and 10 S, with the Somalia basin on its western end; the Bay of Bengal (BOB); and, the Arabian Sea (AS). It is unique for the semiannual reversal of the monsoon winds and due to twice changes of the monsoon winds, there are semiannual reversal of upper ocean circulation of the NIO. The occurrence of the South-West Monsoon (SWM) and the North-East Monsoon (NEM) over the ocean implies that the winds are strongly seasonal and these variations are of large amplitude. Due to this variation of winds different surface circulations are observed over NIO. Many works have been done individually on the AS and on the BOB. Decade back a review work on the NIO currents was reported but that is limited to large scale structure. Main aim of this paper work is to provide a comprehensive review work on the NIO currents along with mesoscale eddies and gyres for different months of the year. The seasonal geostrophic circulation patterns are shown using Sea Surface Height Anomaly (SSHA) (January 1995 to December 2005) climatology and Ocean Surface Current Analysis-Real time (OSCAR) climatology data (January 1993 to December 2013) to reveal the monthly surface circulation pattern in the ocean. These two climatological datasets are combined product of 11 and 21 years mean respectively. Finally, the pictorial representations based on literature review and OSCAR currents of NIO surface circulation associated with eddies and gyres are also shown. These will help the new generation NIO modellers to validate their results and will be a comprehensive base for feature modelling of this region. Interannual variation of eddy activities indicates that El Niño may have an important impact on eddy genesis and these have been shown using SSHA datasets (October 1992- December 2010). Seasonal and monthly surface circulations of NIO using SSHA (maps of sea level anomalies /MSLA) and OSCAR climatology datasets capture the surface currents of NIO such as East India Coastal Current (EICC), Western Boundary Current (WBC), Summer Monsoon Current (SMC), Winter Monsoon Current (WMC), West India Coastal Current (WICC), Somali Current (SC) and Wyrtki Jet (WJ) although the duration of existence of such currents slightly differ from the previous literature. The interannual variability of NIO surface circulation by Empirical Orthogonal Function (EOF) analysis shows many oceanic events and its link with El-Nino Southern Oscillation (ENSO).

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Figure 1: Monthly means of ocean surface current (ms-1) from OSCAR for June. Colour

shading shows the magnitudes while the arrows show the directions.

Figure 2: First interannual EOF of the NIO surface circulation variability. (a) Spatial

structure of the first interannual EOF and (b) Amplitude time series of the first interannual

EOF.

References Shankar, D., P.N. Vinayachandran, A.S. Unnikrishnan. 2002. The monsoon currents in the north Indian Ocean. Progress in Oceanography, 52, 63–120. Shetye, S. R., I. Suresh, D. Shankar, D. Sundar, S. Jayakumar, P. Mehra, R. G. Prabhudesai, and P. S. Pednekar, 2008. Observational evidence for remote forcing of the West India coastal current. Journal of Geophysical Research 113, C1100, doi:10.1029/2008JC004874. Sil. S., and Arun Chakraborty, M. Ravichandran. 2010. Numerical Simulation of Surface Circulation Features over the Bay of Bengal using Regional Ocean Modeling System. Advances in Geosciences, Vol. 24, 117-128. Sil, S., and Arun Chakraborty. 2011. Simulation of East India Coastal Features and Validation with Satellite Altimetry and Drifter Climatology. Ocean and Climate Systems, Vol. 2, No. 4, 279-289.

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RETRIEVING OF TEMPERATURE AND SALINITY OF THE INTERIOR OCEAN FROM HIGH RESOLUTION SATELLITE SEA SURFACE TEMPERATURE

D. Sarkar1*, A. Chakraborty2, Raj Kumar3, Rashmi Sharma3 1Centre for Oceans, Rivers, Atmosphere and Land Sciences, Indian Institute of Technology Kharagpur;

[email protected] 2Centre for Oceans, Rivers, Atmosphere and Land Sciences, Indian Institute of Technology Kharagpur;

[email protected] 3Atmosphere and ocean sciences group, EPSA, Space Application Centre, Ahmedabad

Temperature and Salinity are key parameters for the forecast of ocean states. Accurate forecast of ocean state using numerical model requires accurate initial T-S profiles of the ocean. Model generally uses climatic T-S profiles as back ground. Model is integrated for certain time to attain quasi-equilibrium state from which initial condition is used for forecast simulation. The model internal variability moves the forecast initial condition from accuracy. In this study an algorithm is being developed to fill up the above gap. A methodology is being presented to generate the 3-D structure of temperature and salinity fields using high resolution satellite derived sea surface temperature. In the steady state case, the heat equation in the thermocline and deep zones is the balanced of vertical advection with vertical diffusion as the other terms are being small with comparison. The convergence and divergence in the mixed layer lead to circulations in the deeper water. For a short time scales, the vertical transfer dominate and horizontal advection and diffusion may be neglected (Pond and Pickard, 1983). Combining steady state heat equation (Pond and Pickard, 1983) for thermocline and deep zones and steady state temperature equation (Pond and Pickard, 1983) for mixed layer, a structure function ( ) can be defined as,

HzforyxTyxT

yxTzyxTzyx

bs

b

0

),(),(

),(),,(),,( .Using structure function we reconstructed

the three dimensional temperature (T) structure in the reverse process with Sea Surface

Temperature input as, HzforyxTzyxyxTyxTzyxT bbs 0),(),,(),(),(),,( . The

salinity structure is determined by using the structure of conductivity ratio ( CNDRR ) following

Fofonov and Millard (1983) as, )0,15,35(

),,(C

pTSCrRRR TTpCNDR . This can be

useful to generate synoptic initial condition which is required for short term Regional Ocean model forecasting. It has been validated using October 2008 TMI Satellite pass as well as ARGO floats over Bay of Bengal. The root mean square error is very less in both at the surface and greater depth. The salinity profiles are in good agreement with ARGO profiles in conductivity approach calculation compared to TS-diagram approach.

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Fig.1. Vertical profile of Structure function (φ) over Bay of Bengal (75°E to 100°E, 0°N to

20°N) for January.

Fig.2. Vertical profile of Root Mean Square Error of temperature over Bay of Bengal (75°E to 100°E, 0°N to 20°N) for January,

2008.

Fig. 3. vertical structure of temperature using structure function over Bay of Bengal for the month of January to June, 2008 at 88°E and 0°N to 20°N.

References: Boyer, T. P., S. Levitus, H. E. Garcia, R. A. Locarnini, C. Stephens, and J. I. Antonov, 2005: Objective analyses of annual, seasonal and monthly temperature and salinity for the World Ocean on a 0.25°grid. Int.J. Climatol., 25, 931-945. Carolina, N., 2009: NAO impact on Gulf of Maine Circulations during 1995. M.Tech thesis, School of Marine Science and Technology, University of Massachusetts, Dartmouth, USA. C. Maes and D. Behringer, 2000: Using satellite-derived sea level and temperature profiles for determining the salinity variability: A new approach. J. Geophys, Res., vol. 105, no. C4, pp 8537-8547. C. Maes, 1999: A note on the vertical scales of temperature and salinity and their signature in dynamic height in the western Pacific Ocean: Implications for data assimilation. J. Geophys. Res., vol. 104, no. C5, pp. 11037-11048.

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SUBSURFACE TEMPERATURE BIAS IN THE EQUATORIAL INDIAN OCEAN IN NCEP CLIMATE FORECASTING SYSTEM

G. Srinivas*, J. S. Chowdary, Rashmi Kakatkar, Anant Parekh and C. Gnanaseelan

Indian Institute of Tropical Meteorology, Pune-411008; [email protected]

Abstract

This study examine the factors responsible for equatorial Indian Ocean subsurface temperature biases in National Centers for Environmental Prediction Climate Forecasting System version 2 (CFSv2). CFSv2 is a fully coupled ocean-atmosphere-land model with advanced physics and increased resolution. The model is integrated over a period of 100 years, and used the climatology of last 60 years for the present study. It is noted that the model displays strongest Sea Surface Temperature bias (SST) cold bias (~2°C) in the Tropical Indian Ocean (TIO) during boreal spring and fall seasons. Whereas subsurface temperature near Thermocline depth is warmer throughout the year with maximum bias during summer and fall seasons. In particular, subsurface bias around 100m depth is stronger in the western equatorial Indian Ocean, which is mainly due to misrepresentation of equatorial currents in the model. Equatorial surface and subsurface current bias in CFSv2 is mainly due to the unrealistic representation of winds over the TIO. Therefore in order to improve the vertical thermal structure of TIO in CFSv2, it is essential to reduce the biases in surface wind forcing and improve the vertical mixing processes.

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A REVIEW OF LATE HOLOCENE CLIMATE CHANGE FROM WESTERN INDIA: HUNTING ARCHIVES FOR RECONSTRUCTING HIGH RESOLUTION CLIMATE

DYNAMICS

Nisarg Makwana1*, S.P. Prizomwala1, N.P. Bhatt2, B.K. Rastogi1 1Institute of Seismological Research, Raisan, Gandhinagar 382009; [email protected]

2Department of Geology, The M. S. University of Baroda, Vadodara 390002

Indian Summer Monsoon (ISM) is considered as chief governing factor for climate variability in the Indian subcontinent. The ISM variability during the Holocene period has been topic of research since long and hence now there exist a fairly good understanding at millennial to centennial scale variations. However there is a vital need to reconstruct the climatic variability at multi-decadal scale. The climatic variability during the Late Holocene period (i.e. Last 4ka) has been reported by few suggesting a dry climate during 3.5 to 4 ka, followed by fluctuating strength of ISM during 3.5 to 2 ka. The strength of ISM increased during 2ka to 1.5 ka followed by a short dry spell and again increase in strength from 1ka to 0.6ka. Few studies have even documented the dry spell at 0.2 ka correlating with the Little Ice Age. However there is a need to explore more archives which would help in reconstructing high resolution multidecadal climatic variability of ISM. This is of vital importance as this period coincides with the collapse of the neighbouring Indus Valley civilization.

Gujarat region in western India, experiences semi-arid to arid climatic regime with 90% precipitation derived from the ISM. The mighty Great and Little Rann of Kachchh has not been studied for palaeoclimatic reconstruction but is considered to be a depocenter since Holocene period. Similarly mudflats of Gulf of Kachchh and Gulf of Khambhat show a monotonous geomorphology and dominant depositional processes compared to erosional pattern. The sediments to these archives are derived from hinterland rivers, where semi-arid climate prevails with characteristic episodic discharge. This makes them sensitive to abrupt climatic fluctuations. The processes acting in these environments hint them to be robust archives for reconstructing palaeoclimatic fluctuations. Preliminary chronological constraints suggest the mudflats of Gulf of Kachchh and Great Rann of Kachchh have a high sedimentation rate (> 2mm/a) and hence may serve as robust archives to reconstruct high resolution climatic fluctuations during the Late Holocene period.

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NUDGING OF THERMODYNAMIC PROFILES: IMPACT ON REPRESENTATION OF INDIAN SUMMER MONSOON

Raju Attada, Anant Parekh*, C. Gnanaseelan and J. S. Chowdary

Indian Institute of Tropical Meteorology, Pune 411 008; [email protected]

The study examines the impact of assimilation of thermodynamic soundings from AIRS satellite on simulation of Indian summer monsoon (ISM). Two experiments are carried out for the period of 2003 to 2011, the first one (CTRL) is forced with the NCEP FNL while the second one is same as first one but AIRS retrieved temperature profiles (TQEXP) are assimilated throughout the model integration using nudging technique. Assimilation of these profiles shows significant improvement in the simulation of ISM as follows. (1) The strength and location of circulation elements are improved. (2) Unrealistic double ITCZ like rainfall pattern disappeared. (3) The meridional distribution of pressure, temperature, moisture field, MSE and wind shear have improved. (4) Vertical structure of moisture, vorticity, divergence and vertical velocities also improved.

Assimilation of satellite retrieved temperature and water vapour profiles could significantly improve the moist physical process over MT region associates with ISM. TQEXP showed improved spatial distribution of precipitation and improved statistical skills scores over the land regions compared to CTRL. The assimilation of temperature and moisture profiles data improves the thermodynamic structure and it influences the moisture convergence and the associated spatial distribution of precipitation patterns through dynamic interaction of deep convection with the boundary layer. It indicates that assimilation of temperature and water vapour complements each other in a consistent way. Finally, the assimilation is performed throughout the entire simulation, showing how the proposed approach can be used to improve meteorological analyses in terms of moist convection and rainfall associated to ISM. On the other hand, there are few some zones where the assimilation performs poorly with respect to the precipitation simulation. This strongly advocates the need of improvements in the parameterized physics and the dynamical core of the model.

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INTERCOMPARISON OF NIOT WAVE BUOY DATA WITH DATAWELL WAVERIDER BUOY

J. Vimala1*, K. Ramesh2, G. Latha2 and R. Venkatesan2 1Research Scholar, Sathyabama University, Chennai; [email protected]

2National Institute of Ocean Technology, Chennai

Under the moored buoy programs of National Institute of Ocean Technology (NIOT), ocean wave measurements are made. In order to compare the wave parameters derived from these measurements using Motion Reference Unit (MRU) sensor, another datawell waverider (DW) buoy has been acquired and both the buoys were deployed off Agatti within a spacing of 1.4 nm. The work carried out on inter comparison of wave parameters such as significant wave height, zero crossing wave period, peak period and wave spectrum for the period from April 2011 to November 2011. The comparison of the time series wave parameter obtained from both buoys shows good agreement. The correlation coefficient of the significant wave height, peak period and zero crossing wave periods are 0.87, 0.69 and 0.65 respectively. The trend in the variation of wave spectrum matches well for both buoys with datawell waverider buoy measure higher wave energy. The major reason could be the different locations of observation and the measurement interval.

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SOIL MOISTURE DURING SOUTHWEST MONSOON PERIOD AND ITS RELATION WITH INDIAN OCEAN SEA SURFACE TEMPERATURE

H. Varikoden1*and J. V. Revadekar1, 1Indian Institute of Tropical Meteorology, Pashan, Pune-08; [email protected]

Soil moisture plays an important role in global and regional scale climate systems by modulating the surface albedo and on the partitioning between sensible and latent heat fluxes. Many global and regional climate modeling studies have stated the importance of the initialisation of the soil moisture in their simulations of regional hydrological distribution. Soil moisture is considered as one of the important parameter in the prediction of hydrological parameters during the southwest monsoon season. However, it is not in common use due to its inconvenience in measurement. Very recently satellite soil moisture data is made available from 1979 onwards with high spatial resolution. Using these satellite based measurement, we have tried to understand the role of soil moisture and sea surface temperature on rainfall. On seasonal scale, the spatial pattern of soil moisture and rainfall are not similar, however, the annual cycle follows the unimodal variation. Sea surface temperature over the Bay of Bengal show negative correlation with the central Indian soil moisture even though the rainfall over this region is higher. This may be due to the topographic influence and presence of large river basins. This needs to be studied in detail.

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RESPONSE OF BAY OF BENGAL TO CYCLONE PHAILIN FROM MOORED AND SATELLITE DATA

Chaudhuri. D1*, Vekatesan. R2, Ravichandran. M3, Sengupta. D4

1CAOS, Indian Institute of Science, Bangalore; [email protected]

2National Institute of Ocean Technology (NIOT), Velachery–Tambaram Main Road, Pallikaranai, Chennai

3Indian National Center for Ocean Information Services (INCOIS), Hyderabad

4CAOS, Indian Institute of Science, Bangalore

Cyclone Phailin is the second-strongest tropical cyclone ever to make landfall in India (IMD 2013, Venkatesan 2013). Phailin matured over the Bay of Bengal (BoB) during 9-14 October 2013. The response of the upper-ocean to Phailin is analyzed with the help of in situ observations from an NIOT mooring BD10 and Argo float 2901335 directly under the storm; and NIOT moorings BD08, BD09 and an INCOIS mooring near 18°N, about 200 km to the right of the storm track. We also use satellite observations: Aquarius Sea Surface Salinity (SSS) and TMI/AMSRE Sea Surface Temperature (SST). Our main findings are that (i) As expected for post monsoon cyclones in the north Bay of Bengal (Sengupta 2008), SST cooling is small (≈ 0.2ºC). (ii) Post-storm SSS increases by 1.6 psu at the three moorings near 18°N (Figure 1); the change in Aquarius SSS agrees with the moored observations. SSS increases by 2-4 psu close to the storm track, due to storm induced vertical mixing to at least 50m depth. (iii) SSS increases throughout the western Bay (Figure 2) after the passage of the storm. (iv) The largest-amplitude inertial currents (0.5 m/s) are observed directly under the cyclone. (v) Velocity observations from an Acoustic Doppler Current Profiler (ADCP) on mooring BD09 suggest that shear-induced mixing (D'Asaro 2014) deepens the mixed layer from pre-storm values of less than 10m to about 50 m after the storm. (vi) Estimates of energy input from wind stress indicate that about 60 percent of the energy goes into increased potential energy of the water column due to vertical mixing.

Figure 1: Hourly a) Wind stress b) c) d) time series of salinity from three moorings at different depths.

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Figure 2: Post (16-21 October 2013) minus Pre- (3-8 October2013), a) TMI/AMSRE Sea Surface Temperature (0.25º daily), b) Aquarius Sea Surface Salinity (1º daily).

References: D'Asaro, E. A., Black P. G., Centurioni, L. R., Chang, Y. T., Chen, S. S., Foster, R. C., Graber, H. C., Harr, P., Hormann, V., Lien, R. C., Lin, I. I., Sanford, T. B., Tang, T. Y., and Wu, C. C., Impact of typhoons on the ocean in the pacific. Bull. Amer. Meteor. Soc.,2014, 95, 1405–1418. IMD, 2013. Very severe cyclonic storm. Phailin over the Bay of Bengal (8–14 October 2013): a report India Meteorological Department, New Delhi, p. 43, (2013). Sengupta, D., Bharath Raj, G. and Anitha, D. S., Cyclone-induced mixing does not cool SST in the post-monsoon north Bay of Bengal. Atmos. Sci. Lett., 2008, 9, 1–6. Venkatesan, R., Simi Mathew, J. Vimala, G. Latha, M. Arul Muthiah, S. Ramasundaram, R. Sundar, R. Lavanya, and M. A. Atmanand. "Signatures of very severe cyclonic storm Phailin in met–ocean parameters observed by moored buoy network in the Bay of Bengal", Current Science, 2014, 107(4), 589.

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69

INDIAN SUMMER MONSOON AND THE OCEAN HEAT BUDGET SIMULATED IN CFSV2 MODEL

Gibies George1*, D. Nagarjuna Rao1, C.T. Sabeerali1, A. Suryachandra Rao1

1Indian Institute of Tropical Meteorology, Pune; [email protected]

As a result of cold SST bias in the tropical Indian Ocean, the seasonal mean rainfall over the Indian landmass is underestimated in the CFSv2 hindcast run. Simulated weak monsoon results in simulating westerly wind core associated with AISMR located along the equator while in observation there is clear cross equatorial flow. This is because the tropospheric temperature gradient in CFSv2 hindcast run is not strong enough to drive the cross equatorial flow. Analysis have clearly highlighted that the prediction skill of All India Summer Monsoon Rainfall (AISMR) in CFSv2 is basically coming from the ENSO-monsoon relationship in the model and it is reasonably captured. Further, it is noticed that the cold SST bias in the tropical Indian Ocean is to be minimized to improve the magnitude of the AISMR simulation whereas the correct representation of Indian Ocean coupled dynamics is essential to improve the AISMR prediction skill. Therefore, this study highlights the need to improve the Indian Ocean coupled dynamics in CFSv2 for the further improvement of simulation and prediction skill of AISMR.

The model simulate major precipitation zones reasonably well except that there is underestimation of land rainfall and overestimation of ocean rainfall. The model simulate enhanced precipitation over Konkan coast of Arabian Sea, Myanmar coast of Bay of Bengal, Foot hills of Himalaya, Indonesian coast in the eastern equatorial Indian Ocean, Philippine coast and the western Pacific. The model underestimate the precipitation over land region especially northwest India, Pakistan, Srilanka and South America. Strong dry bias is observed in Indian land region and South America, while there is strong wet bias over tropical Indian Ocean and western Pacific. These biases are also noticed in many of the CMIP models (Sabeerali et al., 2013). Saha et al. (2012a) have studied the relation between Indian Land Dry Bias and Eurasian Snow Cover. The surface fluxes during JJAS try to warm northern Indian Ocean and cool southern Tropical Indian Ocean. But this is balanced by the horizontal transport of warm water. In CFSv2 overestimation of the southward heat transport from Arabian Sea, and underestimated surface fluxes results cold bias over Arabian Sea. On the other hand underestimated westward heat transport from Indonasian region and overestimated surface fluxes results in cold bias over southern tropical Indian Ocean.

References: C. T. Sabeerali, A. Ramu Dandi, Ashish Dhakate, Kiran Salunke, S. Mahapatra, and A. Suryachandra Rao. Simulation of boreal summer intraseasonal oscillations in the latest CMIP5 coupled GCMs. J. Geophys. Res. Atmos., 118(10):4401–4420, May 2013. ISSN 2169897X. doi: 10.1002/jgrd.50403. Subodh K. Saha, Samir Pokhrel, and Hemantkumar S. Chaudhari. Influence of Eurasian snow on Indian summer monsoon in NCEP CFSv2 freerun. Clim. Dyn., 41(7-8):1801–1815, December 2012a. ISSN 0930-7575. doi: 10.1007/s00382-012-1617-4.

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Suranjana Saha, Shrinivas Moorthi, Xingren Wu, and Jiande Jun Wang. The NCEP climate forecast system version 2. J. Clim., 2:1–61, 2012b. Zuojun Yu, Julian P. McCreary, Max Yaremchuk, and Ryo Furue. Subsurface Salinity Balance in the South China Sea. J. Phys. Oceanogr., 38(2):527–539, February 2008. ISSN 0022-3670. doi: 10.1175/2007JPO3661.1.

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71

PREDICTION AND ERROR GROWTH IN THE DAILY FORECAST OF PRECIPITATION FROM THE NCEP CFSV2 OVER THE SUBDIVISIONS OF INDIAN

CONTINENT

Shailendra Rai1, *, Dhruva Kumar Pandey1, A. K. Sahai2 and S. Abhilash2 1K. Banerjee Centre of Atmospheric and Ocean Studies, University of Allahabad; [email protected]

2Indian Institute of Tropical Meteorology, Dr. Homi Bhabha Road, Pashan, Pune.

The understanding in the peculiarity of the Indian summer monsoon and its accurate prediction is still a challenge for the scientific community involved in the process. In the present study we have used Climate Forecast System version 2 (CFSv2) of National Centre of Environmental Prediction (NCEP). The CFSv2 is a fully coupled general circulation model used in seasonal forecasting (Saha et al. 2010). Recently, CFSv2 has been extensively used by India for operational long range prediction under ‘National Monsoon Mission’ (NMM) (Abhilash et al. 2013) and reliable prediction was obtained (Sharmila et al. 2013).

The main focus of the previous studies are related to summer monsoon rainfall over the entire India as a whole and very few studies are related with the predictability studies over sub-divisional level. However, the accurate and timely prediction at sub-divisional level is also important keeping in mind the needs in terms of agriculture, power etc. of the population living in these regions. The main goal of the present study is to investigate the forecast skill and predictability of the south Asian monsoon in CFSv2 on daily time scale for the whole Indian region and the different regions of the Indian subcontinent.

In the present work, we have used the CFSv2 model runs with the initial conditions on 31st May, 30th June, 30th July, 29th August and 28th September during 2001-2013 having 11 ensemble members and each run gives forecast for 45 days (Abhilash et al. 2013). We will denote the forecast initialized on 31st May, 30th June, 30th July, 29th August and 28th September as June, July, August, September and October forecast respectively.

It has been observed that the daily mean climatology of precipitation over the land points of India is underestimated in model forecast as compared to observation. The monthly model bias of precipitation shows the dry bias over the land points of India and also over the Bay of Bengal, whereas the Himalayan and Arabian Sea regions show the wet bias. We have divided the Indian landmass in five subdivisions namely Central India, Southern India, Western Ghat, North East and Indonesian region based on the spatial variation of mean observed precipitation in JJAS season. The underestimation over the land points of India during mature phase was originated from the Central India, Southern India and Western Ghat regions.

We have computed forecast error by taking the difference between the predicted value and the observed value on each calendar day of each year. Further, we calculated root mean square error (RMSE) during 2001-2013 for each ensemble member and the ensemble mean is taken. It was observed that the error growth in June forecast is slower as compared to July forecast in all the regions. We have computed predictability error of a model by taking one ensemble member as truth and taken difference of precipitation from rest of the

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ensemble members with this member. The error in the forecast is due to the uncertainty in the initial conditions and predictability error gives the upper bound of predictability of the model (Lorenz 1982). The predictability error also grows slowly in June forecast as compared to July forecast in most of the regions.

Table 1: The doubling time of errors of the NCEP CFSv2 forecast for different indices initialized on 31st May (June forecast) and 30th June (July forecast).

Regions June Forecast July Forecast

IMR (Indian Monsoon Region) 4.4 3.5

Central India 4.4 3.6

Indonesia Region 3.9 3.4

North East 3.7 3.4

Southern India 3.3 3.6

Western Ghats 3.2 3.4

We have estimated the predictability error quantitatively using the empirical formula by Lorenz (1982). The doubling time of predictability error was estimated to be in the range of 3-5 days for all the regions and is shown in table 1. It is clear from the table that the Southern India and Western Ghat are more predictable in the July forecast as compared to June forecast, whereas IMR, North East, Central India and Indonesian regions are having the opposite nature.

References: Abhilash S., Sahai A. K., Pattnaik S., Goswami B. N., Kumar A. (2013), Extended range prediction of active-break spells of Indian summer monsoon rainfall using an ensemble prediction system in NCEP climate forecast system, Int J Climatol, 34, 98-113. doi: 10.1002/joc.3668. Saha S. K., Pokhrel S., Chaudhri H. S., Dhakate A., Shewale S., Sabeerali C. T., Salunke K., Hazra A., Mahapatra S., Rao A. S. (2014), Improved simulation of Indian summer monsoon in latest NCEP climate forecast system free run. Int J Climatol 34:1628–1641. doi: 10.1002/joc.3791. Sharmila S., Pillai P. A., Joseph S., Roxy M., Krishna R. P. M., Chattopadhyay R., Abhilash S., Sahai A. K., Goswami B. N. (2013), Role of ocean– atmosphere interaction on northward propagation of Indian summer monsoon intra-seasonal oscillations (MISO), Clim. Dyn., 41, 1651–1669. doi: 10.1007/s00382-013-1854-1. Lorenz E. N. (1982) Atmospheric predictability experiments with a large numerical model. Tellus, 34, 505–513, doi: 10.1111/j.2153-3490.1982.tb01839.x.

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73

MODELING THE HYDROGRAPHY AND CIRCULATION OF THE BAY OF BENGAL USING A HIGH-RESOLUTION OCEAN CIRCULATION MODEL

Atul Srivastava1,2*, Suneet Dwivedi1,2 and Alok Kumar Mishra1,2 1M N Saha Centre of Space Studies, University of Allahabad, Allahabad, UP 211002; [email protected] 2K Banerjee Centre of Atmospheric and Ocean Studies, University of Allahabad, Allahabad, UP 211002

A limited-area high-resolution Bay of Bengal Circulation Modeling has been performed using the MITgcm in the region [80E-95E; 5N-20N] for a period of 15 years from 1998-2012 followed by a spin-up run during the years 1993-1997. The model uses the horizontal resolution of 10 km and the highest vertical resolution of 5 m. The model uses the open boundary condition on all sides and is forced with the 6-hourly NCEP reanalysis air-sea forcings, namely air temperature, relative humidity, zonal and meridional winds, downwelling shortwave and longwave radiations, precipitation and evaporation. The eddy-resolving mesoscale model results of hydrography (temperature and salinity) are compared and contrasted with ORAS4 and GODAS reanalysis data. The area averaged SST anomaly over the domain [85E-90E; 8E-16E] depicts strong monthly variability. It decreases from June to January and starts increasing from February to May. The months of January and May show minimum and maximum SST anomaly over the domain, respectively. The subsurface temperature and salinity values are also well matched with the observations. The variability of the mixed layer depth is also examined. It is found that the MLD maximum is observed during the winter season. The zonal and meridional currents are compared with the OSCAR data. The heat-flux through the region is also computed.

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USING THE TELESCOPICALLY VARYING HORIZONTAL AND VERTICAL GRIDS FOR MODELING THE INDIAN OCEAN VARIABILITY

Anupam Kumar Dixit1* and Suneet Dwivedi1,2 1K Banerjee Centre of Atmospheric and Ocean Studies, University of Allahabad, Allahabad, UP 211002;

[email protected] 2M N Saha Centre of Space Studies, University of Allahabad, Allahabad, UP 211002

Efforts are made to run an ocean circulation model, MITgcm over the Indian Ocean in the domain [45°E-130°E; 25°S-25°N]. The model uses the open boundary conditions. The bathymetry is derived from the Smith and Sandwell’s data. The air-sea forcings are extracted from the Common Ocean-ice Reference Experiments version 2 (CORE II) data. The model uses telescopic horizontal grid with maximum horizontal resolution of 10 km in the domain [65°E-95°E; 5°N-25°N] and then telescopically increasing to 100 km. Similarly, maximum horizontal resolution of 5m is taken near the surface and then gradually increased to 500m near the ocean floor. The model is spun-up for years 1984-1988. The simulation run is carried out for the years 1989-2007. The model output is compared to the GODAS data. The results indicate that the hydrography and circulation properties are very well simulated by the model over the region of study. The well known SST anomaly index, namely, the Indian Ocean Dipole (IOD) is also compared with the observation. The Bay of Bengal and Arabian Sea salinity variability is also examined on a seasonal and interannual basis. The effect of monsoon rains and runoff from Ganga, Brahmaputra, Godavari, and other neighbouring rivers is also examined in this context. The Indonesian throughflow is also computed.

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POSSIBLE INTERACTIONS BETWEEN SUBSURFACE OCEAN BIASES AND THE SURFACE INTERANNUAL VARIABILITY IN COUPLED MODELS.

Shikha Singh1*, Vinu Valsala1

1Indian Institute of Tropical Meteorology, Pune; *[email protected]

Analysis for the possible impacts of deep ocean biases on the surface variability of interannual signatures in the model is carried out. Few candidate models (CFSv2 and IITM-Earth System Model) and outputs from selected CMIP-5 models are analyzed. CFSv2 is a coupled ocean atmosphere model by NCEP and it is the core-part of the IITM-ESM. Both in CFSv2 and in IITM-ESM, when used for climate simulations of hundred-years, the models develop internal warm bias in the Indian Ocean, which is a property commonly observed in other CMIP-5 candidate models considered here as well. In CFSv2 and IITM-ESM, it is also seen that there are occurrences of Indian Ocean Dipole in the early part of the year within Jan-April, whereas in reality, IOD starts in May-June, peaks in September and decays by November-December of the year. The possible role of internal biases in the IOD is hypothesized using the relation between the Brunt-Vaisala frequency and baroclinic wave speeds (i.e. WKJB approximation). Using both WKJB approximation and the normal mode decomposition (Chelton et al., 1998), it is seen that most of the models analyzed here have a higher baroclinic speed compared to the observations. Since the wave dispersion is faster, it has a possibility to affect the planetary scale events such as IOD in terms of their life cycle, periodicity, seasonality and the duration.Further analysis based on simple ocean-atmospheric coupled models is utilized to examine the role of ocean biases in the interannual variability of the tropical oceans.

References: Chelton, D.B., de Szoeke, R.A., Schlax, M.G., El Naggar, K., Siwertz, N., 1998. Geographic variability of the first baroclinic Rossby radius of deformation. Journal of Physical Oceanography 28, 433–460.

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NORTH-SOUTH HEMISPHERIC THERMAL CONTRAST AND INDIAN SUMMER MONSOON RAINFALL VARIABILITY

Lekshmi Mudra. B1* and H. N. Singh2 1Academy of Climate Change Education & Research, Thrissur, Kerala; [email protected]

2Indian Institute of Tropical Meteorology, Pune

Rainfall variability across the country and its possible causes in the wake of changing global climatic scenario is multifold. Some extreme weather and climate events have increased in recent decades. The understanding of the science of climate changes and its impact has been an important thrust area amongst the atmospheric researchers due to its strong influence on the socio-economy. The 2.5 DSG isobaric level meteorological parameters (years 1949-2014) viz. MSLP, Surface Temperature, Sea Surface Temperature, Precipitable water, cloud cover, geopotential height at different isobaric levels, temperature a different isobaric levels, etc) downloadable from the NCEP/NCAR reanalysis have been analyzed for better understanding of the monsoon system as well as the possible causes of decreased monsoon rainfall in the wake of global warming. The characteristics of various meteorological parameters for five good monsoon years and five weak monsoon years have been analysed to understand their distinct features. The spatio-temporal variability of the composite as well as anomaly of the good and weak monsoon years for various parameters has also been analysed. Similar analysis was repeated for the five strong El-Nino and five La-Nina years. Global pattern of change in tropospheric parameters from 1949‒1978 to 1979‒2014 have been examined. The tropospheric temperature (TT: 1000-200-hPa) across the globe has been experiencing a heterogeneous increase since 1979. Compared to the period 1949–1978, the rise in the TT over different climatic zones is different. During monsoon season (JJAS: June through September), the rise in the TT over equatorial belt is 0.45°C, the north polar 0.60°C, the north subtropic +0.32°C, the south subtropic +0.77°C and the south polar region +0.66°C, higher increase in polar regions than equator. Though rising over different climatic zones, the temperature over the Southern Hemisphere is rising at a faster rate than that of the Northern Hemisphere resulting into reduction of the tropospheric temperature gradient (TTG) from Northern Hemisphere to Southern Hemisphere. The reduction in the TTG from north extratropic to south extratropic is by 0.95°C, from north temperate to south temperate 1.01°C and from Arctic to Antarctic 1.11°C. Similar pattern have also been observed for the tropospheric (1000-200-hPa) geopotential thickness. The main effects of this reduction in the north-south thermal contrast are the weakening of the general atmospheric circulation and the Asia-Pacific monsoon circulation. Consequently, the easterlies were weakened but raised the SSTs over the Niño region.

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STUDY OF INDONESIAN THROUGHFLOW USING HYBRID COORDINATE OCEAN MODEL

Vivek Kumar Pandey*, Sudhir Kumar Singh, Satyam Srivastava

K. Banerjee Centre of Atmospheric and Ocean Studies, Institute of Interdisciplinary Studies, University of Allahabad, Allahabad, UP 211002, INDIA; [email protected]

We are representing here the application of the “HYbrid Coordinate Ocean Model (HYCOM)” for the world’s most complicated geometry Indonesian Throughflow, which is isopycnal in the open, stratified ocean, but uses the layered continuity equation to make a dynamically smooth transition to a terrain-following coordinate in shallow coastal regions, and to z-level coordinates in the mixed layer and/or unstratified seas. The hybrid coordinate extends the geographic range of applicability of traditional isopycnic coordinate circulation models. HYCOM is designed to provide a major advance over the existing operational and preoperational global ocean prediction systems, since it overcomes design limitations of the present systems as well as limitations in vertical and horizontal resolution. It maintains the significant advantages of an isopycnal model in stratified regions while allowing more vertical resolution near the surface and in shallow coastal areas, hence providing a better representation of the upper ocean physics and become more streamlined system with improved performance for coastline, shallow and complicated ocean geometry of the Indo-Pacific region.

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ROLE OF UPPER OCEAN STRATIFICATION IN THE INTENSIFICATION OF THE SEVERE CYCLONE “HUDHUD”

K.Maneesha*, Y.Sadhuram and V.S.N.Murty

CSIR- National Institute of Oceanography, Regional centre, Visakhapatnam- 530017 [email protected]

The recent cyclone “Hudhud” formed on 7th October 2014 as a depression over north Andaman Sea and crossed Visakhapatnam on 12th October 2014 as a very severe cyclone. This is the first cyclone to hit Visakhapatnam after 30 years .The central pressure was 950 Hpa (drop of 54 Hpa) and the maximum wind was more than 100 knots (www.imd.gov.in).

The importance of upper ocean heat content (UOHC) and eddies in the intensification of cyclones over Bay of Bengal have been reported earlier1,2 . A threshold value of >60 kj/cm2 has been identified for the intensification of a cyclone during pre (March-May) and post monsoon (October –December) seasons over Bay of Bengal. It is found that slow (fast) moving cyclones require high (low) UOHC to intensify. In general, slow moving storm induces surface cooling and results in negative feed back from the ocean which does not favor intensification. In case of Hudhud, the UOHC along the track varied from 45-110 kj/cm 2 and the vertical wind shear is of the order of 10-20 knots (www.imd.gov.in) which is not favourable for intensification. Surprisingly, the storm reached very high intensity ( T4.0 to T5.0) from 11th to 12th October , before crossing the Visakhapatnam city. The possible explanation for the intensification is examined in this preliminary study using the Argo , in situ and model outputs prior and during the cyclone. Data on cyclone track and other details are taken from IMD website (www.imd.gov.in). The following equations are used to compute UOHC and UOHC with stratification (S) (UOHCs).

Stratification (S) is computed from the Brunt –Vaisala frequencies (Nmax & No)

√

(1)

∫ ( )

(2)

UOHCS =UOHC*S (3)

Normally , in most of the earlier studies , UOHC is computed from eq.2 which does not consider stratification while in eq.3 ., stratification (S) is considered to estimate UOHC .The climatological value of S ranges from 2 to 4 in Bay of Bengal during post monsoon season 1. Translation speeds (TS) are computed at 3 hourly interval from the track of the cyclone (www.imd.gov.in) and found to be low ( 1-3 m/sec) . Just before the cyclone, high SST (>29.5oC) and low salinities 29-31 PSU were observed in the western Bay of Bengal. This may be due to the heavy rainfall occurred during September 2014 along east coast of India. HYCOM +NCODA model out puts are also showing the high water influx along the east coast of India. Hence high values of S ( >4 ,higher than the climatological value) were observed in the western Bay of Bengal which caused a high value of UOHCs ( >300 KJ/cm2 ), double to the climatological value (120 KJ/cm2 ) . This high UOHCs opposes the surface cooling

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induced by the storm and helps in the intensification by supplying the enthalpy flux which was also found to be higher ( 180-280 w/m2 ), double the climatological values.

From this preliminary study, it is inferred that the upper ocean stratification off Visakhapatnam might have helped in the intensification of the cyclone “ Hudhud”even though the vertical wind shear (10-20 knots) is not favourable.

References: Maneesha, K., 2012: Role of upper ocean in the intensification and movement of tropical cyclones and their associated biogeochemical response in the Bay of Bengal., Ph.D., Thesis, submitted to Andhra University, Visakhapatnam Sadhuram, Y., Maneesha, K., and Ramana Murty, T.V., 2012: Intensification of Aila (2009) due to a warm core eddy in the north Bay of Bengal, Nat. Hazards., 63, 1515-25

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SEASONAL CHANGE IN THE TROPICAL CYCLONE CHARACTERISTICS BETWEEN PRE- AND POST-MONSOON SEASONS IN THE BAY OF BENGAL: RESPECTIVE

INFLUENCE OF THE OCEAN AND ATMOSPHERE

M. Teesha 1, S. Neetu 1, M. Lengaigne 1,2, J. Vialard 2, G. Samson 1

1CSIR-National Institute of Oceanography, Goa, India, [email protected] ,[email protected]

2Laboratoire d'Océanographie Expérimentation et Approches Numériques,IRD/ CNRS/ UPMC/ MNHN , Paris,

France

The North Indian Ocean accounts for 7 % of global tropical cyclones with larger number of cyclones in Bay of Bengal (BoB) compared to Arabian Sea, which poses serious threat to the vulnerable coastal countries .14 of the 20 deadliest tropical cyclones in history formed over BoB. The two primary cyclone seasons in BoB are pre-monsoon and post-monsoon. It has been demonstrated that stronger upper ocean salinity stratification and deeper thermal stratification reduce the surface cooling under the TCs during the post-monsoon, and this inhibited cooling may promote the surface evaporation and releases large amount of latent heat, which is the fuel for intensification of cyclones. This leads to suspect more stronger cyclones in the post-monsoon as compared to the pre-monsoon season. In the present study we are addressing this issue by analysing observations and a high-resolution regional ocean-atmosphere coupled model which is able to simulate TCs and related air-sea interactions over the BoB. In contrast of what has been previously hypothesized, observational and model analysis reveals that TCs are however stronger during the pre-monsoon than during the post-monsoon season. We demonstrate that this behaviour can be attributed to the seasonal atmospheric changes during this two seasons: the pre-monsoon season indeed exhibits weaker vertical wind shear, increased relative humidity and reduced stability of the atmosphere column, which ultimately promote stronger TCs during the pre-monsoon compared to post-monsoon season. Using sensitivity experiment the impact of air-sea coupling is shown to considerably reduce the number of TCs during both seasons and to reduce TCs intensity during the pre-monsoon because of enhanced TC-induced surface cooling. The seasonal change in atmospheric background state explain the stronger TCs during the pre-monsoon, but the effect is reduced by stronger air-sea coupling during this season.

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REMOTE AND REGIONAL OCEANIC INFLUENCE DURING SOUTH-WEST SUMMER MONSOON 2014.

Milind Mujumdar1*, Swapna P.1, M. K. Roxy1, Sabin T.P.1, C. Gnanaseelan1, and R. Krishnan1

1Indian Institute of Tropical Meteorology, Pune-411 088; [email protected]

The modulation of El Niño and south-west monsoon rainfall during summer months of 2014 was peculiar. The month of July, August and September of 2014 remained relative wet over south-Asia, as compared to that of June. The month of June 2014 indicated stronger El Niño conditions over Pacific, while the subsequent modulation of the El Niño was observed during July, August and September. The Indian Ocean processes seem to have significant influence on the remote and regional unique SST patterns during 2014 summer monsoon. The sub-tropical Indian Ocean warming persisted throughout the season. Interestingly, co-occurrence of anomalous warming over the Arabian Sea and eastern equatorial Pacific during June 2014 subsided during July, August and September months. The Indian Ocean warming, in particular over Arabian Sea seems to be one of the crucial factor in modulation of El Niño and Indian summer monsoon rainfall.

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82

ON THE POSSIBLE CAUSE OF DISTINCT EL NIÑO TYPES IN THE RECENT DECADES

Jyoti1 J, Swapna1* P, Shamal Marathe1 and K. Ashok1,2 1Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune; [email protected]

2University of Hyderabad, Hyderabad, India

Distinct El Niño types have been observed in the recent decades with warm anomalies in the eastern Pacific (Canonical El Niño, EL) and central Pacific (El Niño Modoki, EM). Among these, a basin wide tropical Pacific (TP) warming is seen during 2009, and El-Niño-like warming during 2014. We carried out data analysis and numerical simulation experiments to understand the possible cause for different El Niño flavours. The results reveal that the co-evolution of ocean-atmospheric conditions is critically important. Stronger (weaker) boreal spring (Mar-May) through summer (June-September) westerly wind anomalies (WWA), with relatively stronger (weaker) ocean pre-conditioning result in EL (EM), while stronger ocean preconditioning and weaker WWA lead to basin wide warming pattern. The strength of the WWA is crucial in determining the strength of the ocean dynamic response and the thermocline displacements in the Pacific. The study has important implications for understanding the nature of El Niño in advance.

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22-24 March 2015


83

INTRASEASONAL TO INTERANNUAL VARIABILITY OF SURFACE LAYER TEMPERATURE INVERSION IN THE BAY OF BENGAL

Pankajakshan Thadathil1, I. Suresh1, S. Gautham1*,S. Prasanna Kumar1 , Matthieu Lengaigne2, R.R.Rao3, S. Neetu1 and Y.K. Somayajulu1

1CSIR-National Institute of Oceanography, Dona Paula, Goa 403004; [email protected]

2LOCEAN, Institut Pierre Simon Laplace, Paris, France


Surface layer temperature inversion (SLTI), a warm layer sandwiched between surface and subsurface colder waters, have been reported to occur in conjunction with barrier layers in the three tropical oceans, with potentially commensurable climatic impacts. The present study take benefit from the Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction (RAMA) buoys to improve the description and the understanding of the SLTI variability in the Bay of Bengal (BoB). SLTI are found to be considerably more frequent, thicker (~50m) and of larger amplitude (~1°C) at the northernmost buoy (15°N; 80°E). SLTI at this location shows a distinct seasonal cycle, appearing sporadically from October onwards and being most frequent (65% of the time) and of larger amplitude (0.8°C) from December to February. SLTI amplitude and thickness are virtually unrelated to each other. They both exhibit larger variations at intraseasonal than at interannual timescales. While surface heat loss and downward penetration of the surface shortwave radiation below the mixed layer favour the SLTI formation, our analysis suggest that these mechanism do not account for the SLTI intraseasonal and interannual variations. Rather, the observed variability is largely explained by horizontal advection of a cold and freshwater lence over warmer and saltier waters. Finally, SLTI is shown to damp the amplitude of the winter cooling in the BoB by shedding the possessed heat by SLTI to the mixed layer through vertical processes of entrainment and diffusion.

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84

EFFECT OF RIVER DISCHARGE IN SIMULATION OF SEA SURFACE SALINITY USING ROMS MODEL

K. K. Sandeep1*, Vimlesh Pant1, A. D. Rao1, Arulalan T1

1Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi-110016;

[email protected]

The two divisions of the North Indian Ocean (NIO) basin, namely Arabian sea (AS) and Bay of Bengal (BoB) exhibit quiet distinct physiochemical properties even though they are lying in the same latitudinal belt. The large amount of fresh water flux due to river runoff and excess precipitation over evaporation makes BoB comparatively fresher than the AS throughout the year. Substantial change in salinity and temperature due to river runoff results in a change in ambient sea-water density near river mouths in coastal regions. Major rivers like Ganges, Brahmaputra, Mahanadi, Godavari, Krishna, and Irrawaddy discharge large amount of freshwater volume to the BoB. In the present study, we simulate the circulation features of the NIO, particularly in the BoB using a high resolution three dimensional ocean circulation model, i.e. Regional Ocean Modelling System (ROMS). ROMS is a free-surface primitive equation model with hydrostatic approximation which implements the terrain following sigma coordinates in the vertical. The model domain for BoB confined between 10°N-24°N, 79°E-100°E with 1/8 x 1/8 degree horizontal resolution. The northern, eastern and western boundaries are closed and the southern boundary is relaxed to climatology. The model is initialized with annual mean climatology of temperature and salinity and forced by monthly climatological forcing fields from Comprehensive Ocean Atmosphere Data Sets (COADS). The model is spun-up for 10 years to simulate the important oceanographic parameters like temperature, salinity and currents. In order to examine the effect of river discharge in the BoB, the climatological freshwater discharge from the Ganges-Brahmaputra (GB) river system was supplied to the ROMS model using 10th year spun up stage as initial condition. The GB river freshwater discharge was appropriately distributed in the first four model sigma levels. The river discharge was supplied to four model grids corresponding to the GB river mouth as a point source of low salinity to represent the discharge. The model simulated salinity was compared with North Indian Ocean Atlas (NIOA) salinity climatology. It was observed that the model represents the freshwater distribution in the BoB better when forced with the river discharge as compare to without river.

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22-24 March 2015


85

ROLE OF IOD AND ENSO ON THE INTER-ANNUAL VARIABILITY OF TROPICAL INDIAN OCEAN

Anju S1,2*, P. Swapna1, K.Ashok1,3, Sandeep1 and Jyoti1 1Center for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, India

2Department of Atmospheric and Space Science, Savitribai Phule Pune University, Pune, India

3University of Hyderabad, India

Indian Ocean Dipole (IOD) is a coupled ocean-atmospheric phenomenon in the tropical Indian Ocean. The El Niño-Southern Oscillation (ENSO) being the dominant mode of variability in the tropics, have large impact on the inter-annual variability of the Indian Ocean. El Niño and IOD are two independent climate modes, many of the IOD events in the past have co-occurred with El Niño. Recent studies have also identified different El Niño types based on the spatial pattern of sea surface temperature anomalies in the tropical Pacific. The role of different El Niño types on the inter-annual variability of Indian Ocean; especially during IOD events were not understood. An attempt is made in the study to understand the physical and biological process associated with different IOD events that occurred independently and during different El Nino Types. Observed data sets, reanalysis products and an ocean general circulation model with interactive ocean bio-geochemistry is used for the first time in the Indian Ocean to study the bio-physical feedbacks associated with different IOD events. Comparisons of the ocean model simulation with remotely sensed data show that the simulation reasonably reproduces the seasonal cycle and inter-annual variability of SST and chlorophyll anomalies during IOD events. The preliminary results of the study show that the effects of pure IOD and co-occurring IOD-ENSO flavors on the tropical Indian Ocean are entirely different during the IOD evolution. The study also emphasizes the role of equatorial undercurrents (EUC) in supplying cold subsurface water to surface and thus enhancing the upwelling in the south eastern equatorial Indian Ocean during IOD events. The co-occurrence of IOD with different El-Niño types has altered the circulation of Indian Ocean, formulation of EUC and thus the strength of IOD events. The bio-physical feedback during IOD events is also addressed in the study.

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86

RELATIVE ROLE OF EL-NINO SOUTHERN OSCILLATION AND IOD EVENTS ON MONSOON ACTIVITY OVER INDIA

S. Gopika1*, M. R. Ramesh kumar2 1Academy of Climate Change Education and Research, KAU, Kerala ; [email protected].


The relative influence of the El-Nino,Southern oscillation and Indian Ocean Dipole (IOD) events on the Indian summer (June-September) monsoon rainfall (ISMR) have been studied for the period 1950-2007 . In the present study, we investigate the reasons for annual and interannual variability of ISMR. In order to look into the role of El-Nino on the monsoon , the SST data over five regions namely eastern pacific (80°W-120°W,10°S-10°N), central pacific (180°E-140°W,10°S-10°N), western pacific (120°E-160°E,10°S-10°N), western IOD box (50°E-70°E,10°S-10°N) and eastern IOD box (90°E-110°E,10°S-0°) were studied. All India rainfall data, homogeneous and macro-regional rainfall dataset, available from IITM, Pune were also used. The impact of ENSO and IOD conditions on monthly, seasonal, and yearly changes of ISMR at macro-regional scales were studied . Results shows that El-Nino indicators NINO1+2 (Far eastern tropical Pacific Ocean) , NINO3 (Eastern tropical Pacific ocean ), NINO3.4 (Central tropical Pacific Ocean ) and NINO4 (Western tropical Pacific ocean) shows significant negative correlation with summer monsoon rainfall of india. During 1950-1969 Enso and IOD events are more independant. From the result it is seen that after 1969 ENSO and IOD events co-occur, and also it is noticed that the frequent occurence of posetive phase of IOD events assosiated with El-Nino after 1970. The extent of El-Nino and SOI correlation with ISMR is higher than that of IOD. But each of the individual monsoon months, IOD variability have notable effect on ISMR . El-Nino and IOD events shows a significant negative correlation with rainfall over India while SOI events shows positive correlation.

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22-24 March 2015


87

PROCESSES ASSOCIATED WITH THE ARABIAN SEA MINI WARM POOL FORMATION AND THEIR EPOCHAL CHANGES

Aniket Barphe1, 2,*, C. Gnanaseelan1 and P. Pradeep Kumar2 1Indian Institute of Tropical Meteorology, Pune- 411 008

2Savitribai Phule Pune University, Pune-411007; [email protected]

Arabian Sea Mini warm Pool (ASMWP) is the anomalous pool of warm surface water in the South Eastern Arabian Sea (SEAS) prior to the onset of south-west monsoon. It is found that the warm pool forms almost all the years but the formation of well-established warm pool is closely associated with El Nino formation in the Pacific. The warming patterns in the El Nino developing years and El Nino decaying years are different. The warming during the El Nino developing year is the response of Arabian Sea to the remote forcing from Pacific through atmospheric fluxes, whereas the warming during the decaying years are forced by Indian Ocean dynamics through planetary waves. The monthly HadISST data and NCEP-NCAR reanalysis surface wind fields from March to Aug over 40°E-80°E, 10°S-20°N for period of 1948 to 2006 are used to understand the epochal changes in the ASMWP. The averaged March-May SST during 1948-2008 shows expansion in region of ASMWP extending south-westward. In El-Nino years Epoch 1 (1948 to 1976) displayed weak warming during March-May due to strengthening of mean wind. However June to August experienced warming due to reduced upwelling along the Somalia coast driven mainly by weaker mean winds. The weak mean winds are caused by the anomalous winds opposing the mean winds. Epoch 2 (1978 to 2006) is warmer during March-May of the years following El-Nino years (especially in May). The lead lag correlation between ASMWP and Nino3.4 index further strengthen our findings.

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88

INDIAN OCEAN WARMING – ITS EXTENT, AND IMPACT ON THE MONSOON AND MARINE PRODUCTIVITY

Roxy M. K.1*, K. Ritika1, A. Modi1, P. Terray2, R. Murtugudde3, K. Ashok1,4, B. N. Goswami1,5, S. Masson2, V. Valsala1, P. Swapna1, S. Prasanna Kumar6 and M. Ravichandran7

1Indian Institute of Tropical Meteorology, Pune; *[email protected]

2Sorbonne Universitees, Paris, France

3University of Maryland, Maryland, USA

4University of Hyderabad, Hyderabad

5Indian Institute of Science Education and Research, Pune


7Indian National Centre for Ocean Information Services, Hyderabad

Indian Ocean warming has captured the attention of a handful of studies in the recent years, but the cause and effect of this warming has remained enigmatic – until now. In the current study, we demonstrate that the Indian Ocean has been warming for more than a century, at a rate and magnitude larger than what was thought before (1.2°C in 100 years). This intense, monotonous warming turns out to be the largest contributor in-phase with the global ocean surface warming, with a firm grip on the global climate. We find that the long-term warming trend over the Indian Ocean is due to an increase in the frequency and magnitude of El Nino events during recent decades, which is likely due to anthropogenic forcing [Roxy et al, 2014].

Consequences of this excessive warming of Indian Ocean are large, especially on the physical and biological dynamics over the South Asian domain, and eventually on the socio-economic livelihood of the surrounding countries. Our analysis with observed data and model simulations show that the Indian Ocean warming has resulted in weakening the land-sea thermal contrast, an essential driver of the monsoon. This has weakened the monsoon circulation, and in turn reduced the rainfall over a large area extending from Pakistan through central India to Bangladesh [Roxy et al, 2015]. The excessive warming have also resulted in the ocean surface stratification over the western Indian Ocean–one of the most biologically productive regions among the tropical oceans. We find that these increasingly stratified ocean waters have suppressed the upwelling of nutrients from the subsurface waters, and have resulted in a reduction of up to 20% in the marine primary production. Altogether, the Indian Ocean warming is a factor to be vigilant of, while assessing long-term changes in the monsoon, the marine productivity, and the global climate.

References: Roxy M. K., K. Ritika, P. Terray, S. Masson, 2014: The curious case of Indian Ocean warming. J.Climate, 27, 22, 8501-8509. Roxy M. K., K. Ritika, P. Terray, R. Murutugudde, K. Ashok and B. N. Goswami, 2015: Warm ocean, weak monsoon. Nature Communications, Revised.

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22-24 March 2015


89

FLAVOURS IN THE DECAY PHASE OF EL NIÑO AND THE ASSOCIATED RESPONSE ON MONSOON CIRCULATION AND RAINFALL

H. Sree Harsha1,2*, J. S. Chowdary1, C. Gnanaseelan1, C.V. Naidu2, G. Srinivas1, A Parekh1 and Prasanth Pillai1

1Indian Institute of Tropical Meteorology, Pune – 411008

2Dept. of MeteorologyandOceanography Andhra University, Andhra Pradesh; [email protected]

Impact of developing phase of El Niño on Tropical Indian Ocean (TIO) and Indian Summer Monsoon (ISM) is well established, whereas influence of El Niño decay phase on ISM circulation and rainfall is not well understood. In this study we have used 142 years (1871 to 2012) of Twentieth Century Reanalysis (20CR,V2) monthly mean winds, Extended Reconstructed Sea Surface Temperature (ERSST) and 112 years (1901 to 2012) of rainfall data from India meteorological department (IMD) to understand the response of Indian summer monsoon to different El Nino decays. In general it is known that El Niño in the Pacific develops during summer season, peaks by winter and decay in next spring. On the other hand, TIO SST warming as a response to El Niño induced subsidence persists till the following summer even after the dissipation of El Nino in the Pacific. However, our analysis revealed that some El Nino’s decay rapidly after the winter and some decay late (in mid-summer). Three categories of El Nino decay phases are identified based on their decay timing (1) early decay (ED; decay before spring), (2) late decay (LD; decay by mid-summer) and (3) no decay (ND; no significant cooling in the eastern Pacific or developing of next El Nino by summer). It is found that variations in decay phase of El Nino have different impacts on ISM circulation and rainfall. During El Nino ED, basin-wide TIO warming does not persist from winter to summer. Cross-equatorial flow associated with summer monsoon is stronger and rainfall over most of Indian subcontinent is positive during ED years. Basin-wide TIO warming persisted until the following summer during El Nino LD years. In response to late decay, north-easterly wind anomalies over the Bay of Bengal, associated with northwest Pacific anticyclone, and south-westerly wind anomalies from the Arabian Sea converge over the Indian subcontinent. This results in positive rainfall over most of the Indian land region. During El Nino ND years, monsoon circulation is weaker and rainfall is negative over the Indian subcontinent. This study highlights the importance of El Nino decay variations in influencing the ISM circulation and rainfall. Further, atmospheric general circulation model forced with observed SST from 1871-2007 supported our results.

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90

SUB-SURFACE TEMPERATURE TRENDS IN THE NORTH INDIAN OCEAN AND OCEAN VERTICAL PROCESSES

Anand babu Amere1, 2*, Anant Parekh1, Fousiya T.S1, G.Bharathi2, C.Gnanaseelan1 and J.S.Chowdary1

1Indian Institute of Tropical Meteorology, Pune-411008

2Department of Meteorology and Oceanography, Andhra University, Visakhapatnam

*Email: [email protected]

North Indian Ocean [10oS to 30oN and 30oE to 110oE] sea surface temperature (SST) trends known to have strong impact on the climate over the Asia Pacific region. Many studies have reported increasing trend in SST over the Indian Ocean. This is the first study exploring the concurrent surface and sub-surface temperature trends in the North Indian Ocean using observations from Array for Real time Geostrophic Oceanography (ARGO) as well as multiple ocean models outputs [Ocean reanalysis (ORA), Simple Ocean Data Assimilation (SODA), Global Ocean Data Assimilation (GODAS)] for the recent two decades (years 1990 to 2012). The study revealed that there is increasing trend in SST and decreasing trend in subsurface temperature during first decade (years 1990 to 2001). Whereas no such trend in SST is evident in the second decade (years 2002 to 2012). On the other hand increasing trend in subsurface temperature is found in the second decade. The results are consistent in both observations and reanalysis data sets. Detailed analysis revealed that the upper ocean vertical gradient in density display negative (positive) trend during the second (first) decade leading to weak (strong ) buoyancy. This supports more vertical mixing in the second decade. In addition to that, the vertical shear of horizontal current increased in the recent decade. Thus vertical mixing due to weakening buoyancy and increasing current shear is responsible for the observed surface warming trend in the recent decade.

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22-24 March 2015


91

THE STRUCTURE OF INDIAN OCEAN MERIDIONAL OVERTURNING IN OCEAN REANALYSIS DATASETS AND AN OGCM

S Rahul, C Gnanaseelan*

Indian Institute of Tropical Meteorology, Pune, India; [email protected]

The tropical oceans, on an annual average, receive net heat input from atmosphere, which has to be transported polewards to maintain surface heat balance. This is achieved by Meridional Overturning Circulation (MOC). The tropical shallow branch of the MOC transports warm tropical waters to the subtropics where they exchange the net heat gained in the tropics back to the atmosphere, sinks down and is transported back to deep tropics and is replenished to surface by net upwelling. As MOC plays a major role in the surface heat balance, understanding the MOC structure is crucial for understanding the surface heat balance.

The Indian Ocean (IO) currents from reanalysis data sets and an OGCM are decomposed to separate the rotational and divergent components of the horizontal currents using Helmholtz decomposition. Meridional overturning stream functions (MOS) are derived from zonally integrated divergent currents. This methodology helps to visualize the MOC structure south of 5oS in IO which was not otherwise achievable because of divergence created by Indonesian through flow transport. The mean MOS in ocean reanalysis data sets displays the conventional structure of IO MOC, i.e. a shallow south equatorial cell and a deep cross equatorial cell. The OGCM displays a deeper MOC transport compared to the reanalysis data sets. EOF analysis of MOS in reanalysis data sets showed that inter-annual variability in IO MOC structure is confined to the upper 1500m. A long term trend is superimposed on this variability, but is in opposite direction in the two data-sets considered in this study.

The variability of MOC is coherent with the variability of zonal circulation in reanalysis data sets. The differences in mean MOC structure and variability within the reanalysis data sets and the OGCM suggests that the closure of energy budget (which is absent in reanalysis) can significantly affect the simulated MOC structure and strength.

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92

MESO-SCALE EDDIES IN THE NORTH INDIAN OCEAN AND THEIR PROPAGATION PATHWAYS

T.N. Shyni and P.V. Hareesh Kumar

Naval physical & Oceanographic Laboratory, Kochi-21; [email protected]

Meso-scale eddies and associated variability is a major component of oceanographic research today; since these features play an active role in the general ocean circulation, distribution of seawater properties, mixed and sonic layer variability and acoustic propagation. The North Indian Ocean (NIO), one of the most dynamic regions among the world oceans, is famous for the occurrence of meso-scale eddies of varying dimensions. Despite the importance, the eddy activities in the NIO have not been substantially described. Therefore, in this study the eddy characteristics viz., lifespan, amplitude, vorticity, spatial dimension, propagation speed and their pathways in the NIO are examined. The eddies are detected and tracked from 18 years of sea level anomaly data (years 1993-2010) following Isern-Fontanet parameter (Q) and flow geometry based algorithm. The analysis revealed 2123 meso-scale eddies having life span of more than 4 weeks over a period of 18 years; moreover is a slight dominance of anti-cyclonic eddies over cyclonic eddies. Majority of eddies are having life span between 4-8 weeks and the eddy count drop off rapidly with increasing life time. It is also noticed that the number of eddies formed in the Arabian Sea is significantly high compared to that in the Bay of Bengal. The propagation pathways of these eddies exhibit a westward movement with slight north-south deflection and got dissipated on the western boundaries of the ocean.

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22-24 March 2015


93

PHYSICAL PROCESSES CONTROLLING MIXED LAYER VARIABILITY IN THE NORTHERN INDIAN OCEAN

Jayu Narvekar* and S. Prasanna Kumar

CSIR-National Institute of Oceanography Dona-Paula, Goa 403 004, India; [email protected]

Seasonal mixed layer variability and processes controlling it was studied in the northern Indian Ocean using in situ and remote sensing data. Compared to zonal variability, meridional variability is more in the Arabian Sea and the Bay of Bengal, while reverse is the case in the equatorial Indian Ocean. Hence, three areas in the northern Indian Ocean were considered to understand the seasonal variability of mixed layer depth (MLD) in the central Arabian Sea (equator to 25oN and 62oE to 66oE), central Bay of Bengal (4oN to 20oN and 87oE to 91oE) and equatorial Indian Ocean (5o N and 5oS and 40oE and 100oE). Mixed layer showed a strong semi-annual variability in the Arabian Sea and the Bay of Bengal with deep mixed layer during summer and winter and shallow mixed layer during spring and fall intermonsoons. During summer MLD in the Arabian Sea was controlled by Ekman dynamics associated with the Findlater Jet. Under the influence of the cyclonic wind-stress curl the MLD in the northern Arabian Sea shoaled while the anti-cyclonic wind-stress curl deepened the MLD in the southern Arabian Sea. In contrast, the MLD in the northern Bay of Bengal during summer was not regulated by the Ekman dynamics, but was controlled by the fresh water flux (both oceanic precipitation and river discharge), which remained very shallow (~10 m). In the southern Bay, however, wind forcing along with advection of high salinity waters from the Arabian Sea controlled the MLD. During winter, cooling and convective mixing regulated MLD in the northern Arabian Sea, while in the south Rossby waves influenced the MLD. In the northern Bay of Bengal, the perennial presence of the low salinity waters stratified the upper layers and the wind forcing did not significantly influence MLD. In the southern Bay, the low stratification during winter allows greater wind-driven mixing which leads to deepening of mixed layer. During spring and fall intermonsoons, the weak winds along with strong incoming solar radiation lead to the formation of thin, warm and stratified mixed layer in both the Arabian Sea and the Bay of Bengal. In contrast to the semi-annual variability seen in the Arabian Sea and the Bay of Bengal, in the equatorial region the MLD showed an annual signal, with deep mixed layer during June-September and shallow mixed layer from October to May. The deep MLD during summer (June-September) was due to the combined effect of strong winds and low net heat flux while the shallow MLD in winter was driven by the weak winds and negative E-P. The presentation also discusses the role of inter-basin advection of high and low salinity waters as well as propagating waves on mixed layer variability.

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94

VARIABILITY AND TRENDS IN THE TROPICAL INDIAN OCEAN SEA SURFACE SALINITY, IN A CHANGING CLIMATE

Vivek Shilimkar 1*, M. K. Roxy2

1Department of Atmospheric and Space Sciences, Savitribai Phule Pune University, Pune;

[email protected] 2Indian Institute of Tropical Meteorology, Pune.

Variability and trend in tropical Indian Ocean sea surface salinity (SSS) during boreal summer is studied using SODA reanalysis and CMIP5 historical simulations for the past six decades. The current study finds that SSS over the Indian Ocean exhibits a dipole-like trend. Extended analysis of the physical parameters show that the dipole like trend in salinity is driven by similar trends in SST and precipitation. Similar to Cai et al. (2014), the current study also indicate a skewness towards positive dipole events with increasing SST gradient between west and southeastern Indian Ocean. Such a trend has resulted in enhanced convective precipitation over the west and suppressed convection over the southeast. This has resulted in associated trends in salinity also. A possible consequence of such a trend in salinity is decreased southward transport of water, which is evident from the observations. The changes in climate that could have caused by this trend in salinity are examined with model experiments.

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22-24 March 2015


95

IMPACT OF AQUARIUS SEA SURFACE SALINITY ASSIMILATION IN IMPROVING THE OCEAN STATE

Vivek .S1,2*, P. Sreenivas1, C. Gnanaseelan1 and K. V. S. R. Prasad2 1Indian Institute of Tropical Meteorology, Pune; *email: [email protected]

2Dept. of Meteorology & Oceanography, Andhra University, Visakhapatnam

Seasonal and Extended range prediction of Indian summer monsoon has been a challenging task for meteorological communities. It is a well established fact that accurate representation of ocean state is very essential for better seasonal as well as short term weather forecast. Any inaccuracy in the representation of upper ocean thermal structure in the ocean initial state will lead to drastic errors in coupled model forecast. The data assimilation techniques have promising role in achieving an accurate ocean state in the context of recent advances in ocean and atmospheric observational networks. The structure of ocean salinity controls the density field and thereby playing a major role in influencing the ocean dynamics. It has been a challenging task to understand the strong intra-seasonal and inter-annual variability of salinity structure in the regions of large fresh water discharge and high precipitation such as Bay of Bengal. Even the well organized assimilation schemes/models have limitations in producing accurate salinity analysis due to the lack of significant salinity observations (both spatially and temporally). Recent advancement in satellite technology has made possible the measurement of sea surface salinity (SSS) with unprecedented spatio-temporal coverage. Aquarius is the recent operational mission which measures the global SSS since 2011. We assimilated Aquarius SSS in the Global Ocean Data Assimilation (GODAS) for the period 2011 to 2014. GODAS is the assimilation module for MOM4 (ocean component of CFS, the forecast model used in India and many other countries). The assimilation scheme in GODAS is 3DVAR. The present study addresses the impact of assimilating Aquarius SSS in improving the ocean analysis and the intra-seasonal and inter-annual variability of salinity in the key regions such as Bay of Bengal. The results are validated with ECCO2 model and in-situ RAMA buoy observations. The results are discussed in this study.

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96

DYNAMICAL LINK BETWEEN TROPICAL INDIAN OCEAN AND CYCLONES

P. Sreenivas1*, C. Gnanaseelan1, J.S. Chowdary1 and K.V.S.R. Prasad2

1Indian Institute of Tropical meteorology, Pune – 411008; [email protected]

2Dept. of Meteorology & Oceanography, Andhra University - 530008.

The socio-economic impact of tropical cyclones is considerable, depending on the intensity and region of landfall, the cyclones give rise to copious rainfall, major inland flooding which often causes damage and loss of life in the coastal areas of the Indian subcontinent, Bangladesh, and Myanmar. The present study examines the role of ocean surface in cyclogenesis and vice-versa i.e. the role of cyclones on the ocean surface variability in the Indian Ocean. The analysis of cyclogenesis characteristics in the Bay of Bengal over the past 65 years revealed that the active (suppressed) phases of cyclogenesis are coinciding with the downwelling (upwelling) planetary waves which influence the cyclone heat potential by altering the thermocline depth. Also the interannual variability of cyclogenesis (number of cyclones) is varying in correlation with propagating planetary waves. We also examined the role of surface ocean processes on the life cycle of severe cyclonic storm “Jal” as a case study.

The above findings infers the impact of surface ocean processes on cyclogenesis and their propagation; in the latter section of this study, we addressed the key issue of role of cyclones on large scale dynamics in the Indian ocean by conducting a thorough examination of Tropical cyclones (TC) and equatorial dynamics. The equatorial Indian ocean is characterized by a strong narrow currents often called as Wyrtki jets (WJ). These jets peak during November and play a vital role in the energy and mass transport in the tropical Indian Ocean (TIO). Maximum number of TCs is observed over TIO during November with longer than normal life span (8–15 days). These TCs enhance equatorial westerly winds (surface) and amplify monthly mean WJs (both at surface and subsurface) by 0.4 ms-1 (anomalies exceed 0.7 ms-1 during TC), which is about half of the climatological amplitude. Intensified WJs increase the heat content of eastern TIO and modulate air-sea interaction. It is also shown that movement of TCs is mainly responsible for the westward phase propagation of WJs, a previously unexplored mechanism. These features are evident in ECCO2 simulations as well.

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22-24 March 2015


97

ASSIMILATION OF ALTIMETRY DERIVED TEMPERATURE AND SALINITY IN GODAS AND ITS IMPACT ON MONSOON PREDICTION

P. Sreenivas, N. Pavan Kumar, R. Kakatkar and C. Gnanaseelan

Indian Institute of Tropical Meteorology, Pashan, Pune. 411008; [email protected]

SARAL-ALTIKA is one of the recent among the series of satellites observing ocean surface anomalies. It has extremely good spatial coverage and reasonable temporal resolution. The raw along track data of SARAL-ALTIKA obtained from MOSDAC is first gridded using in-house developed algorithm and subsequently sea surface height anomalies (SSHA) data sets are extracted. Observed SSHA and ARGO data are combined to derive synthetic profiles of Temperature and Salinity using multivariate empirical orthogonal function (EOF) technique. The multi-mission altimetry (TOPEX/POSIEDON, JASON 1 & 2) SSHA has been utilised for training purpose and SARAL data has been utilised for real time derivation of synthetic profiles.

The SSHA derived synthetic profiles of temperature and salinity are assimilated in the Global Ocean Data Assimilation (GODAS), the assimilation module for ocean component of NCEP Climate Forecast System, CFSv2, which is the operational seasonal forecast model used in many countries including India. The assimilation scheme in GODAS is 3DVAR. The accurate representation of SST is an important factor for an accurate forecast of monsoon. Using synthetic profiles, assimilation is done to generate best estimate of ocean state as initial condition for CFS to understand the impact of altimeter assimilation on the Indian summer monsoon forecast and the associated large scale circulation changes.

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98

EQUATORIAL INDIAN OCEAN SUBSURFACE CURRENT VARIABILITY IN AN OCEAN GENERAL CIRCULATION MODEL AND ITS IMPACT ON REGIONAL

CLIMATE.

Aditi Deshpande* and C. Gnanaseelan 1Indian Institute of Tropical Meteorology,Pune; [email protected]

The vertical structure and the subsurface current variability over the equatorial Indian Ocean have not been addressed in detail due to lack of observational data. In this study, we have focused on the vertical structure of Wyrtki jets and the equatorial Indian Ocean subsurface current variability in an ocean general circulation model (OGCM). Empirical Orthogonal Function (EOF) analysis of depth averaged (80-120mts) subsurface zonal currents at the equator reveal that the first mode of variability is associated with Indian Ocean Dipole (IOD). However, the first principal component shows strong peaks during some IOD years, and no significant peaks during others. Based on the classification given in Deshpande et al. (2014), the IOD years were further classified as strong IOD years and weak IOD years. The evolution of the equatorial undercurrent during these years was studied using a high resolution OGCM. It is found that the equatorial undercurrent evolves consistently during the strong IOD years and it is much stronger than the climatological or the undercurrent observed during the weak IOD years. The evolution of undercurrent is not very consistent during weak IOD years with a well defined under current visible only in the peak phase of IOD. The undercurrent supports the intensification of upwelling in the eastern box of IOD (90°E-110°E, 10°S-Equator). Since, the strong undercurrent during strong IOD years is well defined since the evolution of IOD, the sea surface temperature (SST) anomalies and thermocline anomalies evolve coherently. There is a strong thermocline-SST coupling during strong IOD years, which is absent during weak IOD years. The strong IOD years are found to co-occur with significant enhancement of monsoon circulation over north Indian Ocean and positive rainfall anomalies over India. During weak years, no such significant anomalies are seen in monsoon rainfall or circulation.

References: A.Deshpande, Chowdary J.S. and Gnanaseelan C., (2014) Role of thermocline–SST coupling in the evolution of IOD events and regional impacts. Climate Dynamics doi:10.1007/s00382-013-1879-5.

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22-24 March 2015


99

INTER-ANNUAL VARIABILITY OF UPPER OCEAN STRATIFICATION IN BAY OF BENGAL: OBSERVATIONAL AND MODELING ASPECTS

T.S. Fousiya1*, Anant Parekh1 and C. Gnanaseelan1

1Indian Institute of Tropical Meteorology,Pune; [email protected]

This study presents the mean annual cycle and interannual variability of stratification in Bay of Bengal (BoB) from Global Ocean Data Assimilation System (GODAS) and observations during 2003-2011. Annual cycle of stratification in BoB displays a bimodal distribution with maxima during spring and fall (spring peak due to high insolation and weak winds, fall peak due to strong surface fresh water forcing) and is in phase with SST cycle. The mean stratification and its interannual variability in BoB are weaker in GODAS than observation even though it has more fresh water flux. Further analysis based on recent in-situ observations reveals that enhanced vertical mixing in GODAS is partly due to improper critical Richardson number for BoB. This supported strong unrealistic mixing in GODAS to an extent even excess fresh water flux at the surface could not maintain stratification. El Niño (La Niña) years are characterized by less (more) stratification in BoB due to weaker (stronger) fresh water flux, which are misrepresented in GODAS. As stratification modulates air-sea interaction over BoB especially during El Niño or La Niña years, such misrepresentation of stratification may lead to improper coupling. As GODAS is used to initialize Coupled Forecasting System for seasonal prediction of Asian monsoon, proper representation of stratification is essential. This study concludes that representation of mixing processes and horizontal advection in GODAS need improvement as they primarily determine the stratification and its interannual variability.

References: Shenoi, S. S. C., Shankar, D., and Shetye, S. R.: Differences in heat budgets of the near surface Arabian Sea and Bay of Bengal: Implications for the summer monsoon, J. Geophys. Res., 2002, 107(C6), 3052.

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100

A NEW MODE OF VARIABILITY IN THE TROPICAL INDIAN OCEAN SUBSURFACE TEMPERATURE AND ITS CLIMATIC IMPACTS

C. Gnanaseelan* and Sayantani Ojha


The first two leading modes of interannual variability of sea surface temperature in the Tropical Indian Ocean (TIO) are governed by El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) respectively. TIO subsurface however does not co-vary with the surface. The patterns of the first mode of TIO subsurface temperature variability and their vertical structure are found to closely resemble the patterns of IOD and El Niño co-occurrence years. These co-occurrence years are characterized by a north-south subsurface dipole rather than a conventional IOD forced east-west dipole (Sayantani and Gnanaseelan, 2014). This subsurface dipole is forced by wind stress curl anomalies, driven mainly by meridional shear in the zonal wind anomalies. A new subsurface dipole index (SDI) has been defined in this study to quantify the intensity of the north-south dipole mode. The SDI peaks during December to February (DJF), a season after the Dipole Mode Index peaks. It is found that this subsurface north-south dipole is a manifestation of the internal mode of variability of the Indian Ocean forced by IOD but modulated by Pacific forcing. This mode has strong correlation with the SST evolution in the TIO and summer monsoon precipitation over the Indian subcontinent. The thermocline SST interaction associated with this mode plays an important role in the basin scale TIO warming and cooling associated respectively with El Niño or La Niña in the Pacific. It also plays a dominant role in the formation and propagation characteristics of Madden Julian Oscillation. Most of the current coupled models including CMIP models capture this leading mode of subsurface variability. The persistence of this north south dipole pattern for two to three seasons alter the mean thermal structure of the tropical Indian Ocean, which in turn has great impact on the regional climate.

Reference: O. Sayantani and C. Gnanaseelan, ‘Tropical Indian Ocean subsurface temperature variability and the forcing mechanisms’, Climate Dynamics, 2014, DOI 10.1007/s00382-014-2379-y

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22-24 March 2015


101

INTER COMPARISON OF DIFFERENT OCEAN MODELS OVER THE TROPICAL INDIAN OCEAN

Ananya Karmakar*, Anant Parekh, Jasti Chowdary, and C. Gnanaseelan

Indian Institute of Tropical Meteorology (IITM), Pune- 411 008; [email protected]

This study presents the inter comparison of the physical parameters of Tropical Indian Ocean (TIO) in different ocean models like Modular Ocean Model v3 (MOMv3), Modular Ocean Model v4 (MOMv4), Nucleus for European Modelling of the Ocean (NEMO) and Parallel Ocean Physics (POP). These models are used to produce ocean reanalysis Global Ocean Data Assimilation System (GODAS), Geophysical Fluid Dynamics Laboratory (GFDL), Ocean Reanalysis System 4 (ORAS4), and Simple Ocean Data Assimilation (SODA POP) respectively. Recent studies have reported that many ocean models have larger discrepancy in simulating the surface and subsurface features of Indian Ocean. Present study mainly analyzes the long term mean vertical structure of temperature, salinity and currents in different models/analysis compared to observations (WOA-2013, OSCAR etc). All these models/analysis have warm sea surface temperature (SST) bias (0.05 - 0.25oC) and negative bias in sea surface salinity (SSS) (-0.05 to -0.25 psu). Almost all models have deeper mixed layer (especially GODAS has largest bias) with respect to observation. GODAS has large bias in MLD than GFDL even though both models are using more or less same forcing and physics. Furthermore GODAS has zonally asymmetric mixed layer depth bias along 70o E, the associated positive zonal density gradient leads to more vertical shear in the meridional current compared to other models. Similar analysis is carried out for the mean current of Tropical Indian Ocean (TIO). In contrast to the observation, GODAS and GFDL revealed mean westward current over the Equatorial Indian Ocean (EIO) in JJAS. Consistent with the positive MLD bias, the upper ocean currents are underestimated in all the models compared to SODA. This study shows that most of the models have bias within 100-200 m depths in all physical parameters highly questioning the parameterization of upper ocean physics and dynamics in these models.

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102

IMPACT OF PROLONGED ENSO EVENTS ON TROPICAL INDIAN OCEAN IN THE COUPLED MODEL CFSv2 AND OBSERVATIONS

P. Singh*, J.S. Chowdary and C. Gnanaseelan


ENSO is coupled air-sea interaction event which is highly variable in interannual time scale i.e. 1.5 to 8 years. Protracted events are those events in which SST anomalies in the eastern-central Pacific persists for more than 2 years. These protracted ENSO events are the resultant of interactions between quasi-biannual low frequency and quasi-decadal signals in the climate system. In this study we used 50 years of observations and coupled model CFSv2 simulations to study the impact of these events on Tropical Indian Ocean. It is found in both the observation and model simulations that protracted La Nina events occur more frequently than protracted El Nino events. It is also observed that during the transition period i.e. from El Nino to La Nina and vice versa, the western Tropical Indian Ocean is impacted more than the eastern tropical Indian Ocean during June to September (JJAS). The transitions from long lived La Nina leave strong gradient in SST anomalies over the tropical Indian Ocean favouring more convection over the eastern equatorial Indian Ocean. This can significantly affect the monsoon circulation and precipitation.

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22-24 March 2015


103

PHYSICO-CHEMICAL PROPERTIES AND STABLE OXYGEN ISOTOPIC (Δ18O) VARIATIONS OF SEAWATER, ALONG THE CONTINENTAL SHELF DURING POST

NE AND SW MONSOON PERIODS, SOUTH EAST COAST, INDIA.

Nisha.V1* and H. Achyuthan2 1Post Doctoral Fellow, PRL, Ahmedabad; [email protected]

2Dept. of Geology, Anna University, Chennai; [email protected]

Continental shelf studies are important in order to understand the physicochemical properties of sea water as well as biogeochemical systems existing in the marine environment. Lying within the tropical zone the east coast Tamilnadu receives strong monsoonal rains and hence any variation in the intensity and amount of precipitation would reflect in the seawater characteristics along the continental shelf. The present study quantifies the spatial and vertical heterogeneity in the distribution of physico-chemical parameters and stable Oxygen isotopic values (δ18O) of seawater during the 2009 post North East (NE) and South West (SW) monsoon periods along the continental shelf from Chennai to Nagapattinam, East Coast, Tamilnadu. For this purpose, six sampling sites were selected for collecting seawater samples spatially and vertically, based on the seawater column thickness along the continental shelf such as 50 m, 75 m, 100 m and 150 m extending from Chennai to Nagapattinam, East Coast, Tamilnadu. Variations in δ18O, salinity and temperature data of the seawater samples along the continental shelf were studied to understand the influence of monsoonal (post NE and SW) precipitation and evaporation patterns as these parameters are affected by the fractionation and mixing processes. Thermocline in the seawater column existed between 30 m to 60 m depth during post NE monsoon period while during SW monsoon, it was observed between 20 m and 40 m. Halocline existed between 40 m and 70 m during both the monsoon periods. The oxycline was recorded between 40 m to 60 m in all the stations during the post NE monsoon whereas during SW monsoon, it was shallower between 30 m and 50 m depth. The distribution of dissolved oxygen content showed marked variations during both the monsoons, in the surface waters and at various depths which is due to the vertical mixing of riverine inputs along the shallow waters of the continental shelf. The observed values of nutrients (NO3, NO2, NH4 and PO4) in seawater for the post NE monsoon period are low compared to the SW monsoon period. Contour lines plotted indicate seasonal and spatial variations in physico-chemical parameters along the continental shelf of the east coast of India. These observations are also reflected by the stable isotope oxygen data. Salinity, temperature and stable oxygen isotope reconstruction showed that the parameters increased towards the central regions of the coastal stretch, especially along Tarangampadi and Chidambaram. The inferences drawn from the various physico-chemical parameters of water samples at various seawater column depths reveals that during both the monsoon periods (post NE and SW), the salinity, temperature, oxygen and nutrients distinctly varied with depth towards the deeper seawater column following the continental shelf. This is caused due to the enhanced contribution from the easterly flowing rivers and distributaries (Cauvery river), strong influence of precipitation over the East Coast Tamilnadu, seawater mixing processes, industrial influxes and various anthropogenic influences.

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104

DECADAL VARIABILITY IN THE TROPICAL INDO PACIFIC OCEAN AND ITS IMPACT ON INDIAN SUMMER MONSOON

Abhishek Savita1, 2*, C. Gnanaseelan1, S. Rahul1

1Indian Institute of Tropical Meteorology, Pune-411008; [email protected]

2Indian Insttute of Tehnology, Kharagpur

In this study we examined the relation between decadal sea level and walker circulation change over 1993-2006 in the Indo-Pacific region. Satellite observation of sea surface height and wind stress curl showed a large scale decadal variability in the Indo Pacific region at the end of the 20th century (Lee and McPhaden, 2008). The major feature of the decadal change is the rising SSH in the western tropical pacific and southeast Indian Ocean during 1993-2000 period and the decreasing SSH for the 2000-2006. We have defined an index to quantify the strength of the variability. The walker circulation shows increasing trend in convection over the central and northern India during 1993-2000 and on the other hand strong subsidence is seen during 2000-2006. On the contrary southern peninsular India showed trends of subsidence during 1993 to 2000 and convection during 2000 to 2006. The precipitation over the Indian land region also displayed similar patterns. Strong upper level divergence is seen over the western Pacific during 1993 to 2006 inducing surface convergence. On the other hand western Pacific displayed strong subsidence during 2000 to 2006. This study speculates the role of decadal Indo Pacific variability in causing decadal variability in Indian summer monsoon rainfall.

The Walker circulation shows due to the variation in the wind stress in the equatorial Pacific and Indian Ocean region. More variability is seen in the south West Indian Ocean, east equatorial Indian Ocean, western part of Australia, west pacific, north west pacific and south west pacific. The variability in the East equatorial Indian Ocean and Western Australia related to the North West pacific variability through Indian Ocean through flow. We also used the mom4p1 model simulate these variability and compare with the observation data sets.

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22-24 March 2015


105

DYNAMICS OF SUMMER MONSOON OCEANIC EDDIES IN BAY OF BENGAL AND ITS EFFECT ON ATMOSPHERE

Saurabh Rathore1,2*, Anant Parekh1, Mihir Kumar Dash2

1Indian Institute of Tropical Metrology, Pune

2Indian Institute of Technology, Kharagpur; [email protected]

Meso-scale eddies form a distinctive and dynamic feature of ocean circulation and has a profound impact on the large scale flux of heat, salt, momentum in the ocean-atmosphere system. Oceanic eddies are circulating water bodies, and anticyclonic (cyclonic) eddies are associated with high (low) sea surface height and deeper (shallow) thermocline, transport heat and salt from one water mass to another, modifying thermohaline structure, transport and dispersal of dissolved substances and nutrients and affect cyclogenesis. Bay of Bengal (BoB) eddies plays role in the productivity of the bay and the sediment transportation. Meso-scale eddies of BoB affect the cyclogenesis and the intensity of mature cyclone, as the cyclone pass over from the cyclonic eddy its intensity decreases because of cold SST where as its intensity increases as it pass over the anticyclonic eddy due to warm SST. This study is to explore the role of meso-scale features on the dynamic and thermodynamic response of the BoB and its effect on the overlying atmosphere during the summer monsoon period (JJAS).

Okubo-Weiss parameter (OWP) is used to identify the meso-scale oceanic eddies. OWP = Ss

2 + Sn2 – ω2. Where Ss is shear stress, Sn is normal stress and ω is vorticity. The eddy

core is defined as an interconnected region of negative OWP (W < –W0), where W0 = 0.2σw (W0 is threshold value and σw is spatial standard deviation of W for study region)

For this study we used Sea Level Anomaly (SLA) data for the period of 1993-2013 from AVISO/SSALTO DUACS and temperature and salinity profile data from the Argo for the period of 2003-2012. We studied MLD and D20 signature over the eddies location. Wind stress curl over the region is estimated from ERA-Interim data from 1993-2010. For chlorophyll data we use Goddard Earth Sciences Data chlorophyll-a concentration from 2002-2012. In our study, we identified the eddies present in the BoB (790E-1000E, 50N-230N) during JJAS for the period of 1993-2013 by using OWP. We found two cyclonic eddies C1 and C2 centered at 85.70E, 17.90N & 83.70E, 8.70N respectively and one anticyclonic eddy, A1 centered at 84.20E; 14.30N sandwiched between these two cyclonic eddies. At the center of C1 and C2 the measured SLA values are -0.07 m and -0.05 m, whereas the measured SLA values at the center of A1 is 0.06 m. The value of relative vorticity (geostrophic vorticty) at the center of C1, C2 and A1 is 4.56×10-6 s-1, 2.308×10-6 s-1, 1.484×10-6 s-1 respectively. The value of OWP for C1 is 3.5×10-11 s- for C2 and A1 are 8.0×10-

11 s-2 and 3.9×10-11 s-2 respectively. We also studied mixed layer depth (MLD) and thermocline depth (D20) signatures of these eddies and results are consistent with the theory proposed for eddies. As relatively shallow MLD of 17.7 m and 22.3 m and D20 of 109.6 m and 98.7 m are observed for C1 and C2 respectively whereas relatively deeper MLD of 29.8 m and D20 of 122.8 m are observed in case of A1. Eddy Kinetic Energy (EKE) is computed over the area of observed eddies from SLA data from 1993-2013, which showed

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106

the presence of meso-scale activity over identified eddy regions and having fair signal of 4598 cm2/s2,6546 cm2/s2, 5523 cm2/s2 for C1, C2, A1 respectively. In this context wind stress curl over the region was also analyzed for JJAS period and we found that the signature of high rotational component of stress is one of the reasons for generation of eddies. Further-more from the analysis of chlorophyll concentration data, it is clearly shown that cyclonic eddies are fruitful because they bring the nutrients on surface from sub-surface. In our analysis we found the chlorophyll concentration as 0.27 mg/m3, 0.25 mg/m3 and 0.13 mg/m3 over C1, C2 and A1 respectively. Hence cyclonic eddies (up-welling) are more productive as compare to anticyclonic eddies (down-welling). Further expanding the study in the direction to analyze the effect of these meso-scale features to overlying atmosphere, composite of temperature and water vapour mixing ratio anomaly profile is analyzed over cyclonic and anticyclonic eddies. By this analysis we found that cyclonic eddies converge the moisture and make the atmosphere warmer and vice versa happens in case of anticyclonic eddies.

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22-24 March 2015


107

VARIABILITY OF ATMOSPHERIC REFRACTIVE INDEX STRUCTURE PARAMETER (CN

2) – A CASE STUDY AND IT’S PREDICTION USING METEOROLOGICAL DATA

G Nageswara Rao* and Amit Pratap

Center for High Energy Systems and Sciences, DRDO, Hyderabad-500069; [email protected]

There are numerous atmospheric effects that can significantly impact the performance of high power laser systems. Atmospheric turbulence and meteorological visibility (clouds, dust, fog and aerosols) reduces the laser power density at target. Propagation through atmospheric turbulence results in beam spreading, wandering, and in case of strong turbulence, beam will break up into many smaller beams (scintillation). The most important parameter that characterizes the effects of turbulence is the atmospheric refractive index structure parameter. The atmospheric turbulence can be defined by the strength of the fluctuations in the refractive-index, represented by refractive-index structure parameter (Cn

2, units-m-2/3). Many authors have tried to predict the behaviour of the refractive-index structure parameter, and various models have been proposed (Sadot & Kopeika, 1992).

However, these models developed for different atmospheric conditions which may not be directly applicable for Indian climatic scenario. Hence, a new empirical model has to be developed for Indian atmospheric conditions. In order to do the same, data collected by scintillometer (BLS 900) installed at Shaadnagar, Hyderabad with a path length of 671m was utilized. Efforts have also been made to empirically model the Cn

2 using meteorological parameters. The data spans from 15-30 April 2013 with a time interval of 15min.

Results showed that Cn2 had strong diurnal and semi-diurnal variability. Maximum

standard deviation of Cn2 was observed at noon time. The meteorological parameters viz.,

temperature, relative humidity and wind speed also showed diurnal pattern. The correlation values of temperature, humidity and wind speed against Cn

2 were 0.71, -0.62 and 0.68 respectively. An empirical model (multi-polynomial type) has been developed for Cn

2 with a regression coefficient of 0.5 and correlation coefficient of 0.71. However, there was difference in the value at noon. Using this observed and predicted Cn

2 values, laser parameters viz., short term radius, long term radius and beam wander were also computed.

In summary, Cn2 values can be predicted with reasonable accuracy using

meteorological data. However, prediction of Cn2 is difficult during noon time because of its

high standard deviation. The accuracy of the prediction can be improved by including more and more data.

Acknowledgements: Authors are thankful to Director, CHESS for providing the motivation and encouragement to carry out this study. Authors are grateful to Director, NRSC, Hyderabad for providing the scintillometer data. References: Sadot D and Kopeika NS (1992), Forecasting optical turbulence strength on the basis of macroscale meteorology and aerosols: models and validation, Opt. Engg., Vo. 31, No. 2.

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108

EPOCHAL CHANGES IN THE DOMINANT SUBSURFACE MODE OF TROPICAL INDIAN OCEAN

Ojha Sayantani* and C. Gnanaseelan

Indian Institute of tropical Meteorology, Pune-411008; [email protected]

The patterns of the first mode of TIO subsurface temperature variability and their vertical structure are found to closely resemble the patterns of IOD and El Niño co-occurrence years. These co-occurrence years are characterized by a north–south subsurface dipole rather than a conventional IOD forced east–west dipole. The first mode of variability of depth of 20°C isotherm and 100 meter temperature shows a northern cooling and southern warming over the TIO during the co-occurrence years. The intensity of subsurface dipole mode is quantified by using subsurface dipole index (SDI) which is defined as the difference in d20 anomalies between the regions 60°E–90°E, 15°S–5°S and 70°E–100°E, 5°S–10°N. This subsurface dipole is forced by wind stress curl anomalies, driven mainly by meridional shear in the zonal wind anomalies. The subsurface temperature variability and its north-south dipole pattern show differences in the pre and post climate shift period. The subsurface variability has been examined before and after 1976-1977 which is known as the period when the characteristics of ENSO evolution and its related teleconnection have revealed major changes. The southern TIO warming is stronger and extended over a broader region in post-76 period. The seasonal variability also shows differences in spatial pattern. In post-76 period during all the three seasons (SON, MAM and DJF) the southern warming is located mainly in the central TIO whereas in the pre-76 it can be seen in the western TIO. In the recent epoch the Arabian Sea is warmer in all the three seasons which is not the case in the pre-76. The forcing mechanism also shows prominent differences in the two cases. The meridional wind shear is stronger in the recent epoch which causes strong anticyclonic wind stress curl. The anticyclonic curl induces downwelling Rossby wave in the southern TIO which propagates westward and keeps the western basin warm. This wind stress curl and associated wave propagation are weaker in previous epoch. The correlation of SDI and wind stress curl supports this mechanism. The persistence of warming in the recent epoch is evident from the strong correlation of barrier layer and SDI. The impact of the subsurface variability is seen in the SST anomalies. During pre-76 positive SST anomalies are present in the southern TIO and it persists up to April of the following year. But in recent time period SST warming can be seen almost over the entire TIO which persists up to next July. The subsurface mode influences the summer precipitation also. The correlation of summer monsoon precipitation with SDI is strong over the Western Ghats and southern peninsular India in post-76 period whereas in pre-76 period the correlation is comparatively weaker. The composite of precipitable water also supports this pattern. So the meridional subsurface mode has a strong impact on SST variability and summer precipitation which is getting stronger in the recent years.

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109

VALIDATION OF GEKCO AND OSCAR PRODUCTS FOR THE INDIAN OCEAN REGION USING IN – SITU OBSERVATIONS FROM MOORINGS

A Phanindra Reddy*, Simi Mathew, G. Latha and R. Venkatesan

National Institute of Ocean Technology, Chennai; [email protected]

Ocean surface currents obtained from downward looking Acoustic Doppler Current Profiler (ADCP) attached to the moorings of National Institute of Ocean Technology (NIOT) buoys has been inter compared with the two satellite derived surface currents; namely Ocean Surface Current Analysis Real-time (OSCAR) and Geostrophic and Ekman Current Observatory (GEKCO) at eight locations, four in Bay of Bengal (BoB) and four in Arabian sea (AS). A period of 22 months buoy data is compared with satellite products for the Bay of Bengal and around 10 months buoy data is compared with satellite products for Arabian Sea. From the validation exercise carried out, it can be inferred that both the products showed good agreement with the corresponding components of buoy observed surface currents. The correlation coefficients for buoy and OSCAR are exceeding 0.7 and 0.6 for BoB & AS respectively. The correlation coefficients for buoy and GEKCO were reasonable for BoB with exceeding 0.6; while there is poorer correlation was observed for buoys in the AS with GEKCO product. Even though OSCAR product is showing good correlation in open ocean but coastal regions are less correlated with buoy data.

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IMPACT OF CLIMATE MODES ON THE INTER-ANNUAL VARIABILITY OF ZONAL CURRENTS IN THE EQUATORIAL INDIAN OCEAN.

Chinnu Sachidanandan* and P.M. Muraleedharan

CSIR-National Institute of Oceanography, Goa; [email protected]

The study aims at investigating the variability of zonal current in the equatorial Indian Ocean in response to the climate mode signals like Indian Ocean Dipole (IOD) and Elnino Southern Oscillation (ENSO). We have used Acoustic Doppler Current Profiler (ADCP) data at three locations at the equator (77°E, 80°E, 90°E) from 2004 to 2007 collected under Ocean Observing Program initiated jointly by Department of Science and Technology (DST) and National Institute of Oceanography (NIO). The ADCP data at the eastern equatorial Indian Ocean collected under the international program RAMA (Research moored Array for African-Asia Australian Monsoon Analysis and Prediction) has also been extensively used in this study. A model data for a longer duration to address the inter-annual time scale has also been used. The data is generated using an Ocean General Circulation Model widely known as NEMO (Nucleus for European modelling of ocean) forced from 1958 to 2007.

The validation performed on inter annual scales indicated that model currents are significantly correlated with observations at both surface and subsurface depths. Empirical Orthogonal Function (EOF) analysis performed on currents at the surface and the entire water column showed zonal currents are more variable at upper layers than at depths. The first leading mode of the EOF performed at depths significantly lead the second with 4 months, a clear indication that first mode often associated with the features of equatorial jet and second one explains the under current. The simple correlation between principal components (PCs) of first leading modes from EOF performed on surface and column data produce significantly high values further emphasising the variability at the surface layer.

Linear regression performed between PC’s of surface currents and surface wind vector/Sea Surface Temperature showed that the current responses are coupled with IOD/ENSO climate modes. Partial regression analysis of leading modes of PC's with the respective indices separates out the influence of IOD and ENSO thereby confirming that the upper layer currents are strongly influenced by IOD rather than ENSO.

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111

SPATIO-TEMPORAL VARIATIONS IN SALINITY PROFILES OVER THE BAY OF BENGAL

Kumar Ravi Prakash*, Vimlesh Pant

Indian Institute of Technology Delhi, New Delhi-110016; [email protected]

The surface circulation and freshwater flux, both local (evaporation or precipitation), and from river runoff contribute in determining the thermohaline structure and its variability in the Bay of Bengal (BoB). The northeast and southwest monsoons reverse the direction of monsoon currents and coastal currents in the northern Indian Ocean. In this study, we used salinity profiles from ARGO floats for the years 2005-2013 to study monthly, seasonal, and annual variations in salinity profiles over over three sectors of BoB i.e. northern (NBoB), central (CBoB), and southern (SBoB). These sectors have been selected based on the climatological circulation pattern in the BoB, which plays important role in governing salinity variability at seasonal and interannual time scales. Additionally, the surface currents data from OSCAR and precipitation data from GPCP were used to analyses observations. The effect of large river runoff into the northern sector of BoB is clearly seen in the salinity profiles in NBoB with marked year-to-year and seasonal variability in top 100 m as compare to other two sectors. The CBoB shows reduced, but similar trend, in salinity profile variability with a delay of about a month to that of NBoB. Interannual variability in salinity profiles found to be maximum in NBoB, particularly in post-monsoon (ON) and winter (DJF) seasons, where the differences in surface salinity between the years found to be up to 2 psu. In the SBoB, the effects of summer and winter monsoon currents are clearly visible in modulating seasonal variability in salinity profiles.

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SUPPLEMENTING XBT OBSERVATIONS WITH SALINITY IN THE BAY OF BENGAL

Venugopal Reddy.T1, Ali.M.M2*, Gopala Krishna.V.V3 1INCOIS,Hyderabad

2NRSC,Hyderabad, [email protected]

3CSIR-NIO,Dona Paula, Goa

Salinity and Temperature profiles together required for many of the oceanographic studies. Compared to Conductivity,Temperature,Depth (CTD) observations which provide both temperature and salinity, Expendable Bathy Thermograph (XBT) observations, giving only temperature profiles are more. Hence, T-S diagrams have been used to estimate salintiy from the temperature measurements. In this paper we present a neural network approach to supliment XBT temperature with salinity data over Bay of Bengal (BoB). We considered estimating salinity from temperature in the BoB as a challenging problem beacause of strong salinity gradients, highly variable stability in both temporal and spatial scales due to large fresh water flux.

For this purpose we used climatological (WOA-09) temperature and salinity profiles. Present Neural Networks algorithm has one input layer with 5 neurons, one hidden layer with 7 neurons and one output layer with one neuron. Since T-S relation have temporal, spatial as well as depth dependencies we considered Time (month),Space (latitude,longitude,depth), and Temperature as input to the model and salintiy as the output.

This model has been used to estimate salinity using the above inputs from CTD observations. Estimated salinity has been compared with actual CTD salintiy. The RMSE varies from 0.643 at surface to 0.048 at 700 m.

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MARINE TECHNOLOGY & MARINE ACOUSTICS

SESSION - 03

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114

GPS/GSM BASED SEAMLESS IN-SITU PROFILER FOR ATMOSPHERIC BOUNDARY LAYER

Femy Paulose*1,2, Feby Paulose1, Gibies George2

1Sree Narayana Gurukulam College of Engineering; [email protected]


The atmospheric boundary layer (ABL) is the energy source for the entire troposphere. The solar radiation received at the earth surface is partially absorbed and partially reflected by the surface depending on the nature of the surface. Absorbed energy is radiated as the thermal (long wave) radiation, which is the primary energy source for the atmosphere. The atmosphere also receives the sensible and latent heat from the surface. Temperature and humidity profile of the atmospheric boundary layer provides the basic information’s on the energy budget of the atmosphere especially in small scale.

Operational meteorological agencies used to take upper air sounding (Wang et al. 2001) twice a day (more frequently on special cases). But they have their own limitation in monitoring minute details of the mesoscale (small scale) variability in the temporal and spatial (horizontal and vertical) distribution of the ABL parameters. In this study we have designed and implemented a new and simple instrument to build up the capability of local bodies like panchayath, municipalities and corporations to directly monitor the local weather conditions. Earlier Sankar and Norman (2009) attempted for such an instrument. Recently, Femy et al. (2014) developed the minimal version of the instrument and conducted the sensor calibration and temporal profiling of a single surface station. The new instrument can be used in three different modes (a) Temporal profiling of single surface station; (b) Horizontal profiling at the surface while mounted on an automobile; (c) Vertical profiling using balloon. An improved version of the same with better GPS altitude resolution can be used for a combined temporal cum vertical profiling while mounted with pulley and rope on a tower observatory. This can also be used attached with an Unmanned Aerial Vehicle (UAV) for three dimensional profiling of some specific systems like thunder storm. Here we are presenting the basic system design and the preliminary analysis.

GPS-GSM based seamless in-situ profiler system consists of an observing platform and a ground station. Observing platform is the balloon/automobile on which the embedded systems along with the atmospheric sensors are mounted. A GSM module (SIM900) in the instrument transmits the observed data along with the GPS information to the ground station. Ground station is a laptop personal computer with a similar GSM modem (or a mobile phone or a tablet system) to receive the data transmitted from the observing platform. The atmospheric sensors BMP085 (pressure and temperature measurement) and SY-HS-220 (humidity sensor) and GPS module (GTPA010) are driven by the microcontroller (LPC2148, based on a 16-bit/32-bit ARM7TDMI-S CPU with real-time emulation).

The GPS module provides the information about the time, latitude, longitude and altitude of observation platform to the microcontroller. Most computer programs that provide real time position information understand and expect data to be in NMEA format. This data includes the complete PVT (position, velocity, time) solution computed by the GPS

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receiver. The idea of NMEA is to send a line of data called a sentence that is totally self contained and independent from other sentences. So to collect data on horizontal here using GPGGA (Global Positioning System Fix Data) sentence code.

The whole data is transmitted to the ground station through the GSM transmitter in the observation platform. The instrument has a temperature sensor with resolution 0.1 degC, pressure sensor with resolution 0.01 hPa and humidity sensor with resolution 1% RH connected to the microcontroller. The range of humidity measurement is between 30% and 90% relative humidity. The range of pressure measurement is between 300 hPa and 1100 hPa. The valid range of temperature measurement is between negative 40 degC and positive 85 degC Accuracy of pressure sensor is 0.01 hPa and that of humidity sensor is about +_5%RH. The time required for BMP085 module to calculate temperature and pressure are 4.5 ms and 7.5 ms respectively.

References: Femy Paulose, Aby Mathew, Gibies George (2014) “GPS/GSM based embedded system for atmospheric boundary layer profiling and weather monitoring” International Journal of Science and Research (IJSR), Volume 3 Issue 9, September 2014. Sankar.P, Suresh.R.Norman (2009) Embedded System for Monitoring Atmospheric Weather Conditions Using Weather Balloon International Conference on “Control, Automation, Communication and Energy Conservation”-2009 Wang J., Cole H.L., Carlson D.J., Paukkunen A (2001) Performance of Vaisala RS80 radiosonde on measuring upper tropospheric humidity after corrections, 11th Symposium in Meteorological Observations and Instrumentation, American Meteorological Society, Jan. 2001.

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116

ESTABLISHMENT OF SHIPBOARD AWS ON INDIAN RESEARCH VESSEL SINDHU SADHANA

K. Vijay Kumar, Prakash Mehra, Yogesh Agarvadekar, Govind Ranade, G.P Naik, Ryan Luis, Bharat Harmalkar, Devika V. Ghatge, Narayan Satelkar, and Pramath Keny

CSIR- National institute of Oceanography, Goa - 403 004; [email protected]

A seaworthy measuring system suitable for mounting aboard ship has been developed and deployed at onboard Research Vessel Sindhu Sadhana (RV Sindhu Sadhna). The system, Shipboard AWS (SAWS), contains tower-mounted meteorological sensors for surface meteorological parameters, radiation sensors for radiative flux, sea surface temperature (SST) for thermodynamics property of surface sea water, echo sounders for ocean depth information, inertial navigational system and GPS for wind correction, ship attitudes and geographical position respectively. SAWS is a state-of-the-art fully in-house designed and developed system has capability to relay the information on local area network (LAN), which has been tested over RV Sindhu Sadhana LAN configuration and data were viewed from various nodes over the ship (for example, chief scientist cabin, data acquisition lab and physics lab). The system is useful for surface meteorological observation, marine boundary layer dynamics and air-sea interaction studies in conjunction with fast esponse high frequency sensors for air-sea flux observations. It is also useful for coupled air-sea model calibration and validation.

Fig.1 Installation of SAWS at onboard RV Sindhu Sadhana

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SPATIAL DISTRIBUTION OF SOFAR CHANNEL PARAMETERS OVER BAY OF BENGAL

K.Ashalatha1, T.V.R.Murty2, K.V.S.R.Prasad3 1Department of Meteorology & Oceanography, Andhra University, Visakhapatnam; [email protected]

2CSIR- NIO, Regional centre, Visakhapatnam; [email protected]

3Department of Meteorology & Oceanography, Andhra University, Visakhapatnam; [email protected]

The Present work reports the analysis of the derived SOFAR channel parameters (such as channel depth, axial sound velocity, Conjugate depth, Sonic Layer depth (SLD), and Mixed Layer Depth (MLD) in the Bay of Bengal. Sound is the prime source of energy to explore into the ocean interior. It can use for long range underwater communication, detection of underwater targets, etc. and also to determine the depth of the Ocean. To understand the sound velocity distribution and it’s characteristics in the Bay of Bengal (0.5° – 23.5°N; 78.5° – 100.5°E), Levitus 2009 annual data is used. The SOFAR channel (Sound Fixing and Ranging channel) is a horizontal layer of water in the ocean at which depth of sound speed is minimum. The depth of Minimum sound speed within a sound channel called channel depth. The depth of sound channel axis varies between 1100-1750 m in the Bay of Bengal. In general, the depth of the channel axis Increases towards the northern latitudes in the Arabian Sea, while it decreases in the Bay of Bengal. The depth below the deep sound channel axis where the sound speed equals the speed at the source depth called conjugate depth. Conjugate depth varying between 180 m – 420 m in the Bay of Bengal. Sonic layer depth is the depth of maximum near-surface sound speed above the deep sound channel. The range of sonic layer depth is varying between 10m – 40m. The quasi homogenous region of the upper ocean, where physical properties like density, salinity and temperature are nearly constant with depth called mixed layer depth .It shows the variation from 4m-11m. The Bay of Bengal has depth limited nature of the profile. Then, the effective sound channel lies much below the sea surface. As, a result, In underwater acoustics, that region in the water column where the sound speed first decreases to a minimum value with depth and then increases in value, due to pressure. Above the depth of minimum value, sound rays are bent downward; below the depth of minimum value, rays are bent upward, resulting in the rays being trapped in this channel and permitting their detection at great ranges from the sound source

References: RamanaMurty, T.V., Prasanna Kumar, S., Somayajulu, Y.K., Sastry, J.S., De Figueiredo, R.J.P., “Canonical sound speed profile for the central Bay of Bengal”, J. Earth. Sys. Science, 253-263, 1989. Munk, W.H., and Forbes, A.M.G., “Global Ocean Warming: An acoustic measure?” J. Phys. Oceanogr. 19, 1765-1778, 1989.

Chen, C.T., and Millero, F.J., “Speed of sound in sea water at higher pressure”; J. Acoust. Soc. America, 60, 129-135, 1977.

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DEVELOPMENT OF MICROBIAL FUEL CELL BASED ENERGY HARVESTING SYSTEM USING MARINE SEDIMENT FOR UNDERWATER APPLICATIONS

P. Janani*, S. Sakthivel Murugan, N. Archana 1ECE Department, SSN College of Engineering, OMR, Chennai -603110; [email protected]

Underwater acoustic communication in shallow/deep water is a fast developing area of research. Various systems used for underwater applications such as disaster warning tsunami buoy systems, underwater sensor networks, underwater seismic observing systems, Autonomous Underwater Vehicle, manned submersible vehicles, acoustic signal processing submersibles used for defense purposes etc requires major power for operation. In general batteries are used to power the systems. In this paper an energy harvesting system for low power devices are proposed. This harvesting system uses marine sediments (available in shallow/deep water) Microbial Fuel Cell (MFC) as a source for power generation.

The system consists of marine sediment MFC and a power management system. The voltage developed by the MFC is less than 0.7V. So, a power management system is used between the MFC and the load to power the electronic devices in ocean water. The power management system consists of Charge Pump Circuit, Super capacitor and Interleaved Boost Converter. The charge pump circuit generates an output voltage of 1.4 V twice that of the input voltage of MFC which is then stored in a super capacitor. The voltage stored in a super capacitor is transferred to the Interleaved Boost Converter which boosts the voltage of 1.4V to 6.8V which is the requirement of the load. Thus the design of a new underwater energy harvesting system provides relentless and justifiable power supply for remote underwater sensing, surveillance devices including data collections. Simulation results of energy harvesting system are carried out using MATLAB.

References: Guoxian Huang, 2013, A Biomass-based Marine Sediment Energy Harvesting System, Low Power Electronics and Design(ISLPED), 359-364. Meehan.A, 2011, Energy Harvesting with Microbial Fuel Cell and power management system, IEEE Transactions on Power Electronics, 26, 331-355.

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119

RAIN FALL ANALYSIS USING NOISE MEASUREMENTS IN SHALLOW WATERS OFF ANDHRA COAST

M. Ashokan*, G. Latha2, K. Nithyanandam3


Ambient noise measurements have been made in shallow water of Indian east coast by deploying a moored buoy having a 21 element vertical hydrophone array of frequency band 100 Hz to 20 kHz. The ambient noise data has been acquired and stored periodically in a Real Time Operating System (RTOS) based data acquiring system. The sampling frequency was kept at 50 kHz and sampling duration was 30 seconds. The noise data sets were collected in once in every 3 hrs. The measurement periodicity of the data acquisition has been monitored by an indigenously developed power controller board. The noise data sets collected by the hydrophone element nearer to sea surface was taken for analysis. Along with this moored buoy, another moored buoy has been deployed very near, for measuring the surface weather parameters such as wind speed, wind direction, outside air temperature and rain fall events. The rain fall events have been measured by using RM Young make precipitation type rain gauge. The watch circle between these buoys was around 500 m. The depth of the location is 25 m, whereas the hydrophone array was kept at mid water column. Noise data sets and surface weather parameters have been collected from 28 October 2014 to 17 December 2014. Within this period, totally 353 noise data sets have been collected and 30 have been fallen in the rain fall events. The preliminary analysis of measurements showed that predominantly the noise field is due to rain during rain events, regardless of the wind [Ashokan et al., 2015]. This paper presents the work carried out on the estimation of noise level pertaining to different rain fall rates such as light rain (drizzling) and heavy rain in shallow waters off the North West Bay of Bengal. This research has applications in finding different types of rain fall rates from the acquired ambient noise data sets [Ma Barry B et al., 2005].

References: Ashokan M., Latha G., and Ramesh R. (2015), Analysis of shallow water ambient noise due to rain and derivation of rain parameters, Applied Acoustics, 88, 114-122. Ma Barry B, Nystuen Jeffrey A, Lien Ren-Chieh. (2005), Prediction of underwater sound levels from rain and wind, J. Acoust. Soc. Am., 117, 3555-3565.

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CONVERTED WAVE AVO ANALYSIS FOR RESERVOIR CHARACTERISATION

Prabhakar Nayak, A. K. Rai

Indian Institute of Technology Bhubaneswar, Odisha-751007

Rock formation are characterised by their physical properties like elastic parameters (modulus of rigidity, bulk modulus, lame parameter), mineral composition, porosity, fluid content, etc. These properties are reflected in their seismic attributes as well. Change in one of these parameters affects the ratio of compressional wave velocity (Vp) to Shear wave velocity (Vs) of a formation. Poisson’s ratio, which is a function of Vp and Vs will vary with physical properties of the rocks. Modern techniques of data acquisition and processing provide tools using which converted S- wave information can be extracted. This PS- wave analysis can provide us seismic attributes that can be analysed to obtain shear wave reflectivity as well as density contrast information. The shear wave information from PS-wave AVO modelling can be used along with PP- wave AVO analysis to find better models of Poisson’s ratio variation. Poisson’s ratio variation and density contrast information from PS-wave AVO analysis can be useful for better characterisation of reservoirs, and determining saturation of fluid in the formations. Poisson’s ratio variations in formations may be better attributes for reservoir characterization. Also the density considerably varies with the porosity and fluid content. Therefore, Poisson’s ratio and density variation together may provide better constraints than seismic wave speeds and other parameters.

References Antonio, C. B., Ramos and Castagna, John P., 2001, Useful approximations for converted-wave AVO, Geophysics, 66, 1721–1734. Xiucheng, W., Tiansheng, C., and Ji Yuxin, J., 2008, Converted wave AVO inversion for average velocity ratio and shear wave reflection coefficient, Applied Geophysics, 5, 35-43.

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DEVELOPMENT OF DUAL MODE COMMUNICATION A NOVEL TECHNIQUE FOR REAL TIME TSUNAMI BUOY SYSTEMS

R.Sundar, M.Arulmuthiah, S.Elango, D.Gowtham, R.Venkatesan, M.A.Atmanand

ESSO-National Institute of Ocean Technology, Pallikaranai, Chennai-100

Ocean Observation System erstwhile National Data Buoy Programme a group of National Institute of Ocean Technology, Ministry of Earth Sciences was established in 1997 and is being maintain the Moored Buoy network in the Bay of Bengal and the Arabian Sea. To detect and measure the tsunami events, NIOT has developed and installed the Tsunami buoy systems in the Northern Indian Ocean Region from 2007 onwards which are transmitting the real time water level data using INMARSAT communication. Currently seven Tsunami buoy systems are working in the ocean and the data being shared to National Data Buoy Corporation (NDBC), USA. Since the Tsunami event data is more critical and these event datasets are transmitted through INMARSAT telemetry and normal tidal variation datasets are transmitted through INSAT telemetry to reduce the cost and to achieve self-reliance in technology for that a dual mode communication (INSAT & INMARSAT) novel technique was implemented in Tsunami buoy systems. This paper describes about the development, features and the successful implementation of dual mode communication system for Tsunami buoy system for real time water level data transmission.

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AMBIENT NOISE VARIABILITY ALONG THE CENTRAL WEST COAST OF INDIA – OFF GOA

R. Kannan*, G. Latha, G. Raguraman

National Institute of Ocean Technology, Pallikaranai, Chennai; [email protected]

Time series measurements of ambient noise were collected during the pre-monsoon period March, April and May, 2013 off Goa in the shallow waters of Arabian Sea with an interval of 3 hours between records. The buoy location is shown in Fig. 1. The twelve element omni-directional hydrophone array is used for collecting ambient noise in the frequency range 0.1 to 10 kHz. The wind speed measurements were also collected simultaneously and it is used for verifying its influence on the ambient noise. Monthly average wind speed is shown in Fig. 2. Since the fishing vessel activity in Goa is around 20 m water depth [and the buoy location is also in the same region, it is decided to examine the time series measurements of ambient noise at site off Goa with different source distribution for long period variations (i.e., noise variations extending to periods of a month) in the frequency band 0.1–5 kHz. The fishing information from the fisheries department of Goa is used to validate the fishing vessel activity [Report of Directorate of Fisheries, 2010]. The statistics of ambient noise datasets are reported in terms of regression analysis and standard deviation. The spectrum was calculated using Welch’s method of averaging modified periodograms windowed with a Hanning window, and fast Fourier transformed with 50% overlap to provide multiple spectra which are averaged.

The results of empirical fitting [NL = Intercept + 20*slope*log (wind speed)] based on analysis were used for noise level prediction and the model predictions [Ramji et.al., 2008] compare well with the measured noise level and it is shown in Fig. 3. It is observed during pre-monsoon period that higher the beaufort scale, higher the noise level. To study the influence of wind on noise variability, the datasets are segregated according to wind speed from 2 to 4 beaufort and the standard deviation is checked for frequencies upto 5 kHz shown in Fig. 4. During pre-monsoon period, the predominant wind direction is from NW and NE in which the wind comes from NW direction is stronger in magnitude which implies that the sea breeze effect is more compared to land breeze effect from NE direction. Further it was observed that the wind and vessel generated noise level measured in the pre-monsoon period falls approximately in the same range (62 to 73 dB). Since the buoy location is near to a fishing range, local fishing vessel contributes to a large extent to the overall ambient noise and hence the variability of ambient noise is high in the low frequency band upto 2.5 kHz. The flat ambient noise variability at high frequency band shows the predominance of wind noise which is uniform at the sea surface. Wind generated noise source has a strong influence in the higher frequency band after 2.5 kHz. The average wind speed during premonsoon period is 5.1 m/s. So the noise at this site is contributed by wind as well as fishing vessel. The results are in good agreement with the literature [Sanjana et. al., 2010]. Further it is planned to extend the analysis for different timings of the pre-monsoon period.

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FISH CHORUS RECORDED IN THE SOUTHEASTERN ARABIAN SEA: A COMPARISON STUDY WITH OTHER SHALLOW WATER ENVIRONMENTS

M. M. Mahanty*, G. Latha and A.Thirunavukkarasu

National Institute of Ocean Technology, Pallikaranai, Chennai-100; [email protected]

Passive acoustic noise measurements were made in shallow water in the southeastern Arabian Sea using an autonomous system, during month of January-May, 2011. Based on the spectrogram analysis, two fish chorus are identified and primarly belonging to the family Terapontidae and Planktivorous fishes. The recorded fish chorus are distinctive patterns in daily timing, frequency content and call characterstics throughout the period. The recordings are species-specific and can be compared with other shallow water environments. The frequency content and call characterstics of two fish chorus are comparable with the chorus recorded in shallow waters of Scott reef and Maret Island, Australia which have been previously studied by McCauley (2012).The Terapontidae chorus shown after dusk, maximal at the beginning of January to end of March, but ceased down by month of May, whereas planktivorous fish peaked before midnight that displaying lunar trend during 22ndJanuary-8thFebruary.The two chorus types differs significantly in their acoustic characterstics, the planktivorous fish chorus are single broadband pulse from one contraction of swimbladdar, where as Terapontidae chorus are a series of pulses of the swimbladdar by anterior muscles contraction consecutively (McCauley, 2001). The Terapontidae pulse repetition rate appeared in the frequency spectra at 0.1-0.12 kHz and swimbladder resonant spectral peak is extended over 1-1.8 kHz. The planktivorous fish chorus spectral maxima is observed near 0.6 kHz. The sharp dip at 0.9 kHz in the spectra of the planktivorous chorus suggesting the fish were calling near the surface.The planktivorous chorus are associated with feeding whereas,Terapontidae chorus related with spawning. The spectral level during fish chorus is relatively 30 dB higher than the average ambient noise spectra.

References: McCauley, R.D. (2012), Fish choruses from the Kimberley, seasonal and lunar links as determined by long-term sea-noise monitoring, Proceedings of Acoustics 2012 Fremantle, Western Australia, November, 21-23. McCauley, R.D. (2001), Biological sea noise in northern Australia: Patterns of fish calling. PhD. Thesis, James Cook University Library.

mailto:[email protected]

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NOISE LEVEL VARIABILITY AND SPECTRAL CHARACTERISTICS OF SHALLOW WATER AMBIENT NOISE AT VIZAG

K.K Noufal*, M.C Sanjana, G. Latha

National Institute of Ocean Technology, Pallikaranai, Chennai-600100, India; [email protected]

Shallow water ambient noise (AN) is well known for its level and frequency variability because of different sources such as wind, rain, ship, biological organisms and anthropogenic activities. AN measurements were carried out off Vizag at ~ 20 m water depth during February-April 2014, in the range 0.025-20 kHz covering the entire sonic band of frequencies, has been used for analysis. The data have been analyzed for wind induced wave breaking, shipping and other prevailing noise sources.The measurement period spans winter and summer months, seasonal variability in noise characterestics for this extreamly shallow site is investigated. Further, the spectral content in noise due to tidal, hydro dynamic factors etc also addressed. Time series, Average and Standard deviation of NL were investigated for each month. Fluctuations of noise level during three months for different frequencies, beaufort windscale and tide level were analyzed. Average noise spectrum pattern were similar for all three months with slight level variation and Standard deviation for NL, decreases with increasing frequency. Within the studied period and frequency range NL shows significant variation below 5 kHz and modest change above 10 kHz.

References: Gordon M Wenz (1962), Acoustic Ambient Noise in the Ocean: Spectra and Sources, The Journal of The Acoustical Society of America. 34, 1936-1956. Sanjana, M.C. (2010), Fluctuation and variability of shallow water ambient noise from time series measurements, World Scientific Publishing Company 9(2), 193–202. Mahanty, M.M. (2014), An investigation on the fluctuation and variability of ambient noise in shallow waters of south west bay of Bengal, Indian Journal of Geo-Marine Sciences,43(5), 747-753.

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HINDUSTAN UNIVERSITY AUTONOMOUS UNDERWATER VEHICLE: DESIGN AND IMPLEMENTATION OF THE POSEIDON AUV

S.Suryakumar*, Gokulavasan, Indrajeet Ghosh, A.Muthuvel, N.Prakash, K.Kamalakkannan

Hindustan University, Semmandalam, Cuddalore(dt), Tamil Nadu-607001; [email protected]

Abstract—POSIEDON is the first Hindustan University autonomous underwater vehicle (AUV) designed and built by a team of 5 undergraduate students during the academic year of 2014-2015. Completed the AUV in a six month design cycle, the vehicle was fully modelled using Solidworks software is shown in Figure 1.2 and extensively simulated the structural and flow analysis with ANSYS ,STARCCM+ software’s and manufactured almost entirely in our campus. Grid Independent studies were carried out for the structural and flow analysis. Various Turbulence models are selected based on the literature survey for the flow analysis. Based on the Grid independent studies simulation is carried out for various speeds for 0.1-0.5 m/sec. During generation of the meshes, attention is given for refining the meshes near the AUV so that the boundary layer can be resolved properly. The typical mesh for AUV and domain is shown in Fig 1.3 and a magnified view near the solid wall of AUV is shown in Fig 1.4. The analysis is carried out for 0.25 million grid with 37 N force acting on the thruster clamps. The FOS for materials is 3.2 and the yield strength is 172 Mpa (the Maximum yield strength) of the material is 350Mpa hence the design is safe as shown in Fig 1.1. From the Pressure contour diagram, the variation of the velocity of flow over the AUV is seen at the velocity of 0.5 m/sec. At the bow of the AUV, stagnation condition is clearly captured. Also, boundary layer formation is seen near the walls. As the flow advances over the body, the velocity increases gradually and then reduces in the cap region due to curvilinear nature of the cap geometry as shown in Figures from 1.5 and 1.6. Poseidon presents a cheaper, stronger, lighter in weight of 22 kg and compact size of 0.7m*0.5m*0.5mas length, width and height of the vehicle and capable of working under 25 m depth. New advancements include full vehicle control of six degrees of freedom, a dual-hull cantilevered electronics rack and hulls, overhauled wire routing for electrical systems, and significant software for mission reliability and robustness. Poseidon sensor suite comprises of inertial measurement units (IMUs), two vision cameras, and humidity sensors, water sensors for kill switches, a depth sensor and an internal pressure sensor. Returning features include a vacuum-assisted sealing system; hot-swappable battery pods, unified serial communications, and flexible mission software architecture are installed. In unstructured mesh, polyhedral mesh was chosen as it gives more accuracy for lesser number of cells, thus the computational time is reduced. Testing of AUV is under progress.

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Figure 1.1 Factor of Safety for AUV

Figure 1.2 Isometric view of the AUV

Figure 1.3 Section views of AUV and Domain with

unstructured mesh

Figure 1.4 Unstructured mesh - magnified view near

the wall mesh

Figure 1.5 Pressure contour on the starboard side

Figure1.6 Pressure contour on the bow side mesh

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MAPPING SLOPE MORPHOLOGY OFF GOA, WESTERN CONTINENTAL MARGINS OF INDIA

Andrew Menezes*, S. M. Karisiddaiah, Bishwajit Chakraborty, K. Haris, William Fernandes

CSIR-National Institute of Oceanography, Dona Paula, Goa 40300; [email protected]

The slope morphology of the submarine gullies, ridges and the adjacent slump zone off Goa, along the western continental margin of India were mapped utilizing multi-beam bathymetric and single-channel seismic data (Chakraborty et al., 2014). Spatial data analysis employing ArcGIS could uncover the fluid flow migration signature in the form of pockmark seepages, traces of mud volcanoes and enhanced reflectors in the area. The analysis of the thirty-three depth profiles from the gully, ridge and slump areas revealed down-slope progression in gully incision and varying gradients in the gullies (1.19–4.07°) and ridges (2.13–3.70°), whereas the gradients of the profile in the slump zone were comparatively steady (2.25–2.51°). The scatter plot of the three slope characteristics, viz., gradient, mean depth and root mean square (rms) relief, characterizes the profiles of the gullies, ridges and the slump zone into three distinct clusters. The Principal Component Analysis (PCA) adopted for validation also revealed similar categorization wherein the gullies and slumps showed prominent clustering. The rms relief and gradient of the slump region display a positive relation. The rms relief is a measure of the large-scale roughness, exhibiting increasing roughness with declining slope gradient. Likewise increasing depth also contributes to increasing roughness. However, relationship between the mean depth and the slope gradient is negligible in the slump zone. Analysis using PCA to examine data variability suggests that rms relief, gradients and mean depths are the influencing factors that control the profile characteristics in the ridge, gully and the slump region respectively. It was observed that the first two principal components (PC1 and PC2) together explain 94.33 % of the total variance in the data.

Reference: [1] Chakraborty, B., Karisiddaiah, S.M., Menezes, A.A.A., Haris, K.., Gokul, G.S., Fernandes, W.A., and Kavitha, G. “Characterizing slope morphology using multifractal technique: A study from the western continental margin of India,” Natural Hazards: 73(2); 2014; 547-565.

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A METHOD FOR IMPROVING MULTIBEAM BATHYMETRY DATA QUALITY AFFECTED BY ERRONEOUS SOUND SPEED

William A. Fernandes*, Bishwajit Chakraborty

CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India; *[email protected]

The multi-beam echo-sounder systems operable at mid to high frequencies (12–400 kHz) are commonly employed to map the seafloor. The bathymetry and co-registered backscatter data acquired using the echo sounding system can facilitate remote acoustic seafloor studies. During data acquisition, we usually measure concurrent sound velocity profile data from the survey area as well as continuous probing of the sound speed at the face of the transducer array. The depths corresponds to each beam are assessed by the echo sounding system employing ray bending and ray -tracing methods based on the sound velocity of the profiled data [Beaudoin and Clarke, 2004]. The continuously probed sound velocity data at the face of the transducer array is used for beam-forming. Based on the computed reception angle the beam-steering has been achieved by applying suitable time delay.

In the tropical environment the sound velocity pattern varies periodically. During the survey, the spatial and temporal variations in sound velocity of the study area cause artifacts in the acquired bathymetry and co-registered backscatter data. The analysis carried out during the post-processing indicates that such artifacts are due to fluctuations in measured sound velocity profile. These artifacts influences the slant ranged beams and results distortion in the swath shape. Here, we have endeavoured to rectify refraction error that causes the smiling or frowning distortion in the swaths. As mentioned above the refraction error occurs due to incorrect sound speed at the face of transducer array or sound velocity profile measured in the water column [Fanlin Yang et. al, 2007].

In this work, a technique has been developed during the data post processing stages by applying correction coefficients computed from the acquired data and effectively applied to enhance the data quality that results improved bathymetry map [Fernandes, 2011]. The developed algorithm extracts the required parameters such as: beam Incidence angles, Time Varied Gain (TVG) cross-over angles, raw depths, raw ranges, surface sound speed, sound velocity profiles and related position data with total number of beams from the datagram stored in the raw data. The shape of the swaths has been examined for the refraction artifacts. The data are processed and the computed offsets are subsequently applied to correct the refraction errors. At the end, the developed algorithm generates improved bathymetry data and exported as ASCII format. The resulting output can be imported to additional softwares including ArcGIS (to creating spatial maps) and Matlab (for advanced statistical analysis). Additionally, the processed data has been converted to the binary formats compatible to commonly used sonar data processing softwares. The proposed technique can improve the bathymetry data quality affected by erroneous sound speed and the resulting bathymetry map can be utilized for seafloor studies.

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References: Beaudoin, J. and Hughes Clarke, J.E., “Retracing (and re-raytracing) Amundsen's Journey through the Northwest Passage”, Proceedings of the Canadian Hydrographic Conference 2004, Ottawa,2004. Fanlin Yang et. al, “A Post Processing Method for the Removal of Refraction Artifacts in Multibeam Bathymery Data”, J Mar. Geo 30; pp. 235-247, 2007. Fernandes, W. A., “A Method to Eliminate Refraction Artifacts in EM1002 Multibeam Echosounder System”, NIO Technical Report, NIO/TR-01/2011.

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RECENT ADVANCES IN THE DESIGN OF SONAR HUMAN MACHINE INTERFACE

*Anjaly C Gopi, G K Nagarajan, Sumi A Samad and V S Shenoi

Naval Physical & Oceanographic Laboratory, Thrikkakara PO, Kochi – 682 021; [email protected]

In an era of technology where systems are controlled by software, User Interface (UI) is one of the major factors that decide the usability of a system. UI otherwise known as Human Machine Interface (HMI) is the most essential part of a distributed real time system involving operator intervention. SOund Navigation And Ranging (Sonar) is one such electromechanical system where human interaction is made possible only through HMIs. Now a days various approaches are available to enhance HMIs which enable a single operator to control the entire system.

In this paper an attempt has been made to showcase some of specialized techniques that are used in enhancing sonar HMIs.(1).Integration of surveillance camera for audio/video streaming to view/control the activities taking place away from Sonar Control Room in the ship. (2)Picture In Picture (PIP) facility to preview the offline secondary page to have an overview of the entire Sonar pages to take tactical decisions. (3)2D Visualization of Towed array dynamics to visualize the dynamics of towed array when deployed underwater. (4) Integration of computational intensive systems like Sonar Performance Modeling System (SPMS) to Sonar HMI using Virtual Network Computing (VNC), which enables the operator to control such systems through operator console. (5) Real time theme selection to change the look and feel of HMI online to adapt to different environments in the platform.

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REFINEMENT OF SHALLOW WATER DEPTH ESTIMATION ALGORITHM USING WEIGHTED LINEAR REGRESSION APROACH

Vinayaraj Poliyapram1, Venkatesh Raghavan1, Glejin Johnson2 and V.V. Sanil Kumar2

1Graduate School for Creative Cities, Osaka City University, Osaka, Japan, [email protected] 2CSIR-National Institute of Oceanography, Goa

Information concerning water depth of near shore water region is one of the most basic requirements for coastal zone management. Bathymetry is especially important for near coastal lines, where changes can occur rapidly due to sedimentation and erosion. Here, an approach has been demonstrated to refine the shallow water depth estimation algorithm using multi-spectral Landsat-8 data. The Visible+NIR bands (0.43 – 0.88 µm) from Landsat8 image were used to estimate bottom classes and depth. The common practice of previous studies has been to calibrate a single global bathymetric inversion model for an entire image scene. The performance of conventional global models is limited when the bottom type and water quality vary spatially within the scene. To address the inadequacy of the conventional global models, this paper presents a geographically adaptive weighted regression model to better estimate depth. Atmospheric and water column correction of five bands (0.43 – 0.88 µm) are carried out by Short Wave Infrared band (1.57-1.65 µm) using following equation [Vinayaraj et al., 2014]

( ) (( ( )) ) (1)

Heterogeneous bottom type and water quality often lead to spatial non-stationarity of the mathematical relationship between the remotely sensed pixel radiance and depth. The corrected bands is used to estimate depth from geographically varying coefficients derived Geographical Weighted Regression (GWR) between multi- spectral bands and in-situ depth LiDAR for test site in Puerto Rico. The following equation explains the depth estimation using multi-spectral bands by GWR [Su et al., 2013]

( ) ( ) (2)

Where, is the estimated depth, ( ) geographical coordinates of point i and

( ) is the calculated value of the continuous function ( ) in point from depth estimation carried out by multiple regressions from a global coefficient. The result derived from the GWR is compared with the conventional global multiple regression. The accuracy of the results has been evaluated with LiDAR data. GWR (R2 = 0.96, RMSE = 1.4 meter) and global multiple regression (R2 = 0.75, RMSE = 1.5 meter). This study concluded that GWR model is a better method in order to estimate depth from shallow water.

References: Haibin Su, Hongxing Liu, Lei Wang,Anthony M.Filippi, William D. Heyman and Richard A.Beck (2013), Geographically adaptive inversion model for improving bathymetry retrieval from satellite multispectral imagery, IEEE transactions on Geosciences and Remote Sensing, 52(1), 465-476. Vinayaraj, P., Venkatesh Raghavan, Shinji Masumoto, Glejin Johnson and Masita Dwi Mandini Manessa, (2014), Investigation of algorithm to estimate shallow water bathymetry

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from Landsat-8 images, International symposium on Geinformatics for Spatial-Infrastructure in Earth and Allied Sciences GIS-IDEA 2014, Vietnam.

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A VLSI BASED INTEGRATED DATA ACQUISITION SYSTEM FOR POLAR OBSERVATORY

Lydia Kiruba R1*, M.Arul Muthiah2, R. Venkatesan2, A. Sivagami1

1Asan Memorial College of Engineering and Technology, Chennai; [email protected]

2National Institute of Ocean Technology, Chennai

This paper presents the development of a novel technique for subsurface multi sensor mooring for Polar waters. Earth System Science Organisation (ESSO), National Institute of Ocean Technology (NIOT) under the Ministry of Earth Sciences, is involved in the installation of instrumented moorings for Polar waters to understand the Polar Region processes and their influence on the Indian monsoon system. As real time data telemetry is not possible due to the ice cover in surface, submerged self recording instrumented moorings are being installed as a part of the study. The Polar observatory has threats of malfunction due to the floating ice bergs and continuous ice cover in the Polar Regions. Hence there is a chance that the system may get detached resulting in the loss of data and equipment.

As the collected data is more valuable, this design is being adapted to add adequate data redundancy and to ease downloading facility. The objective is to design a hybrid system using Inductive telemetry, VLSI and Acoustic technology. A reliable, low power and low cost FPGA based Integrated Data Acquisition system is developed for the Polar Observatory. The system is designed by programming the modules using VHDL in Xilinx, ISE design Suite 14.3. The whole system is programmed and tested using the FPGA Spartan 3E kit and its competence is observed.

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COLLECTION OF OCEANOGRAPHIC DATA IN MACRO TIDAL REGIME- GULF OF KHAMBHAT EXPERIENCE.

M.Sankar, K.M.Sivakholundu, B.K.Jena, Vijaya Ravichandran, V.Suseentharan, Karunakar Kintada


Oceanographic data like wave, tide and current were observed in Gulf of Khambhat (GoK) over a year period during 2012-2013. Being a macro tidal regime, GoK poses a challenging environment for any sustained observation campaign. This paper describes the difficulties faced to install the observation systems and sustain them for more than one year. A detailed account on planning, equipment selection, installation and retrieval schemes have been presented. The split observatory system for tide, expendable platform for tide and current were some of the improvisation made to overcome site difficulties. High currents accompanied with scouring seabed warranted a customized observatory scheme to overcome sinkage issues. The standard installation structures supplied by Original Equipments Manufacturer meant for open sea were found to be inadequate for collection of data in the GoK conditions. In order to overcome the difficulties prefabricated steel tower with raft foundation, improvised life boats for current observations, expendable frames for tide gauge installations were designed found to be cost effective and suitable for local conditions. The iterative processes of starting from system configuration to the customized system solution are explained after successful observations. Cost comparison between the split tower configuration and conventional observatory tower works out to be 1:4 ratio with no compromise on the final data quality.

The design and methodology used to measure Wave, Tide and current will be presented in this paper. As a result, now the GOK has been observed for tide, current and wave at more than 20 locations over a year period which perhaps is the first time occurrence in this part of the country in terms of the spatial coverage and duration.

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DEVELOPMENT OF DRIFTER BUOY FOR MEASURING CURRENTS IN SURF ZONE

V Suseentharan1*, K M Sivakholundu2, Basanta Kumar Jena3, M Ravinder4, R Balaji5

National Institute of Ocean Technology, Chennai; *[email protected]

This paper proposes a cost effective method of measuring surface currents in surf zone using two technologies such as General Packet Radio Service (GPRS) and Global positioning System (GPS). ARM based a low power module was developed with built-in high accuracy GPS receiver and GSM modem powered from 14.5V, 56aH battery pack and integrated in 30cm diameter buoy. An application has been developed to track GPS location and send it with GPS time stamp to central server. The module is having flexibility to change the configuration through SMS like sampling rate, data transfer interval, GPRS settings and target server settings such as FTP, IP server details, sub-folder and so on. Modules are available in different communication modes such as GPRS, Wi-Fi and INSAT based telemetry system. The system has been implemented with more than one telemetry systems with depending on site conditions. To minimize the wind driven movement of the buoy, a 2m or 5m drogue would be used based on the depth profile. A simple program has been written to calculate surface velocity and direction based on Lagrangian method. The data set is expected to be useful to oil spill model validation, HF Radar data validation and so on. The paper discusses the basic architecture of module, options that can be made and the experience gained during validation with LEO measurements

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HIGH STRENGTH TERMINATION TECHNIQUE FOR VECTRAN FIBRE ARMOURED UNDERWATER TOW CABLES

Kiran Govind V*, Anshath Hussain, Thulasidas K R, Sabu Sebastian M

Naval Physical & Oceanographic Laboratory, Thrikkakkara (P.O), Kochi-21, Kerala; [email protected]

A typical towed sensor array system wet-end consists of electro optic-mechanical cables, towed body and towed sensor array modules followed by a tail rope at the aft-end. An active cum passive towed sensor array system uses negatively buoyant Heavy Cable (HC) of length varying from 100 to 500 m, a neutrally buoyant Light Cable (LC) of length 100 m to 600 m, array modules of length 20 m to 30 m and a tail rope of length 10 m to 30 m.

The electro optic-mechanical (EOM) tow cables provide the optical, electrical and mechanical connection of the towed body and array with electronic processors on-board the ship. The tow cables transmit power to the underwater equipment and carry signals for underwater surveillance. The steel armored Heavy Cable is negatively buoyant and plays an important role in depth keeping of towed body and the array. The fibre armoured Light Cable is nearly neutrally buoyant cable which ensures sufficient trail or standoff distance of the linear array from the ship to keep the array away from self-noise of the platform and also helps the array modules to be in the same depth as towed body.

The EOM tow cables used in towed array sensor systems have to meet contrasting design requirements. In addition to having multiple numbers of electrical and optical lines, the cables should have high tensile strength, optimum weight/ meter, radial hydrostatic sealing at large hydrostatic pressure, minimum elongation, ease of operation & stowage, all within a minimum overall diameter. The cables should also be capable of withstanding the harsh marine environment and hydrodynamic forces experienced due to waves and currents during operation.

The tow cables derive their mechanical strength from high strength armour materials. The mechanical termination of the armour is a critical technique by which the loads on the armour are transferred to mechanical structural member on either ends of the tow cable without affecting the electrical or optical conductors inside. The final breaking strength of the cable is determined by the efficiency of cable termination. An ideal cable termination restrains the cable core and external strength members in such a manner as to duplicate the stress distribution in the cable elements which would be present in an undisturbed continuation of the original cable.

The mechanical strength for Light Cable to withstand high towing loads is provided by the high strength fibre armour which lies just below the outer sheath. One of the high strength fibre armour material most suited for underwater tow cables is Vectran, which is a high performance thermoplastic multifilament yarn spun from liquid crystal polymer (LPC). It has exceptional strength, superior fatigue and abrasion resistance, excellent creep characteristics and moisture resistance.

In the present study, the evolution of a high strength termination technique for mechanical termination of Vectran fibre armoured Light Cable is discussed. The technique

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employs a resin filled socket termination mechanism in which an epoxy based resin along with a hardener is used for termination. Tensile tests were conducted on multiple terminated cable samples using various epoxy-hardener combinations for achieving maximum termination efficiency. Based on the study, a suitable epoxy-hardener combination could be finalized which can provide the Light Cable a terminated tensile strength of more than 150kN. The termination technique has been widely applied for terminating Light Cables in various towed array systems and has successfully proved its functionality during exhaustive sea-trials.

References: Bash, F. J and Berian G. A (2001), Handbook of Oceanographic Winch, Wire and Cable Technology. Nowatzki, J. A. (1971), Strength Member Design for Underwater Cables, Underwater Cable and Connector Committee, MTSE. Bowers.W. (1973), High Strength-to-Weight Cable for Deep Ocean Projects, Proceedings of the 22nd International Wire & Cable Symposium, 279 -285 Triantafyllou. M. S (1991), "Dynamics of cables, towing cables, and mooring systems", Shock and Vibration Dig., vol. 23, pp.3 -8

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INTER-COMPARISON OF COLLOCATED CUP TYPE AND SONIC ANEMOMETER ON THE MOORED COASTAL BUOY

Jagadeesh Kadiyam, G. Vengatesan, M Arul Muthiah, J. Vimala and Dr. R Venkatesan

National Institute of Ocean Technology (NIOT), Chennai; [email protected]

National Institute of Ocean Technology (NIOT) under the Ministry of Earth Science (MoES), Govt. of India, started deployment of moored buoys in the Bay of Bengal and Arabian Sea in 1997 to provide continuous time series measurements of surface meteorological and oceanographic parameters at selected locations. These observations help to improve the understanding of ocean dynamics from seasonal, intraseasonal, annual and interannual time scales [1].

All the buoys are deployed with meteorological sensors like wind sensors, pressure sensors, temperature and humidity sensors etc., out of which wind speed measurement is important to study the cyclonic storms which are associated with low atmospheric pressure and strong winds which induce divergent circulation in the upper ocean [2]. The aim of the paper is to intercompare two types of anemometers viz. cup (Lambrecht, Germany) and sonic (GILL Instruments, USA), which were collocated on a moored buoy. Currently, NIOT deploys cup type anemometers in all the locations and this inter-comparison is done at one of the Coastal buoys deployed in Bay of Bengal off Krishnapatnam, Andhra Pradesh at 14° 16’ 55’’N/80° 11’ 58” E for a period of 1 year. Later the retrieved sonic anemometer is calibrated along with new sonic anemometer and Cup type anemometer in a Wind tunnel at FCRI, Palghat. The comparison results of both the co-located field anemometers are done to assess the performance of different types of anemometers in the marine environment.

References R. Venkatesan, V. R. Shamji, G. Latha, Simi Mathew, R. R. Rao, Arul Muthiah and M. A. Atmanand, (2013), New in-situ ocean subsurface time series measurements from OMNI buoy network in the Bay of Bengal, Current Science, 104, 9. R. Venkatesan, Simi Mathew, J. Vimala, G. Latha, M. Arul Muthiah, S. Ramasundaram, R. Sundar, R. Lavanya and M. A. Atmanand (2014) Signatures of very severe cyclonic storm Phailin in met–ocean parameters observed by moored buoy network in the Bay of Bengal, Current Science, 107, 4

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A REVIEW ON THE INDIRECT ESTIMATION OF GEO-ACOUSTIC PROPERTIES OF SEABED

V.K. Unny*, C.P. Uthaman, Nitheesh Thomas

Naval Physical and Oceanographic Laboratory, DRDO, Thrikkakara PO, Kochi-682021; [email protected]

Acoustic propagation in shallow water is viewed as a wave-guide phenomenon, with the sea surface and seabed forming the boundaries. The acoustic properties of the seabed to a depth of several wavelengths can have a strong effect on propagation. The modelling of propagation requires estimates of such parameters as sound speed, density, attenuation, and layer thicknesses etc which are collectively called the geo-acoustic properties of the seabed. The direct measurement of these quantities is difficult and time consuming. Therefore, methods have to be devised to infer these values from geo acoustic experimental data. The swath multibeam echo sounders, digital side scan sonars and sub-bottom profilers are the modern geo-acoustic instruments used for the sea bottom mapping. These instruments can provide high resolution and high precision images of sea bed and are capable to differentiate the roughness or softness of the bottom from the back scattering strength of the acoustic signals. There are methods developed to determine the geo acoustic parameters indirectly from the acoustic reflection and back scattering strength of sea bottom. These are estimated from the vertical reflection profile data. This study reviews the comparison of methods and results obtained with sample data collected.

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COOPERATIVE MOTION CONTROL OF MULTIPLE AUVS – CHALLENGES IN IMPLEMENTATION

Manish Singh*, Nupur Thakker, Pramod Maurya, Gajanan Navelkar, Antonio Mascarenhas

National Institute of Oceanography, Dona Paula, Goa 403004; [email protected]

The past decade has seen the rapid development of AUVs in many countries. The AUVs are now built from well proven technology products that are commercially available. In order to achieve high performance and time efficient ocean exploration, the researchers in marine robotics have shown an increased interest in cooperative motion control of multiple AUVs. The challenges in cooperation include design of robust control algorithms to execute missions of increasing complexity in the presence of communication losses without direct supervision of human operators.

The literature on cooperative control algorithm is extensive and the types of algorithm available vary in accuracy, complexity and theoretical robustness [1], [2], [3]. Despite these advances, the literature published to address the issues of implementation is scarce. It is crucial to emphasize that a proper implementation is at the core of a number of methods used for multiple vehicle cooperative control to guarantee their practical robustness.

This paper addresses the issues and challenges of implementation of cooperative motion control algorithms. As a contribution towards the development of robust implementation, Robot Operating System (ROS) will be used to show its efficacy for cooperation among two AUVs, one developed at NIO, Goa and other being developed at CMERI, Durgapur. ROS is a cross language platform working in a distributed environment. It can be used to establish a network among multiple vehicles for distributed intelligence as well as to control each vehicle’s motion.

Finally, a distributed simulation environment was established and a series of hardware in loop simulation were carried out to demonstrate the efficacy of implementation in ROS.

References Reza Ghabcheloo, António Aguiar, António Pascoal, Carlos Silvestre, I. Kaminer, J. Hespanha, (2009) Coordinated path-following in the presence of communication losses and time delays. SIAM - Journal on Control and Optimization, 48, 1, 234-265 António Aguiar, João Almeida, Mohammadreza Bayat, Bruno Cardeira, Rita Cunha, Andreas Häusler, Pramod Maurya, André Oliveira, António Pascoal, A. Pereira, Manuel Rufino, Luís Sebastião, Carlos Silvestre, Francesco Vanni, (2009). A Cooperative Autonomous Marine Vehicle Motion Control in the scope of the EU GREX Project: Theory and Practice, Proc. of OCEANS 2009 IEEE Bremen, Germany Skjetne, R., Moi, S., and Fossen, T.I. (2002) Nonlinear formation control of marine vessel. IEEE Conference on Decision and Control 2(10-13), 1699-1704

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VALIDATION OF INDIAN TSUNAMETER IN LABORATORY ENVIRONMENT

Tata Sudhakar* and G.A. Ramadass


Tsunameter is an instrument for the early detection of Tsunamis. Any violent geological disturbance under the water, which can cause displacement of large amount of water, can cause tsunami. Earthquakes, landslides, volcanic eruptions, explosions are some of the known causes of tsunami. The resultant tsunami surface wave can cause widespread damage to property.

After the 2004 Indian Ocean Tsunami, India has implemented Tsunami Early warning system using inputs from Seismic, Deep ocean pressure recorders (DOPR), tide gauges and HF radars. The data from DOPRs play very important role in confirming the existence of Tsunami wave in the deep sea. India has developed DOPR with help of industries (Sonardyne (UK), Envirtech (Italy) and Oceanor (Norway)). As the manufactures are developing the systems for the first time, It is very important to validate the newly developed systems for Tsunami response before Deployment at Sea as the Tsunami is a rare event. The authors developed methods to validate the systems in laboratory environment. Simulation studies based on the NOAA’s tsunami detection algorithm have been carried out and the program developed has been successfully employed on the data obtained from Tsunameter in the validation trails at NIOT. New test methods, hitherto not available, were designed and Tsunameter consisting of pressure recorder, acoustic modem and buoy were tested under simulated conditions. After successful validation of these DOPRs were deployed in Bay of Bengal and Arabian Sea. The warning system was operational from September 2007 and results obtained during detection of tsunami on 12th September 2007 at 18.10 UTC were discussed

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UNDERSTANDING EARTHQUAKES AND TSUNAMI HAZARD IN BAY OF BENGAL

Saroj K. Dash, A. K. Rai*

Indian Institute of Technology Bhubaneswar, Odisha – 751007, [email protected]

The Northern Bay of Bengal is located near several complex tectonic zones, such as the Sumatra-subduction zone, the NE Himalayas and Eastern Ghats. Observations show that earthquakes of magnitude 5 and above (Fig. 1) are common in the Northern Bay of Bengal. A recent earthquake of magnitude 6 near the Puri coast suggests that neo-tectonic stress is accumulating in the region. More than 10 km thick loose sediments are accumulated in the Bay of Bengal over the geologic time-scale. Any moderate to large size earthquake may induce submarine landslides in canyons located in Bay of Bengal. Strike-slip earthquake may also disturb steep slopes and cause stability failure in loose sediments. Local tsunami generated due to such submarine landslides can cause severe devastation along the coasts of Ganga Bhramaputra delta where over 60 million people live within 10m of above sea-level.

Fig. 1. (a) Earthquakes in Bay of Bengal. Focal mechanisms are taken from CMT earthquake catalog, and plotted if available. (b) Number of earthquakes vs. magnitude plot, indicating

that magnitude 5 and above earthquakes are dominant in Bay of Bengal.

Moderate size local tsunami may be generated by these earthquakes and submarine landslides at the sides of deep canyons with thick sedimentation. Studying relation between spatial distribution of earthquakes, their source parameter, and submarine canyons can provide useful information about tsunami hazard in Bay of Bengal.

References Cummins, Phil R., 2007. The potential for giant tsunamigenic earthquakes in the northern Bay of Bengal. Nature, Vol. 449, no. 6, 75-78 Matthew J. Hornbach et. al., 2010. High tsunami frequency as a result of combined strike-slip faulting and coastal landslides, Nature Geoscience, Vol. 3, 783–788

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ROLE OF MARINE TRANSGRESSION IN THE FORMATION OF KACHCHH BAUXITE, GUJARAT, INDIA

P.S.Choudhury1, G.N.Jadhav1 and D.U.Vyas2 1Dept. of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai; [email protected]

2Gujarat Mineral Development Corporation, Gujarat, India

India is home to most high grade bauxite deposits that occur along the coastal belts with a maximum lateral extension of 30-60Km located in the Kachchh region, Gujarat, India. These bauxite deposits formed over the flood basalts of Deccan Volcanic Province and oriented from NE to SW direction. The bauxite belt was a result of subsidence, sea level fluctuations, ground water circulation, marine transgression and marine regression during early Eocene (~ 56Ma) period.The pure bauxite which is whitish to light/ bluff coloured is generally poor in iron content and occur near to the shore while the impure bauxite which is more iron rich gradually occur in landward direction. The segregation of Al-rich horizon, alucrete zone and the Fe-rich horizon, ferricrete zone which is due to the highly mobile nature of iron radicals than the aluminium under optimum Eh- pH condition. A well-developed vertically zoned profile of bauxite occur in Kachchh region, Gujarat, India; where the top layers of bauxite zone is followed by lithomargic clay containing kaolinite overlying a clearly visible and altered basaltic parent rock. In many saprolitic bauxite there is preservation of well-developed relict basaltic textures.

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EVALUATION OF NUMERICAL MODELS FOR PALAEOTSUNAMI/PALAEOSTORM DEPOSITS FROM SAURASHTRA COAST,

WESTERN INDIA

Drasti Gandhi1, 2*, S.P.Prizomwala1, N.Y.Bhatt2, Kapil Mohan1, B.K. Rastogi1 1Institute of Seismological Research, Raisan, Gandhinagar 382009, India; *[email protected]

2 The Geology Department, M. G. Science Institute, Navrangpura, Ahmedabad 380009, India

Since last two decades, studies pertaining to detachment, transport and emplacement of coastal boulders have received wide attention among scientists. A detailed study of the deposited boulder features – size, shape and rock density and their initial position prior to the transport – is extremely important when reconstructing the possible morphodynamic scenarios (Pignatelli et al. 2009). Nott (1997, 2003) derived equations for boulder responses to Palaeo - storms and tsunamis waves. But the application of Nott’s equation and its accuracy has been debated by several workers in different scenarios. Nott’s (2003) equation assumed that boulder before being detached had only one side exposed to wave and is limited by five sides while Pignatelli et al. (2009) considered only three faces and the under surface of the boulder in Joint bounded block Scenario.

Several scattered and imbricated ridge of boulders are found along the Southern coast of Saurashtra above high tide level and as inland as 30m. Possible wave heights and wave responsible for dislodging boulders from offshore and transporting them inland have been calculated for Diu Coast using both the equations by Prizomwala et al. (2015). The results concluded that a tsunami wave of 3.5 m height transported all the boulders to their present position. However the same numerical model applied to the boulders of SW Saurashtra coast suggested their possible deposition by a storm wave. Similarly comparison of historical storm data with tsunami models suggest conflicting remarks, hinting at a need to re-evaluate these numerical models in light of local geomorphic and geological setting.

References: Nott, J (1997), Extremely high-energy wave deposits inside the Great Barrier Reef, Australia: determining the cause—tsunami or tropical cyclone. Mar Geol 141, 193–207. Nott, J (2003), Waves, coastal boulder deposits and the importance of pre-transport setting. Earth Planet Sci Lett 210, 269–276. Pignatelli, C., Sanso P., and Mastronuzzi G. (2009), Evaluation of tsunami flooding using geomorphologic evidence. Mar Geol 260(1–4), 6–18. :10.1016/j.margeo.2009.01.002. Prizomwala, S. P., Drasti Gandhi, Vishal M. Ukey, Nilesh Bhatt and B. K. Rastogi (2015), Coastal boulders as evidences of high energy marine events from Diu Island, west coast of India: storm or palaeotsunami? Natural Hazards. DOI 10.1007/s11069-014-1371-5.

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DEMARCATION OF NEAR SUBBOTTOM SEDIMENT STRATA OF SHALLOW WATERS USING IMAGE PROCESSING

Satyanarayana Yegireddi

Center for High Energy Systems and Science, DRDO, Hyderabad-500069; [email protected]

Demarcation of shallow water sediment strata and sedimentation pattern provides vital information on depositional environment and prevailing dynamics of any area. Such information is useful in offshore geo-engineering activities, planning and dredging of navigation channels, and neotectonics investigations. Sediment coring throws light on the sediment structure to a limited depth, is expensive and time consuming. Conventional geophysical investigations like shallow water seismic reflection studies can hardly delineate thin layers due to poor resolution. Sub-bottom profilers operating at a relatively high frequency are being used to resolve thin sediment layers. But at times, the quality of images from sub-bottom profilers is very poor and difficult to distinguish any thin sediment layers due to high ambient acoustic noise interference. Low acoustic impedance contrast among recent sediments and change in the direction of depositional pattern also cause masking of the features and difficulty in discrimination of the sediment layers.

Therefore, degradation in acoustic image quality due to strong ambient noise and depositional environment variability, poses a major challenge in delineation/ identification of thin upper sediment layers from conventional geophysical signal processing. Present studies address the above mentioned problem using image processing and successfully demonstrates with application to noisy sub-bottom acoustic images.

Image processing techniques known for their applications in medical imaging, pattern recognition and remote sensing applications, are being used in identification, tracking/search and classification problems effectively. Image processing exploit the statistical measures are efficient in even detecting weak boundaries of the features, as they utilise the spatial variations. Image segmentation techniques using pixel based and continuity based method are widely used both qualitative and quantitative analysis of image feature. Continuity based method utilises threshold level adjustment (Al-amri et al, 2010) and Gaussian low pass filter applied with the test images under study appears to be promising. Intensity histogram is the prime importance in segmentation process and fixing the thresholding strategies.

The methodology was applied to two subbottom images of subbottom profiler with operational frequency of 6-12 kHz, acquired from two different offshore locations with water depth ranges from 60-65m (Satyanarayana and Thomas, 2014). Both the images show strong reflections associated with the seabottom, as the acoustic impedance contrast was quite strong between water and seafloor sediments. However, weak layer interfaces corresponding to first image and distorted, discontinuous interfaces associated with second image show no improvement in clear demarcation of the boundary of subsurface layers through conventional geophysical signal processes sing. Interestingly, image segmentation able to clearly demarcate the weak acoustic reflectors and further infers the splitting of upper sediment layer in the second image into two layers, associated with very weak

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reflectors. The sediment structure suggests the variation in local depositional environment and instability of the area. Such information has significance in offshore construction and other dredging operations. Classification from textural analysis using grey level co-occurrence matrix (GLCM), a method using higher statistical moments suggests that the inferred layers features vectors derived from GLCM, exhibits the more similarities of the upper layer.

Therefore, some image processing tools like segmentation and textural analysis methods can effectively be exploited to supplement the other geophysical methods, in shallow water applications.

References : Al-amri S, Kalyankar NV, Khamitkar SD (2010), Image segmentation by using threshold techniques, J Comput. 2(5):83-86. Satyanarayana Yegireddi and Nitheesh Thomas (2014), Segmentation and classification of shallow subbottom acoustic data using image processing and neural networks, Mar. Geophys. Res. 35, 2, 149-156

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DISTRIBUTION OF REE IN SEDIMENT CORES FROM THE THANE CREEK, MUMBAI

Lina L. Fernandes *, Pratima M. Kessarkar, V. Purnachandra Rao

CSIR-National Institute of Oceanography Dona Paula, Goa -403 004; [email protected]

Sediments from two cores from the Thane creek, Mumbai, one near the creek head and another near creek mouth, were analyzed for their grain size, mineralogy and REE chemistry to better understand the down-core distribution of REE and controls on REE. The sediments were largely clayey silts or silty clays. Smectite -dominated sediments were the most dominant in both cores. The REE content ranged from 112-127 µg/g near the creek

head and 117-136 g/g near creek mouth and were lower than in Post-Archean average Australian Shale (PAAS). The PAAS-normalized REE patterns showed MREE- and HREE-enrichment with positive Pr, Eu and Y anomalies. The results further showed low REE values at middle portions of both cores. The Y values also increased at the middle portions of the core near the creek head and decreased in the core near the creek mouth. REE distribution is controlled largely by source rock composition in both cores. Eu anomaly was largely due to plagioclase feldspar. It appeared that the core at creek mouth showed the signatures of early diagenesis which were masked by the primary REE depositional conditions, whereas the core near the creek head exhibited the influence of both source rock composition and early diagenesis.

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GEOCHEMISTRY OF THE SURFACE SEDIMENTS WITHIN AND BELOW OXYGEN MINIMUM ZONE FROM THE SOUTHWESTERN CONTINENTAL MARGIN OF

INDIA

Pratima M. Kessarkar*, G. Parthiban, J.N. Pattan, Lina L. Fernandes, Supriya G. Karapurkar, Siby Kurian, V. Purnachandra Rao

CSIR-National Institute of Oceanography Dona Paula, Goa -403 004; [email protected]

Surface sediments within and below the oxygen minimum zone (OMZ) across the transect of the continental slope off Goa, Mangalore and Kochi were investigated for grain size, clay mineralogy, environmental magnetic properties, total organic carbon (TOC), total

nitrogen (TN), CaCO3, 15N, 13C, major, trace and rare earth elements (REE). The dissolved oxygen in near bottom waters was low off Goa (0.03-2.30 ml/l) and increased towards south, i.e., off Mangalore (0.11-2.50 ml/l) and Kochi (0.23-2.64 ml/l). Median grain size of the sediments ranged between 6.3 and 41.7 µm, with relatively finer grain size along Goa transect. Smectite and kaolinite were dominant minerals followed by illite and chlorite in sediments of all transects. Smectite showed increasing trend offshore with increasing depth.

Magnetic susceptibility (lf) values ranged between 13 and 42 ×10-8m3kg-1, with relatively high values off Goa and Mangalore compared to Kochi. The CaCO3 content ranged from 20 to 67 %, with relatively higher values off Goa, whereas TOC (0.9-8.6%) and TN (0.90-0.98 %) contents showed decreasing trend in sediments below ~ 1200 m depth in all the profiles.

The 15N ranged from 3.6 to 7.2 ‰, with higher values off Goa. The total-REE (∑REE) content was lower in Goa than in Mangalore and Kochi. The terrignous elements (Sc, Rb Sr, Th) were lower in sediments off Goa than in Mangalore and Kochi transects. The concentrations of redox sensitive elements (Mn, Cr, V, Mo) were lower in sediments associated with OMZ and their concentrations increased with increasing depth in oxygenated sediments below OMZ.

The results suggest that the sediments at relatively shallow depth were hinterland –derived, whereas those at deeper depths may be Deccan trap-derived. It appears that the sediments off Goa received low concentrations of terrigenous elements than those off

Mangalore and Kochi. Organic matter is largely marine in all the three transects. Higher 15N values in sediments off Goa compared to Mangalore and Kochi suggest higher water column denitrification rates with probable contribution from the perennial denitrification zone. Lower concentrations of redox sensitive elements in sediments with low oxygenated waters and higher values with more oxygenated waters indicate oxidation of sediments during early diagenesis.

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DELIVERY OF PARTICULATE ORGANIC CARBON DURING THE GREAT FLOOD OF KRISHNA RIVER IN OCTOBER 2009

C. Prakash Babu*, V. Ramaswamy, P.S. Rao


The Krishna River experienced unprecedented floods during October 2009. High rainfall combined with water release from dams in the upper reaches triggered intense floods downstream. The nature of fluvial organic matter transferred to the coastal region was studied by analyzing suspended particulate matter (SPM) from the Krishna estuarine region for C:N ratios and δ13Corg collected during the flood from a bridge downstream Vijayawada. The SPM showed high C:N ratios (14-19) and heavy δ13Corg values (-21 to -23‰) during the initial flood period which drastically changed to low C:N ratios (7-9) and light δ13Corg values (-26 to -27‰) during the later part of the flood. We show that the particulate organic matter during the initial period of the flood is derived from the semi-arid region of India as coherence is noticed between SPM and riverbed sediments. In contrast, the receding waters during the later period of the flood carried mainly C3 type organic matter organic matter from the deltaic region.

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MINERALOGY AND RARE EARTH ELEMENTS IN SEDIMENT CORES FROM THE MANDOVI ESTUARY, WESTERN INDIA: INFERENCES ON SOURCES OF THE

SEDIMENTS

Prajith, A., Rao, V. P.* and Pratima M. Kessarkar

CSIR- National Institute of Oceanography, Dona Paula, Goa-403 004; [email protected]

Mineralogy and rare earth elements (REE) of bulk sediments in the gravity cores collected along transect of the Mandovi estuary, western India were analyzed to determine the sources and controls on REE distribution. The collected four sediment cores from the Mandovi estuary represent four environmentally significant sites (upper, middle, lower estuary and Aguada Bay). The length of recovered cores varied between 79 cm and 47 cm, and was longer in cores from upper/middle estuary than in lower estuary/bay. Quartz was the predominant mineral in sediments of all cores. The upper and middle estuary sediments showed higher proportion of iron ore minerals than in lower estuary / Aguada Bay. The sandy sediments from the middle estuary and bay showed high proportions of feldspars.

REE of sediments varied from 37 to 160 g/g in different cores and were lower than in

Post-Archean Australian Shale (PAAS; 185 g/g). The total Y of sediments varied from 8.5 to

37.1 g/g. REE showed strong positive correlation with both clay and silt fractions (correlation ranges from 0.53 to 0.9) and were higher in clayey silts than in sand/sandy silts. The light to heavy REE ratios (LREE/HREE) of sediments (range from 15.8 to 18.7) were lower than in PAAS (24.7). The PAAS-normalized rare earths and yttrium (REY; Y inserted between Dy and Ho) patterns of sediments showed middle REE (MREE)- and HREE-enrichment with positive Eu anomaly (Eu/Eu*) and variable Ce anomaly (Ce/Ce*). The upper estuary showed positive Ce/Ce* and this value decreased towards bay sediments. The gradual decrease of Ce/Ce* with increasing organic carbon (OC) towards core top of the upper estuary and inverse correlation between OC and Ce anomaly indicated reduction of Ce in early diagenetic conditions. High positive Eu/Eu* values were associated with high sand content in the sediments. Positive Ce and Eu anomalies are inherited from ore material. High Y/Ho ratios in clayey silts are due to redistribution of Y and Ho by adsorption onto organic-rich, clays. Variations in Sm/Nd ratios are similar to that of Eu/Eu* in cores from the lower estuary/bay and are controlled by mineral constituents of the sediments. The REY of sediments is primarily controlled by its texture and REE of source sediment, which is ore material-dominated in the upper/middle estuary and silicate material-dominated in the lower estuary/bay.

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STABLE ISOTOPIC INVESTIGATION OF PORITES CORAL FROM MINICOY ISLAND

A. A. Fousiya1, S. Chakraborty2*, H. Achyuthan1, Naveen Gandhi2, Nitesh Sinha2, Amey Datye2 1Department of Geology, Anna University, Chennai, *corresponding author; [email protected]

2Indian Institute of tropical meteorology, Pune

Corals are the most important component of the marine ecosystem found in vast areas of the tropical oceans. Reef building corals are one of the best known archives that provide high quality records of ocean atmospheric variabilities on sub seasonal resolution spanning up to a few hundred years. The isotopic and chemical tracers incorporated in coral skeleton are known to provide useful information, such as, sea surface temperature, salinity, upwelling intensity, oceanic circulation etc. Lakshadweep Islands and Maldives in the north Indian Ocean harbor various types of corals and several workers have studied them for paleoclimatic/paleo environmental reconstruction. It has been demonstrated that isotopic analysis of corals from these regions are useful proxies for SST (Chakraborty and Ramesh, 1997) and monsoon rainfall over the Kerala coast (Sortz et al. 2010, 2011).

The Minicoy Island belonging to the Lakshadweep Archipelago also contains various types of corals and some workers have studied their morphology and distribution (Pillai 1971; Jayabaskaran, 2009). But corals from the Minicoy Island did not receive much attention for palaeoclimatic investigation. Minicoy Island is strategically located as far as monsoon circulation is concerned (Gardiner, 1900). Additionally the oceanographic characteristics of this region may offer some added advantage for coral analysis. For example, the climatology of the monthly SST and salinity variations show that they are almost out of phase (Figure 1). Since coral δ18O is inversely proportional to SST but directly varies with SSS, the effects of these two parameters are expected to get added, resulting enhanced coral isotopic signal.

Figure 1: Climatological (1989-2013) variations of sea surface temperature (red) and sea surface salinity (blue) around the Minicoy Island (8.0N-9.0N, 72.5E-73.5E).

We have collected a Porites spp. from the Minicoy Lagoon (MSL: 13ft, 08°16’55 N, 73°03’17 E) at a water depth < 2m during low tide condition on Oct/21/2013. The x-ray picture of this sample identifies annual banding spanning for 24 years (1989-2013). The

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mean annual extension rate over this period is ca. 7.7mm.yr-1. Stable carbon and oxygen isotopic analysis of these bands reveal that the isotopic composition is controlled by kinetic fractionation. The isotopic records have been examined in respect of various ocean-atmospheric parameters to explore their potentials as a proxy for past climatic / environmental conditions.

The SST anomaly (deviation relative to the long term monthly mean of 1989-2013) was calculated for the months of Jul-Aug-Sep when sea surface cools due to monsoon induced upwelling. High negative anomalies were observed in 1992, 1996 and 2013. Out of these three years the coral δ18O showed increased values in 1992 and 2013, implying that coral δ18O is sensitive to changes in sea surface temperature. The coral δ18O showed somewhat weak but very significant correlation with the SST (r= -0.32, p< 0.002, n = 77). The relationships between coral δ18O and Indian monsoon indices have also been examined. It has been found that coral δ18O is weekly correlated (r=0.16) with the rainfall over the Peninsular India as well as with the all India rainfall index (r=0.12).

Chakraborty et al. (2012) demonstrated that δ18O of corals are sensitive to the thermodynamic index of Indian summer monsoon (TISM, defined in Xavier et al. 2007). We have examined this relationship in case of Minicoy coral. TISM has been calculated for the period of 1989-2013 as outlined in Xavier et al. (2007) and then correlated with the mean annual values of coral δ18O (r=0.23). Though the connections between coral δ18Oand monsoon indices are not strong, however they are similar to that observed in case of other corals belonging to the Indian ocean (Chakraborty et al. 2012).

References: Chakraborty, S. and Ramesh, R. (1997), Environmental significance of carbon and oxygen isotope ratios of banded corals from Lakshadweep India, Quat. Int. 37(3), 55-65 Chakraborty et al. (2012), Pacific coral oxygen isotope and the tropospheric temperature gradient over the Asian monsoon region: a tool to reconstruct past Indian summer monsoon rainfall, J. Quat. Sci. (27) 269-278, DOI: 10.1002/jqs.1541 Storz, D. & Gischler, E. (2011), Coral extension rates in the NW Indian Ocean reconstruction of 20th century SST variability and monsoon current strength, Geo-Mar Lett DOI: 10.1007/s00367-010-0221-z Jeyabaskaran, R. (2009), New record of corals from Lakshadweep Islands, Rec. Zool. Suv. India, 109 (part-1), 53-64. Pillai, C.S.G. (1971), The distribution of shallow water stony corals at Minicoy Atoll in the Indian Ocean with a checklist of species, Atoll, research Bulletin, No-(141), 1-12. Xavier, P.K & Goswami B.N. (2007), An Analog Method for Real-Time Forecasting of Summer Monsoon Subseasonal Variability, American Meteorological Society, DOI: 10.1175/2007MWR1854.1.(133), 749-764.

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ANTHROPOGENIC IMPRINTS ON A SEDIMENT CORE OFF GOA FROM THE ARABIAN SEA – A ROCK MAGNETIC & GEOCHEMICAL APPROACH

Tyson Sebastian*, Sangeeta Naik, B.Nagender Nath, D.V.Borole


Rock magnetic and geochemical analyses combined with 210Pb dating were carried out on a 1.03 m long gravity core collected off Goa from Arabian Sea at 15°30.07'N; 73°39.21'E to investigate the mining induced sedimentation changes. A drastic increase in linear sedimentation rate from 0.187 cm/year to 1.63 cm/year subdivides the core clearly into two sections at a depth of 37 cm corresponding to an age of 1979 AD. The mineral magnetic

concentration parameters – low frequency magnetic susceptibility (LF), Susceptibility of

Anhysteric Remanent Magnetization (ARM), Saturated Isothermal Remanent Magnetization (SIRM) - also experience a sharp increase at 37 cm suggesting a common origin. The core location in this study is close to the mouth of Mandovi – Zuari River system, which flows through the mining belt of Goa. The open cast iron ore mining in Goa and its transport through road and waterways necessitates the removal of surface material overlying the ore formations and thereby generates abundant debris most of which ultimately reach the Arabian Sea either waterborne or windborne. The iron ore production in Goa has increased from 1.09 Million tonnes (Mt) in 1953 to 30.73 Mt in 2007. The comparison between magnetic susceptibility and the production of iron ore through mining from 1950 – 2000 AD indicates that the increase in sedimentation rate and magnetic concentration parameters are coeval and can be attributed to mining.

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WET DEPOSITION OF MIDDLE-EAST DUST OVER THE INDIAN PENINSULA

V. Ramaswamy*, Prakash Babu

National Institute of Oceanography, Dona Paula, Goa 403004; [email protected]

During June to September when the southwest monsoon spreads humid maritime air over the Indian Peninsula resulting in a substantial reduction in ambient surface- aerosol concentrations, the northwesterly Shamal Winds lift dust from the MiddleEast and transport it eastward over the Arabian Sea. In this study we show that the dry, warm and dusty Shamal Wind override the low-level Findlater Jet of the SW monsoon and transport large amounts of dust over Indian Peninsula at heights above 1.5 km. The total wet deposition of dust wet deposited over Goa annually is ~20 g m-2. Mineralogy, chemistry and isotopec studies show them to be derived from the Middle-East. The crustal dust neutralizes the acidity and increases the pH of rainwater over Peninsular India. After the Shamal winds subside in mid-August, the composition of rainwater reverts from alkaline to acidic range due to soluble ions derived from local carbonaceous aerosols.

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PRELIMINARY OBSERVATIONS OF GEOMORPHOLOGICAL, SEDIMENTOLOGICAL AND MINERALOGICAL CHARACTERISTICS OF THE

ARNALA BEACH AND ARNALAPADA ISLAND, THANE DISTRICT, MAHARASHTRA, INDIA

S. D. Iyer, A. R. Gujar, D. K. Naik, S. S. Gaonkar, R. A. A. Luis, F. K. Badesab


Investigations are underway along the ~20 km long coastal belt of Arnala beach, Thane District, Maharashtra. The area lies between the rivers Vaitrana in the north and Ulhas in the south and also includes the Arnalapada Island that is located across the mouth of River Vaitarna. Minor creeks intersect the beach before joining the Arabian Sea. More than three decades ago the Directorate of Geology and Mines (Maharashtra) and the Geological Survey of India reported the occurrences of heavy minerals and presence of mercury, respectively from the above areas. Besides these there are no detailed reports of the Arnala beach and Arnalapada Island. Our comprehensive studies include seasonal profiling (16 profiles, 5 seasons, 6 field works), geological and geomorphological observations and collection of

sand samples from the surface (57) and from (61) layers from 16 pits of 1 1 1 m dimension. Analyses were carried out to characterise the sediment parametres and mineralogy.

The foreshore is flat with a gentle gradient while in the backshore a temporary berm and semi-consolidated karal rocks are present. The latter is composed of quartz and shell and at places extends for at least 1 km as a raised beach. The area was divided into 4: north Arnala near the Vaitarna mouth (Area A), central Arnala (Area B), south Arnala i.e., Vasai beach near Ulhas River (Area C) and Arnalapada Island (Area D). The areas A, C and D are highly disturbed due to human activities (fishing, jetty constructions, tourists etc). In Area B, rock platform of altered fine grained basalts occurs in the intertidal zone and also offshore. This ~2 km long platform is exposed during the low tide and probably represents the shoreward extension to the offshore islands including Arnalapada. Fair season and pre-, during-, and post-monsoon observations revealed severe erosion at some places and accretion at others. For e.g., in Area B the raised beach at Bhuigaon and end of Rangaon have been largely destructed while in Area C trees have been uprooted.

The surface sediments are fine grained, nearly uniform in size (mean 3Φ) and derived from more than one source. Silt and clay increases between Areas B and C due the proximity of the Ulhas River mouth and presence of extensive mudflat and mangroves. Significant concentration of heavy minerals occurs in the surface sediments. Heavy minerals present in the backshore and in the raised beach, are up to 93% and contain ilmenite (<1 to 37%) and magnetite (<1 to 47%). The pit sediments are medium to very fine grained (mean 2.62Φ). Significant concentration of heavy minerals occurs in surface sediments and are up to 65% with ilmenite (<2 to 27%) and magnetite (<1 to 35%).

Based on seasonal topographic data and sedimentology, quantification of sediment erosion and accretion and changes in coastal configuration and heavy minerals are


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evaluated. Furthermore, magnetic susceptibility studies and their relevance to palaeo-sediment deposition would also be investigated.

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PARTITIONING OF METALS IN DIFFERENT BINDING PHASES OF MARINE SEDIMENTS: IMPORTANCE OF METAL CHEMISTRY

P. Chakraborty

CSIR-National Institute of Oceanography, Dona Paula, Goa, [email protected]

Distribution of metals in different binding phases of marine sediments provides chemically significant description of metals-sediment interactions. This study describes the influences of ligand field stabilization energy (LFSE), Jahn-Teller effect and water exchange rate (k-w) on metal distribution in different binding phases of marine sediment. It was found that Cu had highest affinity for organic binding phases in the studied sediments followed by Ni and Pb. However, Pb had highest association with Fe/Mn-oxide phases followed by Ni and Cu. Faster k-w of Cu (II) (1×109 s-1) increased the rate of complex formation of Cu2+ ion with the ligand in the organic phases. The Cu-ligand (from organic phase) complexes gain extra stability by the Jahn-Teller effect. The combined effects of these two phenomenons increased the association of Cu in the organic phases of the sediments than Ni and Pb. The smaller ionic radii of Ni2+ (0.72 Å) than Pb2+ (1.20 Å) increase the stability of Ni-ligand complexes in the organic phase of the sediments. In addition to that high LFSE of Ni (II) (compared to Pb2+ ions) make Ni-organic complexes increasingly stable than Pb. High k-w (7×109 s-1) of Pb did not help it to associate with organic phases in the sediments. The high concentration of Pb in the Fe/Mn-oxyhydroxide binding phase was probably due to co-precipitation of Pb2+ and Fe3+. High surface area or site availability for Pb2+ ion on Fe-oxyhydroxide phase and greater binding strength over simple precipitate surface was probably responsible for the high concentration of Pb in Fe/Mn oxyhydroxide phase. The decreasing concentrations of Cu in Fe/Mn–oxyhydroxide phases with the increasing Cu loading in the sediment suggest that Cu did not prefer to associate with Fe/Mn oxyhydroxide phases. Increasing concentrations of Cu in organic phases with the increasing Cu-loading suggest that enough binding sites were available for Cu in the organic binding phases of the sediments. This study also describes the influence of sedimentary organic carbon (terrestrial and marine derived OC) in controlling these metals distribution and speciation in marine sediment.


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ISOTOPIC FINGERPRINTING OF ATMOSPHERIC DUST OVER ARABIAN SEA

A. Kumar*, K. Suresh, P. P. Padalkar, C. Prakashbabu, V. Ramaswamy

CSIR- National Institute of Oceanography, Dona Paula, Goa-403004; [email protected]

The Arabian Sea (AS), one of the most biologically productive oceanic regions (Barber et al., 2001) surrounded by the arid and semi-arid (Arabian and Omani deserts on the west and Thar Desert in the north-east) area, receives a significant amount of aeolian dust deposition (Shao et al., 2011) due to its proximity and favourable meteorological conditions. In addition, a very recent study (Duchi et al., 2014) over southern Himalayas have indicated the influence northern African dust during winter months, making the majority of tropical dust belt area as an important contributor of dust to the AS. Apart from wind driven coastal upwelling during summer monsoon (Barber et al., 2001) and convective mixing in winter period (Madhupratap et al., 1996), dust deposition has been hypothesized to be an important driver for phytoplankton productivity (Naqvi et al., 2010) in the AS from daily to seasonal time scale. In order to assess the impact of dust deposition to the biogeochemistry of the Arabian Sea, it is very important to identify the sources of transported dust. Several proxies (e.g. elemental and mineralogical composition and their ratios) have been used to track the transport and sources of dust. Naturally-occurring radiogenic isotope systems (e.g. Sr, Nd, and Pb) are, however, one of the robust tracers for dust provenances and have been efficiently used for tracing regional to inter-continental dust transport (Kumar et al., 2014). For example, Kumar et al. (2014), have clearly shown a very similar Sr and Nd isotopic signature in the aeolian dust samples collected from Mali (a sampling location in northern Africa; mean 87Sr/86Sr = 0.713, ƐNd = -12.2) and in Tobago and US Virgin Islands (mean 87Sr/86Sr = 0.711, εNd = -12.2 and mean 87Sr/86Sr = 0.710, εNd = -12.1, respectively) located across the Atlantic Ocean and thus demonstrated the transatlantic dust transport using radiogenic isotopes. In this study, the potential source areas of mineral dust contributing to Arabian Sea, will be scrutinized based on satellite images and then geochemically characterized by analyzing radiogenic isotopes (Pb, Sr, and Nd) in the surface soil/sediment samples The sources located in the northern Africa have been characterized to infer dust provenace in the coastal African region as well as in the Amazone basin (Abouchami et al., 2013). A similar strategy will be applied to comprehensively characterize the sources located in the Middle East and north-western part of India (Thar Desert) and will be used to decouple dominant sources impacting towards the dust load over the AS on spatial as well as temporal scales. In this presentation, some of the preliminary results related to the source (Thar Desert) characterization will be discussed.

References: Abouchami, W. et al., (2013), Geochemical and isotopic characterization of the Bodélé Depression dust source and implications for transatlantic dust transport to the Amazon Basin. Earth and Planetary Science Letters, 380, 112-123.

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Barber, R. T.,et al. (2001), Primary productivity and its regulation in the Arabian Sea during 1995, Deep Sea Res., Part II, 48, 1127–1172. Duchi R., et al. (2014), Synoptic-scale dust transport events in the southern Himalaya, Aeolian Res., 13, 51–57 Kumar, A., et al. (2014), A radiogenic isotope tracer study of transatlantic dust transport from Africa to the Caribbean, Atmos. Environ., 82, 130–143. Madhupratap, M., et al. (1996), Mechanism of the biological response to winter cooling in the northeastern Arabian Sea, Nature, 384, 549–552. Naqvi, S.W.A., et al. (2010), The Arabian Sea as a high-nutrient low-chlorophyll region during the late Southwest Monsoon, Biogeosciences, 7, 2091–2100, doi:10.5194/bg-7-2091-2010. Shao, Y., et al. (2011), Dust cycle: An emerging core theme in Earth system science, Aeolian Research, doi:10.1016/j.aeolia.2011.02.001

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DISTRIBUTION AND SPECIATION OF PB IN COASTAL SEDIMENTS AROUND INDIA

Sucharita Chakraborty*, Parthasarathi Chakraborty and B. Nagender Nath

CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004; [email protected]

Distribution and speciation of Pb in the coastal sediments around India were investigated in this study. An attempt was also made to identify the factors that control Pb speciation and its bioavailability in the coastal sediments. The average total Pb concentrations in the coastal sediments were found to be 21.6 ± 8.05 mg.kg-1 in the east coast and 14.99 ± 6.04 mg.kg-1 in the west coast of India.

Geochemical fractionation study showed that Fe-Mn oxyhydroxides phase was the major binding phase for Pb and controlled Pb-speciation in the oxic coastal sediments around India. In average highest percentage of total Pb was found to be associated with Fe-Mn oxyhydroxide phases in the sediments collected from the northern part of both the coasts followed by the south west >central east and central west, and minimum amount of Pb was found to associate with Fe-Mn oxyhydroxide phases of the sediments collected from the south east coast of India. Organic carbon was the second major binding phase (among the non-residual phases) of Pb in the coastal sediments. However, except central west coast, binding sites of organic carbon were not available for Pb in the coastal sediments.

Labile complexes of Pb (a good indicator of bioavailability) (water exchangeable and carbonate-bicarbonate complexes of Pb) was found to increase with the increasing total Pb loading in the coastal sediments form central west coast of India. This study indicates anthropogenic input of Pb in the coastal sediments in this area may increase bioavailability of Pb in future.

The concentrations of Pb associated within the structure of the sediments (residual phase) was found to carry source rock signature along the coast. The concentrations of Pb in the residual phase of the sediments were found to show regional similarity in the northern part of the east coast and the northern and central part of the west coast of India. This finding suggests that similar source rocks probably contributed to the respective coastal sediments. However, sediments collected from the central, south east and south west coast of India showed variation in Pb concentration in the residual phase suggesting different source rock contribution to the coastal sediments in these areas. This is the first study that describes Pb distribution and its speciation in coastal sediments around India.

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HIGH RESOLURION HOLOCENE PALEOMAGNETIC SECULAR VARIATION RECORDS FROM BAY OF BENGAL

A. Usapkar1, P. Dewangan1*, F.K. Badesab1, A. Mazumdar1, T. Ramprasad1, K.S. Krishna1, N.

Basavaiah2 1CSIR-National Institute of Oceanography, Dona Paula, Goa; [email protected]

2Indian Institute of Geomagnetism (IIG), Panvel, Navi Mumbai

Paleomagnetic studies are being carried out worldwide to establish high resolution paleosecular variation records (PSV) that can be used to correlate regional stratigraphy and to understand the geodynamo processes responsible for the generation of Earth’s magnetic field. PSV records obtained from rapidly deposited, well-dated sedimentary sequences act as a continuous and reliable recorder of Earth’s intensity and directional variations. Prior to direct observations, the variation of Earth’s magnetic field can be reconstructed using the PSV records which can help in understanding the temporal and spatial variations of Earth’s magnetic field. During Holocene, most of the PSV records are documented from Europe, North America, central Asia and South East Asia. However, such high resolution PSV records are not available in the high sedimentation regions of Bay of Bengal. Therefore, we attempt to establish the high resolution, continuous PSV records from Krishna-Godavari (KG) basin, Bay of Bengal using two Calypso piston cores MD161/8 (~30m, water depth-1033m, 15° 51.8624'N, 81° 50.0692'E) and MD161/13 (~29m, water depth - 647m, 16°01.9684'N, 81°42.7909'E) acquired onboard M/V Marion Dufresne for gas hydrate studies. The PSV records are evaluated for their potential to act as a reliable tool for magnetic stratigraphy as well as to understand the geodynamo processes over Bay of Bengal.


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INITIATION OF OCEAN BOTTOM SEISMOMETER EXPERIMENT IN THE ANDAMAN BACK ARC BASIN

K.A. Kamesh Raju*, Pawan Dewangan, Aswini, K.K., Yatheesh, V., Pabitra Singha, Kiranmayi S


The Indo-Burmese range and the Andaman arc system in the northeast Indian Ocean define a zone of underthrusting of the Indian plate below the Southeast Asian plate, leading to the formation of a major island arc trench system. The Andaman island arc including the Andaman and Nicobar islands together with the Andaman back arc basin is a part of this major arc trench system. The deep Andaman back arc basin is formed due to the initiation of spreading activity within the central Andaman trough separating the Alcock and Sewell seamounts. The complex tectonics of the region results from the oblique subduction, varied rates of subducting Indian plate beneath the SE Asian plate along the zone of subduction and the large variation in the age of the subducting plate along the length of the trench. The region is seismically very active and witnessed the devastating M9.3 tsunami event of December 2004 and its aftershocks. A passive Ocean Bottom Seismometer (OBS) experiment was planned in the Andaman Sea to study the pattern of microseismic, local and teleseismic earthquakes. The primary objectives of the OBS experiment are to define the stress pattern and to understand the crustal structure of the Andaman back arc basin using the velocity model estimated from the earthquake data. Twelve units of three component broad band seismometers were deployed in the Andaman back arc basin during December 2013. The deployment locations were selected based on the tectonics and the seismicity. These units were recovered in May 2014, resulting in a 4 month period of continuous recording. The OBS receivers documented in greater detail an earthquake swarm that occurred in the Off Nicobar region during March 2014 due to an M6.5 event. The analysis of data is in progress to understand the seismological characteristics of the earthquake swarm events, micro earthquakes, local events and the teleseismic events in order to gain insights into the crustal structure of the region.

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SULFUR AND IRON SYSTEMATICS OF A CORE (MD161-15) FROM THE KRISHNA-GODAVARI BASIN, BAY OF BENGAL

M. Carvalho, A. Mazumdar*

CSIR- National Institute of Oceanography, Dona Paula Goa – 403004 Corresponding author: [email protected]

Here, we present the concentration profile of pyrite sulfur (CRS - Chromium Reducible Sulfur) and highly reactive iron (FeHR) in a core (MD161-15) off Krishna-Godavari Basin, Bay of Bengal. The core was recovered on board R/V Marion Dufrense from a water depth of 983m at 16°00.5700'N; 82°03.4502'E. The available reactive iron (ferrihydrite: FeOOH•0.4H2O+lepidocrocite:γ-FeO(OH)+goethite FeO(OH)+hematite: Fe2O3) in the sediment (FeD) was extracted with buffered sodium dithionite solution following standard method. The highly reactive iron (FeHR) is the sum of dithionite bound iron (FeD) and pyrite bound iron (FeCRS). A total of 105 and 70 samples were analysed for CRS and FeD concentrations respectively. CRS concentration profile in the present study essentially represents pyritization trend through the sediment column. The CRS concentration in the core varies from 0.0028 to 1.3 wt% and shows overall progressive increase in the concentration from top to bottom of the core with several high & low concentration peaks.The low CRS concentrations may be attributed to the reduced flux of reactive iron bearing minerals and/or reduced production H2S required for sulfidization. Focused H2S production at the paleo-sulfate methane transition zone could also lead to enhanced pyritization. The FeHR concentration varies from 0.76 to 2.8 wt%. The FeHr concentration decreases gradually from 1.7 to 0.76 wt% downcore to the depth of 1192 cmbsf and from here it progressively increases upto 2.81wt% at 3077 cmbsf with several intermediate concentration spikes.The TOC content ranges from 0.2 to 2.2 wt%. TIC content ranges from a negligible amount to ~4 wt%. A sharp rise in the TIC content (high content of foraminifera) is observed between 10 to 13 mbsf spanning the approximate time of the last glacial maxima (LGM). The high TIC content (up to 3 wt%) between 27-30 mbsf is attributed to the presence of authigenic carbonates (Joshi et al., 2014) formed via anaerobic oxidation of

methane pathway, as evident by the highly depleted 13C values (−41 to −52‰ VPDB).

Reference: Joshi , R.K., Mazumdar A., Peketi , A. Ramamurty , P.B. Naik , B.G. Kocherla , M. Carvalho , M.A. Mahalakshmi , P., Dewangan P. and Ramana,M.V.,(2014), Gas hydrate destabilization and methane release events in the Krishna – Godavari Basin, Bay of Bengal, Marine Petroleum Geology, 58.

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INFLUENCE OF LAND USE PATTERN ON DISTRIBUTION OF ORGANIC MATTER IN A TROPICAL LAGOON

Arindam Sarkar*, B.Nagender Nath


Elemental concentration, stable isotope of organic carbon (OC) and nitrogen (TN) in bulk sediments and different size fractions were determined to investigate the nature and burial patterns of sedimentary OC in a tropical lagoon from the southwest coast of India. This study revealed that anthropogenic activity and land use pattern had a significant control on the composition and distribution of organic matter (OM). The overall OC concentration (0.25 to 4.49%, avg. 2.05±1.18%) was low compared to other eutrophic lakes because of clastic dilution as large amount of sediments are being discharged here. Southern part of the lake contained higher OC (avg. 2.21±1.20 %) compared to northern part of the lake (avg. 1.80±1.18%) possibly due to better preservation of OM in the sediments overlain by lower oxygenation conditions and deposition of significant amount of soil organic matter (SOM) from agricultural fields, which had higher preservation efficiency. The discrimination diagram of δ13Corg vs. N/C molar ratio (following the method of Keli et al., 1994) for clay fraction confirms presence of significant proportion of SOM in the southern region of the lake. The contribution from SOM decreased towards north corresponding to the change in land use pattern in the adjacent watershed area of the lake. The watershed area surrounding the southern part is extensively cultivated present day. Thus this region seems to receive huge amount of SOM as surface run-off from these agricultural land. However, the northern region is mostly urbanized and it was reflected by negligible concentration of SOM in the sediments. A quantitative estimate using four end-member analysis revealed that about 32% and 21% of the total OM were constituted by SOM in the sediments collected from the southern and northern part of the lake respectively. It also revealed that the marine contribution was higher in the northern area.

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NATURE OF SULFIDIZATION WITHIN A SEDIMENT COLUMN OFF MAHANADI BASIN, BAY OF BENGAL, INDIA

Brahmanand Sawant1, A. Mazumdar1*, Maqbool Yousuf2, Aditya Peketi1

1CSIR-National Institute of Oceanography, Goa 403004; [email protected]

2Sector 2A, Al-Farooq Mosque; H.NO. 152 Srinagar - 190018

A sediment core (MD161-19) was recovered from the Mahanadi offshore basin for pore fluid chemistry and Fe-S speciation. The ~39 m long core was recovered onboard Marion Dufresne from a water depth of 1480m at 85°41.1669’E; 18°59.1020’N. Sulfate concentrations were measured using Dionex-600 Ion chromatograph. Total alkalinity was measured on board following gran titration using Metrohm Autotitrator (Titrino 799 GPT). The sulfate concentration profile shows quasi-linear trend with a gradient of 1.61 mM/m. The sulfate methane transition zone (SMTZ) lies within 1500-1900 cmbsf. The total alkalinity increases steadily downcore and reaches a maximum of 22 mM at the SMTZ and subsequently decreases gently. Chromium reducible sulfur (CRS-pyrite) was extracted from the sediment using boiling 1 M CrCl2 (in 6N HCl) in an oxygen free reaction vessel with continuous nitrogen flow. H2S trapped by reduction of sulfide is trapped as CdS in a cadmium nitrate solution and subsequently re-precipitated as Ag2S by adding AgNO3. The colloidal suspension of Ag2S was boiled for 10 minutes to produce consolidated Ag2S lumps which are subsequently collected on 0.2 µm nitro cellulose filter paper and washed with distilled water. The Ag2S lumps were oven dried and weighed for CRS content (Canfield et al 1986). A total of 250 samples were analysed for CRS concentration. The CRS concentration varies from 0.002 to 0.64 wt% and shows multiple zones of high well defined high concentration peaks. The degree of pyritization ranges from 0.3 to 56 %. High DOP suggests significant sulfidization by hydrogen sulfide produced via organoclastic or AOM driven sulfate reduction. The highly reactive iron concentration (FeHR) ranges from 0.34 to 3.17 wt%. A high resolution δ34CRS, δ13TIC measurement may help in detailed understanding of the pyritization process in the sediment column.

References: Canfield, D., R. Raiswell, J. Westrich, M. Christopher, C. M. Reaves, and R. A. Berner (1986), The use of chromium reduction in the analysis of reduced inorganic sulphur in sediments and shales, Chem. Geol., 54, 149–155, doi: 10.1016/0009-2541(86)90078-1.


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DEPOSITIONAL ENVIRONMENT OF THE SURFACE SEDIMENTS IN CENTRAL INDIAN BASIN (CIB), INDIAN OCEAN BASED ON THEIR MAJOR ELEMENT

COMPOSITION

Simontini Sensarma1, Ranadip Banerjee1* and Subir Mukhopadhyay2 1CSIR-National Institute of Oceanography, Dona Paula, Goa 403004; [email protected]

2Department of Geological Sciences, Jadavpur University, Kolkata 700032

In order to establish the depositional environment of the surface sediments in the Central Indian Basin (CIB) of the Indian Ocean, major element composition of surface sediments at 65 locations were studied. The study area, bounded by 11°- 16°S latitude and 73°-79°E longitude, is comprised of calcareous (bordering the ridge areas and basinal highs, mostly calcareous ooze), siliceous (covering the central part, comprised mostly of radiolarian and diatomaceous oozes) and pelagic clay or red clay (covering the south eastern and southern part, comprised mostly of Fe-oxide rich clay particles of both authigenic and detrital origin) sediments.

Oxidative environment (Mn*) although present throughout the basin, but in variable intensity, possibly indicate non uniform pattern of movement of oxygen rich Antarctic bottom water (AABW) in the study area. Although the overall sedimentation pattern is hydrogenetic in both calcareous and pelagic clay domains, in siliceous ooze region, diagenetic influence seemed to be more dominant due to high biogenic silica input and less oxidative environment (low Mn* value). Both iron (Fe) and manganese (Mn) content, especially their non-terrigenous part, were lowest in siliceous sediment, compared to calcareous and pelagic clay regions. Using shale normalized Ti content as an indicator of terrigenous input (Terri%), it was observed that the Terri(%) is variable in all sediment types, while the signature of Terri(%) is traceable till 15°30’S latitude. The variable distribution pattern of Mnexcess and Feexcess indicate that in addition to continental source, there is definite additional source of supply of both these elements through sediment diagenesis and weathering of adjacent mid-oceanic ridge rocks. Presence of volcanic precursors almost in all sediments also could be a source for Feexcess in these sediments. CaCO3 distribution pattern in these sediments shows its enrichment close to the shallower elevated regions adjacent to mid-oceanic ridge, in a highly oxic environment.

High Al/Ti ratio (>22 on average) of the studied samples indicates influence of volcanic precursors including acidic, vitric ash and plagioclase, possibly derived from the adjacent ridge systems and past volcanic activities in this area depicted through the presence of numerous seamounts present in this basin. Also, the higher proportion of “excess” aluminium (Al) adjacent to the ridge areas and fracture zones suggests that not all Al content in these sediments were derived from the continental rocks as was considered earlier.

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TERRESTRIAL AND MARINE PRODUCTIVITY: SOME COMMON THREADS 1R. DaSilva, 1A. Mazumdar*, 2R.K. Joshi, 3A. Shaji, 4P. Mahalakshmi, 1B.G. Naik

1CSIR, National Institute of Oceanography-403004, India; [email protected]

2Geological Survey of India, Kolkata-700 091, India

3Centre for Marine Living Resources & Ecology-682030, India 4Flat No. CS-1, Block-C, Astral Garden, Panaji, Goa-403002

We report here high resolution vertical profiles of total inorganic carbon (TIC wt%),

and 13CTOC values from a core MD161-19 acquired off Mahanadi basin, Bay of Bengal onboard R/V Marion Dufrense (May 2007). Based on the AMS 14C dates (generated at the

NOSAMS, Woods Hole Oceanographic Institution, USA) and 18O (G.ruber) values the maximum depositional age of the core is estimated at ~300 ky covering 8 marine isotope stages. The C and O isotope ratio measurement of G.ruber was carried out using a Finnigan MAT 253 IRMS with dual inlet system at the Department of Geological Sciences, University of Florida. The age depth model for sediment core is obtained from the correlation of δ18O profile with the SPECMAP data. TIC measurements were carried out with an UIC carbon

coulometer. The 13CTOC analyses was carried out using a Thermo IRMS (Delta V plus) coupled to an EA. The TIC content ranges from ~0.2 wt% to ~5 wt%. Several well defined TIC

peaks are recognized in the profile. The 13CTOC values range from -15 to -22‰ VPDB. The

13CTOC values show significant vertical variation which is linked to the nature of terrestrial

organic flux (i.e., C3 vs C4) and marine productivity. The 13CTOC values show remarkable correlation with temporal pCO2 change. Additional effects like rainfall/ aridity and

temperature etc., possibly superimposed on the broad13CTOC variation at MIS scale. Remarkable correlation with 12C enrichment in TOC and enhanced TIC content (high content of foraminifera) is observed throughout the core. We presume that the increase in marine productivity during LGM is due to increased regional aridity and decreased stratification resulting from a weak southwest monsoon. Arid terrestrial condition resulted in proliferation of C4 grass type vegetation. Our future study is aimed at high resolution lipid chemistry of the organic content which will help in the understanding of the nature of terrestrial organic loading, marine productivity variation through various marine isotope stages.

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THE EFFECT OF HOLOCENE TEMPERATURE CHANGES ON HUMAN SETTLEMENTS IN ASIA

Rajeev Saraswat

Geological Oceanography Division, National Institute of Oceanography, Goa; [email protected]

The rise and demise of civilizations in Asia has so far been attributed largely to monsoon, presuming negligible effect of limited temperature variability during the Holocene. Here, we demonstrate the unequivocal effect of temperature variations in shaping human civilizations in Asia, during the Holocene. We have reconstructed centennial scale quantitative changes in temperature and precipitation, covering the entire Holocene, from a core collected from the southeastern Arabian Sea. Two intervals, viz. from 10 (9.1-10.6) kyr BP to 6.8 (6.6-7.0) kyr BP, and 4.5 (3.0-5.7) kyr BP to 3.3 (2.4-4.3) kyr BP, of relatively consistent precipitation with warm conditions, are identified. The intervening period is marked by heavy precipitation and fluctuating temperature. The first of these two intervals coincides with the Mehrgarh civilization, and the later interval of steady precipitation and temperature, corresponds with the Harappan civilization. A unique feature of the record is the mid-Holocene shift in local evaporation-precipitation, which is synchronous with an abrupt shift in monsoon induced upwelling intensity, dissolved oxygen in seawater, CaCO3 burial, and increase in organic carbon deposition. The mid-Holocene climate shift coincides with an increase in atmospheric CO2. The Harappan Civilization followed the mid-Holocene climate shift, suggesting that the shift ameliorated the conditions for the proliferation of well-developed human civilization. A subsequent drop in temperature, coupled with an increase in precipitation, beginning at 3.3 (2.4-4.3) kyr BP, marks the decline of Harappan Civilization, suggesting that the rise and decline of human civilization in Indian subcontinent, was modulated by temporal changes in not only precipitation but also temperature.

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SEDIMENT DISPERSAL AND TRANSPORT ON THE CONTINENTAL SHELF OF MYANMAR, NORTHEAST INDIAN OCEAN

P.S. Rao and V.Ramaswamy

CSIR-National Institute of Oceanography, Dona Paula, Goa - 403004, India; [email protected]

The continental shelf of Myanmar is about 2300 km long from Bangladesh border in the northwest to Thai border in the southeast and may be divided into three physiographic domains - the northern Rakhine (Arakan) shelf adjacent to the Bay of Bengal, the central Ayeyarwady shelf and the southern Tanintharyi (Tenasserim) shelf facing the Andaman Sea. The Myanmar shelf receives sediments from some of the largest rivers in the world like the Ayeyarwady (Irrawaddy), the Salween (Thanlwin) and the Ganges–Brahmaputra rivers. The continental shelf of Myanmar is characterized by complex morphology, neotectonic activity, seasonally reversing monsoon winds and coastal currents, periodic tropical cyclones and storm surges, and meso- to macrotidal conditions.

The Rakhine continental shelf is wider in the north (~ 85 km) and narrows towards the south (< 40 km). The shelf topography is complex due to the presence of numerous islands and submerged shoals. The shelf break occurs at a water depth of about 100 m in the north and shallows to about 70 m in the south. The upper part of the shelf is shallow and deltaic while the central part is more or less rocky and devoid of sediment. The southern part consists of silty-clays on the inner shelf and coralline sands and shell fragments on the outer shelf.

The Ayeyarwady continental shelf is part of a complex geological setting in the Andaman Basin. The shelf width is about 170 km off the Ayeyarwady River mouths and increases to more than 250 km in the center of the Gulf of Martaban. Seafloor in the Gulf of Martaban and adjacent inner shelf is generally smooth whereas the outer shelf has a rough surface with relief of 2–20 m and has topographic features such as pinnacles, highs and valleys, buried channels and scarps. The shelf break is at 110 m isobath, beyond which the depth increases rapidly to about 2000 m. A well defined canyon, the Martaben Canyon, incises the Ayeyarwady shelf and follows the N-S trending Sagaing Fault System. Three distinct areas of sediment texture could be identified on the Ayeyarwady shelf (i) fine-grained muds in the Gulf of Martaban and adjacent inner shelf, (ii) outer shelf relict sands and (iii) mixed sediments in the Martaban Canyon. Redistribution of sediments in the canyon by turbidity currents, gravity-driven mass flows and perhaps by tidal currents, has resulted in the formation of mixed type sediments from silty clays in the north to sands and silty sands in the deeper portion.

The Tanintharyi shelf is about 1200 km long aligning roughly in north–south direction. The shelf topography is complex due to the presence of numerous islands and shoals. The shelf break occurs at about 100m in the north and slightly deeper (110 m) in the south. A prominent feature in the southern part of the Tanintharyi shelf is the presence of 85-140 m wide Myeik Terrace. Sediments within the protected embayments of the Tanintharyi shelf are mostly carbonate-rich, except for an isolated patch of fine-grained muds indicating a local source, probably the Dawei (Tavoy) River. The Myeik Terrace is covered with muddy

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sands with subangular to rounded quartz grains, and mixed with carbonate shells and some fine-grained material.

The major source of the terrigenous sediment to the Myanmar Continental Shelf is the Ayeyarwady River. The sediments discharged by the Ayeyarwady River are displaced eastwards by a combination of tidal currents and clockwise flowing SW monsoon current and deposited in the Gulf of Martaban along with the sediments discharged by the Salween River, forming one of largest mud belts of the world. The Gulf of Martaban experiences perennially high-suspended sediments due to re-suspension of bottom sediments by strong tidal currents. Part of the suspended sediment flows into the Martaban Canyon and is transported towards the slope in the form of bottom nepheloid layers. The Martaban Canyon acts as a conduit for sediments to the deep Andaman Sea. During the NE monsoon period (November–January) the surface currents flow towards west transporting some of the suspended sediments westwards into the eastern Bay of Bengal. The sediments carried into the Bay of Bengal may move northwards by the anti-cyclonic circulation of NE monsoon and probably reach the Rakhine shelf.

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IDENTIFICATION OF SOURCES AND FREQUENCY OF MINERAL DUST OVER THE MIDDLE-EAST AND SOUTHWEST ASIA BY USING SATELLITE DATA.

K.Suresh*, V.Ramaswamy, C.Prakashbabu

CSIR- National Institute of Oceanography, Dona Paula, Goa-403004, [email protected]

Mineral dust plays a major role in regulating the atmospheric radiation budget, ocean biogeochemical cycles and productivity. Deposition of the aeolian dust provides macro and micronutrients to the surface oceans which impacts phytoplankton productivity. Major sources of mineral dust to the Arabian Sea are the arid & semi-arid regions, ephemeral lakes and dried lake beds of the Arabian Peninsula and SW Asia. Information on sources and the frequency of dust events are important as composition and frequency of dust injected into the atmosphere vary significantly in different source regions. In the presented study, a number of satellite derived products including the EUMETSAT’s Dust RGB data and MODIS-Aqua Aerosol Optical Depth (AOD) data have been used to identify the major dust sources as well as frequency of dust events in this region for the period September 2012 to August 2013.

Most dust storms originate from one of these six geographic areas: (i) Syrian Desert, (ii) flood plains of Tigris-Euphrates, (iii) Endorheic basins of Iran, Afghanistan and Pakistan, (iv) Al-Dhana Desert, (v) Coastal region of Arabian Peninsula and (vi) Makran coast. Dust is most likely from the ephemeral lakes, wadis, alluvial plains and coastal areas of the above regions.

Two geographic regions frequently have dust events; one is the area comprising Syrian Desert and flood plains of Tigris-Euphrates River in which lot of alluvium is available and the other one is endorheic basins of Iran, Afghanistan and Pakistan where many ephemeral lakes are situated. There are 67 dust events observed in each of the above said regions for the study period.

References: Banerjee, P., and S. Prasanna Kumar (2014), Dust-induced episodic phytoplankton blooms in the Arabian Sea during winter monsoon, J.Geophys. Res. Oceans, 119, doi: 10.1002/2014JC010304. Ginoux, P., J. M. Prospero, O. Torres, Chin, and M., 2004: Long-term simulation of global dust distribution with the GOCART model: correlation with North Atlantic Oscillation. Environ. Model. Software, 19, 113-128 Kaufman, Y., I. Koren, L. A. Remer, D. Tanre, P. Ginoux, and S. Fan (2005), Dust transport and deposition observed from the Terra-MODIS spacecraft over the Atlantic Ocean, J. Geophys. Res., 110, D10S12, doi: 10.1029/2003JD004436 Schepanski K., Tegen I., Macke A. Comparison of satellite based observations of Saharan dust source areas, Remote Sensing of Environment 123 (2012) 90–97 doi:10.1016/j.rse.2012.03.019

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PHOSPHATE UPTAKE BY MICROBIAL COMMUNITES IN THE CONTINENTAL MARGIN SEDIMENTS

S. S. Mamatha*, P.P.Sujith, S. Benjamin, D. Vaigankar, T. Singh, T.R.A. Thomas, B. Nagender Nath, P.A. Loka Bharathi

CSIR-National Institute of Oceanography, Dona Paula, Goa-403004, India; [email protected]

Phosphorous is an essential element in life forms as it is a component of nucleic acid and cell membrane. In the marine ecosystem, recycling of phosphate is rapid which makes it a limiting nutrient in primary production as well as deposition in sediment. Microbes could play an important role in the global phosphorous cycle as the earlier studies support their activity towards the production of phosphatic deposits and phosphorite formations. Hence, in the present study we tried to understand the extent of microbial uptake of phosphate which is released by the oxidation of hypophosphite in sediment. The experiment was carried out on a short sediment core from a topographic high off Goa, where the occurrence of phosphatic pellets and grains containing carbon flourapatite (CFA) had been earlier encountered. The major components in the experimental medium were 2g of glucose, 1g of NH4Cl and 5 μM of hypophosphite (Spectrochem, AR grade) per litre of seawater. The sediment dilutions from different subsections of the core namely 0-2, 4-6, 8-10 10-15 and 30-35 cm were used to inoculate the experimental tubes. The experimental set up was incubated in replicates of five under suboxic conditions over a period of two years at 12±3°C and changes in phosphate concentration was measured according to Grasshoff et al. (1983). It was observed that there is net phosphate uptake in the sediments throughout the depth (figure 1). The maximum uptake was at a depth of 0-2 cm followed by 8-10 cm below the surface. There was also an increase in the cell number as the depth increased till 10-15 cm (figure 2). Cell size ranged from 0.5 to 4 µ with an average of nearly 2 to 2.5 µ at depths where high uptake of phosphate was observed (figure 3 and 4). The maximum cell size was observed at 8-10 cm depth which also showed relatively high cell abundance and uptake of phosphate. On the contrary, though the phosphate utilization was relatively less, high cell abundance and cell size were observed at 30-35 cm depth. This could be due to simultaneous release and uptake of phosphate by microbes in the sediment and also increase in cell size could be linked to the accumulation of phosphate inside the cell. On the whole, phosphate uptake, cell abundance and cell size were synchronous at 8-10 cm depth. These observations suggest the potential involvement of microbial communities of the continental margin sediments in the oxidation of hypophosphite, uptake and accumulation of phosphate.

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Figure 1. Phosphate concentration at different depths after two years of

incubation under suboxic condition

Figure 2. Cell abundance at different depths after two years of incubation under suboxic

condition

Figure 3. Cell size at different depths after two years of incubation under suboxic

condition

Figure 4. Bacterial cells ranged from 3-4µm

References Sterner, R. W., and Elser, J. J. (2002), Ecological Stoichiometry: The Biology of Elements from Molecules to the Biosphere, Princeton University Press, Princeton, NJ. Benitez-Nelson et al. (2005), Digenetic effects on particulate phosphorus samples collected using formalin-poisoned sediment traps. Limnology and oceanography: methods, 3, 308-317. Grasshoff et al. (1983), Methods of sea water analysis. Verlag Chemie GmbH, D-6940 Weinheim. Lepland et al. (2014), Potential influence of sulfur bactertia on plaeoproterozoic phosphogenesis, nature geosciences, 7, 20-24.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3389779/#B9



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SURFZONE CURRENTS AT MIRAMAR BEACH OF GOA, INDIA: A COMPARISON OF OBSERVATION AND THEORY

Yadhunath E.M, Jaya Kumar Seelam*, Jishad, M, Gowthaman R, Pednekar P.S


Surfzone currents are generally classified as longshore currents and cross shore currents. In the nearshore region, longshore currents are both generated as well as affected by breaking waves. Studies regarding longshore currents improve the knowledge about sediment transport at that location, and changes in beach morphology. Near shore topography also has an important role in longshore current generating mechanism, which direct the longshore fluxes and also transforms itself according to waves and currents (Sheremet et al., 2011). Another factor that is important in estimating the longshore currents is the beach face slope. There are many theories which can describe longshore current velocity. Most of the theories are based on principle of conservation of momentum or energy; few are based on regression analysis and continuity relations. Comparison studies of measured and estimated currents were carried out in different scenarios throughout the world. Along Indian coastline Hameed et al. (1986) identified modified equation of Longuet-Higgins (1970), herein after refereed as LH70 and Komar (1975) give better correlation with measured data of Valiyathura and Aleppey coasts, Kerala, India. Chandramohan et al. (1992) based on field data between Ratnagiri and Mangalore coasts on west coast of India observed that LH70 gave 25% higher values than Galvin (1987). Kumar et al. (2000) observed that LH70 over predicted by 32% and Galvin by 6% for the data sets from Kannirajapuram coast, Tamil Nadu.

Yadhunath et al. (2014) measured the longshore current using RCM9 for a period of 2hr and wave parameters measured using Seabird wave and tide gauge from a single measurement location off Candolim and Miramar beaches of Goa. Instruments were deployed at the swash zone of depth 0.5m, in which RCM9 is buried inside the sea bed with sensor head placed above the sea bed. These measured currents were compared with eleven theoretical equations by applying the measured wave data. They observed that with modified coefficients, the LH70 and Komar equations could give better result with a magnitude range from 5-10% lesser than that of measured velocity. In the present study, measurements were carried out at Miramar beach which include deployment of three InterOcean S4 current meters for a period of one tidal cycle in alongshore direction in the surf zone, with a distance of about 100m between them. At the same time co-located RCM9 and Pressure transducers (PT) at a cross shore distance of 70m away from each S4 were also deployed in the swash zone. In this experiment the changes in alongshore and cross shore current speed due to oblique wave action is analyzed. The measured wave parameters are used in estimating the longshore current at this cross section using different theoretical equations by LH70, Komar (1975), Galvin (1987), Putnam et al. (1949), Harrison (1968), Brebner and Kamphus (1964), Inman and Quinn (1951), Bruun (1963), Fox and Davis (1972), Pilarczyk (1999). Therefore, compared to previous study of Yadhunath et al. (2014), this study analyzes longshore current variations over a region and estimates the longshore

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current velocity using breaking wave parameters and corresponding transformed wave parameters in the swash zone.

References: Brebner, A., and J. W. Kamphuis (1964), Model tests on the relationship between deep water wave characteristics and Longshore currents., Proc. 9th ICCE, Lisbon, pp 191-196 Bruun, P. (1963), Longshore currents and longshore troughs, Journal of Geophysical Research, 68(4), 1065-1078. Chandramohan, P., B. U. Nayak, N. M. Anand, and V. Sanil Kumar (1992), Filed measurement on lonshore current variation between Ratnagiri and Mnagalore, west coast of India, in Proceedings of Eighth Conference of International Association of Hydraulic Research, CWPRS, Pune, edited. Davis, R. A., and W. T. Fox (1972), Coastal Processes and Beach Dynamics at Sheboygan, Wisconsin, July, 1972.Rep., Williams College, williams town, mass. Galvin, C. (1987), The continuity equation for longshore current velocity with breaker angle adjusted for a wave-current interaction, Coastal Engineering, 11(2), 115-129. Hameed, T. S., M. Baba, and K. V. Thomas (1986), Computation of Longshore currents, Indian Journal of Marine Sciences, 15, 92-95. Harrison, W. (1968), Empirical equation for longshore current velocity, Journal of geophysical Research, 73(22), 6929-6936. Inman, D., and W. Quinn (1951), Currents in the surf zone, Coastal Engineering Proceedings, 1(2), 3. Komar, P. D. (1975), Nearshore currents: Generation by obliquely incident waves and longshore variations in breaker heights, In: J. Hails and A. Carr (eds), 17-45. Kumar, V. S., P. Chandramohan, K. A. Kumar, R. Gowthaman, and P. Pednekar (2000), Longshore Currents and Sediment Transport along Kannirajapuram Coast, Tamilnadu, India, Journal of Coastal Research, 16(2), 247-254. Longuet-Higgins. (1970), Longshore currents generated by obliquely incident sea waves,2, Journal of geophysical Research, 75(33), 6790-6801. Pilarczyk, K. W. (1999), Design of Dikes and Revertments- Dutch paractise, in Handbook of Coastal Enginering, McGraw-Hill. Putnam, J. A., and W. H. Munk, and M.A.Traylor., (1949), The prediction of longshore currents, Transactions, American Geophysical Union, 30, 337-345. Sheremet, A., S. Jaramillo, S. F. Su, M. A. Allison, and K. T. Holland (2011), Wave-mud interaction over the muddy Atchafalaya subaqueous clinoform, Louisiana, United States: Wave processes, Journal of Geophysical Research, 116(C6) C06005, doi:10.1029/2010JC006644. Yadhunath, E. M., J. K. Seelam, M. Jishad, R. Gowthaman, C. Rajasekaran, and P. S. Pednekar (2014), Surfzone currents at Candolim and Miramar beaches of Goa, India: measurements and comparisons, Indian Journal of Marine Sciences, 43, 7.

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CHANGE DETECTION STUDIES ALONG VENGURLA COAST, INDIA THROUGH REMOTE SENSING AND GIS

R. Gowthaman*1, Y.G. Harikrishna Sharma2 and V. Sanilkumar1 1CSIR-National Institute of Oceanography, Dona Paula, Goa-403004; [email protected]

2Mangalore University, Mangalagangotri, Mangalore -574199

The study area Vengurla is located in South Maharashtra near the border of Goa and is part of the Konkan Coast. The northern coastline of Vengurla is rocky, but not in southern region. River Karli flows from east to west and borders the northern part. River Talvada flows from north-east to south-west and joins the sea at Mochemad. Two more rivers join the sea at the Vengurla port hill, situated on the northern and southern sides of the hill. The shoreline is very irregular, associated with features like cliffs, notched, promontories, sea caves, embayments, submerged shoals and offshore islands. GIS technique is used to study the shoreline changes and Land-Use/Land Cover (LU/LC) classification of the study area utilizing the Indian Remote sensing satellite (IRS-1D, IRS-P6 and LANDSAT-7) data during 2002, 2011, 2013, 2014 and Toposheet of 1954. Base maps are scanned and registered using ERDAS imagine software and map composition is done using ArcGIS software. Long-term shoreline changes from 1954 to 2014 show accretion of 0.04 km

2 and

erosion of 2.25 km2. Erosion of 0.79 km

2 and accretion of 0.45 km

2 is observed during the short-term (2011-

2014). The validation of the 2014 satellite data is done with field measurements using GPS. The major LU/LC types in the study area are built-up areas, vegetation and water body. The changing trend in the land use pattern between the years 2002, 2011, 2013 and 2014 is estimated. During 2002-2014, 0.009 % of spit area, 2.73 % of vegetation, 2.58 % of water body, 0.106 % of plantation and 1.54 % of built up area increased. During the same period, 0.53 % of sand area, 6.22% of barren land, 0.09 % of mangroves and 0.05 % of rocky coast decreased. Seasonal variation in accumulation and erosion is seen at Vengurla Beach, which is moderate to very low during the pre-monsoon, high to low during the monsoon, and low to very low during the post-monsoon season.

Fig. 1 Study Area

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Fig 2. Shoreline changes from 1954 to 2014

Fig.3 LU/LC Classification in 2014

References: Chandramohan, P. Sanilkumar, V. Nayak, B.U and Pathak, K.C. (1993) ‘ Variation of longshore current and sediment transport along south Maharshtra coast , West coast of Indian, Indian Journal of Marine Science, 22, 115-118p. Praveen B. Gawali, Nathani Basavaiah, and Pramod T. Hanamgond (2010)’ Mineral Magnetic Properties of Sediments of Beaches, Redi–Vengurla Coast, Central West Coast of India: A Seasonal Characterization and Provenance Study’, Journal of Coastal Research , 26(3), 569-579.

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UPWELLING FEATURES OFF SOMALIA AND OMAN COASTS FROM MODEL SIMULATIONS

Tanuja Nigam*, Vimlesh Pant

Indian Institute of Technology Delhi, New Delhi-110016; [email protected]

Upwelling process in the ocean brings the colder and nutrient rich subsurface waters to the sea surface, and thereby reduces the sea surface temperature and may increase the biological productivity. The reduction in SST affects the regional weather, such as fog formation and reduction in convection. In the present study, coastal upwelling features were simulated using a hydrostatic, free surface, primitive equation ocean model Regional Ocean modelling system (ROMS) over the northern Indian Ocean domain. The model follows sigma coordinate in the vertical. The horizontal and vertical resolutions of model are 0.25° × 0.25° and 32 vertical levels, respectively. During Indian summer monsoon (June-September) the strong southwest winds blows over the North Indian Ocean (NIO) basin, producing upwelling at the coasts of Somalia and Oman. The model simulations were analyzed for the coastal upwelling off Somalia and Oman coasts. In general, the model simulated upwelling signatures are in good agreement with the observations. The maximum Ekman transport during July off the Somali coast, calculated from the wind forcing data indicates higher transport as compare to the Oman coast, and up to four times larger values than that of southwest coast of India. Moreover, there is a significant difference in the different wind forcing data sets. The ROMS model is forced by two forcing data sets of Comprehensive Ocean Atmosphere Data Sets (COADS) ocean surface monthly climatology and National Oceanography Centre (NOC). The difference between NOC and COADS forcing is about -0.008 N/m2

in the month of January and about -0.024 N/m2 in the month of July is observed over Somalia and Oman regions. Model simulated vertical profiles of temperature with COADS and NOC forcings are validated against the World Ocean Atlas 13 (WOA13) data set over Somali, Oman and West Coasts. It is found that NOC simulations are in better agreement with observed data comparative to COADS simulations. The model simulated vertical velocity is also validated with Simple Ocean Data Assimilation (SODA) data. The simulated magnitude (8 x 10-3 cm/sec) of vertical velocity off Somalia coast during August-September is well comparable with the observed data.

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EVALUATION OF MITIGATION OPTIONS FOR SUSTAINABLE SHORELINE MANAGEMENT FOR POOMPUHAR COAST

Abhishek Tavva*, S Sankar, Vijaya Ravichandran, KM Sivakholundu


Sedimentation and erosion processes at a site play a key role during development of any coastal project along the Tamil Nadu coast. The east coast of India has northerly littoral movement for most of the time during a year due to which any obstruction to littoral movement like breakwater placed across the shore causes accretion to the south of the structure accompanied by erosion to the north. National Institute of Ocean Technology (NIOT) had carried out marine Environmental Impact Assessment (EIA) study for the proposed fishing harbour consisting of breakwaters at Poompuhar in Tamil Nadu. This paper deals with the effects of breakwater construction on the shoreline and evaluation of various mitigation strategies for erosion prevention.

The model for shoreline evolution for Poompuhar was setup using LITLINE module of LITPACK. The coastline is oriented 355o to true North. The predominant wave direction was from South-East. Modelling was carried out for a stretch of 6km with a grid spacing of 100m along the shore. Data from both primary and secondary sources were used as inputs for the model. Bathymetry and beach profiling data were collected by NIOT at Poompuhar and GEBCO data for the remaining area of the domain of the model were interpolated and used. A profile best representing the bathymetry of the area was used as input. Wave data obtained from NIOT wave model was used as input. Sand particles of mean diameter of 150 µm was used as input for grain size. The fall velocity was calculated based on Stokes law.

The model was run for 1 year shoreline evolution in the absence of the proposed breakwaters. Validation was carried out for shift in shoreline based on data available from beach profiling and a close match was obtained. Model run was carried out for shoreline evolution in the presence of proposed breakwaters for fisheries harbour. It was observed that the shoreline undergoes severe erosion to the north in the presence of proposed breakwaters for fisheries harbour. The shoreline undergoes erosion to an extent of 1.5km along the shore with an erosion of 40m into the shore.

Various strategies were evaluated to mitigate the erosion to the north of proposed breakwaters and each of these cases was modelled. One of the options was a groin field to the north of the breakwaters. Based on model studies it was found that erosion continued to persist northwards of the groin field. The other option was a shore parallel detached offshore segmented breakwater which yielded better results as it showed lower erosion to the north of the breakwaters proposed for fisheries harbour. It is therefore concluded that offshore segmented breakwaters provide a sustainable shoreline management in the case of Poompuhar Coast.

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EFFECT OF WIND DRIVEN CIRCULATION ON INTERNAL WAVES: A CASE STUDY

Sachiko Mohanty*, Himansu K Pradhan, A D Rao

Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi-110016; [email protected]

Internal Waves (IWs) occur in the interior stratified region of strong density discontinuity (thermocline/pycnocline) in the sea and are mostly generated by a flow over topography. The variable bottom topography, the altering stratification throughout the year and the tides make the western Bay of Bengal (BoB) an ideal region for generation of internal waves.

MITgcm, a non-hydrostatic, 3D z-coordinate primitive equation model is configured over the western BoB to study IW characteristics during November-December 2013. A high resolution mesh extending from 15°N to 20°N and 82°E to 87°E is prepared from GEBCO (30 sec) dataset with an horizontal extent of 270km and 520km towards east and north directions respectively. The resolution in the offshore direction varies from 200m near the coast to 1500m in the open ocean while the resolution is about 3km along the coast. The model is initialized with density fields calculated from the monthly climatology of temperature and salinity from WOA09. The model is forced by the real-time surface wind stress from the daily ASCAT for the months of November and December 2013. For the IWs simulation, the dominant tidal constituents over the BoB namely M2, S2, K1 and O1 are derived from the global tidal model TPXO7.2 and incorporated to the MITgcm model at the eastern boundary. The model integration is continued for 2 months and the results for surface currents and vertical temperature are compared with OSCAR and ARGO datasets respectively for the months of November-December. During this period, the currents are towards the south (EICC) which is simulated well in comparison with OSCAR currents. The model reproduces the temperature inversion of about 0.5°C well present in the ARGO data off Gopalpur and Kalingapatnam. In-situ temperature, salinity and current data were collected off Gopalpur for two locations where station depths of 110m and 400m during November and December. These ADCP, Microcat, RCM, TP sensor data are available at various depths which are used in computing the spectral analysis for identifying IWs characteristics. The spectral estimate of model simulated density is compared with the in-situ data. It is observed that the spectral estimates are in good agreement with the observations for both the locations.

The experiments are also made without wind forcing and compared with the simulations with wind. The conclusions are drawn on the effect of currents on the internal waves at different cross-sections based on the spectral estimates computed from the density.

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VALIDATION OF STORM SURGES USING A COUPLED SURGE-TIDE-WAVE MODEL: A CASE STUDY FOR TAMIL NADU COAST

Smita Pandey*, Jismy Poulse , A D Rao

Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi-110016; [email protected]

India is frequently affected by tropical cyclones which are among the most lethal and costly natural hazards affecting humankind. Coastal flooding as a response of storm surges associated with tropical cyclones is one of the greatest vulnerability that occurs along the coast. A proper understanding of the factors responsible for generating and its contribution to the total water elevation along the coast is highly desirable. The rise of total water elevation at the coast is caused primarily by three factors that include storm surges, tides and wind waves.

For this study, a hydrodynamic finite element based Advanced Circulation 2D depth integrated (ADCIRC-2DDI) model is used to compute storm surges and water levels along the Tamil Nadu coast considering the non-linear interaction with the tide. ADCIRC solves equations of motion of a moving fluid to compute velocity and elevation that can be obtained from the solution of continuity equation. The modeling of storm surges in complex terrain requires true representation of coastal geometry as well as detailed onshore topography and bathymetry. For this purpose, the bathymetry of the domain is derived from the latest available GEBCO dataset with a resolution of 30sec (900m) and topography from SRTM (90m). The surface wind associated with tropical cyclone is the main driving force for storm surges. The cyclonic winds are calculated by using a dynamic storm model of Jelesnianski and Taylor (1973). Tidal forcing along the open boundary is derived from FES2004 database. The model is coupled with the SWAN model in order to study the impact of wind waves on the storm surges. The experiments are performed to validate the total water elevation generated for three cyclonic cases: Cuddalore 2000, Thane 2011, and Nilam 2012 cyclones with available tide gauge data during this period. On comparison of model surge residuals with the observed ones, it is inferred that the contribution of wave set up caused by wind waves plays an important role on the total water elevation. The significance of each factor responsible for the computation of total water elevation is highlighted.

References: Jelesnianski CP, Taylor AD (1973) NOAA technical memorandum. ERL, WMPO-3, p 33

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EVIDENCES OF HIGH ENERGY MARINE EVENTS FROM THE GUJARAT COAST, WESTERN INDIA: STORM OR TSUNAMI DEPOSITS?

S.P.Prizomwala1*, Drasti Gandhi1, 2, N.P. Bhatt3, B.K. Rastogi1 1Institute of Seismological Research, Raisan, Gandhinagar 382009, India; *[email protected]

2The Geology Department, M. G. Science Institute, Navrangpura, Ahmedabad 380009, India

3Department of Geology, The M. S. University of Baroda, Vadodara 390002, India

The east coast of India has been highlighted as most prone to major marine inundations as evidenced by recent tsunamis. Presence of tsunamigenic sources in northern Arabian Sea namely Makran Subduction Zone (MSZ) and Owen Fracture Zone (OFZ) qualifies the west coast of India to hold signatures of past tsunamis. However the western coast of India has remained deprived of any such studies. Here we present geological evidences of palaeo-storm / palaeo-tsunami from the coastline of Gujarat. The Kachchh coast shows presence of palaeo-tsunami dating back to 1000 AD in the form of sand layer sandwiched between mud layers from Mundra and Bhadreshwar. The sand layer shows basal erosional contact with the mud layer, lack of sorting in sediments and broken microfossils. Similarly large boulders are found in imbricated and scattered forms on the rocky southern Saurashtra coastline. The numerical modelling shows these boulders were derived from offshore with a wave of 3.5 m of wave height at the shoreline. OSL dating suggests this event dates to a period within last 3436 ± 234 years. The source for palaeo tsunami sand layer in Kachchh is more likely an event at Strait of Hormoz / Makran Subuction Zone and for boulder deposits of southern Saurashtra segment is the Southern Oven Ridge. We postulate an earthquake along Makran Subduction Zone and a mega-landslide along southern Saurashtra coastline as causal mechanism for these palaeotsunami events.

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PERFORMANCE OF DELFT3D-WAVE MODULE IN THE NEAR-SHORE WAVE TRANSFORMATION OFF RATNAGIRI, WEST COAST OF INDIA

Glejin Johnson and V. Sanil Kumar*

CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004 India; [email protected]

Waves are the dominant factor influencing the nearshore processes .Wave refraction and wave breaking are responsible for large fluid motions not only to drive currents, sediment transport and bed changes but also influence the surf zone heat budget and air bubble entrainment. Long-term in-situ measurements in the nearshore and surf zone are a tedious task due to heavy fishing and biofouling in the area. In this study, we investigate the performance of nearshore transformation off Bhatya beach, Ratnagiri using Delft3d-wave module (Delft Hydraulics, 2011) developed by WL∣Delft Hydraulics. This model is an adapted version of the SWAN model (Booij et al., 1999) which takes the effects of complicated interactions and transformations experienced by waves propagating through space: refraction due to bottom and current variations, shoaling, blocking and reflections due to opposing currents, transmission/blockage through/by obstacles, effects of wind, white capping, depth induced wave breaking, bottom friction and non-linear wave–wave interactions. Wave data collected off Ratnagiri at 14 m water depth using Directional wave rider buoy is used as source at boundary for the numerical modelling. Different cases are simulated by including different physical processes. Wave data for validation of nearshore wave transformation model is measured using the InterOcean S4DW wave gauge for a period of one week each during the onset of summer monsoon in May 2012 and post-monsoon period in November 2012. The average significant wave height during May was 0.9 m and was 0.5 m during November. The model results show satisfactory (r ~0.7) results with measured wave data. Due to the presence of irregular coastal landforms and dominance of wind-sea over swells by the local wind system in the study area, the sensitivity analyses carried out show that besides the wave input inclusion of the tide and wind input improves the model output.

References: Booij, N., R. C. Ris, and Leo H. Holthuijsen.(1999) A third‐generation wave model for coastal regions: 1. Model description and validation, Journal of Geophysical Research: Oceans 104, C4, 7649-7666. Delft Hydraulics (2011). Delft3d User Manual. Delft. The Netherlands.

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MODELLING THE BIOLOGICAL ACTIVE LAYER CIRCULATION IN THE SOUTH-EASTERN ARABIAN SEA

Vijay Kumar

Centre for Atmospheric Sciences; Indian Institute of Technology Delhi; New Delhi 16, India

Biological active layer (upper layer of Ocean) circulation plays important role for the marine ecosystem. Most of the biological activities happen in the upper layer and circulation influence transportation and population dynamic of plankton and forage fish. It is mainly a wind driven circulation. The surface winds blow from the northeast during the winter monsoon (November to February) and from the southwest during summer monsoon (May to September). This semi-annual reversal of winds influences the surface layer of the basins and generates a seasonal cycle in sea surface currents. Salinity and density of Upper Ocean are nearly constant. The mixed layer of ocean can be considered as homogenous and the depth of mixed layer in the Arabian Sea is between 20-100 m.

The shallow water equations are used to simulate the upper ocean circulation. As a case study, the shallow-water model is applied to the South-eastern Arabian Sea (4°12’N to 19°48’N and 65°30’E to 81°51’E) along the west coast of India. The region is important because of the high prevalence of plankton and forage fish that is highly influenced by the reversal monsoonal currents. The model is forced by the seasonally varying surface winds. Finite difference schemes are used for performing numerical experiments. The simulation the upper ocean circulation mainly depends upon the horizontal turbulent viscosity besides the input surface wind stress. Input data of wind stress for the domain of study are taken from the website of INCOIS (http://las.incois.gov.in/thredds/dodsC/las/id-quick_daily/data_home_las_datasets_quick_daily.nc.jnl). The model simulated results are well validated with INCOIS data of ocean current available on the website (http://las.incois.gov.in/thredds/dodsC/las/id-57b2fa3cc8/data_home_las_ datasets_ocean_analysis_NRIG_uv_5day.nc.jnl).

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TIDAL INLET CLASSIFICATION ALONG THE COASTS OF GOA AND KARNATAKA

M. Vikas1, Jaya Kumar Seelam2*, Subbarao1 1National Institute of Technology Karnataka, Surathkal, India

2CSIR-National Institute of Oceanography, Goa, India; [email protected]

Tidal inlets are openings along the shore that connect the open ocean with the river, bay or lake system over the land. Tidal inlets play a greater role in regulating the flow between the water bodies over the land and the open ocean. Choking of these tidal inlets could cause major flooding of the rivers and also results in reduced flow of sediments in the open seas which results in changes of near shore sediment transport. In order to understand the behaviour of the tidal inlets, these are classified based on their morphology and also based on the major forces acting on the inlets.

In this study, an attempt has been made to classify these inlets based on hydrodynamics (Hayes, 1979) and also based on dimensionless parameters using the wave height, river discharge and Tidal prism (Thuy, 2013) for different seasons. A database was compiled for 38 inlets along the coasts of Goa and Karnataka (Fig. 1). The database contains spring tidal range, the average near shore significant wave height, and river discharge for certain inlets and the bay or lagoon areas. The tidal inlets are classified considering the variation in wave heights averaged annually, during North-East monsoons, during South-West monsoon and during fair weather season. It is observed that a tidal inlet can fall into the category of tide dominated with barrier formation during certain time of the year whereas they fall into wave dominated during other times. This kind of variations in the tidal inlet classification could mean that tidal inlets should not be generalised for the whole of a region without considering the morphological and hydrodynamic settings and its variations with seasons. This paper presents the methods and results of the tidal inlet classification along the coasts of Goa and Karnataka.

Fig. 1 Location map of the field investigations

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References: Hayes, M. O. (1979), Barrier island morphology as a function of tidal and wave regime. In: Leatherman, S. (ed.), Barrier Islands, from the Gulf of St. Lawrence to the Gulf of Mexico, Academic, New York. Thuy, V. T. T. (2013), Aspects of Inlet Geometry and Dynamics, The University of Queensland, Brisbane, Australia.

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A STUDY ON SEASONAL MORPHOLOGICAL CHANGES AND CLASSIFICATION OF TIDAL INLETS ALONG GUJARAT AND KERALA COASTS

N. Amarnath Reddy1*, M. Vikas1, Jaya Kumar Seelam2, Subbarao1 1National Institute of Technology Karnataka, Surathkal, India; [email protected]

2CSIR-National Institute of Oceanography, Goa, India

A tidal inlet is an opening in the shoreline through which water penetrates the land thereby providing a connection between the ocean and bays, lagoons, marsh, and tidal creek systems. The tidal inlet morphology has to be examined and studied to understand the near shore coastal processes. The tidal inlets are classified to know the type of dominance and to find if this changes with time. Also, inlet migration and closure are the two factors that are strongly influenced by seasonal variation in wave climate. Some of them are found changing when the seasonal variation of wave height is taken into consideration. This classification, in a broader view is necessary for the management of tidal inlets. The type of dominance over the tidal inlets in Gujarat is found very different for northern and southern parts of the state. In this paper geo-morphological, hydrodynamic and classification based on few dimensionless parameters has been done. In this study, two regions of contrasting tidal and wave regime i.e., Gujarat and Kerala coasts, along the west coast of India are considered. Gujarat coast has macro-tidal regions with mild to moderate wave climate whereas Kerala coast experiences micro to meso tidal range with high wave climate. Under these contrasting oceanographic regimes, the tidal inlets and their behaviour are varied.

Classification of these inlets based along Gujarat and Kerala coasts (Fig. 1), for different seasons, is carried out based on two methods, (i) based on hydrodynamics of the region (Hayes, 1979) and (ii) based on non-dimensional parameters obtained from the wave height, river discharge and Tidal prism (Thuy, 2013). A total of 63 inlets were considered in Gujarat and 68 inlets were considered in Kerala. A database on the tidal range, near shore significant wave height at about 10m water depth and river discharge details, if available and the size of bay or lagoon. This paper presents the methods and results of the tidal inlet classification carried out for inlets along the coasts of Kerala and Gujarat.

Fig. 1 Location map of the field investigations

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References: Hayes, M. O. (1979), Barrier island morphology as a function of tidal and wave regime. In: Leatherman, S. (ed.), Barrier Islands, from the Gulf of St. Lawrence to the Gulf of Mexico, Academic, New York. Thuy, V. T. T. (2013), Aspects of Inlet Geometry and Dynamics, The University of Queensland, Brisbane, Australia.

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MORPHOLOGICAL CHANGES DUE TO DEVELOPMENTAL ACTIVITIES AT PARADIP PORT

S.G. Manjunatha*, K.B. Bobade, M.D. Kudale

Central Water & Power Research Station, Khadakwasla, Pune-411 024; [email protected]

For the development of the port on the open coast, provision of long breakwaters for ensuring wave tranquility in the harbour is essential. The breakwaters cause obstruction to the littoral transport. As a result, excessive accumulation on the up-drift side and severe erosion on the down-drift side of the breakwater are inevitable. An artificial lagoon type harbour at Paradip (Photo-1) located on the East Coast at Lat. 20°16'N, Long. 86°40'E is one of the twelve Major ports of India which caters to large portion of the sea-borne trade of the northeast part of the country. The port is provided with two breakwaters to provide desired tranquility in the harbour area, ‘South breakwater’ with the present length of 1517m and the, ‘North breakwater’ with a length of 538m. The construction of the breakwaters was completed by the year 1965 up to a length of 1217m for southern breakwater and 538m for north breakwater. The 300m extension of south breakwater for providing wave tranquility in the ship stoppage reach and mitigating sand encroachment in the navigation channel was implemented during 1999 to 2013. The port became operational on 18th April 1966.

Photo-1: Imagery of Paradip Port

Prior to the development of port, the yearly littoral drift was estimated to be 1.5 million cum from south to north and 0.5 million cum from north to south. Initially, beach nourishment of the northern shoreline was not easily possible due to various difficulties like damage to sand pump, non-availability of dredgers having shore pumping capability.

As a result, severe erosion occurred on the northern shore. In order to protect property, a sea-wall construction started in 1970 and total length of 6000m has been constructed. Over the years, due to severe wave action on the seawall, excessive deepening has taken place in front of seawall. The bypassing of sand from sand trap to northern

South Breakwater

North Breakwater

Sea-wall

Accumulation of sand

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shoreline was possible to a very limited extent due to wave disturbance at sand trap and inability of the dredgers to approach the northern shore, which was not able to form the beach on permanent basis. As such, there is a need for adequate beach nourishment. The analysis of hydrographic charts and dredging/sand bypassing details supplied by the Port Authority indicated that, large changes in shoreline and amount of littoral drift has taken place and it was also noted that large amount of sand was deposited during the each cyclone at various locations in the port. This paper highlights the changes in the shoreline and utility of the sand obtained from capital and maintenance dredging operation for shore protection.

References: Ananth P. N., Sunder V. (1990) ‘Sediment budget for Paradip Port, India’ Ocean and shoreline Management, 13 (1990), pp69-91 Basco, D. R. (1983), Surfzone currents, Coastal Engineering, 7(4), 331-355. Report on ‘Morphological and nautical studies for the extension of the port of Paradip’, Delft Hydraulic Laboratory, 1969 Report on ‘Study of siltation process at Paradip port’, Central Water and Power Research Station, 2008.

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PREDICTION OF SHORELINE DYNAMICS USING GEOSPATIAL TECHNOLOGY: A CASE STUDY OF ENNORE COAST, TAMIL NADU, INDIA

S. Saravanan1*, R. Manjula2, S. Sivaranjani1 1National Institute of Technology Tiruchirappalli, [email protected]

2Bharathidasan University, Tiruchirappalli.

The shoreline is one of the most important feature of the coastal eco system. Various geological processes like erosion, deposition, sedimentation, periodic storms, flooding and sea level rise are affecting the shoreline dynamics. A recent study using multi-temporal Landsat imagery of the Ennore coast indicated significant variation in erosion and accretion trends from 2000 to 2013. The shoreline changes is studied by using satellite and field data along the Ennore to Adayar creek. The base map was prepared using Survey of India topo-sheets on 1:50,000 scale. An integrated approach comprising visual image interpretation and maximum likelihood supervised classification have been employed to classify the coastal landforms by using LandSat and IRS P6 LISS-IV data for the period of 2000-2013.

In this study, an analysis was made to quantify the extent of erosion and accretion of the Ennore to Adayar coast in Tamilnadu, India and predicts the dynamics in the future. Shorelines were demarcated by using the End Point Rate (EPR) method in the Digital Shoreline Analysis System (DSAS) extension in ArcGIS® and Remote Sensing techniques. The rate of shoreline change were calculated for 500 transects generated at 100 m intervals along the entire study area shoreline in order to determine the statistics of net shoreline movement and shoreline change envelope by the Linear Regression of Rate of Change. It is found that the shore line changes observed during the period of 2000 to 2013 ranges from 5.0 to 37.8 meters.

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TIDE MODULATION OF SURFZONE WAVES OFF MAHARASHTRA COAST ON THE CENTRAL WEST COAST OF INDIA

M. Jishad*, Jaya Kumar Seelam

CSIR-National Institute of Oceanography; AcSIR, School of Oceanography, Goa; [email protected]

Tidal modulation of wave height not only impacts recreational surfers but also has serious ramifications in the area of near shore sediment transport (Davidson et.al., 2009). Most of the numerical models neglect the effects of tidal variation on sediment transport. Not many field studies exist pertaining to surfzone wave height variation with tides. This study aims at providing insight into the modulation of surfzone wave heights during a falling tide in outer surfzone. The surf zone wave characteristic studies were carried out using Wave Rider Buoy (WRB) and Wave and Tide Gauge (WTG) over a period of 6 hours off Vengurla beach, Maharashtra, located on the central west of India. These WRB and two WTG s are deployed at 3 locations in the cross-shore direction at 10m, 5m and 3m water depth respectively in the cross-shore direction (Fig. 1). Wave characteristics analysed using FFT at low tide, mid tide and high tide for all the locations. The variation of the spectra and the derived parameters in terms of energy, wave steepness, etc., at each location with respect to the tide is studied. A cross-spectral analysis of the wave height time series, tidal displacement and dissipation of wave energy in the surfzone is also studied.

The cross-shore wave height variation is modelled using SWASH (Zilema et.al., 2011) -A non-hydrostatic numerical model. SWASH is capable of simulating free surface flows and rotational flows. The wave spectral simulations are carried out over the bathymetry, which is used to simulate the wave propagation and to estimate the dissipation rate.

Fig. 1. Location map

References: Davidson, M. A., T. J. O’Hare, and K. J. George (2009), Tidal modulation of incident wave heights: Fact or Fiction?, Reef Journal, 1(1), 16-32. Zijlema, M., G. Stelling, and P. Smit (2011), SWASH: An operational public domain code for simulating wave fields and rapidly varied flows in coastal waters, Coastal Engineering, 58(10), 992-1012.

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SPRING-NEAP VARIABILITY IN RESIDUAL FLUXES THROUGH COCHIN INLET

Vinita J*, Revichandran C., Muraleedharan K.R., Lallu K.R., Jineesh V.K.

CSIR-National Institute of Oceanography, Regional Centre, Dr. Salim Ali Road, P.B.No.16161, Kochi, Kerala; [email protected]

Interactions across the land-ocean boundary are currently the focus of regional and global research to quantify fluxes of materials from the land to the coastal region which determines the anthropogenic effects on the coastal environment (Lane et al., 1997, Jay et al., 1997). With the advent of Acoustic Doppler Profilers (ADPs) more accurate estimation of cross sectional fluxes is far accomplished in unsteady and bi-directional flow conditions of estuaries. This paper reports for the first time the discharge measurements conducted across Cochin inlet using ADP to examine the spring-neap variability in residual fluxes of water and nutrients during dry season.

Figure 1. Map of Cochin estuary and Cochin inlet. Transect sampled across inlet using ADP and CTD sampling station is shown.

A 24-h field experiment was carried out at Cochin inlet for two consecutive tidal cycles of neap (22-23 February 2010) and spring (1-2 March 2010) tides during the least runoff period (Figure 1). Water level was recorded at 10 minute intervals using SBE 26 plus Tide Recorder with accuracy 0.1% of full scale (Strain Gauge Pressure) which was installed at the sampling cross sections. A Sontek ADP (1500 kHz) with bottom track capability was towed across the inlet for every hour which acquired vertical velocity (± 1 % accuracy) profiles at 5s averaging rate and 0.9m of vertical resolution (cell size). Downstream currents are assigned positive and upstream currents are assigned negative. The discharge computations were made using the proprietary software Sontek’s River Surveyor. Salinity profiles were taken using SBE Seabird 19 plus CTD (conductivity ± 0.001 Sm−1) with a bin size 0.2 m for every one hour interval at the middle of the transect (depth of 10 m) (Figure 1). Current profile at this CTD sampling station was extracted from the ADP cross-channel data to examine the evolution of currents and stratification over tidal cycles. Using this data, the gradient

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Richardson number (Ri), which provides stability of the water column were computed from equation,

(

) ------------------ (1)

At the same location, water samples were also collected from the surface and bottom for 3 h intervals for both tidal phases. Water samples for various dissolved inorganic nutrients (Nitrite, Nitrate, Ammonia, Silicate, Phosphate) were filtered and analyzed within 3h of sampling using a UV-VIS Spectrophotometer (Shimadzu 1650PC) according to the methods described in Grasshoff et al. (1983). Nutrient transport at instantaneous discharge values were multiplied by the corresponding nutrient concentration. Net fluxes are represented in tons per day (t d-1).

The maximum tidal range for neap tide was 75.4cm which increased to 93.9cm for spring tide. Pronounced diurnal inequality was observed for neap tide particularly during low tides (36.9cm). The currents were vertically homogeneous and were unidirectional for both tides. The salinity field under neap tides showed stratification during ebb (Ri ~ 0.9) and well mixed water column during peak flood (Ri ~ 0.3). During spring tide, there was turbulent mixing and Ri values were less than 0.25 throughout the observation period.

From cross-channel measurements, during neap the maximum mean velocity obtained was 98 cm.s-1 in the ebb direction (270°). In the flood direction (90°), the maximum mean velocity was 68 cm.s-1. During spring, the maximum ebb and flood currents were 96cms-1 and 84cms-1 respectively. The computed residual fluxes of water over the tidal cycles were 4990.8 m3s-1 and 2149.7 m3s-1 for neap and spring tides respectively, directed seaward during both tides.

Generally, the computed net nutrient fluxes were all positive, indicating export of filterable nutrients into the sea. Ammonia fluxes were the highest which showed positive fluxes during neap while negative fluxes during spring tides. The export fluxes of DIN and silicate of Cochin estuary were larger compared to the estimates from other Indian estuaries. The intense flushing caused by strong ebb currents compounded with the increased nutrient concentrations during ebb resulted in the export of all nutrients into the sea. The findings of this study highlight the consequences of anthropogenic interventions in the estuary and their effects on the fluxes on ecologically relevant substances.

References: Lane, A. et al., (1997), Measuring fluxes in tidal estuaries: Sensitivity to instrumentation and associated data analyses, Estuarine, Coastal and Shelf Science, 45, 433-451. Jay, D. et al., (1997), A review of recent developments in estuarine scalar flux estimation, Estuaries, 20, 262-280.

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VARIABILITY OF SUSPENDED SEDIMENT CONCENTRATION AND ITS TIDAL INFLUENCE IN THE GULF OF KACHCHH, INDIA

R. Ratheesh*, A.S. Rajawat, R. Smitha

Geo-Sciences Division, Space Applications Centre, Ahmedabad; [email protected]

Empirical Orthogonal functional (EOF) analysis also known as Principle Component analysis has been used widely on ocean data to describe the spatial properties and temporal dynamics of different ocean features (Hernandez-Guerra and Nykjaer, 1997). In the resent study, complexity of the temporal sediment variability within the Gulf of Kachchh is resolved into major modes of variations using EOF analysis. Suspended sediment concentration (SSC) derived Ocean Colour Monitor (OCM) is used to study the temporal variations in Gulf of Kachchh (GoK) and to investigate the hydro-meteorological parameters influencing the temporal variability of SSC. Temporal EOF analysis has been performed on sequential OCM derived SSC subsuming the area over GoK region during the spring inter-monsoon season of 2011. Variance accounted collectively by the first four modes is around 80% (Table 1) and the principle component (PC) of each mode, representing the temporal variations is correlated with different hydro-meteorological parameters influencing the hydrodynamics of the gulf (Fig. 1).

Fig.1 Different modes of PC and its comparison with ocean state parameters a) PC1 comparison with averaged tidal current speed between consecutive OCM observation (PC1

is also compared with temporal variation in the mean SSC); b) PC2 comparison with the

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instantaneous tidal height; c) PC3 comparison with instantaneous wind speed component to the axis of GoK; d) PC4 comparison with instantaneous tidal current speed

The hydro-meteorological parameters are classified in the order of precedence of influencing the sediment dynamics of the region. PC1 contributing 50% of the total variance is statistically correlated with average of the simulated current velocities between consecutive images, indicating the variation of tides from neap-spring ranges (r2=0.86) (Table 1). During spring tides, strong tidal currents induce re-suspension of sediments causing SSC values to increase while during neap tides, deposition of SSC occurs under weak currents, reducing suspended sediment within gulf. PC2 contributing 20% of the total variance has been correlated with the tidal height at the time of OCM pass (r2=0.93), where during high tide, sediment loaded water are flooded into the gulf while during low tide, sediment rich water are drained out of the gulf. Component of wind along the axis of the Gulf is co-related with PC3 (r2=0.69), which contribute 6% of the total variance while PC4 (4%) is co-related with the tidal currents (r2=0.59) at the time of OCM pass.

Table 1 Percentage of variance accounted by the EOF modes and comparison of different modes of PC with the ocean state parameters and its correlation coefficient

PC mode

Percentage Cumulative percentage

Comparison with Correlation coefficient

PC1 50.4 50.4 Average of the current speed (Prevailed between two OCM

passes)

0.86

PC2 19.3 69.7 Tidal height (At the time of OCM pass)

0.93

PC3 6.3 76 Wind (At the time of OCM pass) 0.69

PC4 3.8 79.8 Current speed (At the time of OCM pass)

0.59

The present work has sequenced the ocean state parameters in the order of their importance in influencing the suspended sediment variability. The temporal variation in SSC is largely depended on the current conditions that have been prevailing within the gulf (spring and neap) while the transient current speeds at the time of OCM pass have smaller influence to the sediment dynamics. The sediment re-suspension and deposition processes will commence on increase or decrease in the current speed but to have an impact on the total sediment concentrations within the gulf, the characteristic speed of the current should sustain for a considerable duration and hence the duration of the current conditions is an important factor in relating to the sediment dynamics. Next in the order of influence is the tidal height at the time of OCM pass, which determines the volume of water within the controlled volume of the gulf. Tidal height is followed by the contribution of the wind, which is observed to have a subtle role in the temporal dynamics of the sediment concentrations. Deposition of the suspended sediments and its re-suspension during respective favourable conditions is the pivotal process while studying the sediment dynamics of the gulf. With

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respect to the temporal variability of the sediment concentration, GoK, during the spring inter-monsoon period, can be considered as a self sustained system, where the sediment are deposited and re-suspended within gulf.

References: Hernandez-Guerra, A. and Nykjaer, L. (1997), Sea surface temperature variability off north-west Africa: 1981-1989. International Journal of Remote Sensing, 18, 2539-2558.

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AN EVALUATION OF FACTORS CONTROLLING DECADAL-SCALE SEA LEVEL RISE IN THE MACRO-TIDAL GULF OF KACHCHH

Onkar S. Chauhan

CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004 India; [email protected]

The short and long term changes in the trend of the sea level, derived from the available tide gauge date, have been obtained for the Gulf of Kachchh for vulnerability assessment. We have found a large spatiotemporal variability in the sea level within the gulf. At the mouth of the gulf (at Okha), the sea level rise was found to be 1.48 mm yr-1, which was higher compared to Mumbai (~ 0.77 mm yr-1) and that of Karachi (0.61mm yr-1 ). The long term rate of sea level rise at the head of the gulf (Kandla) was found to be higher (2.85 mm yr-1) compared to that at the mouth. Wadinar station located in the middle gulf (which had a short data span from 2005-2010), was found to have sea level rise of 24.24 mm yr-1. Considering a reported local GIA rate of 0.48 mm yr-1 for this region, the averaged long term rate at Kandla (Okha) works out to be 3.33 (1.96) mm yr-1, and that is several fold higher than global trend. The decadal-scale sea level variability was found also to be several folds higher, and it varied significantly from the head (-7.33 - 24.18) to the mouth (-7.68- 9.50 mm y-1). The temporal variability in the sea level rise had been evaluated vis-a-vis historical events of seismic activities.

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PRELIMINARY RESULTS OF RADIANT HEATING RATE OF THE COASTAL AND ESTUARINE WATERS OF GOA

Priya Rauth1*, T Suresh1, Prakash Chauhan2, Arvind Sahay2 1National Institute of Oceanography, Dona Paula, Goa 403004; [email protected]

2Space Application Centre, ISRO, Ahmedabad, India

Solar light on the earth is the natural source of energy and plays a vital role in controlling the biogeochemical and physical processes of the coastal waters. The solar heating in the water column is controlled by the bio-optical properties. [Lewis et al., 1990, Ohlmann, 2003, Sathyendranath et al., 1991]. Study of radiant heating rate (RHR) is meaningful in the coastal and estuaries due to relatively shallow mixed layer and high absorption due to CDOM, chlorophyll and detritus. Here results of the radiant heating rate evaluated within one meter of water column of the coastal and estuarine waters of Goa (India) for the year 2010 to 2011 are presented, along with its effect on the bio-optical parameters. The studies have been carried-out using the in-situ measured, optical and physical parameters derived from the radiative transfer simulations.

The temperature and salinity showed characteristics typical of such waters with horizontal gradations with temperature increasing from the coastal waters towards the head of the estuary (26.49 - 31.73°C) and the salinity was nearly invariant in the coastal waters and decreased towards the furthest in the estuary (12.68 - 35.04 psu). The two parameters used to derive the radiant heating rates, specific heat (Cp) and density of water (ρ) which are often considered constants for the calculation of radiant heating rate, (Cp = 4100 J/kg°C and ρ = 1022 kg/m3) were found to vary from the coastal to estuarine waters due to the gradients observed in the salinity and temperature. The density in these waters varied from 1005.25 to 1022.38 kg/m3 and Cp varied from 4002.92 to 4116.42 J/kg°C. These parameters varied while moving towards the head in the estuary and were nearly invariant in the coastal waters with a mean value of Cp = 4008.88 J/ kg°C and ρ = 1021.29 kg/m3 ).

The spectral solar irradiance measured was used to obtain the spectrally integrated solar radiation for the visible or PAR region (400-700 nm) and the mean value was 348.74 ± 84 W/m2. For the visible solar transmission in water column of one meter a minimum and maximum value of 28.29 % and 72.20 % with mean of 52.77 % was observed. The radiant heating rates for the visible range of solar radiation within one meter of water column were within a range of 0.052 to 0.222 °C/hr with a mean value of 0.128 °C/hr. RHR was found to increase from coastal waters towards the head of the estuary. [Fig. 1]

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Fig. 1. Variations of RHR in the coastal and estuarine waters.

Various bio-optical parameters such as absorption, scattering, diffuse attenuation, CDOM and chlorophyll were also studied to look at their effect on the radiant heating rates in the visible range. The radiant heating rates were found to be controlled primarily by the optical property of absorption. It also showed linear relation with radiant heating. Similarly the chlorophyll fluorescence and CDOM apparently followed the trend of absorption. [Fig. 2]

Fig. 2. Variations of RHR and absorption (a (440)) and chlorophyll fluorescence (Left) and RHR and absorption (a (412)) and CDOM (Middle) and RHR and diffused attenuation

coefficient (Kd (490)) and back scattering (bb(650)) (Right).

Since absorption was found to correlate with scattering, the total scattering, back scattering and diffuse attenuation coefficient were also found to correlate linearly with radiant heating rate.

References: Lewis, M. R., M. E. Carr, G. C. Feldman, W. Esaias, and C. McCain (1990), The influence of penetrating irradiance on the heat budget of the equatorial Pacific Ocean, Nature, 347, 543-545. Ohlmann, J. C. (2003), Ocean Radiant Heating in Climate Models, Journal of Climate, 16, 1337-1351. Sathyendranath, S., A. D. Gouveia, A. R. Shetye, P. Ravindran, and T. Platt (1991), Biological control of surface temperature in the Arabian Sea, Nature, 349, 54-56.

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NEARSHORE CURRENTS OF AN UPWELLING REGION, SOUTHWEST COAST OF INDIA

V.K. Jineesh*, C. Revichandran, K.R. Muraleedharan, K.R. Naveen Kumar

CSIR-National Institute of Oceanography, Regional Centre, Dr. Salim Ali Road, Kochi; [email protected]

The nearshore circulation and structure of the upper ocean along the southwest coast of India (SWCI) during pre-monsoon are described. The near-shore environment of the West India Coastal Current (WICC) is dominated by an equatorward flow and a shallow ekman dynamics. Shoaling isolines of temperature, salinity and sigma-t revealed the onset of upwelling off Kollam. Upwelling filaments as characterized by AVHRR images and hydrographic sections have appeared to be advected only 7 km offshore at 9° N. Near shore currents in the region is significantly influenced by the seasonal wind.

Data on currents and sea level were collected off Kollam (T1) and off Kannur (T2) (Figure 1) for a month during April-May 2006. Currents were measured using Aanderaa self-recording current meters (RCM-9 type) on the inner shelf within the 20 m isobaths. An SBE Seabird 911 plus CTD onboard FORV Sagar Sampada was used to obtain temperature, salinity and potential density (sigma-t) profiles in the study region. Stations were distributed along two zonal transects at Kollam (9° N) and Kannur (12° N). Daily wind speed and direction deduced from QuikSCAT satellite were used to study the influence of wind on coastal currents at T1 and T2.

Figure 1. Station locations along the Kerala coast

The cross-shore and along-shore component of currents were higher at T1 (south) and compared to T2 (north). The along-shore components of currents were high in surface layer and decreased rapidly with depth at T1. The pronounced variations in cross-shore component were absent. The along-shore component of current dominated than the cross-shore component results a strong along-shore flow than the cross-shore flow.

As the prevailing winds were northerly or north-westerly, with the offshore transport of surface water, the conditions were favorable for upwelling. The average speed at T1 and T2 were 5.79 and 5.21 m s-1 respectively. The cross-shore wind stress (τx) was generally greater than along-shore wind stress at T2; whereas the along-shore wind stress (τy) was dominant at T1.

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SST was high (>30.94° C) in the offshore stations, but in coastal stations at 9° N, it was lower (<30° C). Surface salinity was found to increase towards north than offshore (<35.1). The prevalence of upwelling was evident in the vertical structures of temperature, salinity and sigma-t. The up-sloping of isolines were more pronounced at the southern transect off Kollam (Figure 3a). Shoaling of these signatures were absent in the northern transect off Kannur. Upwelling as a result of equator-ward alongshore winds lower the SST, which commences at the southern tip of India and propagates north-ward along the coast with the advancement of monsoon (Rao et al., 2008).

(a) Off Kollam (9° N)

Figure 3. Hydrographic section of temperature, salinity and sigma-t.

References Rao, A.D., Madhu Joshi and Ravichandran, M (2008), Oceanic upwelling and downwelling process in waters off the west coast of India, Ocean Dynamics, 58: 213-226.

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PRELIMINARY OBSERVATIONS ON OCCURRENCE, SPATIAL DISTRIBUTION AND IDENTIFICATION OF PLASTIC RESIN PELLETS IN SEDIMENTS AROUND AGATTI

ISLAND, LAKSHADWEEP ARCHIPELAGO

S. Veerasingam1*, M. Mugilarasan2, R. Venkatachalapathy2, P. Vethamony1 1CSIR – National Institute of Oceanography, Dona Paula, Goa – 403 004, India; [email protected]

2Faculty of Marine Sciences, Annamalai University, Parangipettai, Tamil Nadu – 608 502, India

Plastic resin pellets (0.1 to 0.5 cm in diameter) are transport medium for toxic chemicals (including persistent organic pollutants and trace metals) in the marine environment. Plastic resin pellets are worldwide persistent pollutants that accumulate in ocean, especially on sandy beaches. However, their characteristics, accumulation zones, and transport pathways remain poorly assessed. To improve the knowledge of occurrence, spatial distribution and identification of plastic resin particles and their impact on coral reef area of Lakshadweep Sea, a preliminary monitoring survey was carried out around Agatti Island in November, 2014. For the quantification of plastic pellets along the inter-tidal region, the 1 x 1 m quadrates were sampled in 20 locations around Agatti Island. The collected pellets were air dried for 24 h to remove the moisture. Pellets were sorted out and classified based on colour into three categories, namely, white, black and yellow. The dry weights of individual plastic pellets were determined and recorded to the nearest 0.0001 g on an electronic balance. The polymeric composition of each pellet was determined using Fourier Transform Infrared Spectroscopy (Shimadzu FTIR spectroscopy). The transmission FTIR spectra were recorded in the mid-infrared region (4000 – 400 cm-1).

The overall spatial distribution varied showed that higher occurrence of pellets was found along the southwest part of Island. Significantly higher plastic litter accumulation was found along the western part than eastern part of island. The white coloured pellets were predominant with 75% by number of items and 66% by weight. The pellets on the beaches were identified as polyethylene (PE), polypropylene (PP) and polyurethane (PU). In June, 2014 the Vietnam cargo ship ‘Viet Long’ was sunk off Summer Island, Maldives (southern part of the study area). We suspect that this accident might have led to the plastic pellet pollution of Agatti Island and other Lakshadweep Archipelago. Studies are required to correlate marine debris accumulations with currents and shipping lanes to determine sources of the plastic pellets, and to target clean up and prevention efforts. The effect of plastic resin pellets on coral reefs, including toxicity of pellets and fragments that wash up on the beaches throughout the Lakshadweep Archipelago, remains unknown, but should be investigated.

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SEDIMENT TRANSPORT DURING NILAM CYCLONE AT KADALUR PERIYAKUPPAM COAST, TAMIL NADU

A. S. Kiran*, B. K. Jena and K.M. Sivakholundu


Kadalur Periyakuppam (KPK) comprising of three fishing villages is located near Kalpakkam in Tamil Nadu. These villages are surrounded by Palar River on the north and a small creek on its south. The coastline of Kalpakkam is prone to erosion due to high wave activities during monsoon and cyclones. Fish landing centers, belonging to Tamil Nadu Government Fisheries department are under severe threat due to erosion. The erosion got aggravated during Thane (2011) Nilam (2012) and Madi (2013) cyclones. National Institute of Ocean Technology (NIOT) was approached by the Fisheries department to study the coastal processes and suggest a suitable coastal protection measure.

NIOT has started various field studies, hydrographic surveys and Oceanographic data collection from 2012 onwards. Monthly beach profile and shoreline variation is mapped by using Realtime kinematic GPS (RTK-GPS) (Sivakholundu et al, 2014a). Hydrodynamic and morphological modelling studies are carried out to understand the coastal processes based on the in-situ data collected. Wave data is adopted from NIOT wave model/ NIOT wave Atlas for the studies (Rajesh et al, 2009 & Sivakholundu et al, 2014b). Sediment transport along the coast was studied using DELFT 3D model. The DELFT 3D results were analyzed using DETRAN, a package developed by Deltares for estimating the cross-shore and along-shore sediment transport. As the major beach erosion occurs during cyclones as per field data collection, a specific model study was carried out to understand the sediment transport pattern during cyclones at KPK site. Nilam cyclone was selected for the study. In addition to the data collected by NIOT, cyclone data is taken from Indian Meteorological Department (IMD) and Joint Typhoon Warning Center (JTWC) websites.

The model results were compared with the actual beach loss measured using RTK-GPS survey during the cyclone for validation. The actual beach loss during the cyclone for a beach length of 300 m was 15000 m3 while the model results showed 13000 m3. The model results show net and gross long shore transports during the cyclone as 0.09 x 106 m3 and 0.13 x 106 m3 respectively. The net and gross cross-shore transports during the cyclone are 0.06 x 106 m3 and 0.077 x 106 m3 respectively.

References: Rajesh, P.R., Jossia, J.K. and Chaudhary, R.R. (2009). “Modeling of wave characteristics in North Indian ocean”. Proc. of Int. Conf. in Ocean Engg., IIT Madras. K.M. Sivakholundu., R. Vijaya., A.S. Kiran. and T. Abhishek. (2014a). “Short term morphological evolution of sandy beach and possible mitigation: A case study off Kadalur Periyakuppam”, Proceedings of Fifth Indian National conference on Harbor and Ocean Engineering (INCHOE2014), 5-7 February 2014, CSIR-NIO, Goa. K.M. Sivakholundu., Jossia, J.K. and Jena, B.K. (2014b). “Wave Atlas of the Indian Coast”,ESSO-National Institute of Ocean Technology, Chennai.

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OPTIMIZATION OF ENTRANCE CHANNEL IN A TIDAL INLET FOR FISH LANDING JETTY

L.R.Ranganath*, A.K.Singh, M.Karthikeyan and M.D.Kudale

Central Water and Power Research Station, Khadakwasla, Pune-411 024; [email protected]

There is a proposal for development of fish landing centre at Manjaguni, for providing berthing facilities for fishing boats in Gangavalli River flowing entirely in the western Karnataka into the Arabian Sea. As this proposed fish landing centre is located in the inlet connecting to the open sea and sufficient landing space is available inside the inlet. Initially two parallel breakwaters were proposed with a spacing of 160m to facilitate fishing boats to enter the fish landing facility inside the estuary. The hydraulic model studies were carried out to understand the tidal hydrodynamic behavior of flow, probable siltation pattern in the fishing harbour and also helps in evolving layout of training walls/ groynes. The stretch of shore region at the proposed site near Manjaguni is oriented in NNW-SSE direction. Semi diurnal tide was observed in the site. The analysis of the current data indicated that there is a reversal of flow during flood and ebb phase. The average value of suspended sediment concentration is 0.01kg/m3 was considered in the model studies. The average D50 value of the sediments was observed to be around 0.10 mm at site, which was considered for simulation. MIKE21 mathematical model has been used to study the hydrodynamic processes and to suggest a suitable layout including entrance channel. Further the sedimentation pattern in the region was also studied using MIKE21 ST model. From remotely sensed data of west coast it is found that Gangvalli river mouth has become narrow as sediment accretion has increased on both the sides of river mouth, since spit has shifted 70 m down south on the north and 105.2 m shift north up on the southern part of the mouth (Richa Choudhary et al., 2013). From the hydrodynamic studies it can be concluded that the parallel breakwaters with 140m opening and dredging the channel and basin to -3m the current magnitude in the channel has increased facilitating natural flushing of the channel to some extent. Sedimentation studies reveal that the maintenance dredging tends to increase the basin area. The annual deposition of siltation is expected, and this tendency of sediment deposition in the harbor basin needs to be tackled by maintenance dredging. The frequency of maintenance dredging may be decided by regular monitoring of the sedimentation pattern post construction of fish landing facility at Manjaguni Jetty.

References Richa Choudhary, et al (2013), “Shoreline change detection from Karwar to Gokarna- South West Coast of India using remotely Sensed data” Int. J. of Earth Sciences and Engineering., vol. 6, No. 03; June 2013, P. P. 489- 494.

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ROLE OF CURRENTS ON THE INTRUSION OF THE BAY OF BENGAL WATER MASS TO SOUTHEASTERN ARABIAN SEA

Rajith, K., Rao, A. R. and Anil Kumar, K.

Naval Physical and Oceanographic Laboratory, Cochin 682021; [email protected]

Major current systems which are dynamically connecting the Bay of Bengal and the Arabian Sea are the East India Coastal Current (EICC), the West India Coastal Current (WICC), the Southwest (SMC) and the Northeast Monsoon currents (NMC). All these currents are seasonally reversing with the seasonally reversing wind systems viz Southwest monsoon and Northeast monsoon. These seasonally reversing currents play an important role in the distribution of physical properties (temperature and salinity), chemical and biological properties between the Arabian Sea and the Bay of Bengal. Another important feature which has direct link with the current system is the intrusion of the Bay of Bengal Water in to Southeastern Arabian Sea (SEAS). Earlier studies explains the dynamics and water mass characteristics using modeling and satellite measurements and also from CTD data and water quality analysis. However, the role of currents on the intrusion of Bay of Bengal water mass based on in-situ measurement of currents is not addressed. Hence, detailed physical oceanographic surveys were carried out in the SEAS from October 2013 to March 2014. Spatial surveys on monthly basis were conducted along seven transects from 5°N to 11°N (during October and from 8°N to 11°N in the subsequent months). Spatial data on subsurface currents were collected using vessel mount ADCP. Along the transects, CTD data were also collected with sample spacing of 30 NM. This paper depicts the salient physical oceanographic features observed during the period of measurements. Observations reveal favorable poleward current from the month of October onwards. During the first week of November, low salinity waters observed in the eastern side of the transects. The observations showed that, in the subsequent months, with the favourable poleward current the low salinity water infringe up to 11°N. The study also reveals influence of the prevailing eddy on current system. An attempt is also made to bring out the hydrodynamic processes in the SEAS utilizing satellite data.

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CHANGING DEPOSITIONAL ENVIRONMENT ALONG NORTH MAHARASHTRA COAST: REASONS AND POSSIBLE IMPLICATIONS

Volvoikar S. P1*, Nayak G. N2, Mazumdar A1, Peketi A1 1CSIR- National Institute of Oceanography, Dona Paula, Goa – 403 004; [email protected]

2Department of Marine Sciences, Goa University, Goa – 403 206

2

Mudflats and mangroves present along intertidal regions of estuaries and creeks are known to favor deposition of fine grained sediments, associated metals and organic matter. North Maharashtra along the west coast of India is one of the rapidly industrializing and urbanizing regions. Large number of dams has been built and freshwater is being diverted from rivers joining estuaries and creeks. The region has also experienced a change in precipitation pattern over the past few years. Estimates of mean sea level rise along the coast of India have indicated a rise of slightly less than 1mm/year. All these processes have a potential to change the type and amount of sediment particles, metals and organic matter deposited within the coastal and near-shore environments. Such changes are known to affect the natural biogeochemical processes operating within the coastal regions. In the present study therefore an attempt is made to understand the response of intertidal sediments of north Maharashtra coast to these rapidly changing environmental conditions.

Sediment component (sand:silt:clay), total organic carbon (TOC), bulk sediment chemistry (Fe, Mn, Al, Cu, Zn, Co, Ni and Pb), metal speciation, sedimentary stable isotope (δ13Corg, δ

15N) ratio and TOC /TN ratio analyses were carried out on intertidal core sediments of estuary and creeks present along north Maharashtra coast. The results indicated a change in hydrodynamic energy conditions from past to present all along the studied coastal region. Organic matter proxies namely, TOC, δ13Corg and TOC/TN suggested significant decrease in organic matter (terrestrial) input to Vaitarna estuary in recent years and is attributed to decrease in freshwater influx. As a consequence of decrease in freshwater input, greater amount of sea water seem to have intruded within the estuary as evident from the results. In addition, δ15N results pointed towards anthropogenic input to Vaitarna estuary in recent years from agricultural fields, domestic sewage and waste water. While metal concentration and speciation in a creek present in near vicinity of an industrial zone has suggested drastic increase in anthropogenic metal input in recent years. All such natural and anthropogenic changes within relatively minor estuaries and creeks present along the west coast of India therefore together may have a potential to significantly alter the natural biogeochemical processes operating in the adjacent coastal Arabian Sea.

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DISTRIBUTION OF SUSPENDED PARTICULATE MATTER IN THE MANDOVI AND ZUARI ESTUARIES: INFERENCES ON THE ESTUARINE TURBIDITY MAXIMA

Suja S , Pratima M. Kessarkar*, R. Shynu, V. Purnachandra Rao

CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India; [email protected]

The suspended particle volume concentration was studied along Mandovi and Zuari (Ma-Zu) estuaries of Goa to decipher the spatial distribution of suspended particulate matter (SPM). The SPM concentrations are lower in the Mandovi (2 to 1934 µl/l) than in Zuari (3 to 3698 µl/l), whereas the grain size range (7- 370 µm) is similar in both estuaries. The salinity values range between 0 to 34 and 0 to 35 in Mandovi and Zuari, respectively. High concentrations of SPM occur at the river mouth in both estuaries and are associated with high salinities (30 to 34) and restricted to top two meters. High SPM concentrations are also observed at distance from mouth ~3.3 km in Mandovi and about 5.2 km in Zuari estuary that extends vertically down to 8 m. These high SPM are associated with the salinity gradient (30 to 4) that is observed up to ~ 18 km for Mandovi and 25 km for Zuari, beyond this, salinity is< 4 and SPM is less than 100 µl/l. These two zones of high SPM are related to the estuarine turbidity maximum (ETM) occurring at the same time. The first ETM at sea end of the estuary is associated with high salinity, and is due to resuspension of particles due to wind-induced and tidal currents, whereas the second ETM at upstream is associated with salinity gradient and due to flocculation and coagulation and settling of SPM.

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IMPACT OF THE VERY SEVERE CYCLONIC STORMS – THE PHAILIN AND HUDHUD – ON THE BEACH PROCESSES ALONG THE VISAKHAPATNAM COAST

Hani, T.*, Ganesan, P. and Murty, V.S.N.

CSIR – National Institute of Oceanography, Regional centre, Visakhapatnam – 530 017; [email protected]

Beaches offer an extremely interesting phenomenon with their continuous dynamic changes, but maintaining equilibrium through accretion and/or erosion of sand along the beach. On the east coast of India, the processes of sand deposition and erosion on the beach exhibit seasonal changes and cause beach morphological variations. In order to assess the beach morphological changes along the Visakhapatnam coast over a longer period, weekly beach profiling is being carried out at 5 locations along the Visakhapatnam beach between Rishikonda and Fishing Harbour. This study analyses the weekly profiling over a period of 43 months beginning from May 2011 to December 2014. In this period, the Visakhapatnam beaches experienced the impact of two Very Severe Cyclonic Storms namely, the Phailin in October 2013 and Hudhud in October 2014. This study also aims at to identify the possible safety locations along the beach to minimize the drowning death cases. The rates of erosion and deposition at each location are estimated and compared. It is found that the beaches at the 5 locations underwent appreciable rates of erosion/deposition during the study period. Maximum (~45 cu.m) sand erosion occurred at North of the Submarine (Station 3) in January 2013. All 5 stations underwent severe erosion during southwest (SW) monsoon and deposition during winter monsoon and maintain beach equilibrium during pre-monsoon period. It is found that this normal trend is reversed at North of the Submarine (Station 3), wherein the beach is more stable during SW monsoon period, and more vulnerable for erosion in winter and pre-monsoon period. The Rishikonda beach appears to be safe place throughout the year. During the ‘HUDHUD’ cyclone in October 2014, the beach erosion effect was very severe, and a net volume of sand of about 1457 cu.m was lost over a beach stretch of 14 km. Weekly waterfront changes were large up to ±35 m at each location during the study period. Seawater advanced by 35 m onto the beach and up to the beach road at most of the places during “HUDHUD’’ cyclone. A good correlation (r=0.6) between weekly waterfront changes and weekly sand volume changes occurs at the north of Submarine beach and Fishing harbour beach and a negative relationship with a poor correlation is noticed at the Ramakrishna beach, where severe erosion occurred during both Phailin and Hudhud cyclones. However, drowning death cases in the beach waters are reduced greatly, partly due to improved public awareness by the local government authorities.

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SEASONAL AND INTER-ANNUAL VARIABILITY OF COASTAL CURRENTS AND CIRCULATION OFF VISAKHAPATNAM DURING 2010-2014

V.S.N.Murty1, D.Gayatri Vani1*, Y.Steeven Paul1, V.Fernando2, T.A.Prakash2, Almeida Anselmo2 and A.Suryanarayana2

1CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam – 530017; [email protected]

2 CSIR-National Institute of Oceanography, Dona Paula, Goa – 403004

Analysis of the Acoustic Doppler Current Profiler (ADCP) measured time-series currents data at a shallow (~100 m depth) and a deep (~1000 m depth) station off Visakhapatnam during May 2010-February 2014 is presented. The currents data in the water column (20 – 100 m & 45-355 m) and water temperature at the depth of ADCP (100 m and 400 m) were acquired at time-intervals between 15 minutes and 1 hour. The time-series of zonal (u) and meridional (v) currents were 36 hour low-pass filtered and daily averaged. This filtered data is used to examine the low-frequency variability in the currents and depth integrated volume transports off Visakhapatnam. Fast Fourier Transformation (FFT) spectral analysis is carried out to identify the dominant spectral peaks (above 95% confidence interval) in the observed coastal currents.

The analysis reveals the presence of sub-seasonal, seasonal and inter-annual variability in the coastal currents off Visakhapatnam. Higher spectral density peaks occurred at 8-10 day and 50-100 day periods in zonal currents and at 7-8 day and 33-80 day periods in meridional currents. Observed currents attained high magnitudes (120 cm/s) in April, when the seasonal East India Coastal Current (EICC) flowed northward during January – April. EICC flow reversal occurred during October – November. During Southwest monsoon period, the coastal current is directed towards southwest, as part of the cyclonic eddy off Visakhapatnam. The annual variation of monthly mean zonal and meridional volume transports show northeastward transport of 4-6 Sv (1 Sv = 106 m3/s) during February – April, and southwestward transport of similar magnitude from mid-July to October. The transports in 2010 and 2011 exhibited large variability in accordance with the anomalous wind field and coastal circulation in association with the negative and positive Indian Ocean Dipole (IOD) events in these years. Large interannual variability is noticed in the volume transports of coastal currents during 2010-2013.

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ROLE OF LITHOLOGY AND STRUCTURE ON THE COASTAL LANDFORMS OF GOA, INDIA

G. Q. Fernandes1*, S. D. Iyer2, K. Mahender 3 1Don Bosco College of Engineering, Fatorda, Goa; [email protected]

2CSIR-National Institute of Oceanography, Dona Paula, Goa

3Goa University, Taleigao, Goa

The Indian Plate together with Madagascar rifted from East Africa during Late Jurassic (150 Ma) and subsequently in Late Cretaceous the Indian Plate separated from Madagascar (Chatterjee S., Scotese C., 1999). This breakup of the Indian Plate from the Gondwana resulted in the present coastline of western India and was subsequently shaped by oceanic processes.

Goa (area 3700 sq km) has three broad physiographic divisions: a wide coastal plain, an undulating midland hilly region and the western ghat. The coastal plain is 105 km long and comprised of pocket and straight beaches, dunes, estuaries, wave cut platforms and headlands amongst others.

We studied the rocks exposed along the coast of North Goa (Arambol, Morjim, Chapora, Baga, Aguada and Mormugao) to examine the geological structures and coastal processes. The lithology is mainly metagreywackes of the Goa Group, Dharwar Supergroup, and best exposed as sea cliffs, headlands and wave cut platforms. There are intrusions of dolerite dykes contemporaneous to Deccan Trap time. At several places occur laterite cappings and tablelands.

The metagreywackes have a strike of NE-SW and an average dip of 30°. Various sedimentary depositional features like laminations, tabular cross bedding and ripple marks are seen. Graded bedding and Bouma sequence are distinct and indicate deposition from turbidity currents (Bouma, A. H., 1962). Warping is observed in the laminations, which are formed due to the crustal adjustments of the stresses. This is demarcated by massive bedding with graded bedding followed by parallel laminations and with convolute bedding. Liesegang rings occur across the bedding plane, which are arranged in a regular repeating pattern.

The area has been subjected to various geological processes (deformation, erosion, deposition, and diagenesis) from the time the coastline formed to the present time. The depositional stage was followed by intrusive events, which led to the emplacement of dykes of two generations, showing cross cutting relations along with quartz vein intrusions. This intrusive phase was followed by deformation phase leading to folding, faulting and brecciation. Small scale folding is seen locally. An anticlinal fold is delineated at Vagator with a limb dipping due north and the other due south. Micro-faulting is seen in metagreywackes. A sheared zone is present in metagreywacke along with the quartz veins, which are brecciated and mylonitised. Finally, the coastal wave action led to the erosional structures, which are seen as box work and scour marks. In the present environment, the sediment substrate is subjected to scouring current action and is eroded.

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In contrast to the above, South Goa has long sandy beaches with a paucity of headlands. Further South at Canacona, gneiss and granites form hillocks and cliffs that are intruded by mafic dykes.

In summary, the variable coastal landforms at North and South Goa have resulted due to interaction of the different lithology and structure with the coastal processes. The coastline is been categorized by Fernandes (2009), as submerged and emergent coast. The shorelines with dominant sandy beaches are formed by active deposition, characterizing these as an emerged coast. Whereas, the prominent outcrops as cliffs, headland and rocky terrain were formed due to the continuous wave action and are typical of a submerged coast.

References: Davidson, M. A., T. J. O’Hare, and K. J. George (2009), Tidal modulation of incident wave heights: Fact or Fiction?, Reef Journal, 1(1), 16-32. Hayes, M. O. (1979), Barrier island morphology as a function of tidal and wave regime. In: Leatherman, S. (ed.), Barrier Islands, from the Gulf of St. Lawrence to the Gulf of Mexico, Academic, New York. Thuy, V. T. T. (2013), Aspects of Inlet Geometry and Dynamics, The University of Queensland, Brisbane, Australia. Zijlema, M., G. Stelling, and P. Smit (2011), SWASH: An operational public domain code for simulating wave fields and rapidly varied flows in coastal waters, Coastal Engineering, 58(10), 992-1012. Bouma, A. H. (1962), Sedimentology of Some Flysch Deposits, Elsevier, Amsterdam. Chatterjee S., Scotese C. (1999), The breakup of Gondwana and the evolution and biogeography of the India plate. In: Proceedings of the India National Science Academy. Vol 65, No. 3, pp 397-425. Fernandes O. A. (2009), The evolving coast of Goa: a geological perspective. In: Natural resources of Goa: A geological perspective. Geol. Soc. Goa. pp 25-34.

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INTERNAL TIDES ON THE CONTINENTAL SHELF AND SLOPE OFF THE EAST COAST OF INDIA

A.K. Jithin*, A.S. Unnikrishnan, Fernando Vijayan, M.P. Subeesh, R. Fernandes, S. Khalap, S. Narayan, Y. Agarvadekar, M. Gaonkar, P. Tari, A. Kankonkar, S. Vernekar

CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004; [email protected]

Internal tides are internal waves at tidal frequencies, generated by the interaction of barotropic tide with the topographic features like continental shelf, slope and ridges in a stratified ocean. Time series observations obtained from moored Acoustic Doppler Current Profilers (ADCP) deployed on the shelf and slope off Gopalpur (19.4°N), Kakinada (16.3°N), Ramayapattanam (15°N) and Cuddalore (12.01°N) during 2009 - 2011, were used to study the spatial and temporal variability of both barotropic and internal tides along east coast India. Magnitude of barotropic tidal currents varies from 2.4 to 9.9 cm/s from southern to northern part of the shelf. Harmonic analysis showed that semidiurnal tidal current is dominant at all locations with M2 and S2 tidal components having magnitudes of 1.7 to 3.6 cm/s and 1.0 to 1.8 cm/s respectively. Diurnal tidal components are found to be relatively small at all locations. Barotropic tidal current increases from southern to northern part of the shelf. Barotropic tidal current ellipses are oriented perpendicular to the isobaths at Cuddalore and Ramayapattanam, while at Kakinada, they are parallel to the isobaths. At Gopalpur, barotropic currents have comparable magnitude in both parallel and perpendicular directions. Spectral Analysis of baroclinic tidal currents showed large peaks at semidiurnal frequencies in all locations. EOF analysis describes structure of internal tides, where they are dominated by first mode. However, higher modes are also found to be essential to describe the variability. Temporal variability associated with vertical structure and amplitude of internal tides are expected because of the seasonal changes occurred in stratification. Internal tides do not show spring - neap cycles but occasional intensification is evident from the time series observations. Computed variance in different vertical levels shows that bottom amplification of the internal tide is a characteristic feature of internal tides on the shelf. We computed criticality of the slope region for the generation of internal tides using available data on hydrography and bathymetry and found that continental shelf and slope regions are critical for the generation of semidiurnal internal tides.

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NEARSHORE PROCESSES AND LITTORAL SEDIMENT TRANSPORT AT AN OPEN BEACH ALONG THE NORTH TAMIL NADU COAST

D. Sathish Kumar1, Basanta Kumar Jena1*, Usha Natesan2 and K.M.Sivakholundu1

1National Institute of Ocean Technology, Chennai, 600100; *[email protected]

2Centre for Water Resources, Anna University, Chennai, 600025

Littoral sediment transport plays a major role in understanding the nearshore and beach system. A study has been carried out to examine the site specific nearshore processes through a detailed field observation. Variations in the littoral environmental characteristics had been measured daily for a period of one year at three locations with an interval of about 1 km at Kadalore Periyakuppam. The daily and seasonal variations in nearshore breaker characteristics and longshore sediment transport rate are studied. The field observation has been supplemented by Simulating Waves Nearshore (SWAN) model using the Wave atlas information (NIOT, 2014). The breaker height during post monsoon, pre-monsoon and monsoon season are from 0.8 to 1.5 m, 0.4 to 0.8m and 0.6 to 1.0m respectively. Wave period ranges from 5 to 8 sec. Longshore currents are higher during monsoon from 0.2 to 1 m/s whereas during post monsoon and pre monsoon it was 0.3 to 0.7 m/s and 0.1 to 0.4 m/s respectively. The estimated annual net longshore sediment transport rate (LSTR) for the region is 0.4x106 m3/year and 0.1 x106 m3/year based on CERC and Kamphuis formula respectively. Monthly and seasonal variations in LSTR are primarily influenced by breaking wave height and direction. The comparison between the LSTR calculated using simulated wave at 2 meter contour shows a good agreement with the measured Littoral Environmental Observation. The net LSTR estimated from waves simulated using SWAN are 0.32 x106 m3/year and 0.06 x106 m3/year respectively using CERC and Kamphuis formula. The CERC formula shows a 300 percent higher estimate on LSTR compared to that of Khamphuis for the study area. This variation is largely attributed to the dependence of breaking wave type which is considered in Khamphuis formula. Hence the LSTR estimate based on Khamphuis formula can be considered reliable for the study area. Estimation of Longshore sediment transport rate using recently developed models will be explored to identify the most suitable method for longshore sediment transport rate assessment.

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HYDRODYNAMIC AND WATER QUALITY SIMULATION OF SEWAGE DISCHARGES IN WEST COAST, MUMBAI: PRESENT AND FUTURE SCENARIO

Trupti Mardikar, Ritesh Vijay* and Satish R. Wate

CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra; [email protected]

Mumbai, one of the most populated cosmopolises in the world, is a coastal city with Arabian Sea on the west and Thane Creek on the east. The city generates huge quantity of sewage which is discharged into drains, nallahs, creeks and coastal water after preliminary and primary treatment. Though coastal waters have an extensive assimilation capacity, its quality deteriorates due to this mixing. As sewage is principally organic, it experiences bacterial decay. This bacterial decomposition reduces the dissolved oxygen (DO) concentration in water, thus increasing the biochemical oxygen demand (BOD) of the water. This poses a severe threat to the coastal environment and its alleviation is a serious concern. Researchers have regularly utilised numerical models for water quality assessment and management of coastal water bodies. These models help in interpretation of environmental processes, predicting pollution impacts, and evaluating the future trends in environmental quality. The objective of the present study is to assess the impact of sewage discharges on water quality of west coast, Mumbai using MIKE 21 hydrodynamic and water quality simulation. The water quality in terms of BOD, DO and Faecal Coliform (FC) is assessed for the present condition (2014) as well as predicted scenario of 2025, based on the SW-II standards. A model is conceptualized based on bathymetry, tide and current, coastal water quality, sewage discharges from drains, nallahs, wastewater treatment facilities, and ocean outfalls. The simulation is validated by comparing the hydrodynamic and water quality findings with the in situ observations. The validated model is used in prediction of water quality scenario of 2025 for stipulations like improvement in wastewater collection, appropriate treatment level and disposal of treated effluent from existing and a proposed outfall at Erangal. The simulation results show that the existing water quality of west coast does not comply with standards but improves significantly in the future scenario for above mentioned conditions. The simulation study underlines the need of better planning and management of existing coastal environment and exploring options like reuse and recycle of treated effluents instead of discharging huge quantities in coast as an effort for water conservation.

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IDENTIFICATION OF INLET AND OUTLET FOR COOL SEAWATER DISCHARGE FROM AN LNG FACILITY: A SIMULATION APPROACH

Vikash K. Kushwaha, Ankit Gupta, Ritesh Vijay* and Satish R. Wate

CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra; [email protected]

A simulation study has been carried out to assess the impact of cool seawater discharges from a Liquefied Natural Gas (LNG) facility in the coastal environment using MIKE 21. The research study entails Hydrodynamics (HD) and Advection Dispersion (AD) simulations to assess the dispersion of the seawater discharge from Open Rack Vaporiser (ORV) outlet of proposed LNG terminal in the vicinity of the Gulf of Kutch, India. The modelling system was based on the numerical solution of the 2D incompressible Reynolds Averaged Navier-Stokes equations subject to the assumptions of Boussinesq and hydrostatic pressure. The model conceptualisation consists of equation of mass balance, momentum balance along with transport equation for temperature and salinity. Hydrographic boundary conditions in terms of tidal variations (in time and space) and flux boundary at the open model boundary were defined. The available secondary tidal and current data within the model domain were used for model calibration and validation. The present condition of HD was calibrated and validated by comparing the observed and simulated hydrodynamics in terms of water depths, current speeds and directions within the model domain. The model was significantly correlated with coefficients 0.98, 0.86 and 0.91 for water depth, current speed and direction, respectively. The validated model was extended to predict the AD phenomena under different design scenarios based on positions of inlet and outlet and their discharge rates and temperatures. AD boundary conditions were specified in terms of constant ambient seawater temperature at the model boundaries. These scenarios were formulated in view to minimise the potential impact of cool seawater discharge and to select an environmentally benign and energy efficient option for such cool seawater discharges. The predicted simulation results of cool water discharges were assessed to comply with the existing Environmental Health and Safety, World Bank guidelines for LNG discharge facilities. The key factors which affected the recirculation of cool seawater discharges were identified as the location of inlet and outlet, distance between the inlet and outlet, the spreading behaviour of the cool water from the outlet, the tidal action and the wind stress and its direction. The results suggest that a trade-off is required before taking engineering decisions for selecting an environmentally acceptable and energy efficient option with respect to pumping power and operational efficiencies for such cool water discharges from an LNG facility. An optimum inlet-outlet location along with best possible flow rates and temperature difference between the inlet-outlet is identified and recommended. As there are no standards for cool seawater discharges from an LNG facility at national and international level, research findings of this paper will encourage policy makers to formulate coherent standards for such cool seawater discharges into marine coastal environment.

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VARIABILITY OF INTERNAL TIDES ON THE CONTINENTAL SLOPE OFF JAIGARH, WEST COAST OF INDIA

M.P Subeesh*, A.S Unnikrishnan

CSIR-National Institute of Oceanography, Dona Paula, Goa, India, 403004; [email protected]

A number of long term ADCPs were deployed along the slope and shelf off west and east coast of India by CSIR-National Institute of Oceanography. They were utilized to study the low and high frequency currents in recent years. In an earlier work, we analyzed the ADCPs deployed on the shelf and the characteristic features of internal tides were discussed. In the present work, we report a detailed study of internal tides on the slope off Jaigarh using the ADCP measurements, made in March-October 2008. The observation period comprised of the pre-monsoon (March-April) and SW (South-West) monsoon (May-September) seasons. We focus temporal, seasonal and spatial variation of internal tide in detail. We observe significant internal tides, exceeding 20-25 cm/s during the spring time, which appears to be modulated strongly by local barotropic tidal currents. The internal tide spectral level in the tidal frequencies are elevated above the GM reference spectra. Baroclinic current spectra are dominant in internal tidal frequencies M2, S2, K1 and O1, with stronger signals found in semi-diurnal frequencies compared to diurnal frequencies. A large fraction of cross-slope and along-slope internal tides are phase-locked with the astronomical tides shows the stability of internal tides. EOF analysis shows that about 65% of variance of internal tidal currents are associated with first mode where the upper water column flows in one direction and the lower water column in opposite direction with 180° phase shift. The second and third EOF modes contain 10 and 4% of variance respectively. EOF spatial structure are consistent with the dynamic normal modes. We studied the possible causes of strong internal tides on the slope by determining Baines barotropic body forcing and criticality around the region. It is found that the shelf-edge and slope regions off Jaigarh are favorable for the generation of internal tides. Finally we investigated the seasonality of internal tides on the slope. On the slope internal tides are found to be strong during pre-monsoon and comparatively weak in SW monsoon. Further analysis demonstrates that M2 exhibits strong seasonal variation than other constituents. During pre-monsoon the incoherent internal tides in M2 is found to be contributing a large fraction of total internal tide. Some part of the M2 internal tide here could be coming from elsewhere.

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A CASE STUDY OF SST DISTRIBUTION OVER BAY OF BENGAL DURING HUDHUD CYCLONE

T.S.D.Bhavani*, G.Bharathi, P.Amarendra and P. Hariprasad

Andhra University, Visakhapatnam; [email protected]

Tropical cyclone HUDHUD which developed in the Bay of Bengal during 07th October -14th October 2014. The system crossed off Visakhapatnam coast on 12th October 2014. Temperatures greater than 30oC over most of the bay were present from 05th October 2014. A significant change in the spatial structure in sea surface temperature was observed on 12th October 2014 with a temperature minimum at (16°N, 86°E) and sharp temperature gradients around this area. The cold temperatures are well developed at the time when the centre of the storm is located near 86oE and 16oN. A Sea Surface Temperature decrease of about 4.2oC is apparent to the right of the storm track and areal extent of minimum temperatures is about 1.0o X 1.4o degrees. The maximum sea surface cooling observed after the passage of Tropical Cyclone is 30.5oC. The maximum cooling was observed on 12-10-2014. The cooling of the sea surface persists for about more than a week and is readily detected in satellite images. The recovery of the ocean to the cyclone passage is within seven days.

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THE ROLE OF WAVE CLIMATE ON COASTAL SEDIMENTATION - A CASE STUDY

R. Anjali1, K.Jossia Joseph2*, B. K. Jena2, K.M. Sivakholundu2 and Ravibabu Mandla3 1VIT University, Vellore

2National Institute of Ocean Technology, Chennai; [email protected]

Coastal areas are experiencing a continuous change in the geomorphological system. It is observed that certain areas along the east coast of India are experiencing severe erosion. The severity of erosion increased in the recent past posing threat to life and property in the coastal areas. This necessitates the detailed study of various processes affecting coastal sedimentation. The present study aims to find the impact of wave climate on the coastal sediment transport and change in coastline at two selected locations viz.: Cuddalore and Kadalur Periyakuppam, Tamil Nadu in east coast of India.

NIOT has prepared a Wave Atlas of the Indian Coast using 15 year simulated wave data (Sivakholundu et. al., 2014). The wind and wave data are extracted from the database for the period 1998 to 2012 at the above selected locations. The long term average of monthly, annual and seasonal wave parameters are analyzed to identify the causative effect on coastal sedimentation. LITPACK model is used to compute littoral drift and coastline evolution.

The long term average of Significant Wave Height (SWH) exhibits calm wave conditions with an average of 0.73m, 0.67m at Kadalur Periyakuppam and Cuddalore respectively. The annual average SWH exhibits an increasing trend, which increased from 0.69m in 1998 to 0.82m in 2012 at Kadalur Periyakuppam and 0.64m in 1998 to 0.74m in 2012 at Cuddalore. The maximum SWH of 0.83m (Kadalur Periyakuppam) and 0.76m (Cuddalore) are observed in the year 2011 attributed to the passage of thane cyclone near these locations. The long term average of monthly and seasonal values of SWH exhibits the similar trend at both locations with higher values at Kadalur Periyakuppam. The SWH exhibits lowest values during June to September followed by an increasing trend with maximum values in December. Higher wave activity coincides with North-Northeasterly waves whereas the low SWH is observed during south-southwesterly waves. Preliminary results of LITPACK model indicates higher erosion at Kadalur Periyakuppam compared to that of Cuddalore.

References: Sivakhoulundu, K.M., K. Jossia Joseph and B. K. Jena, (2014), Wave Atlas of the Indian Coast, ESSO-NIOT, ISBN: 81-901338-4-5.

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IMPACT OF CYCLONE ON THE COASTAL AREA THROUGH EMPIRICAL RELATIONS AND NUMERICAL MODEL

P. Vyshnavi1, B. K. Jena2*, K. Jossia Joseph2, J. Rajkumar2 and Ravibabu Mandla1 1VIT University, Vellore

2Coastal and Environmental Engineering, National Institute of Ocean Technology, Chennai; [email protected]

The passage of a tropical cyclone accompanied with strong waves, extreme wind and torrential rain causes severe damage to life and property in the coastal area. The extreme weather conditions make it difficult to measure the impact and moreover necessitate estimation of cyclone impact through empirical relations and numerical modelling. The estimated values can provide a preliminary assessment of the cyclone impact along the coastal stretch.

The recent cyclone HUDHUD (October 2014) which made landfall in Visakhapatnam is selected for the present study. The cyclone track data from India Meteorological Department (IMD) for the period (1960-2014) is utilised to estimate the cyclone frequency, cyclone induced wave height, storm surge and wave power. MIKE21 Spectral Wave model is used to quantify the wave parameters during cyclone passage. The estimated values using empirical relations are compared with model results and are validated using directional wave rider buoy data off Visakhapatnam.

During cyclone HUDHUD, the maximum significant wave height (SWH) estimated through empirical relation is 9.31m for the highest intensity of cyclone (12 October 2014 at 6:00 hrs near Visakhapatnam at 83.4 E, 17.6 N), whereas the model result is 10.49m. The wave power estimated to be 602.24kW, while model result exhibits 706.4kW. Maximum storm surge of 1.40 meters above the astronomical tide has been reported by the tide gauge at Visakhapatnam (IMD report October 2014), whereas the estimated surge height is 1.59m. The maximum SWH observed at buoy location (12 October 2014 at 8:33 hrs near Visakhapatnam at 83.27 E, 17.63 N) is 8.1m, whereas that of model is 8.4m. The wave power computed using measured data is 438.58 kW and model result is 416.54 kW at the buoy location. The result exhibits good agreement between measured, estimated and simulated results for SWH and wave power. The estimated storm surge agrees well with the measured value.

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AN OBSERVATIONAL STUDY ON WAVE CHARACTERISTICS DURING HUDHUD CYCLONE OFF GANGAVARAM

P. Amarendra1,2*, K.Gopala Reddy2, G. Bharathi1, P. Bhanumurthy2 and T.M. Balakrishnan Nair3

1 Center for Studies on Bay of Bengal, Andhra University, Visakhapatnam; [email protected]

2 Department of Meteorology and Oceanography, Andhra University, Visakhapatnam

3 Indian National Centre for Ocean Information Services, Hyderabad

Wave characteristics were studied using buoy observations made at half hourly intervals during recent HUDHUD cyclone. This cyclone had shown strong impact on Coastal areas of Andhra Pradesh were severely damaged by the strong winds in East Godavari, Visakhapatnam and Vijayanagaram districts, winds were reached up to 180kmph as reported by Indian Meteorological Department. System moved very slowly at the rate of 15kmph. From buoy observations, off Visakhapatnam maximum significant wave height observed is 8.1m.

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TIDAL STREAM ENERGY POTENTIAL AT MANDOVI AND ZUARI RIVERS, GOA

Jaya Kumar Seelam1, Manasa Ranjan Behera2, R. Mani Murali1, Aqleema Shah2, D. Ilangovan1, P. Mehra1, R. Madhan1

1CSIR-National Institute of Oceanography, Goa; [email protected]

2Indian Institute of Technology Bombay, Mumbai

The depleting natural fossil fuel deposits and increasing fuel consumption has necessitated a search for sustainable and renewable energy sources. Extraction of energy from oceans is an emerging source of national interest. There have been successful attempts in extracting tidal energy by construction of barrages, impounding of water and utilizing the potential energy or installation of underwater turbines, exploiting the kinetic energy of the flow (Bedard et al., 2005)

In India, high tidal range locations are in the Gulf of Kuchchh, Gulf of Khambhat, and in Sunderbans. The tidal energy potential assessed from these locations is about 8300MW (Ministry of New and Renewable Energy - Tidal Energy., 2013). It is assumed that these potential magnitudes are based on the method of impoundment through barrages. However, detailed studies based on tidal stream potential for the high tidal range sites in India have not been carried out yet.

The study of tidal flow in the Gulf of Khambhat is an endeavour to assess the potential kinetic tidal energy that can be extracted in the Gulf of Khambhat (Aqleema., 2014). Apart from the macro-tidal range locations, tidal inlets with meso-tidal range regions also have tidal stream energy potential which has not been hitherto assessed, which has been focused in this paper. Study has been carried out for two major rivers of Goa, viz., the Zuari River and the Mandovi River. Numerical model studies were carried out to simulate the flow patterns along these two rivers for a period of 15 days to estimate the tidal current speeds across the study area (shown in Fig.1). MIKE by DHI hydrodynamic numerical software suite capable to simulate physical coastal processes has been used for numerical modelling. Tidal current speeds along the two rivers were obtained over the entire estuarine region and analysed for the statistical mean and maximum flow speeds. Salient locations (M1, D1, Z1) have been chosen, each along the Zuari and Mandovi estuaries, where maximum flow speeds were observed, for further analysis of the tidal stream energy potential estimation.

The maximum tidal current speed is found to be of the order of 1.5 m/s (Fig.2). The recent tidal turbines can extract power from current speed less than 1 m/s. It can also be observed that the tidal current speed is sufficient to harness power for some period in one spring neap cycle.

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(a) (b)

Fig. 1 (a) Computational domain considered for present study (b) Estuaries of Zuari and Mandovi

Fig. 2 (a) Typical tidal profile off Goa (b) Velocity profile at locations (M1, Z1 and D1)

References: Aqleema, S. (2014). Assesment of tidal Kinetic Energy of Gulf of Khambhat. Bedard. (2005). Survey and Characterization Tidal In Stream Energy Conversion ( TISEC ) Devices (pp. 1–185). Ministry of New and Renewable Energy - Tidal Energy. (2013). http://www.mnre.gov.in/

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OBSERVED TEMPORAL AND SPATIAL VARIATION OF STRATIFICATION IN THE ZUARI ESTUARY, WEST COAST OF INDIA

D. Sundar1, A.S. Unnikrishnan, G.S. Michael, A. Kankonkar

CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India; [email protected]

To study the temporal and spatial variability of stratification in the Zuari estuary, time series measurements of vertical salinity profiles and currents were conducted over a tidal cycle of 25 hours, during spring and neap tidal cycles and pre-monsoon, monsoon and post monsoon seasons in 2011, at four stations in Zuari estuary located in Bay, in Lower middle estuary, in Upper middle estuary and in Upstream regions. Astronomical tides were predicted at these locations to examine the stratification variability with tidal phase. Mixed tide with semidiurnal dominance is seen in this region. It is observed that stratification at Higher Low water succeeding Lower High water is more intense than that of Lower Low water succeeding Higher High water over a tidal cycle, in the mixed tidal regime with semidiurnal dominance. During monsoon in lower middle estuary, salinity value peaks from fresh water condition of zero to about 10 during neap and 14 during spring at high waters, which seemed similar to the pre-monsoonal conditions at the upstream station. During pre-monsoon at upstream station also, only during the high waters the salinity value peaks from zero to about one. This peaking of stratification at Lower middle estuary during monsoon is found to weaken slightly by about 3 to 4 units at the peak of the high waters, during both spring and neap tidal phases. The incursion of high saline downstream water at Lower middle estuary causes saturation of salinity of near bottom waters for about 3 to 4 hours at about the peak of high water, while surface salinity continues to increase to reach a peak value to fall after high water with the ebb flow. The combined effect of salinity saturation of bottom water and continuous rise and fall in salinity value of surface water, causes the weakening of stratification at high water. The mean salinity over a tidal cycle was calculated for all observations. Only in upper middle estuary during post monsoon, the mean tidal salinity during spring tidal phase was lower than neap phase value. This is unique as during other observations, the mean tidal salinity value is always higher during spring than at neap. Larger tidal excursion of estuarine water during spring tidal phase, leads to advection of very low saline water of post monsoon from quite far regions of upstream to upper middle estuary, causing low mean tidal salinity value.

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EFFECT OF CLIMATE CHANGE ON ESTIMATION OF DESIGN WAVE HEIGHT

V. R. Remsiya and Manasa Ranjan Behera

Indian Institute of Technology Bombay, Mumbai; [email protected]

Design of coastal and offshore structures require proper estimation of design wave height that plays a crucial role in their serviceability and durability. Traditionally, all the marine structures were designed on the basis of available historic data. However, in view of the scenario of potential climate change and global warming (Fig.1), the frequency of extreme wind occurrences as well as regular wind speeds has increased significantly (IPCC 2013). Thus, the wind generated waves are expected to take shape according to the variation in the wind speed and possibly with higher magnitude and frequency. However, it is necessary to quantify the variation in the wave characteristics based on forecasted wind speed data for the changing climate scenarios. In this study, an attempt has been made to establish a relation between the wind speed and wave characteristics in the Arabian Sea for the past events using artificial neural network (ANN), which could help in assessing the future wave climate based on the projected wind speed.

A region along the west coast of India (shown in Fig.2) was considered for this study, where 9 locations were selected to carry out the data analysis. Re-analysis wind and wave height data from ECMWF for past 30years were obtained. The long term design significant wave heights with a return period of 100 years were obtained from the daily mean significant wave height data. Predominant wind directions were also obtained for the selected locations by analysing daily mean wind speed for the same period. An ANN model was developed using the past data for each location. Feed forward back propagation network architecture was used with three different types of layers connected to each other. The training function used was TRAINLM and adaption learning function was LEARNGDM. The correlation coefficient obtained from the ANN model shows robust performance of the neural network. Similarly, ANN model was developed for the off Bombay location (18.595°N, 71.031°E) where the wind speed and significant wave height data from the NDBP moored buoy is available for the time period 1998-2000. The ANN model results using ECMWF data were compared with the moored buoy records for significant wave height and found to be in reasonably good agreement.

The third generation global climatic model wind data will be collected for a period of 30 years (2016-2045) and will be used for obtaining the future wave heights at all 9 locations using the respective neural networks. The design significant wave height for a return period of 100 years will be calculated from the estimated daily mean significant wave height data for the future 30 years. Thus, the effect of changing climate on the design significant wave height can be substantiated.

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Fig. 1 Observed globally averaged combined land and ocean surface temperature anomaly for 1850-2012 (IPCC 2013)

Fig. 2 Study region along west coast of India and the salient locations considered (Image used from Google Earth)

References Deo M. C. and Naidu C S (1999), “Real time wave forecasting using neural networks”, Ocean Engineering, 26, 191-203. Mandal S, Prabaharan N (2006), “Ocean wave forecasting using recurrent neural networks”, Ocean Engineering , 33, 1401–1410. Radhika S, Deo M. C. and Latha G. (2013), “Evaluation of the design wave height used in the design of offshore structures considering the effect of climate change”, Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment, 227, 233-242.

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CHANGES IN SEA LEVEL EXTREMES ALONG THE EAST COAST OF INDIA AND AT THE HEAD OF THE BAY OF BENGAL

A.S. Unnikrishnan1, Charls Antony1 and Philip L. Woodworth2

1CSIR-National Institute of Oceanography, Dona Paula, Goa; [email protected]

2National Oceanographic Center, Liverpool, U.K.

Changes in extreme sea levels along the east coast of India and at the head of the Bay of Bengal are studied by analyzing hourly tide gauge data at Visakhapatnam, Chennai and Hiron Point. At Hiron Point, the increase in the 99th percentile of sea level shows an increase of 5.2 mm/yr, which is consistent with changes in mean sea level. This tide-gauge station is located on the deltaic region. A similar increase in mean sea level rise trend has been reported from the record at Diamond Harbour (Kolkata), which is partly attributed to subsidence of the delta.

The Hiron Point record also shows the presence of lunar perigean subharmonic cycles of 4.4 year period. The amplitudes of the perigean subharmonic cycles also contribute to the extreme sea level variability over interannual time scales.

The 99th sea level percentile time series at Hiron Point, Visakhapatnam and Chennai are correlated with indices of regional climate modes such as IOD and ENSO. It is found that extreme sea level is correlated well with the climate mode indices suggesting that interannual variability associated with IOD and ENSO also influences the height of sea level extremes in the Bay of Bengal.

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UNDERSTANDING SEASONAL CHANGES OF GOA BEACHES USING EMPIRICAL ORTHOGONAL FUNCTION METHOD

Yadhunath E.M* and Jaya Kumar Seelam


Miramar, Candolim and Baga are some of economically important beaches of Goa, India (Fig. 1). Information on the erosion/accretion of these beaches is important for the efficient management of these beaches. Beach profile measurements were carried out from these beaches at monthly intervals over a period of more than one year. These time series measured data are analyzed statistically by Empirical orthogonal function (EOF) also known as Principal component analysis (PCA) method. These beach profile data were linearly interpolated so that all the profiles during different dates have points that are equidistant apart. The objective of this analysis is to represent the data as a function of time and space [Winant et al., 1975]. This technique is useful to understand the spatial and temporal variations of the beach. EOF analysis basically used in beach morphology studies to explain point of greatest variation in the beach profiles, or point of onshore offshore sediment exchange [Aubrey, 1979]. One of the major advantages of EOF analysis is that we can understand the variations of beach at each point along the beach. From this study, it is observed that from February 1999 to April 2000 Calangute, and Miramar beach showed net accretion behaviour despite the occurrence of sediment erosion during Southwest Monsoon. However, sediment erosion was observed at Baga Beach.

Fig 1: Study area

References: D.G. Aubrey (1979) Seasonal patterns of onshore/offshore sediment movement. Journal of Geophysical Research: Oceans, 84, 6347-6354. C.D. Winant, D.L.Inman & C.E.Nordstrom (1975). Description of seasonal beach changes using empirical eigenfunctions. Journal of Geophysical Research, 80, 1979-1986.

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TIDAL CURRENT ENERGY ASSESSMENT IN THE GULF OF KHAMBHAT

Aqleema Shah1 and Manasa Ranjan Behera2 1National Institute of Technology Srinagar, Jammu &Kashmir

2Indian Institute of Technology Bombay, Mumbai; [email protected]

The present dependence on exhausting fossil fuels had lead to a hunt for reinstating the depleting resources by a sustainable and renewable one. The recent developments in the field of ocean energy extraction signify that the source can be considered as a potential boon to aid national needs. The tidal energy extraction is mainly processed by two main approaches; one is to construct barrages and the other is to install underwater turbines in locations where high tidal current velocities exist (Bedard et al., 2005).

Various studies and measurements have pointed that the Gulf of Kachchh, Gulf of Khambhat and Sunderbans are region of high tidal range and currents in India (Ministry of New and Renewable Energy - Tidal Energy, 2013). Gulf of Khambhat, located along the west coast of India, is a potential region in the Arabian Sea where tidal energy is abundant. There is a tidal amplification of about three folds from mouth to the head of the Gulf, along with which the tidal current is expected to be increase along the channel.

This paper presents an effort towards evaluation of tidal currents and possible power potential through 2-D modelling of the tidal dynamics in the Gulf of Khambhat. A 2D shallow water equation model was used with a finite element formulation. It was applied to a domain spanning between 16°N – 22.5°N and 70°E – 74°E (Fig.1a). The domain with interpolated bathymetry from GEBCO is shown in Fig.1(b). The model was forced with tidal elevation from the open/ocean boundaries and simulation was carried out for duration of 1 month. Tidal elevations and currents across the domain were computed and the average current velocity for 1 month duration is presented in Fig.1(c). It is observed that a large region in the Gulf of Khambhat has current velocity higher than 1.0 m/s, which is the cut-in speed for most of the tidal turbines (Bedard et al., 2005). It suggests that there is a high possibility of harnessing tidal kinetic energy from Gulf of Khambhat. The current velocities extracted from the model are compared with the in situ measurements of tidal current data (Unnikrishnan et al., 1999) for a location (Bombay High) as shown in Fig.2. The comparison shows good agreement of the model results with the measurements. The computed velocities were used to obtain the available theoretical power over the domain using the equations given by Bryden et al., (1998). The average theoretical power for 1 month in the Gulf of Khambhat region is shown in Fig.3. This shows that abundant power potential is present in the domain; however, based on a feasibility study the actual extractable power can be obtained. The study can be used as a preliminary analysis for detailed estimation of efficient tidal power extraction sites.

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Fig.1. (a) Gulf of Khambhat region along Indian Coast (b) Bathymetry of the domain and (c) Average current velocity (m/s) over 1 month duration

Fig.2. Comparison of depth averaged currents (m/s) between measured data (Unnikrishnan et al., 1999) and present

model results.

Fig.3. Available average power (KW/m2) for 1 month duration

References A S Unnikrishnan, S. R. Shetye and G. S. Michael (1999). Tidal Propagation in Gulf of Khambhat, Bombay High and surrounding areas. Proceedings Indian Academy of Sciences (Earth Planet. Sci.), 108, No. 3, 155–177 Bedard. (2005). Survey and Characterization Tidal In Stream Energy Conversion ( TISEC ) Devices, EPRI-TP-004-NA, pp. 1–185 Bryden, I. G., Naik, S., Fraenkel, P., & Bullen, C. R. (1998). MATCHING TIDAL CURRENT PLANTS TO LOCAL FLOW. Energy Procedia, 23(9). 699–709. Elsevier Science Limited Ministry of New and Renewable Energy - Tidal Energy. (2013). Retrieved from http://www.mnre.gov.in/schemes/new-technologies/tidal-energy/

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PRELIMINARY RESULTS OF UNDERWATER VERTICAL AND HORIZONTAL VISIBILITY OF THE COASTAL WATERS OF GOA

Shreya S. Joshi1*, T Suresh1, Anil Kumar2 1CSIR-National Institute of Oceanography, Goa; [email protected]

2 Naval Physical Oceanography Laboratory, Kochi, Kerala

Underwater visibility is the ability of human to detect objects in water and it is measured as the distance an object can be identified from the observer. It has importance and relevance to the Navy, marine archaeology, salvage operations, maintenance of ships, inspections of underwater structures, studies of marine flora and fauna and for leisure sports. Underwater visibility is a function of three factors - underwater environment, the object to be recognized or identified and the diver or observer. In our studies we have used the Secchi disk to measure vertical visibility and the optical parameters to model visibility. We have used two models to determine the vertical visibility, based on the visibility contrast model (Weber contrast) [Tyler, 1968, Preisendorfer, 1986] and the second approach based on the modulation transfer function [Hou et al, 2007]. The horizontal visibility is determined using a model based on a self-consistent approach using the radiative transfer model [Haltrin, 1999] and the contrast model. These models were evaluated using the optical properties of water which were derived from the in-situ measurements and also from radiative transfer simulations. The in-situ data used for the studies were measured in the coastal waters of Goa, India. Since the eye perceives photopic parameters, the models are all based on photopic parameters. The spectral radiometric optical properties were converted using empirical relations to photopic luminosity parameters, using the photopic luminosity function of the eye.

The range of vertical visibility (Secchi depths) was 1 to 8.6 m. The photopic beam attenuation varied from 0.55 to 7.86 (m-1) and diffuse attenuation from 0.223 to 0.918 (m-1), while the underwater average cosine was limited to a narrow range of 0.603 to 0.783. The

coupling parameter Γ is an important parameter and is related to contrast, as

min

0lnC

C

where C0 is the inherent contrast between the target and background water and Cmin is the minimum apparent contrast perceivable by the human eye under photopic conditions. The coupling parameter Γ derived using the contrast model of Preisendorfer [1986] is reported to vary between 6 to 9 [Tyler, 1968] and for our study it varied between 6.4 to 7.89 with a mean value of 7.24.

The vertical visibilities derived from the models closely matched the measured (R2 = 0.98) for the model of Hou [2007] and (R2 = 0.98) for the model of Preisendorfer [1986]. The horizontal visibilities evaluated using the model of Haltrin [1999] were within the range of 2.29 and 9.81 m [Fig.1]. The horizontal visibility was about 1.3 times the vertical visibility.

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Fig. 1. Comparisons of measured vertical visibility with the models (Left) and the comparison between vertical and horizontal visibility.

The coupling parameter Γ is modelled as a function of underwater average cosine at 490 nm and the vertical visibilities were derived using the contrast model with the measured optical parameter [Fig.2]. The model was compared with the measured vertical visibility. The measured vertical visibilities were in the range 0.79 to 4.18 m. The results of validation using our empirical algorithm were encouraging, with high correlation between model and measured with R2 = 0.85, mean percent deviation (MPD) of -22% indicating to be slightly underestimated and root-mean squared error (RMSE) of 0.5.

Fig. 2. Comparison of our model and the measured vertical visibility.

References: Haltrin, V. I. (1999), Horizontal visibility of Lambertian object submerged in seawater, IEEE 1999 International Geoscience and Remote Sensing Symposium, IGARSS’99 (Cat. No.99CH36293), 2(99), 1417–1419. Hou, W., Lee, Z., and Weidemann, A. D. (2007), Why does the Secchi disk disappear? An imaging perspective, Optics Express, 15(6), 2791. Preisendorfer, W. (1986), Secchi disk science: Visual optics of natural waters, 3(September). Tyler, J. E. (1968), The Secchi disc. Limnology and Oceanography, XIII(1), 1–6.

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MARINE BIOLOGY SESSION - 06

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BIODIVERSITY AND STATUS OF CORAL REEF IN MALVAN MARINE SANCTUARY, CENTRAL WEST COAST OF INDIA

Kalyan De1 , Sambhaji Mote1, Lobsang Tsering1, Perisamy, R.1, Vishal Patil1, Rahul Nagesh1 , Afreen Hussain1, Sabyasachi Sautya2, Baban Ingole1*

1CSIR-National Institute of Oceanography, Dona Paula Goa, India; [email protected]

2CSIR-National Institute of Oceanography, Regional Centre Mumbai, India

Coral reefs are one of the most important and spectacular marine ecosystem. In India, major coral reef formations are restricted to the Andaman and Nicobar Islands, Gulf of Mannar and Palk bay in Bay of Bengal and on the other side Gulf of Kutch, the Lakshadweep islands in the Arabian Sea. While apart from these reefs there are some patchy fringing reefs also present along the central west coast of India. The Malvan Marine Sanctuary (MMS) is blessed with one of such coral reef formation. The area is declared as Marine Protected Area (MPA) in 1987 under the Wild Life Protection Act, 1972. It covers an area of 29.122 km2 and considered as one of the ‘Biodiversity hotspot’. Earlier studies reported 74 species of fishes, 73 species of seaweed and 9 coral species including 181 species associated flora and fauna. The present study was initiated to evaluate the degree of the biodiversity, health and threats to the coral reef and its environment. Subtidal underwater survey by SCUBA diving and snorkeling was conducted at five locations in the reef region and one location out of the reef area. Belt Intercept Transect (BIT) and quadrate survey methods were employed to assess the biological community structure and composition. The reef area extended between shallow intertidal zone to the 15m in subtidal zone. Average water depth ranged between 3-5 m. Alltogeather 16 of species of building scleractinian coral (Montipora aequituberculata, Cyphastrea serailia, Pseudosiderastrea tayami, Siderastrea savignyana, Favites bestae, F.halicora, Turbinaria mesenterina, T. frondens, Porites lichen, P. lutea, P. compressa, P. astreoides, Goniopora stokes, G.minor), were recorded. Encrusting coral P.tayami and P.lichen were dominant in the intertidal to shallow zone, whereas foliaceous T. mesenterina was conspicuous in the mid-region. G. stutchburyi and P. versipora were the dominant in the deeper region. Overall coral coverage is dominated by stress tolerant T. mesenterina. Despite being a MPA, there has been a noticeable degradation and breakage of corals documented perhaps due to the unregulated tourist trampling, inexperienced diving activities, disturbance in the bottom the sediment by boat anchoring on the reefs flat. Moreover, the coral bleaching observed in several locations on the reef flat signifies the human and environmental pressure on the reefs. Macroalgal coverage was dominated by Sargassum spp. and invasion of turf algae on the coral colonies was also observed. Strong wave action, high turbidity and anthropogenic pressure indicate the adaptability of the coral species to such environment. Awareness creations among the local community, promotion of eco-friendly tourism and strict implementation of legal provisions need to be initiated to protect the reef’s sustainability.

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BENTHIC FLAGELLATE COMMUNITY DISTRIBUTION IN RELATION TO ABIOTIC AND BIOTIC VARIABLES ALONG THE NORTH EAST COAST OF INDIA, BAY OF

BENGAL

Sangeeta Mishra1,2*, Rakhesh Madhusoodhanan1,3, Kalavati Chaganti1, Raman V Akkur1 1Marine Biological Laboratory, Dept. of Zoology, Andhra University, Visakhapatnam, India – 530003;

[email protected] 2State Pollution Control Board, Orissa, Bermunda, Bhubaneswar, India – 751003

3Department of Biology, University of Bergen, Bergen, Norway- 5020

Heterotrophic flagellates are considered as an important component of microbial communities in all types of aquatic ecosystems. Samples were collected from 27 GPS fixed locations along a stretch of 152 km on the northeast coast of India at three different habitats (estuarine, inter-tidal and rock-pool) during February 2007 – July 2008. For qualitative analysis the surface sediments collected up to a depth of about 1 cm of 1 m2 quadrate using a flat spoon. The sediments were placed in plastic trays in 1 cm deep layers. Cover slips (No1. 22×22mm) were placed on lens tissue laid on the sediments. After 12 to 24 h, flagellates were observed using (Leica DMLS) with x400 microscope equipped with photographic facilities. Altogether 64 numbers of flagellates were observed. Numerically flagellate abundance varied from a minimum of 10 nos.g-1 (March 2007) to a maximum of 27118 nos.g-1 (September 2007) and the observed mean was 1159 nos.g-1

. Based on the

numerical abundance, 16 species which together constituted 90% of the population were considered as important. Anisonema sp. (12.4%), Goniomonas sp. (9.2%), Bodo sp. (8.6%), B. cephalophorus (8.3%), Chloromonas sp. (8.3%) and Dinematomonas sp. (7.7%) were important in order of their abundance. Overall, phytomastigophoreans formed the bulk (77.8%) of the population numerically. Habitat-wise, the estuary appeared to support a rich population of flagellates. Mean abundance ranged from 4344 nos.g-1 to 5970 nos.g-1 and mean being 5354 nos.g-1. During this study, heterotrophic flagellate abundance is significantly correlated with sediment chlorophyll (an attribute of phytobentios) and negatively with nitrite, nitrate and phosphates (considered as sources of bacterial production). Through Bray-Curtis similarities it was possible to divide the 27 stations into three groups at 48% similarity. The dendrogram provided a sequence of fairly convincing groups of stations confirmed by MDS plot for the same locations. ANOSIM Global test indicated a significant difference (Global R: 0.98 at 0.1%) in the composition of flagellate assemblages among these habitats. The SIMPROF test also revealed a good demonstration of both ANOSIM and SIMPROF working in conjugation. Overall it may be concluded that locally both in the coastal and estuarine sediments, heterotrophic flagellates are euglenoid dominated and showed a strong segregation into different assemblages in different habitats. Seasonal changes were less marked. More than the abiotic factors, feed availability appeared a major controlling factor for heterotrophic flagellate abundance and diversity.

References: S.K.Sasamal, R.C.Panigrahy, Sangeeta Mishra (2005) Asterionella blooms in the northwestern Bay of Bengal during 2004. International Journal of Remote Sensing, 26(17), 3853-3858.

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Sangeeta Mishra, Gouri Sahu, A.K.Mohanty, S.K.Singh and R.C.Panigrahy. Impact of the diatom, Asterionella glacialis (Castracane) bloom on the water quality and phytoplankton community structure in coastal waters of Gopalpur sea, Bay of Bengal (2005). Asian Jour. Water, Environment and Pollution. 3 (2): 71-77.

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MACROBENTHIC COMMUNITY STRUCTURE IN RELATION TO STRESSORS IN A FISHING HARBOR OF PARADIP, ODISHA, EAST COAST OF INDIA

Dipti Raut*, Himadri Tanaya Panda, Aswini Nayak, Biswaprajna Mohanty, Lipika Patnaik

Environmental Science Laboratory, Department of Zoology, Ravenshaw University, Odisha -753003; [email protected]

Hydrobiological studies in a Fishery harbor in Paradip (Lat 20° 15' 55, 44" N; Long 86° 40' 34.62"E), Odisha, to assess water quality, sediments and benthic fauna in relation to anthropogenic activities revealed 24 species of organisms belonging to diverse groups of animals such as Polychaetes, Crustaceans, Molluscs and Pisces. Of these polychaetes outnumbered other groups both in terms of their diversity and population density (91%), being represented by as many as 14 species. Numerically polychaetes such as the Spionids, Prionospio sp., Polydora sp., Cossurid, Cossura sp., Capitellid, Capitella sp. and Nereid, Nereis sp. were dominant (~70%). In this investigation the complete absence of Maldanids, Lumbrinereis and Terebellids is of interest as their absence is an indication of poor environmental conditions. On the transects closer to the jetties, diversity indices such as the Shannon-Wiener index H’ and Margalef index d were relatively low (<1.37) in comparison to the central transect (>1.69) indicative of stressors such as higher organic load (>1.9%), lower dissolved oxygen (sometimes nil) and increased trawler movements scouring away the sediment infauna, direct dumping of ballast water, trash fish, fish viscera from gutting to name a few. Different faunal groups characterize the transects such as Prionospio-Polydora-Cirratulids-Capitella-Cossura sp. on the west, while Nereis- Capitella sp. on the east and Lycastis-Cossura sp. in the central transect. The presence of Capitellids in the marginal transects is clearly indicative of organic enrichment and gross polluted conditions. Bray-Curtis similarity for benthic fauna revealed three groups at 59% similarity characterizing mouth locations (T4 andT5), mid harbour (T1 and T3) and an independent T2 cluster. Overall, the study revealed characteristic response gradients in the composition and distribution of benthic fauna in relation to sediment nature (texture, organic content) and other physico-chemical characteristics.

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STUDY OF CESTODE INFECTION IN SCOLIODON IN MUMBAI REGION, INDIA

V. V. Andhare*, P. Hatkar and S. Soni

Institute of Science, Fort, Mumbai; [email protected]

Scolidon is consumed as food by most of the people of Mumbai region. It is a common fish which is seen in markets of Mumbai and is also a source of income to fishermen. The population dynamics of Scolidon was studied to see the infection rates of endoparasites specifically the cestodes during the three seasons from November 2012 to December 2013. The methods include statistical applications to know the population levels and distribution of cestode parasites during the above mentioned period.

The present study deals with the rate of infection of cestode parasites in the intestines of Scoliodon from the landing centres of Mumbai during November 2012 – December 2013.

The intestines of Scoliodon were procured from 3 landing centres of Mumbai viz, Bhaucha dhakka, Sasson Dock and Versova Dockyard during the period of 12 months from November 2012 – December 2013. The intestines were dissected longitudinally and observed for infections. Parasites were collected in warm water and stored in 10% formalin. Further they were stained in Harris haemotoxyline and identified upto genus level.

Population dynamics of cestode parasite were determined by the following formulae:

Incidence of infection = (Infected host/ Total hosts examined) x 100 [1]

Intensity of parasites = (No. of parasites in a sample/ No. of infected host) [2]

Index of infection parasite = ( )

( ) [3]

A total of 360 intestines were collected and examined, out of which only 144 intestines were infected and a total of 302 cestode parasites of different genus were found. The value of incidence, intensity and index of parasite infection are as 40%, 2.04% and 0.54 respectively.

Thus the above observation and results show that Scolidon was infected by a number of cestode parasites from different genera like Tetrarhynchus, Nybelinia, Tylocephalum, Phyllobothrium etc. The infection of these parasites was the highest during January to April as the high temperature enhances the hatching of the eggs of parasites, whereas from October to December the infection rate was low as it is the winter season.

References: Sandeep, A., Sushil, J. and Sunita, B. (2011), Population dynamics of cestode parasite in Trygon zugei from Ratnagiri district (M.S.), India International Multidisciplinary Research Journal, 1(8) 24-26. Mani, G., Anu, P. V. and Vijayalakshmi, C. (2012), Population dynamics of metazoan parasites of marine threadfin fish, Eleutheronema tetradactylum (shaw1804) from Vishakhapatnam coast, bay of Bengal, Cibtech Journal of Zoology, 1(1),14-32.

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Sarah, A. J., Vladimir, M., Sami, A. S., Redha, B. F. and Nashwa, A. M. (2014), Biological and Ecological Features of Poecilancistrum Sp. Plerocercoid (Cestoda: Trypanorhyncha) Infection of Arabian Sea , Journal of Research & Development Aquaculture , 5(3). Robert, F., Boy, V. and Gabrion, C. (1990), Biology of parasite populations: population dynamics of bothriocephalids (Cestoda-Pseudophyllidea) in teleostean fish, Journal of Fish Biology, 37(2), 327–342. Carvalho, A. R. and Luque, J.L. (2011),Seasonal variation in metazoan parasites of Trichiurus lepturus (Perciformes: Trichiuridae) of Rio de Janeiro, Brazil, Braz. J. Biol, 71(3), 771-782.

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STRESS RESPONSE TO VARIATIONS IN TEMPERATURE IN FRESHWATER FOOD FISH PANGASIANODON HYPOPHTHALMUS

S. Soni* and V. V Andhare

The Institute of Science, Fort, Mumbai; [email protected]

Stress is an organismns reply to any stimulus or the environment. Fish being aquatic, its physiology and homeostatis regulation is completely dependent on the water in the surrounding environment. Changes in the surrounding water temperature bring about fluctuations in the regulation of homeostasis in fish resulting in stress to the fish. There are alterations in the hormonal and blood parameters and also in the behaviour of the fish. This in turn affects the growth rate, reproduction, lifespan, social behaviour etc of the fish. The present work deals with the study in changes in haemoglobin values and the behaviour mechanisms in the fresh water food fish Pangasianodon hypophthalmus. P. hypophthalmus, a catfish is a common staple food fish worldwide.

Around 120 fish were examined macroscopically in order to observe for any symptoms of diseases or infestation of ectoparasites (Qang, 1998; Woo, 1995; Bullock., 1989). The fish were acclimatized for 15 days under laboratory conditions prior to experimentation. The fish were subjected to varying temperature ranges from 240C-330C for 24 hrs. Immediately after experimentation, haemoglobin concentrations were determined by Cyanmethaemoglobin method (Blaxhall and Daisley, 1973; Tanyer, 1985). The various behavioural activities such as sheltering, grouping and surfacing pertaining to the above experiments were observed. The results were calculated using students‘t’ test. The Hb (haemoglobin) mean values for 24°C, 27°C, 30°C and 33°C are 15 + 0.48, 21.06 + 1.68, 30.70 + 0.50 and 31.66 + 1.52 respectively.

Behavioural responses observed showed no change in behaviour at 24°C and 27°C, whereas at 30°C and 33°C, the fish showed deviation from normal behaviour. At higher temperatures the fish started surfacing for oxygen and preferred being hidden. Fish were also seen swimming alone and not in groups.

From the observations it is concluded that the parameters like haemoglobin and behaviour showed considerable changes when the fish were subjected to various temperatures. The fish undergoes stress resulting in its physiological changes and alterations in its hormones and blood parameters which may also affect the humans that consume it for a longer duration.

References: Kucukgul, A and Aysel, S. (2008), Acute Stress response in Common Carp (Cyprinus Carpio Linnaeus, 1758) of some stressing factors, Journal of Fisheries Sciences, 2(4), 623-631. Acerete, L., Balasch, J.C., Espinosa, E., Josa, A and Tort, L. (2004), Physiological responses in Eurasian perch (Perca fluviatis, L.) subjected to stress by transport and handling, Aquaculture Elsevier, 237, 167-178.

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Kubilay, A and Gulsen, U. (2002), Acute stress on Rainbow Trout (Oncorhynchrus mykiss), Turk J Zool, 26, 249-254. Saglio, P and Trijasse, S. (1998), Behavioural responses to Atrazine and Diurion in Goldfish. Arch, Environ. Contam. Toxicol, 35, 464-491. Cataldi, E., Dimarco, P., Mandich, A. and Cataudella, S. (1998), Serum Paraeters of Adriatic Sirgeon Acipenser naccarii (Pisces: Acipensiformes): effects of temperature and stress, Comparative Biochemistry and Physiology Part A, Elsevier, 121, 351-354. Barton, B.A. (1997). Stress in Finfish in G.k. Iwama, A.D. Pichering, J.P. Sumpter, C.B. Schreck, editors, Fish Stress and Health in Aquaculture, Cambridge university press, Cambridge, 34pp. Little, E. E., Richard. D., Boris. A. F. and Vera. I. K. (1990) Behavioural indicators of sublethal toxicity in Rainbow Trout, Arch. Environ. Contam. Toxicol, 19, 380-385. Bullock, A.M. (1989), Laboratory Methods In Roberts R.J and B. Tindall, editors, Fish Pathology, London, 372-402. Blaxhall, P.C and Daisley K.W. (1973), Routine haematological methods for use with fish blood. Journal of Fish Biology, 5, 771-882.

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STUDY OF BENTHIC FAUNA IN THE NEAR SHORE WATERS OFF GULF OF KUTCH, NORTH WEST COAST OF INDIA.

Shivanagouda .N. Sanagoudra*, U. G. Bhat

Department of Marine Biology, Karnataka University, P.G. Centre, Karwar, Kodibag, Karwar 581 303, Karnataka; [email protected]

The present study was undertaken for a period of two years from December 2010 to May 2012. Studying the benthos of Gulf of Kutch near shore waters is also useful in understanding changes in biological diversity of Gujarat coast. The use of benthos in aquatic ecological research is especially effective in assessing long term changes and detecting input from diffuse sources. The benthos reflects the effects organic enrichment by responding through detectable changes in population dynamics on a time scale of months to years. This is in contrast to plankton which shows a more immediate change to point sources with no long term consequences to the populations (Gray et al 1992). Benthoses were collected from 6 near shore water stations on regular basis and were identified. Altogether 60 species were identified and placed taxonomically during the course of investigation with sediment samples. Benthic environmental relationship species and their limiting biotic and abiotic factors were observed.

Our studies of monthly comparisons have become an interesting and popular approach in ecology and environmental relationships in the past a number of studies have been conducted on the ecology of macro benthic populations of Gulf of Kutch near shore. My research helps in Gulf of Kutch of the west coast of India has become an important economic asset of the country serving commercial navigation and the fishing sector with environmental relation of benthos in the Gulf of Kutch Gujarat. India.

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SPATIAL AND TEMPORAL VARIATIONS OF COLORED DISSOLVED ORGANIC MATTER IN THE ESTUARINE AND COASTAL WATERS OF GOA.

Albertina Dias1*, T. Suresh1, Manguesh Gauns1, Arvind Sahay2, Prakash Chauhan2 1CSIR-National Institute of Oceanography, Goa, India; *[email protected]

2Space Application Centre, ISRO, Ahmedabad, India

Dissolved organic matter (DOM) is a major reservoir of organic carbon and CDOM is the optically active component of DOM that passes through 0.2 micron filter paper and interacts with UV and visible light. CDOM plays a key role in the penetration of UV light in the water column and interaction with aquatic ecosystem. Coastal and estuarine waters are complex and since CDOM has a major contribution to the optical properties hence studies were carried out in waters of Goa from March to Dec, 2014.

Fig 1: Spatial and temporal variation of a375 nm-1

The CDOM absorption at a reference wavelength of 375 nm, a375 (Fig 1) in the coastal waters was found to decrease offshore in all the seasons. In the coastal waters, during the post monsoon and summer, a375 was found to be the highest while it was the lowest during the winter. In the Mandovi and the Zuari estuaries absorption at a375 increases towards the head of the estuary. In the Mandovi estuary, the absorption was found to be high in the summer at the head and then decreases towards the mouth. During winter the absorption was high at the mouth of the estuary and low at the head. In the post monsoon the absorption was the lowest in both the estuaries.

Fig 2: Spatial and temporal variation of S250-600 nm-1

The slope S250-600 in coastal waters was low during summer and increases through post monsoon and was the highest in winter. The general trend in Mandovi estuary of S250-600 was found to be high in winter and lowest during post monsoon, while in the Zuari estuary it followed a reverse trend with high S250-600 in the summer (Fig 2).

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Fig 3: Spatial and temporal variation of S275-295 nm-1

The S275-295 is a good proxy for photo-bleaching (Helms, 2008), which was found to be high in the coastal waters during winter. In the Mandovi and Zuari estuaries S275-295 was found to be high in summer and low during post monsoon (Fig 3).

In the coastal waters SR which is a ratio of S275-295/ S350-400 varied from 1.6 to 2.4. It is low at the coast and increases offshore. In the Mandovi estuary, SR increased from the head to the mouth of the estuary. SR was high during summer and almost similar during the winter and post monsoon. In the Zuari estuary minimal seasonal variations of SR were observed.

Fig 4: Variation of a365 with salinity

The estuaries and coastal waters in Goa show non conservative behaviour of CDOM as seen in Fig 4. Addition of CDOM was seen in all seasons in the estuaries. In the coastal waters, removal was dominant during winter and summer which may be assigned to photo bleaching indicated by high value of S275-295. The high value of S275-295 in the coastal waters indicates that photo bleaching is a perennial problem in these waters

References: Helms, J. R. et al (2008), Absorption spectral slopes, and slope ratios as indicators of molecular weight, source, and photobleaching of chromophoric dissolved organic matter, Limnol. Oceanogr., 53, 955–969.

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STUDY OF EPIPHYTIC DIATOMS ON SEAWEEDS AND ASSESSING THEIR POTENTIAL AS POLLUTION INDICATORS

V. A. Kulkarni1*, S. P. Jagdale2 1Cholamandalam MS Risk Services Limited, QCI Accredited EIA Consulting Organization, 3

rd Floor, Wellesly

Court, Dr. Ambedkar Road, Pune 411001; *[email protected] 2Dapoli Urban Bank Senior Science College, Affiliated to Mumbai University, Dapoli, Maharashtra 415 712

Epiphytic floras of marine macrophytes prominently constitute diatoms, cyanobacteria and fungi [Dere et al., 2002]. Epiphytic diatoms are of a special interest because of their attachment to living substrate and interactions among different components of habitats. Most of the earlier work done on epiphytic diatoms dealt with freshwater and estuarine environments [Sullivan and Currin, 2000]. The limited mobility of epiphytic diatoms makes them likely to reflect long term environmental conditions for a particular area [Fore and Grafe, 2002]. Therefore, they potentially can be use as bioindicators of environmental quality, and may be more effective than other conventional bio-indicators [Fisher and Dunbar, 2007]. Understanding dynamics of epiphytic diatom community would enable exploring their ecological, environmental as well as bioindicator potentials.

The study area selected for this research is central west coast of India which lies between latitude 15° - 17°N and longitude 73° 15’ - 74° 30’E. Sampling locations selected along central west coast were Mumbai, Malvan and Anjuna. Seaweed flora along selected stations was surveyed on monthly interval basis during the period of November 2012 to October 2013, using standard seaweed collection procedure [Dhargalkar et al. 2001].

Epiphytic diatoms on seaweeds’ thalli were isolated by adopting and slightly modifying the HCl digestion methods described for aquatic angiosperms [Shamsudin and Sleigh, 1995]. Total abundance was estimated as No. X 105 g-1 Dry Weight of thallus. Diatom samples were identified as described by Desikachary et al. [1987] and Tomas [1997]. Statistical analysis of data was conducted using PRIMER E6 software. Seawater quality at selected locations was studied using standard methods [Strickland and Parson, 1972].

pH, temperature, salinity, dissolved oxygen and suspended solids were observed to be in normal range and nearly similar at all three locations. However, biological oxygen demand and nutrient values were much higher at Mumbai than that of Malvan and Anjuna.

A total of 62 diatom species were recorded to be epiphytic on seaweeds during study. Licmophora and Biddulphia dominated epiphytic diatom community from Mumbai with average percentage composition of 57.06% and 10.62%, respectively. Rhizosolenia was observed to be dominant on seaweeds from Malvan [22.86%] and Anjuna [41.38%]. In Malvan and Anjuna Navicula, Nitzschia, Grammatophora and Caloneis spp were also found to be dominant during the sampling period. Epiphytic diatom community at Mumbai showed totally different distribution and abundance patterns as that of Malvan and Anjuna.

The cluster analysis of epiphytic diatom communities revealed that diatom assemblages at Mumbai are significantly different from other two locations. Though composition of diatoms assemblages displayed wide temporal variations at Malvan and

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Anjuna, specimens from Mumbai were found to be supportive of one species community hypothesis. The results of draftsman plot show that diatoms such as Biddulphia, Licmophora and Nitzschia observed at Mumbai had strong and positive correlation with pollutant parameters and negative correlation with dissolved oxygen. Similarly Rhizosolenia and Navicula showed negative correlation between pollutant parameters.

Non linear and negative relationship was observed between Rhizosolenia with Biddulphia, Licmophora and Nitzschia. This indicates Rhizosolenia cannot tolerate the environmental conditions in which abundance of Biddulphia, Licmophora and Nitzschia found to be high. Hence Rhizosolenia could act as bioindicator for cleaner water. Licmophora and Nitzschia though showed positive relationship with pollutants, they were occasionally observed at Malvan and Anjuna. However, Biddulphia exclusively occurred at Mumbai and dominated most of the epiphytic population. Hence, it could act as bioindicator for polluted water.

References: Dere P, Karacaoulu D. and Dalkiran N. [2002] A Study on the Epiphytic Algae of the Nilufer Stream [Bursa]. Turkish Journal of Botany. 26: 219 – 233. Desikachary TV, Prasad AKSK, Hema P, Sreelatha M, Sridharan VT and Subrahmanyan R [1987] Marine diatoms from the Arab Sea and Indian Ocean, in: Desikachary TV [ed.], Atlas of diatoms. Fasc. IV. Madras Science Foundation, Madras. 1 – 7. Dhargalkar V.K., Untawale A.G. and Jagtap T.G. [2001] Marine Microalgal Diversity along Maharashtra coast - Past and Present Status. Indian Journal of Marine Sciences. 30: 18 – 24. Fisher J. and Dunbar M.J. [2007] Towards a representative periphytic diatom sample. Hydrology and Earth Systems Science. 11: 399 – 407. Fore L. and Grafe C. [2002] Using diatoms to assess the biological condition of large rivers in Idaho [U.S.A.]. Freshwater Biology. 47: 2015 – 2037. Shamsudin L. and Sleigh M.A. [1995] Seasonal-Changes in Composition and Biomass of Epiphytic Algae on Themacrophyte Ranunculus penicillatus in a Chalk Stream, With Estimates of Production, and Observations on The Epiphytes of Cladophora glomerata. Hydrobiologia. 306 [2]: 85 – 95. Strickland JDH and Parsons TR [1972] A practical handbook of seawater analysis. Fisheries Research Board of Canada. 310 pp. Sullivan M.J. and Currin C.A. [2000] Community structure and functional dynamics of benthic microalgae in salt marshes. In: MP Weinstein and DA Kreeger [Eds.], Concepts and Controversies in Tidal Marsh Ecology. Kluwer Academic Publishers, Dordrecht: 81-106. Tomas C.R. [1997] Identifying Marine Phytoplankton. Ed. Carmelo R. Tomas. Academic Press. 858 pp.

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SPATIAL AND TEMPORAL COMMUNITY CHARACTERISTICS OF ASSOCIATED ORGANISMS IN SARGASSUM CINCTUM

Wasim Ezaz*, Temjensangba Imchen

CSIR-National Institute of Oecanography, Goa; [email protected]

Sargassum cinctum is a typical brown macroalga found growing on the rocky substratum of intertidal and subtidal region. This study attempted to analyze the spatial and temporal variation in community dynamics of associated organisms in relation to Sargassum. More than 31,000 individual species from 8 major taxa were isolated in the present study and they were analyzed qualitatively and quantitatively to describe abundance, species richness and the host specificity of associated organisms. The total community structure showed a positive correlation with plant architecture. The fauna lacked diversity but a few species were found frequently across the year namely amphipods (Gammarus fasciatus, Gammaropsis sp.) and Bivalvia (Modiolus sp.). Most species increased their abundance during the cool season while during summer season the abundance of alga and associated fauna decreased in relation to summer temperature. Comparison of major groups representing Amphipods, Isopoda, Polychaeta and Bivalves from different sampling period indicated that although the temporal variation exhibited higher effect on the community structure, no species showed any significant variation in terms of abundance. Gammarus fasciatus (Amphipoda) was found to be the most abundant species associated with the target alga throughout the study period in the present study.

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ARABIAN SEA LONG TERM PRODUCTIVITY TREND

Prince Prakash1* and Satya Prakash2 1National Centre for Antarctic and Ocean Research, Vasco-da-gama, Goa; [email protected]

2Indian National Centre for Ocean Information Services, Hyderabad

South-western Arabian Sea is the most productive region in the Indian Ocean. Some of the recent observations on the basis of ocean color data have shown contradicting trends in ocean productivity for the Arabian Sea; it has increased by more than 350% over the last 6 years in the western Arabian Sea due to strengthening of the monsoonal winds [Goes et al., 2005] whereas no such trend is seen in the eastern Arabian Sea [Prakash & Ramesh, 2007]. Analysis of SeaWIFS (9-km spatial resolution) Level-3 monthly chlorophyll-a concentration data for the period of 1997-2010 shows a decreasing trend in the summer chlorophyll-a for the south-western Arabian Sea (Somali Coast,47-55°E & 5-10°N) after 2003 (Figure 1). The trend analysis revealed that there was an increase in the summer peak chlorophyll-a concentration from 1998 to 2003 (slope: 0.24 ± 0.06; r2 = 0.85; p = 0.02) but decreased after that (slope: -0.06± 0.03; r2 = 0.44; p = 0.10). Analysis of winds (Cross Calibrated Multiplatform wind and QuickSCAT ) strength and wind stress curl from 1997 to 2003 and from 2004 to 2009 do not show any appreciable change. During the period 1997 to 2003 Satellite derived Sea Level Anomaly (SLA) along the Somalia coast shows a decreasing trend (Slope = -0.06 cm/month, P-value = 0.02) while during 2004 to 2010 the SLA increases (slope = 0.07 cm/month, P-value = 0.03). The sea level change generally reflects thermocline variation: Increase (decrease) in sea level associated with deepening (shallow) of thermocline. This is also reflected in the depth of the 23°C (D23) isotherm, which is a proxy for thermocline depth. Summer (June to September) average of D23 during 1997 was 130 meters which gradually decreased and shoaled upto 85 meters in 2003 and then reached 71 meters in 2004, but after 2004 it again gradually increased and deepened to 109 meters in 2010. As the nutricline and thermocline are closely associated in the Arabian Sea, therefore change in thermocline directly affects the supply of nutrient to the surface layer. Thus the deepening of the thermocline during 2003 to 2010 reduced the supply of nutrients to the euphotic zone and a decrease in surface chlorophyll-a. Our analysis reveals a remarkable change in trend in the chlorophyll concentration of the south-western Arabian Sea after year 2003. Our finding suggests that the south-western Arabian Sea could witness increase/decrees in bloom of phytoplankton not only due to the strengthening/weakening of local wind but sea level anomaly also plays a crucial role. So the bloom in the south-western Arabian Sea is not only due to atmospheric effect but also is a manifestation of oceanic effects. The observed variability in productivity, therefore, may not be an effect of the global warming but part of a decadal oscillation.

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Figure 1: Area averaged monthly time series of Chlorophyll -a for south-western Arabian Sea (47-55°E & 5-10°N). The trend lines shown depict the increasing and decreasing trends

during 1998–2003 and 2004–2010, respectively

References: Goes, J. I., P. G. Thoppil, H. do R Gomes, and J. T. Fasullo (2005) Warming of the Eurasian landmass is making the Arabian Sea more productive, Science, 308, 545–547. Prakash, S., and R. Ramesh (2007) Is the Arabian Sea getting more productive? Curr. Sci., 92, 667– 671.

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ASSESSING THE ECOLOGICAL STATUS OF COASTAL WATERS OF INDIA USING AMBI (AZTI’S MARINE BIOTIC INDEX).

SK Sivadas1*, R. Nagesh1, B.S. Ingole1, GVM Gupta2 1CSIR-National Institute of Oceanography, Goa, India; [email protected]

2Centre for Marine Living Resources, Kochi, India

Marine ecosystem harbours 97% of all species on Earth but is under threat by increased human manipulation of the ecosystem and rapid climate change. The alteration of ecosystem has resulted in the most rapid loss of species in the history of life on Earth (Vitousek et al 1997). One of the greatest challenges when determining the impact from any disturbance is the inability to separate man-made impacts from natural change. This particularly important in tropical regions where environmental variables shows distinct temporal variability influenced by the annual monsoon which is reflected in the distribution pattern of marine communities. Therefore, knowledge of the reference condition is extremely useful for effective conservation plans (Bremner 2008). The benthic communities’ sensitivity to changes makes them good indicators of the ecological status of the marine ecosytem.

There have been many biotic indices formulated to study the ecological status of marine ecosystem. AMBI (AZTI’s Marine Biotic Index) is one such index that is presently used worldwide to assess coastal waters. AMBI (Borja et al. 2000) is based on the ecological group. Although AMBI has been used widely in various ecosystem (Borja et al. 2009), very few studies have used it in tropical region. Since Indian coast is also affected by the increasing urbanization and industrialization we calculated the AMBI index during different season to understand the natural variation in the index and the ecological status of the region. The study area includes Mandovi Estuary, Zuari estuary, Kalbadevi Bay, Kochi and three harbours (Ratnagiri, Mormugao and Karwar). Five distinct temporal regimes are identified based on the rainfall pattern - Lean-Season Regime (LSR; January-May); Monsoon-Onset Regime (MOR; June); Peak-Monsoon Regime (PMR; July-August); End-Monsoon Regime (EMR; September-October) and Post-Monsoon Regime (PMon Regime; November-December). A temporal trend was observed in the AMBI index and highest values were observed during the monsoon (Figure 1). High values of AMBI during monsoon (MOR and PMR) are because the overall macrofaunal community are lower during this period. In general, highest values were observed in the harbours. Our study indicates that the AMBI could be used to assess the health of coastal ecosystem. However, we suggest that the AMBI index could be used with other biotic indices and abiotic factors to give accurate results.


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Figure 1 Seasonal variation of AMBI index in the study area. ZuH Marmugao harbor; ZuE Zuary Estuary; Ma E Mandovi Estuary; Rat H Ratnagiri harbor; Kar H Karwar Harbour; Kal

Kalbadevi Bay; Koc Kochi.

REFERNCES: Vitousek PM, Mooney HA, Lubchenco J, Melillo JM (1997) Human domination of Earth’s Ecosystem. Science 277:494-499. Borja A, Miles A, Occhipinti-Ambrogi A, Berg T (2009) Current status of macroinvertbrate methods used for assessing the quality of European marine waters: implementing the Water Framework Directive. Hydrobiologia 633(1):181-196. Borja A, Franco J, Pérez V (2000) A marine biotic index to establish the ecological quality of soft-bottom benthos within the European estuarine and coastal environments. Mar Pollut Bull. 40:1100-1114

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DIVERSITY OF MACROBENTHOS AND MACROPHYTE RELATIONSHIP ON THE ROCKY SHORE

Uday Gaonkar, Periasamy R., S.K. Sivadas, Vishal Patil, B.S. Ingole*

CSIR-National Institute of Oceanography, Goa, India; [email protected]

Macrobenthic diversity is a major biological productive area on intertidal rocky habitats and it improves ecologically diverse coastal areas. Rocky shore is one of the most fascinating of the ecosystems and this dominates large proportion of world’s coastlines. This rocky shore has huge diversity of macrophyte, because it provides substrate for macrophyte which stables them on the rocky shore. The present study was initiated to evaluate the macrophyte community enhance associated macrobenthos biodiversity at five different rocky intertidal areas, namely Ratnagiri, Anjuna, Cabo-de-Ram, Majali and Ankola situated on the central west coast of India. Samples were collected on January and February 2013 during low tide with quadrant intercept transects method. Spatial distribution of macrobenthos is related to particular macrophyte species by means statistical methods (BIO-ENV). Total 22 macrophyte species were recorded belonging to Chlorophyta, Phaeophyta and Rhodophyta. The macrophyte communities dominated by Dictyota sp. and Sargassum sp. The macrobenthos were represented by overall 47 taxa. The macrobenthos abundance were dominated by Crustacea, Polychaeta and followed by Mollusca. Spearman rank correlation (using BIO-ENV procedure included in PRIMER, V.6) showed significant correlation between macrobenthic diversity and type of macrophyte variables with highest correlation (r=0.606) particularly Rhodophyta community. This study suggests that major environmental factor of Rhodophyta species enhances the macrobenthic species diversity in the central west coast of India.

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EFFECT OF UPWELLING-DRIVEN HYPOXIA ON MACROBENTHIC COMMUNITY OF SOUTH WEST COAST OF INDIA

Sanitha K. Sivadas1*, G.V.M. Gupta2, BS Ingole1 1CSIR-National Institute of Oceanography, Goa; [email protected]

2Centre for Marine Living Resources, Kochi, India

Global warming and anthropogenic activities is increasing the areas and depth of low oxygen waters in the marine system. The sediments off Kochi are one of the most productive upwelling regions along the west coast of India (eastern Arabian Sea). High productivity along the west coast of India is observed during the upwelling period during the monsoon season. The high productivity in the water column increases the organic matter flux to the benthic system which reduces the bottom water oxygen. The focus of the present work was to study the response of macrobenthic community (abundance, biomass, functional diversity) to seasonal hypoxia. For the present study, six stations (14, 20, 31, 41,

50 and 102m) along a transect (997N 7604E to 997N 7564E) were sampled from March to December 2012. Water samples were collected for physico-chemical parameters. Sediment samples were collected using van Veen grab. Statistical analyses were carried out using PRIMER 6 and Statistica 10. Principal Component analysis (PCA) revealed low oxygen and high nutrients during May-July indicating upwelling in the study area. In general, macrofaunal abundance and biomass was high at shallow depth (depth 14-31 m) while species diversity was high at intermediate depth (41-50m). Abundance and biomass at the shallow depths were highest during the low oxygen period (June-July). Further, the species composition also showed a variation with the shallow stations completely dominated by two polychaete species, Magelona sp. and Paraprionospio sp. The deeper stations (41-102 m) were dominated by Paraprionopsio sp., Monticellana sp, Neomediomastus sp. Nemertenia and Amphipoda. The spatio-temporal variability of the macrofaunal community was confirmed by the SIMPROF cluster and SIMPER analysis. Functional traits also showed differences along the transect and seasonally. The community during hypoxia period was dominated by deposit feeders while carnivorous species dominated after the monsoon (October-December). Similarly, the deposit feeders dominated at shallow depths while the density of carnivorous increased with deeper water depth. BIOENV analysis indicates that the macrofaunal community (abundance, biomass and feeding guilds) showed significant positive relation with bottom water chlorophyll and phaeopigment. Our study shows that the variation in physico-chemical parameters and food availability interact and influence the macrobenthic community in seasonally hypoxic coastal habitat.

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MARINE MICROALGA TETRASPORA SP: ABUNDANCE, NUTRIENT AVAILABILITY AND INDICATION OF INTRACELLULAR LIPID AT VERAVAL

FISHING HARBOUR, GUJARAT, INDIA

A. B. Fulke*, M. Dey, A. Ram, R. Hardikar and S.N. Gajbhiye

CSIR- National Institute of Oceanography (CSIR-NIO), Regional Centre, Mumbai-400053; [email protected]

Globally, microalgae are being explored as a potential high-yield feedstock for bioprospection. The key focus of bioprospecting for microalga Tetraspora sp. (Chlorophyceae; average cell diameter 6-9µm) is to identify unique high intracellular lipids producing marine microalgae from west Veraval fishing harbour of Gujarat, India as is most abundant at nearshore stations from almost half decade. This study also appraises the Tetraspora species abundance, nutrient availability in the region and recent importance of this species are discussed.

Water samples for physicochemical parameters and phytoplankton were taken seasonally from three different nearshore stations (V1, V1A, V2) at Veraval. Salinity was determined by argentometric method, dissolved oxygen by winkler’s method and nutrients (DIP, DIN, Silicate) by standard spectophotometric methods (Grasshoff et al. 1983). Phytoplankton sample were collected in 500 ml of bottles by Niskin’s sampler and was fixed with 2% Lugol's iodine. For enumerating and speciation of phytoplankton sub-samples (100 ml) were enumerated under a microscope (40X magnification). For further confirmation of species samples has been analysed in 100 x magnifications (Olympus BX 53F) as well as in analytical research SEM (Zeiss, EVO 18) (Fig.1). We have used concentrated samples rich with Tetraspora cells for nile red (NR) staining(Fulke et al., 2010) and were analyzed for intracellular lipids content in the Tetraspora cells by fluorescence Floid™ Cell Imaging Station (Fig.1). Tetraspora sp. is contributing almost 90% of the total phytoplankton population at Veraval stations (Fig. 2).

Fig. 1 Tetraspora sp. from water samples preserved in Lugol’s iodine: a-f Cells and colony of Tetraspora sp. [pictures taken in Olympus BX53F (a-b) bright field, 100x; (c-d) DIC, 100x; (d)

Analytical SEM, Zeiss EVO 18, (e, f) cells expressing Nile red fluorescence for intracellular lipid droplets examined with a FLoid™ Cell Imaging Station (Life Technologies, France)+.

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Fig. 2: Decadal distribution of Tetraspora sp. and total phytoplankton population at 3 selected station in Veraval

Increasing trend was observed for the total number of Tetraspora population. During 2014 maximum average population (670 × 105 cells/L) was recorded from Veraval. Spearman rank correlation (r) and stepwise regression were used to evaluate the relation between environmental variable and both Tetraspora population with Statistica 7.0 and MINITAB version 13 package. Results showed only strong positive correlation with dissolved nitrate (r=0.417, p<0.007). Regressional equation with other parameters [Tetraspora population (No/L) = -1.25E+08 - 854465 Salinity - 1611635 DO + 6469986 Tw + 4254499 NO2 + 589319 NO3 - 123184 NH4 - 210383 PO4 + 1630458 SiO4] can only explain the variability of 56%. Present study discussed about the effect of various physico-chemical factors and their interactions on natural growth of Tetraspora sp at Veraval. Further, it also explores the enhanced understanding of the effect of nutrient availability on algae cell division and cellular composition like lipid. Henceforth, marine Tetraspora sp. biomass may be remarkable model strain for the commercial utilities like nutraceuticals products, biofuel and other value added products in future.

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ARE BORING SPONGES AN INCREASING THREAT FOR CORAL GROWTH IN MALVAN MARINE SANCTUARY?

Sambhaji Mote1, Kalyan De1, Vishal Patil1, Perisamy R1, Rahul Nagesh1, Sabyasachi Sautya2, Baban S. Ingole1*

1CSIR-National Institute of Oceanography, Dona Paula, Goa; [email protected]

2CSIR-National Institute of Oceanography, Regional Centre, Mumbai

Coral reefs are familiar to us for their impressive biodiversity, productivity and scenic beauty. Coral reefs are undergoing global decline due to numerous stress factors including climate-change related temperature anomalies, suspended sediments and various anthropogenic activity for coastal development that can detrimentally impact on coral health. Apart from this abundance of boring organisms are suggested to be a direct consequence of coral mortality. Clionoid (class Demospongiae, phylum Porifera) is one of major important siliceous sponges known to be bore into calcareous material/ substrata. Since Coral colonies and reefs form as calcareous skeletons, it is suggested that coral reefs are heavily invaded by boring sponges, which are playing a significant role to destruction of their physical structure. The boring sponge Cliona sp. is known to get overpower to the stressed coral which they overgrow at a fast rate.

In India, coral reefs are distributed in six regions viz. Gulf of Kutch, Lakshadweep, Gulf of Mannar, Palk Bay, Andaman and Nicobar Islands and the recently identified reefs of Sindhudurga coast in Maharashtra State. The Malvan Sanctuary (MMS) is one of the marine protected areas in India located in Sindhudurga District, Maharashtra State, Central West coast of India. There are few studies have been conducted to find out the boring sponge threats in Indian coral reefs. Hence we aimed to find the boring sponges and their effect on corals during our survey in Malvan sanctuary. We conducted underwater survey by SCUBA diving and snorkeling at 5 different locations in the Sanctuary in November 2014. The Belt Intercept Transect (BIT) survey method was used to study sponges and associated corals. Sponges were collected from each transect to identify coral sponge encrust. Sponges were identified using standard techniques such as spicule preparation by acid digestion and followed by scanning electron microscopy. Our result suggests Corals are currently invaded by boring sponges (2 species); being the coral reef framework the substrate most invaded followed by the rubbles and the living colonies. The results also indicated that boring sponges are promoting the dislodgment of live colonies and large fragments from the framework. The possible reasons are increased organic material and suspended material promoting the growth of boring sponges. This is the first report on boring sponge invasion to corals in Malvan Sanctuary.

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QUANTIFICATION OF PHYTOPLANKTON PHOTO-PHYSIOLOGICAL STATUS IN A MONSOONAL ESTUARY

J. S. Patil*, A. C. Anil

CSIR–National Institute of Oceanography, Dona Paula, Goa 403 004; [email protected]

In vivo chlorophyll fluorescence induction and relaxation technique measures a suite of photosynthetic parameters [initial, maximum and variable components of Photosystem II (PSII) fluorescence, quantum efficiency of photochemistry, functional absorption cross-section and the kinetics of electron transfer on the acceptor side of PSII] that can be used to assess the physiological status of the phytoplankton. Using this technique, phytoplankton physiological responses to environmental conditions from Dona Paula Bay, west-coast of India, was undertaken. This bay is influenced by distinctly higher runoff and rainfall during south-west monsoon (June–September) compared to post-monsoon (October–January) and pre-monsoon (January-May) season. Such a seasonality in the intensity of freshwater influx influences abiotic and biotic factors. Phytoplankton, which are heterogenous in form and function and also forming a basic link in aquatic food-web, are influenced by such environmental changes. In this study phytoplankton physiological responses were observed every day from October 2008 – May 2010 by quantifying chlorophyll, PSII parameters and environmental conditions at a fixed station in the bay. Results pointed out that the occurrences of chlorophyll peaks are more during monsoon (5 nos.) followed by post-monsoon (2-3 nos.) and pre-monsoon (1 no.). A good agreement between the chlorophyll and variable fluorescence measurements for each season was established. Variable fluorescence, quantum efficiency and functional absorption cross-section ranged up to 279 (relative units), 0.2 to 0.58 (dimensionless) and 178 to 511 Å2 quanta–1 respectively. The high and low values for all the parameters observed during monsoon were due to the changes brought in by the variations in the magnitude of freshwater influx. The variations in species composition and their physiological status could be the other factors influencing the PSII parameters round the year. An overview of these findings will be discussed and presented.

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SPATIO-TEMPORAL VARIATION IN ASSOCIATED FAUNA OF THE SPONGE CINACHYRELLA CAVERNOSA

A. Singh1, D.V. Desai1, N. L. Thakur1* 1CSIR -National Institute of Oceanography, Dona Paula, Goa 403 004; [email protected]

Sponges belong to the phylum porifera serve as habitats for various other fauna. Sponges are soft-bodied organisms having a network of inner channels forming the aquiferous system, which supports variety of organisms (crustacean, molluscs, echinoderms, protists, foraminifera etc.; Ribeiro et al. 2003, Neves and Omena 2004, Gaino et al. 2004, Henkel and Pawlik 2005, Mazzoli-Dias et al. 2007, Schejter et al. 2012).

This paper describes the temporal variation in abundance and diversity of associated fauna of the low intertidal sponge Cinachyrella cavernosa, collected from two different geographical regions: Mhapan, Maharashtra (15°55’27.48” N; 73°33’29.89” E) and Anjuna, Goa (15°34'34.99" N; 73°44' 23.89" E) on the central west coast of India.

A total of 23 annelid species, 7 species of arthropods, 2 species of molluscs and a species of coelentrata were found living inside C. cavernosa. Among them, Syllis sp., Exogone sp., Neries sp. and species belonging to family sabellidae and terebellidae of Annelida were the most frequent species found inside the sponges from both the locations. Several species of annelids (Syllis sp., Neries sp. and other species belonging to family phyllodocidae sabellidae, terebellidae, cossuridae, pisionidae, ampharetidae) and arthropods (species of family penaidae and class insecta) were found in various ontogenetic stages, which is suggestive of their commensalism type of association with the host sponge. The sponge (C. carvernosa) collected from two different locations showed significant difference in the diversity and abundance of associated fauna (p < 0.05). The diversity and abundance of sponge associated fauna was found to be higher in pre-monsoon months (March-April). The experiments in order to understand the role of sponge secondary metabolites in regulating the sponge-associated fauna are underway.

References: Gaino, E., Lancioni, T., La, Porta G., Todini, B. (2004), The consortium of the sponge Ephydatia flviatilis (L.) living on the common reed Phragmites australis in Lake Piediluco (central Italy),Hydrobiologia, 520(1-3), 165-178. Henkel, T.P., & Pawlik, J.R. (2005), Habitat use by sponge-dwelling brittlestars, Marine Biology, 146(2), 301-313. Mazzoli-Dias, M., Ribeiro, S. M., & Oliveira-Silva, P. (2007), Foraminifera associated to the sponge Mycale microsigmatosa in Rio de Janeiro State, south eastern Brazil: An initial approach, Porifera Research: Biodiversity, Innovation and Sustainability: Série Livros, 28, 439-442. Neves, G., Omena, E.P. (2003), Influence of sponge morphology on the composition of the polychaete associated fauna from Rocas Atoll, northeast Brazil, Coral Reefs, 22, 123-129.

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Ribeiro, S.M., Omena, E.P., Muricy, G. (2003), Macrofauna associated to Mycale microsigmatosa (Porifera, Demospongiae) in Rio de Janeiro State, SE Brazil, Estuar Coast Shelf Sci 57, 1-9. Schejter, L., Chiesa, I.L., Doti, B.L., & Bremec, C. (2012), Mycale (Aegogropila) magellanica (Porifera: Demospongiae) in the south western Atlantic Ocean: endobiotic fauna and new distributional information, Scientia Marina, 76(4), 753-761.

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RESPONSES OF PICOPHYTOPLANKTON COMMUNITY TO ENVIRONMENTAL CONDITIONS IN DIFFERENT ECOSYSTEMS

S. Mitbavkar*, A. C. Anil


Picophytoplankton (PP) are the smallest primary producers which form an important component of the phytoplankton community in estuarine, coastal and oceanic ecosystems, encompassing freshwater, brackish water, sea water and hypersaline waters. They also form important components of the marine biofilms. PP comprises two groups of cyanobacteria i.e., Prochlorococcus (PRO) and Synechococcus (SYN) and one group of eukaryotes i.e., picoeukaryotes (PEUK). While PRO is known to occur only in open ocean waters, SYN and PEUK are dominant in the coastal waters. Samples were collected from various ecosystems around India for enumeration of the PP community structure, distribution and abundance with respect to the environmental conditions. The PP community structure exhibited spatial and temporal variations depending on the prevailing environmental factors. In the estuarine waters, salinity gradients played an important role in the PP community structure wherein two groups of SYN were observed, one with phycoerythrin pigment (SYN-PE) dominant in the high saline waters downstream and the other with phycocyanin pigment (SYN-PC) dominant in the brackish and freshwater upstream. In hypersaline ecosystem (salinity > 35), SYN-PE was dominant followed by the PEUK whereas in freshwater ecosystems, SYN-PC was dominant. In the open ocean waters of the Arabian Sea and the Bay of Bengal, SYN, PRO and PEUK were observed, with SYN and PRO as dominant groups whereas in the coastal waters only SYN and PEUK were observed. PP distribution is also influenced by the physical forcing such as tides and freshwater influx in estuarine regions. These observations suggest that PP community structure varies across the different ecosystems depending on the environmental conditions.

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DISTRIBUTION OF CYST PRODUCING DINOFLAGELLATES FROM A MONSOON INFLUENCED TROPICAL EUTROPHICATED ENVIRONMENT

R. V. Rodrigues*, J. S. Patil, K. Sathish, A. C. Anil


Several species of dinoflagellate are capable of toxin production and are important from the harmful algal blooms (HABs) perspective worldwide. Most dinoflagellates produce resting cysts as part of their life cycle or survival alternatives in adverse environmental conditions and serve as seed bank. As a result, dinoflagellates are considered amongst the most unwanted marine bioinvaders. In order to study the distribution of cyst producing dinoflagellates in a given environment it is important to both vegetative forms (VF) and cyst stages and such investigations are limited along the Indian coast. In this study the VF of the cyst producing dinoflagellates from water column and cyst from recent surface sediments from a monsoon influenced eutrophic environment (Cochin port, south-west coast of India) were investigated during post monsoons (October 2011 and November 2012), pre monsoon (May 2012) and monsoon (August 2012). The abundance of VC varied from 89 to 2675 cells L-1 and cysts from 89 to 1721 cysts g-1 dry sediment. High cyst and VF abundance were observed during post-monsoon under high saline and low nutrient conditions whereas low abundance were observed during monsoon under low saline and high nutrient conditions.

In the water column a total of 52 species (29 phototrophic and 23 heterotrophic forms) of planktonic dinoflagellates belonging to 21 genera, were recorded. Out of 52 only 18 species are known to form cysts and their contribution on an average was up to 52% of total dinoflagellate abundance. In sediments, 35 species (18 phototrophic and 14 heterotrophic forms) of dinoflagellate cyst belonging to 14 genera were recorded. A comparison of VF and cysts data from the region reveals the presence of 40 species of cyst producing dinoflagellate. Of which only 13 species, with Pyrophacus steinii (phototropic) as the dominant form, were found both in the VF and cyst stages. Phototrophic and heterotrophic VF were dominant during non-monsoon and monsoon season, respectively. Whereas in the case of cysts, phototrophic forms were dominant during post-monsoon and monsoon, and the heterotrophic forms during pre-monsoon. Comparison with existing reports along the west coast of India indicated that the study region harbours higher cyst abundance. It has been observed that out of 61 cyst producing dinoflagellates only 19 were reported all along the west coast. This also includes the species (Alexandrium cf tamarense, Gonyaulax spinifera complex, Lingulodinium polyedrum, Protoceratium reticulatum, Scrippsiella trochoidea) known for their potential for causing toxic/harmful algal blooms.

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BIODIVERSITY PATTERNS OF MEIOBENTHOS FROM THE INDIAN OCEAN

IVY PEREIRA, B. S. INGOLE*

CSIR-National Institute of Oceanography, Dona Paula, Goa- 403004; [email protected]

Organisms and biological communities differ in a highly regular pattern along geographic gradients. Establishment of a database provides a scheme to aid in setting up conservation priorities as Biodiversity-Hotspots, the key areas and also to minister to our understanding the ecological and evolutionary processes in the sea. Based on the size of the juvenile stage meiobenthic organisms can be divided into permanent and temporary fauna.This review presents a distribution of permanent and temporary meiofaunal groups in the Indian Ocean, and thereby aid to mark up the eco-regions and also broaden our understanding of the biogeography of the dominant meiobenthic groups. We used the species distribution data of the five groups- Nematoda and Harpacticoida- temporary fauna and Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera and Tardigrada belong to the permanent fauna. Two taxonomic distinctness indices (∆+ and λ+) were used to analyse the diversity pattern. The jaccard and Theta cluster analysis was applied for the biogeographic similarity. A total of 177 nematode species belonging to 108 genera and 38 families have been recorded in this region. Most nematode species belonged to Desmodoridae (24 species) and the Xyalidae (21 species) family. 285 marine harpacticoid species belonging to 107 genera and 32 families have been recorded from the Indian Ocean. The family, Miraciidae having the highest (54 species) number of species followed by the Laophontidae (40 species). 10 families have been recorded in the Indian Ocean distributed over 103 gastrotrich species and 27 genera. The most speciose gastrotrich families are Thaumastodermatidae (34 species) and Chaetonotidae (18 species). A total of 47 marine tardigrade species belonging to 22 genera and 6 families have been recorded. Halechiniscidae having the highest (31 species) number of species. Thirteen Kinorhyncha species were distributed over 7 genera and 7 families. Echinoderidae had the maximum (5) species. Few species of Ganthostomulida were documented. The species belonged to genus Gnathostomula. Loricifera Rugiloricus renaudae sp. Nov is the only record in the Indian Ocean till date. The results depict cosmopolitan behaviour by majority of the meiofaunal groups despite the meiofauna dispersal paradox. The observed variation may be related to ocean circulation patterns, seafloor topography and insufficient data. To the best of our knowledge, the present study is the first to report the distribution pattern of dominant meiofaunal groups in the Indian Ocean. An important output of the study is identification of lacunae in the meiofaunal study from the Indian Ocean attributed to the scarcity of data. This is largely due to the lack of studies conducted considering the permanent meiofaunal groups.

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BACTERIOLOGICAL STUDY OF A COMMERCIAL AQUACULTURE POND OF LITOPENAEUS VANNAMEI ALONG SOUTH WEST COAST, INDIA.

Elaine A. Sabu*, Maria Judith Gonsalves, Sreepada A. R, Naseera K., Archana Naik and Ramaiah N.

CSIR-National Institute of Oceanography, Dona Paula, Goa; [email protected]

Aquaculture contributes a major share for sustainable fisheries sector in India. In the recent years, one of the traditionally cultivated shrimp species Penaeus monodon has been replaced by the imported Litopenaeus vannamei due to their better resistance to disease attack. The shrimp production rates, besides being dependent on the species of shrimp, is also related to the pond preparation, maintenance, water and sediment quality, commercially available probiotics, aeration etc. Bacteria – phytoplankton being part of the pond ecosystem play a role in shrimp production rates. Since, baseline data is essential for improving commercial pond management practices, a shrimp pond located near the mangrove regions of south west coast of India was selected for a study on the biogeochemical changes occurring during a production cycle.

Water and sediment samples were collected at regular intervals for the analysis of physico chemical and biological parameters during the production cycle of Litopenaeus vannamei. Estimation of ammonia, nitrite, nitrate, phosphate, dissolved oxygen, BOD5, total suspended solids were performed based on APHA (2005). Chl a and phaeophytin pigments were done following Parsons et al. (1984). Total organic carbon in sediment samples were analysed following the modified Walkley and Black method (Page et al. 1982). Biochemical analysis of the sediments was estimated following the procedures of Kochert (1978), Lowry et al. (1951) and Bligh and Dyer (1959) respectively. Various bacterial groups associated with the pond samples were enumerated using their respective media (Rodina, 1972).

In the pond used for this study the survival rates of the shrimps were 77.86% with an average shrimp weight of 20.83g. In this pond water, the average ammonia level was 0.078 ± 0.12µM, nitrite was 0.009 ± 0.12µM, nitrate was 0.212 ± 0.27µM and phosphate was 0.008 ± 0.004µM during the production cycle. These low levels of nitrogen may be due to applied probiotics and the dynamic cycling by the phytoplankton, heterotrophic bacterial population. The total heterotrophic bacterial plate counts in water were three orders lesser than those of the sediments. The heterotrophic bacteria outnumbered the anaerobes, sulphate reducing bacteria, nitrate reducers, sulfur oxidizing bacteria, methane oxidizing bacteria, and denitrifying bacteria. Organic carbon mineralization by heterotrophic bacteria (r=-0.748, p<0.05), (r=-0.703, p<0.05); sulphate reducers (r=-0.777, p<0.01), (r=-0.641; p<0.05) and total anaerobes(r=-0.777, p<0.01), (r=-0.873, p<0.01) was evident by a significant correlation of these groups with total organic carbon in water and sediment respectively. The different bacterial groups were significantly related to pond parameters indicating their role in driving pond dynamics. The above findings will provide the basis for the development of more advanced, eco-friendly bioremediators which can also improve harvest of shrimps with better nutritional standards for consumption.

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PICOPHYTOPLANKTON CONTRIBUTION TO THE PHYTOPLANKTON BIOMASS IN A MONSOON INFLUENCED TROPICAL ESTUARY

K. M. Rajaneesh*, S. Mitbavkar, A. C. Anil


Picophytoplankton (PP; cell size < 3 µm) is an important group of the phytoplankton community in terms of abundance and primary production in the marine environment. Although this group dominates the phytoplankton community in the open oligotrophic waters, its importance in the coastal waters is being recognized in recent years. However, there is not much information available on PP community structure and its contribution to the total phytoplankton biomass in the coastal regions of the Arabian Sea along the west coast of India. In view of this, an investigation was carried out from October 2010 to September 2011 along the salinity gradient (35 to 0) in the monsoon influenced Zuari estuary, Goa. Four groups of PP were identified and quantified; (1) Synechococcus containing phycoerythrin pigment (SYN-PE), (2) Synechococcus containing phycocyanin pigment (SYN-PC), (3) picoeukaryotes, and (4) Prochlorococcus-like cells based on flow cytometric analysis. PP biomass (< 3 µm) and phytoplankton biomass (> 3 µm) were estimated from the pigment chlorophyll a (chl a). Zuari estuary exhibited wide variations in environmental conditions which are attributed to fluctuations in rainfall during monsoon season and tides during the non-monsoon seasons. This was reflected in monthly variations of PP biomass and > 3 µm phytoplankton biomass. Annually, PP were a major component of the total phytoplankton biomass, contributing up to 41% of the total chl a, with the highest contribution during post-monsoon and lowest during monsoon season. PP biomass contribution was higher upstream during the monsoon and post-monsoon and downstream during the pre-monsoon season. Although lower in abundance, picoeukaryotes were the major contributors to the total PP biomass during different seasons due to their larger cell size. SYN-PE, the most abundant PP group contributed up to 90% to the total PP biomass at the estuarine mouth. High PP biomass in the Zuari estuary suggests that PP plays an important role in the food web dynamics of monsoonal estuaries in tropical regions.

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SALINITY INDUCED PHYTOPLANKTON DOMINANCE ALONG TAPI ESTUARINE ECO- SYSTEM

Prince Prakash Jeba Kumar. J* , Ragumaran.S, Sundararajan.S, Karupasamy.M,

National Institute of Ocean Technology, Pallikaranai, Chennai-600100; [email protected]

A study was carried out to understand the seasonal variation of water quality and phytoplankton diversity along the polluted stretch of Tapi river estuary for a period of one year. Significant seasonal variation recorded among the 10 stations spread along the study area. The phytoplankton were represented by Bascillariophyceae (60.1%), Dinophyceae (0.7%), Cynophyceae (17%), Chlorophyceae (21.6%), Chrysophycea (0.1%) and Xanthophyceae (0.5%). Among these organic pollution indicators like Skeletonema costatum (9493 - 11040 Nos./L ) & Cycloptella sp. (4373- 19200 Nos./L )belongs to Bascillariophyceae recorded typical dominance at non polluted station during premonsoon season of the year 2003. Identified salinity inducted dominance rather than the influence of organic content of the water body and supported by laboratory scale studies on electrophoretic mobility of euryhaline phytoplankton.

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DIVERSITY AND COMMUNITY STRUCTURE OF MACROBENTHOS ALONG THE SALINITY GRADIENT OF AN ANTHROPOGENICALLY STRESSED ESTUARY

J.T. Mulik, S. Sukumaran*, T.V. Vijapure, S.M. Salvi

CSIR-National Institute of Oceanography, Regional Centre Mumbai; [email protected]

Ulhas estuary, located on the west coast of India, is the recipient of uncontrolled discharge of pollutants from both point and non-point sources (Ram et al; 2009). Macrobenthic community structure combined with pertinent abiotic parameters were investigated from 12 stations along the salinity gradient of the estuary. Four sediment samples were collected for macrobenthos analyses using a van Veen grab of 0.04 m2 bite area. The benthic organisms were sorted to major taxa (phylum, order or class), enumerated and expressed as ind.m-2. At each station, bottom water samples were collected in duplicate for analyzing various physico-chemical parameters. Salinity, SS, DO, and nutrients were analyzed using standard methods (Grasshoff et al., 1999). PHc in water was measured with a fluorescence spectrophotometer (LS 3B Perkin Elmer) (IOC-UNESCO, 1984). Corg was analyzed by titration method (Walkey and Black, 1934) and sediment texture by combined sieving and pipette method (Buchanan, 1984).

Totally, 34 macrobenthic taxa were recorded. The dominant taxa, polychaetes (~73%), were then identified upto lowest possible level (Day, 1967; Fauvel, 1953). Univariate indices confirmed poor ecological health of the estuary especially in the mesohaline zone. Macrobenthos was completely absent at stations 8 and 9 situated in the middle estuary. This zone was characterized by high levels of nutrients and organic carbon coupled with low dissolved oxygen indicating that the estuary was highly eutrophic here. Four distinct groups, clearly segregated by the multi-dimensional scale (MDS) analyses (Fig 1A) indicated that salinity was a major influencing parameter.

Figure 1: Non-metric multidimensional scaling ordination of fourth root transformed macrobenthic abundance data (A) and abundance of Streblospio gynobranchiata

superimposed as bubbles (B).

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Macrofaunal abundance was highest (4700±4846 ind. m-2) in the middle zone and was dominated by the opportunistic polychaete, Streblospio gynobranchiata (61.6%)(Fig 1B) which was found to thrive in low oxygen conditions. Margalef’s richness index (d) correlated positively with salinity. All univariate indices correlated negatively with organic carbon and ammonia indicating anthropogenic impact on macrobenthic diversity. The BIO-ENV analyses indicated the combined influence of salinity, NO2

--N and NH4+-N on the distribution patterns

of macrobenthos of the Ulhas estuary (Table 1). Hence, it can be concluded that the macrobenthos community structure was influenced both by natural (i.e. salinity) as well as anthropogenic factors in tandem.

Table 1 : Results of BIO-ENV analyses. The variables marked in bold show the highest correlation.

No. Variables Spearman correlation()

1 Salinity 0.488

2 Salinity, NO2--N 0.454

3 Salinity, NO2--N, NH4

+-N 0.510

4 Salinity, NO2--N, NH4

+-N, SS 0.489

References: Buchanan, J.B., 1984. Sediment analysis. In: Methods for study of marine benthos (second edition) Holme NA and McIntyre AD) Blackwell Scientific publications, Oxford and Edinburgh, 1-65. Day, J.H., 1967. A Monograph on the polychaete of southern Africa, Part I (Errantia) and Part II (Sedentaria). Trustees of the British Museum, Natural History, London, pp. 1-878. Fauvel, P., 1953. Annelida Polychaeta. The Fauna of India including Pakistan, Ceylon, Burma and Malaya pp. 507. Grasshoff, K., Ehrhardt, M., Kremling, K., 1999. Methods of seawater analysis (Verlag Chemie), 1-419. IOC-UNESCO., 1984. Manual for monitoring oil and dissolved dispersed petroleum hydrocarbons in marine waters and on beaches. Manual and Guides No. 13, 1-35. Ram, A., Rokade, M.A., Borole, D.V., Zingde, M.D., 2009. Diagenesis and Bioavailability of mercury in the contaminated sediments of Ulhas Estuary, India. Marine Pollution Bulletin 58, 1685–1693. Walkey, A., Black, I.A., 1934. An examination of the Degtjareff method for determining soil organic matter and a proposed modification of the chromic acid titration method. Soil Science 37, 28-30.

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MACROBENTHIC ASSEMBLAGES OF TWO MARINE PROTECTED AREAS ALONG NORTHWEST COAST OF INDIA: DIVERSITY AND DISTRIBUTION

T.V. Vijapure, S. Sukumaran*, J.T. Mulik, V.R. Joshilkar, S. N. Gajbhiye

CSIR-National Institute of Oceanography, Regional Centre Mumbai; [email protected]

Malvan and Vadinar represent two coralline Marine Protected Areas (MPAs) along north-west coast of India which are considered as biodiversity hotspots that are impacted by different anthropogenic stressors. Vadinar coast is dotted by various oil and gas industries whereas Malvan faces threats of unbridled tourism. The current study investigated status of macrofaunal assemblages with associated hydro-sedimentological data at four stations each at both areas during the critical season i.e. April-May 2013.

Sediment samples were collected in quadruplicate using a van Veen grab of 0.04 m2 bite area. Benthic organisms were sorted up to higher taxa whereas polychaetes were identified up to family level (Day, 1967; Fauchald, 1977).Feeding guilds of polychaetes were determined as per Fauchald and Jumars (1979). Bottom water samples from each station were analyzed for various physiochemical parameters. Salinity, SS, DO, and nutrients were analysed using standard methods (Grasshoff et al., 1999). Sediment samples were studied for sediment texture (Buchanan, 1984) and organic carbon (Walkey and Black, 1934).

Macrobenthic abundances were comparable (Fig.1) at Malvan (1638±1498 ind.m-2) and Vadinar (1543±1676 ind.m-2). Polychaeta was the dominant taxon at both study areas (>65%) and was represented by 27 families in all. Observations on the trophic guilds indicated that the proportion of deposit feeders was more in Malvan whereas omnivores were higher in Vadinar stations (Fig.2).

Fig.1: Macrobenthic and polychaete abundances (error bars represent standard deviation)

Fig.2: Distribution (%) of polychaete feeding guilds

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Fig 3: Canonical correspondence analysis (CCA) ordination plot of 17 polychaete families, 8 stations,7 environmental variables. [Δ:Polychaete families; o:stations; →:environmental

variables]

Univariate indices indicated healthy ecological status of both the ecosensitive zones. One way ANOVA indicated that the Shannon’s diversity index at Vadinar *H’(log2)=3.1±0.2] was higher than that at Malvan *H’(log2)=2.6±0.1]. Possible reasons could be the restricted access to Vadinar MNPS as compared to the unregulated tourism activities at Malvan. CCA analysis (Fig.3) revealed salinity and sediment texture were major responsible factors for distribution of annelid polychaete fauna.

REFERENCES Buchanan, J.B., 1984. Sediment analysis. In: Methods for study of marine benthos (second edition) Holme NA and Mc Intyre AD) Blackwell Scientific publications, Oxford and Edinburgh, pp. 1-65. Day, J.H., 1967. A monograph on the polychaete of southern Africa, Part I (Errantia) and Part II (Sedentaria). Trustees of the British Museum, Natural History, London, pp. 1-878. Fauchald, K., 1977. The polychaetes worms, definitions and keys to the orders, families and genera. Natural History Museum of Los Angeles County Science Series 28, pp. 1-190. Fauchald, K., Jumars, P.A., 1979. The diet of worms: a study of polychaete feeding guilds. Oceanography and Marine Biology: an Annual Review 17, pp. 193-284. Grasshoff, K., Ehrhardt, M., Kremling, K., 1999. Methods of seawater analysis (Verlag Chemie), pp. 1-419. Walkey, A., Black, I.A., 1934. An examination of the Degtjareff method for determining soil organic matter and a proposed modification of the chromic acid titration method. Soil Science 37, 28-30.

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STUDY OF MACROBENTHIC ASSEMBLAGES ON SUBTIDAL NEARSHORE WATERS IN THE VICINITY OF ADANI POWER LTD MUNDRA, GUJARAT, INDIA

Santosh Kumar Singh, Anil Soni and Shivanagouda N. Sanagoudra*

Adani Power Ltd, Mundra, Gujarat; [email protected]

Spatial variation in the abundance of macrobenthic assemblages on subtidal costal zone is known to be related to different environmental variables. Seasonal of the studies have observed that along the costal gradient, Temperature and salinity is the most important environmental variable driving the patterns of the macrobenthic population and biomass assemblages. However, the great majority of studies have been done on Gulf of Kutch, systems in nearshore regions. Our study investigated the relationship between the macrobenthic assemblages in subtidal habitats and the environmental biotic and a-biotic variables along three coastal nearshore zones of Intake, Outfall and offshore monitoring controle sampling stations. From Intake to Outfall nearshore regions we sampled benthic macrofauna, salinity and sediments. The structure of the benthic assemblages was primarily related to salinity. There was a constant in the number of macrobenthic taxa from the Intake to the outfall regions in APL, indicating there is no deviation from nearshore diversity. There were important similarities of taxa abundance along different nearshore study stations. Temperature and salinity gradients which can be properly tested in study regions. Our study advocate that in order to adopt routine monitoring management practices it is essential to identify broad patterns and general rules governing coastal nearshore systems.

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SPATIAL VARIATION OF PHYTOPLANKTON PIGMENTS ALONG THE EASTERN ARABIAN SEA DURING THE ONSET OF SOUTH WEST MONSOON

Ayaz Ahmed*, Chandrasekhara Rao, Siby Kurian, Manguesh Gauns, Amara BM, Bhagyashri N, Hema Naik and S.W.A Naqvi

CSIR-National Institute of oceanography, Dona Paula Goa-403004; [email protected]

Arabian Sea experiences moderate to weak upwelling along the south west coast of India starting from May-June which subsequently propagates towards the north. An attempt was made to monitor the spatial variations in the distribution of phytoplankton groups based on marker pigments using chromatographic technique (HPLC) supported with microscopic and flow-cytometric analyses in the surface and sub-surface chlorophyll maximum (Chlmax) layer along a transect parallel to the coast (8° to 18°N) and perpendicular to the coast (off Trivandrum, TVM) in the eastern Arabian Sea during June, 2012. The depths of sub-surface chlorophyll maximum varied in the range of 10 to 55m. About 15 marker pigments (including fucoxanthin, peridinin, 19’-Hexanoyloxyfucoxanthin, 19’-Butanoyloxyfucoxanthin, zeaxanthin, alloxanthin, divinyl chlorophyll a (Div-chl a) etc.) were characterized by HPLC corresponding to seven major groups of phytoplankton community (diatoms, prasinophytes, chlorophytes, cryptophytes, chrysophytes, dinoflagellates and cyanobacteria,) derived in chemotaxonomic software (CHEMTAX). The concentration of total Chl a and fucoxanthin were higher (upto 5.2 and 2.4µg/l respectively) towards the south west coast of India (off TVM) whereas Div-chl a, marker pigment of Prochlorococcus sp. was present only in the northern stations. Pigment indices derived based on plankton size showed dominance of picoplankton (fpico) (upto 70% in few stations) followed by nanoplankton (fnano) along the northern stations. Contribution of microplankton (fmicro) was comparatively higher in the southern region (30-45%). Flowcytometric analysis of the picoplankton revealed two major types of cells (synechococcus and Prochlorococcus sp.) with carbon biomass ranging from 0.31 to 18.28 x109 and 0 to 0.85x109 ngC/lit respectively in the surface waters whereas the biomass ranged from 0.07 to 8.75x109 and 0 to 0.66x109

ngC/l respectively in the subsurface Chlmax. Abundance of synechococcus was higher towards the southern stations, while prochlorococcus was dominating in the northern region as evidenced by the marker pigment Div-chl a. Microscopic observation revealed the dominance of two major groups; diatoms and dinoflagellates with overall species count of 23 and 29. Quantitatively the diatom cell number along the N-S transect varied from 1.24 to 7.13×103 cells/l in the surface waters and 0.31 to 10.66 ×103 cells/l in the Chlmax with higher numbers towards the south. The cell numbers were much higher along the transect off TVM, which varied from 0.76 to 556.5×103 (surface) and 1.656 to 336.7×103cells/l in the Chlmax. CHEMTAX derived diatom contribution to the total chlorophyll a also showed higher values towards the south west coast of India with highest concentration along the transect off TVM (3.19µg/l in the surface and 2.78µg/l in the Chlmax). Our study clearly showed the dominance of diatoms along the south west coast of India during the onset of upwelling whereas the picoplankton dominance towards the north, which is evident from both chromatographic and microscopic/flow cytometric studies.

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SEASONAL INFLUENCE ON METHANOTROPHIC ABUNDANCE, ITS ACTIVITY AND METHANE PRODUCTION IN A TROPICAL MANGROVE ECOSYSTEM

Delcy R. Nazareth*, M-Judith Gonsalves

CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004; [email protected]

Coastal regions are potential zones for production of methane governed by ecological/ environmental differences or even sediment properties. Mangroves, one of the most productive coastal ecosystems, are characterized by high turnover rates of organic matter and nutrient recycling between the ocean and terrestrial habitats. Mangroves harbour highly reduced anaerobic sediments wherein, one of the processes that aid mineralization of organic carbon is methanogenesis. The methane produced is oxidized by methanotrophic bacteria. These potential biofilters quench the emission of this greenhouse gas and play a vital role in the methane cycle that gets influenced by season. Hence a study was conducted at a model site in a tropical mangrove region in Goa on the west coast of India to assess the influence of season and environmental variables on methanotrophic abundance, its pattern of distribution and its activity. Physico-chemical, sediment, biochemical and bacterial parameters were estimated by standard procedures. The influence of environmental variables on the abundance, production and activity was more marked during the monsoon season. During the monsoon season the methanotrophs were an order higher (1.02±0.47x105) than those during the pre-monsoon. This was corroborated by highest methane production during the monsoons which was positively influenced by TOC (r=0.65; p<0.001). Thus, indicating that methanogensis dominated the terminal pathway of organic carbon mineralization. Lowest methanotrophs and low production and activity rates was observed during the pre-monsoon season. This may be due to seasonal fluctuations which may have lead to changes in the reserves of TOC and the limited methane supply during the summer season. During the pre-monsoon, salinity influenced methane production (r= 0.81; p<0.001) suggesting a co-existence of processes like sulphate reduction and methanogenesis in the presence or absence of non-competitive substrates however, such an influence was absent in the monsoon and post-monsoon seasons. Maximum methanotrophic activity of 1.3x10-4cell-1hr-1 was during the post monsoon which was influenced by TOC (r=0.59; p<0.05). Generally, methane production showed an increasing trend with depth while methanotrophic population and its oxidation decreased with depth. The high methane oxidation rates at the surface, is supported by the presence of a loose organic layer at the surface of the sediment core. Depth wise variation, in these sediments was driven by oxygen permeability and organic matter availability. In general, the methanotropic abundance, its activity and methane production were governed by seasonal influence as evident from the impact of different environmental variables during different seasons.

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TEMPORAL AND SPATIAL VARIATION IN THE ZOOPLANKTON DISTRIBUTION AND ABUNDANCE IN THE ZUARI ESTUARY, WEST COAST OF INDIA

Dattesh V Desai*, Dayakaran P, Monteiro MC, Anil, A.C.

CSIR-National Institute of Oceanography, Donapaula, Goa-403004; [email protected]

Zooplankton are the important component of the aquatic food chain. They are heterotrophic animals and link the microbial food web to the classic food chain, and transfer materials and energy from primary producers to higher tropical levels. They inhabit almost all aquatic habitats ranging from fresh water to estuaries to open ocean. Estuaries are dynamic environment where tidal mixing and fresh water input create large variations in physico-chemical parameters which may affect plankton community composition. In the present study temporal and spatial variability in major groups of zooplankton was studied in the Zuari estuary during pre-monsoon, monsoon and post monsoon seasons at four stations namely Dona Paula, Cortalim, Borim and Sanvordem representing the upstream, middle and downstream region along the estuary. Besides zooplankton sampling, observations were also made on the physico-chemical parameters such as temperature, salinity, dissolved oxygen, suspended particulate matter and chlorophyll to examine their influence on distribution and abundance of major zooplankton groups. The salinity varied from near freshwater to 34psu in the estuary and the abundance and biomass of zooplankton was lowest during low saline conditions. Spatially, zooplankton showed large variation in the upper mid stations (Cortalim and Borim) and least in the downstream station (Dona Paula). In Sanvordem, which is the upstream station, the biomass and abundance was lowest and this can be attributed to very low salinity or near freshwater conditions. Among zooplankton, calanoid copepods contributed maximum to the total abundance followed by cyclopoid and harpecticoid copepods. Copepods were abundant at all salinity ranges exhibiting wide tolerance. Meroplanktons were abundant during non-monsoon months and their abundance coincided with high chlorophyll. The results indicated that changing environment with seasons played an important role in the distribution and abundance of zooplankton.

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VARIATION IN THE CULTURABLE VIBRIO CHOLERAE ABUNDANCE ALONG THE COAST OF INDIA

Lidita Khandeparker*, Gardade L, Kuchi N, Eswaran R, Hede N, Mapari, K.E., Anil, A.C.


Vibrio cholerae has been identified as one of the important pathogenic bacteria that could be translocated through ships’ ballast water from the waters along the subcontinent of India. In view of this, under the Ballast Water Management Program – India (BAMPI), quantification of culturable Vibrio cholerae from different port environments is underway. In this paper, we present the overview of variations in the abundance of V. cholerae from the ports of Mangalore and Kochi. The results from previous studies carried out at Goa and Vishakhapatnam are taken for comparison. Water samples for the quantification of V. cholerae were collected during different seasons viz., Pre-monsoon, Monsoon and Post-monsoon. V. cholerae are ubiquitous in aquatic environments but they are however known to prefer fresh to brackish waters conditions. The observations in these localities showed that the highest abundance was in the post-monsoon season in New Mangalore port (3.03 x 104 CFU ml-1) which is a coastal marine environment where as Kochi port, which is located within the backwaters had highest abundance during the pre-monsoon season (3.67 x 103 CFU ml-1). Observations carried out in Vishakhapatnam and Goa point out high abundance during the monsoon season. Such spatial variation point out that the ecosystem functioning plays an important role in the dynamics of V. cholerae. In view of this, elucidating the variations of V. cholerae population should include, in addition to the environmental factors, the influence of planktonic population, organic matter and nutrient flux.

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DISTRIBUTION AND ABUNDANCE OF MACROBENTHOS FROM MANGALORE PORT

Dattesh V Desai*, Atchuthan P, Noyel V, Anil, A.C.


Benthos are the bottom living communities which play an important role in aquatic ecosystems, such as mixing of sediments, flux of oxygen into sediments and cycling of nutrients and also important in secondary production. Invasion of aquatic organisms through ships' ballast water is considered as a major threat to the biodiversity of world's oceans. During the port biological baseline survey for Ballast Water Management Program, a study was conducted to understand the abundance and community pattern of soft bottom macrobenthic organisms over different seasons in and around Mangalore port. The macrobenthic biomass was maximum during pre-monsoon and minimum during post-monsoon season. It was observed that the higher biomass during pre-monsoon was contributed by the occurrence of pelecypods (gastropods). The abundance was higher during post monsoon, followed by pre-monsoon and monsoon season. Sand was the dominant component of the sediment followed by silt and clay, however, their percentage varied seasonally. Contribution of macrobenthic polychaetes was maximum to the total abundance followed by amphipods and molluscs. The organic carbon which is an important indicator of benthic conditions was higher during post-monsoon season, which is also coincided with higher abundance of macrobenthic organisms.

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RESPONSE OF VIBRIO SPP. TO VARIATIONS IN SALINITY AND TEMPERATURE: ELUCIDATION THROUGH PROTEIN PROFILING

Lidita Khandeparker*, Barnes N, Anil, A.C.


Estuaries are considered as environmental hotspots owing to increased anthropogenic pressures and are known for their rich biodiversity. The interactions between biotic and abiotic factors in this unique environment provide the opportunity to study the response of organisms to various perturbations. We explored spatio temporal variations in the Vibrio spp. (Vibrio cholerae, Vibrio parahaemolyticus, Vibrio alginolyticus) along the transect from the mouth to the head of the Zuari estuary. Microcosm experiments were conducted to evaluate the influence of changes in salinity and temperature on their viability. Response of Vibrio spp. differed with salinity and temperature. V. alginolyticus could survive under varying conditions of salinity and temperature to a greater extent than V. cholerae and V. parahaemolyticus. The protein profiles of bacteria evaluated using MALDI-TOF Mass Spectrometry revealed intraspecies variations.

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MOLECULAR DIVERSITY OF CHROMOPHYTIC PHYTOPLANKTON ASSEMBLAGES FROM SUNDARBANS MANGROVE ECOREGION BASED ON

RBCL GENE SEQUENCING

Brajogopal Samanta and Punyasloke Bhadury*

Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, Nadia, West Bengal; [email protected]

The Sundarbans represent the world largest contiguous mangrove ecosystem located at north-west of the Bay of Bengal, encompasses over 102 islands with a network of innumerable rivers, rivulets, and creeks. This vast deltaic region is formed at the estuarine phase of the Ganges-Brahmaputra and Meghna river system across India and Bangladesh. Phytoplankton is the important constituent of aquatic primary production in Sundarbans wetlands. The phylogeny and diversity based on the amplification and sequencing of rbcL, the large subunit encoding the key enzyme RuBisCO was investigated coupled with traditional microscopy for improved understanding of the community structure and temporal trends of chromophytic phytoplankton assemblages in the Indian part of Sundarbans. Diatoms (Bacillariophyceae) were by far the most frequently detected group in clone libraries as also based on microscopy, consistent with their importance as a major bloom-forming group. Other major chromophytic algal groups including Cryptophyceae, Haptophyceae, Pelagophyceae, Eustigmatophyceae and Raphidophyceae which are important component of assemblages were detected for the first time from Sundarbans based on rbcL approach, but not using microscopy. Many of the sequences from Sundarbans rbcL clone libraries showed identity with key bloom forming diatom genus such as Thalassiosira Cleve and also confirmed by microscopic observations. Principal coordinates analysis showed temporal pattern of OTUs distribution across the study area as also confirmed by other statistical approaches. Additionally, using cultured approach, a new species of diatom, Thalassiosira sundarbana was isolated and described from the study area and this species was found to constitute an important component of the chromophytic phytoplankton assemblages in Sundarbans. This study applied molecular and microscopic tools to delineate chromophytic phytoplankton assemblages in Indian part Sundarbans ecoregion.

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INFLUENCE OF UPWELLING ON THE DISTRIBUTION OF BACTERIA AND ARCHAEA IN PERSISTENT MUDBANK REGIONS OF ALLEPPEY, SOUTHWEST

COAST OF INDIA

Appukuttan V. Sheeba, Saumya Nair, Diana Mathew, Gireesh TR, Abdulaziz Anas*

CSIR- National Institute of Oceanography, Regional Centre Kochi; [email protected]

Mudbanks, a unique feature that appears along the southwest coast of India during southwest monsoon season, are characterized by calm water even during very rough monsoon, turbid seawater and copious fish catch [Gopinathan and Qasim, 1974]. Mudbanks are reported to form during or immediately after southwest monsoon [Varma and Kurup, 1969]. Mudbanks in coastal waters of Kerala are classified as persistent or non-persistent based on their activity and sustenance. The mudbanks of Alleppey activated during monsoon are probably sustained throughout the year with decreasing intensity [Narayana et al., 2008]. The complexity of mudbank formation and its unique water quality has always attracted the researchers. However, the response of microorganisms to these environmental changes is hitherto not studied. In the present study, we monitored the influence of upwelling on distribution of bacteria and archaea in mudbank regions of Alleppey for six months (April to September 2014).

Water samples were collected from three stations M1 (average depth 5 m), M2 (average depth 5 m) and M3 (average depth 11 m) at different depths at subsurface, 3 m, 5 m, 9 m and 11 m using a 5L capacity Niskin water sampler. (Fig. 1). Stations M2 was designated as persistent mudbank region based on previous report, while M1 and M3 were the controls for coastal and oceanic. The nutrient characteristics of water were analyzed following standard protocols [Grasshoff et al., 1983]. Abundance of eubacteria and archaea was determined using fluorescent in situ hybridization (FISH) technique. There was no significant spatial and temporal difference in the abundance of eubacteria. In accordance with the development of hypoxic conditions, there was an enhancement in the archaeal abundance at the two coastal stations (M1 and M2), while such an increase was not evident at M3 (Fig. 2). An increase in archaeal distribution from coastal to oceanic region was reported earlier [Karner et al., 2001; Massana et al., 2000]. Here we observed increased abundance of archaea in coastal regions during mudbank and this may be associated with upwelling, which could transport archaea from oceanic to coastal waters. In short, the present study shows that the upwelling has a strong influence on the distribution of eubacteria and archaea in the mudbank region of Alleppey.

References: Gopinathan, C. K. & Qasim, S. Z. (1974). Mud Banks of Kerala- Their formation & Characteristics. Indian Journal of Marine Sciences 3, 105 - 114. Grasshoff, K., Ehrhardt, M. & Kremling, K. (1983). Methods of seawater analyses. Verlag Chemie. Weinheim, Germany 511, 342-355.


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Karner, M. B., DeLong, E. F. & Karl, D. M. (2001). Archaeal dominance in the mesopelagic zone of the Pacific Ocean. Letters to Nature 409, 507 - 510. Massana, R., DeLong, E. F. & Pederos-Alio, C. (2000). A few cosmopolitan phytotypes dominate planktonic archaeal assemblages in widely different oceanic provinces. Applied and Environmental Microbiology 66, 1777 - 1787. Narayana, A. C., Jag, C. F., Manojkumar, P. & Tatavarti, R. (2008). Nearshore sediment characteristics and formation of mudbanks along the Kerala coast, Southwest India. Estuarine, Coastal and Shelf Science 78, 341 - 352. Varma, P. U. & Kurup, P. G. (1969). Formation of the Chakara (mudbank) on the Kerala coast. Current Science 38, 559 - 560.

Figure 1: Study area showing sampling locations.

Figure 2: Relative abundance of archaea compared to bacteria in stations M1, M2 and M3 during the study period

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RESPONSE OF PHYTOPLANKTON COMMUNITY TO MONSOON INDUCED HYDROLOGICAL VARIATIONS IN THE ALLEPPEY MUDBANK REGION,

SOUTHWEST COAST OF INDIA

Madhu.N.V*, Ullas. N, Ashwini.R, Jyothibabu. R, Muraleedharan. K.R, Balachandran. K. K

CSIR-National Institute of Oceanography, Regional Centre, Kochi-18; [email protected]

Changes in the structural and functional properties of phytoplankton (biomass, abundance and composition) in response to the upwelling was investigated in the coastal waters of Alleppey, a region of recurring mud bank manifestations. The presence of cold (<27°C), high saline (>34), oxygen deficient (<50µM) subsurface waters with high nitrate-

NO3-N (>4µM) and phosphate PO4

-P (>1µM), perceived along the coastal waters (<15m depth) off Alleppey apparently indicates the signatures of upwelling during the southwest (SW) monsoon 2014. Prior to this period (April-May), the coastal waters were characterized by dominance of nanophytoplankton (2-20µm), mainly belonging to pennate diatoms (Thalassionema nitzschioids, Navicula directa, Pleurosigma normanii etc). During peak SW monsoon period (July), there was a community shift as micro-phytoplankton (20-200µm) formed the major contributors (>70%) of chlorophyll a. Multi-species proliferation of diatoms (>20µm) such as Coscinodiscus radiatus, C. centralis, Biddulphia sp., Fragilaria oceanica etc was in the response to the sudden increase in the availability of inorganic

nutrients (NO3-N and PO4

-P) caused by the monsoon upwelling. Furthermore, Fragilaria oceanica, a pennate diatom found to develop as a bloom (>200 x 103 cells L-1) over the entire sampling area for one month period (July), till the signatures of strong upwelling subsided. In September, with the weakening of upwelling, the water column became vertically mixed, oxygen saturated, favouring simultaneous growth of both nano- and microphytoplankton community. This short-term variability may certainly enforce critical constraints for pelagic heterotrophs whose survival depend on nano-and microplankton distribution in quality.

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SULFUR OXIDIZING POTENTIAL IN THE MANGROVE CLAM POLYMESODA EROSA

T.R.A. Thomas, P. A. Lokabharathi*

CSIR-National institute of Oceanography, Dona Paula, Goa; [email protected]

Mangrove swamps constitute one of the most productive ecosystems in the world. The sediments here are rich in organic matter and diversity of species. Continuous degradation of organic matter in these sediments leads to the formation of thick anaerobic zones in the subsurface. Consequently infauna have evolved physiologically to counter the effects of various reductants that keep accumulating. Polymesoda erosa is an exclusive mangrove clam found towards the high tide region burying >70% of its body in the suboxic to anoxic sediment. Therefore we probed the following questions. (1) Do these clams possess sulfide oxidizing potential?. (2) Is this potential due to the bacterial associates?. (3) What would be the their abundance and rate of activity?. (4) What are the major groups?. In order to answer these questions we examined these clams from Chorao mangrove forest for the abundance of associated bacteria in the gill, foot and mantle. Their rate of activity was measured using a stable model compound such as thiosulfate both in the tissues and ambient sediment

Figure 1: (a)Thiosulfate utilization rate of Polymesoda erosa (b) and the ambient sediment [NB –ve values indicate utilization rate and +ve values release rate of thiosulfate]

Thiosulfate utilizing bacteria and activity were detected in all the tissues tested. The observed activity were 5 to 20 times higher in tissues than the ambient sediment. Relatively higher rate of thiosulfate uptake shown by gill (308 µM/hr/g dry wt.) (Figure 1a) could be due to the retention of more sulfur oxidizers like cells (7.91x106) and thiosulfate oxidizing bacteria (2.68x105) (Table 1). In the adjoining sediment maximum rate (80µM/hr/g dry wt.) was observed at 6-8 cm depth (Figure 1b). Coccoid cells with a diameter ranging from 1 to 3 microns and rhodococcoid type cells were encountered in the gills. Though the identity of culturable fraction is yet to be discerned, metagenomic data revealed the presence of unculturable species belonging to the genus Marinobacter and the order Oceanospirillales.

-400

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Time (Min.)

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Unculturable coccoid bacteria belonging to these groups have known to perform chemolithoautotrophy (Kuhn et al., 2014; DeLorenzo et al., 2012; Cao et al., 2014). Autotrophic orders such as chromatiales and thiotrichales which are capable of sulfide oxidation were also present (Thomas et al., 2014). Majority of the sequences belonged to γ-Proteobacteria. On the contrary, in sediment, α-Proteobacteria dominated. Prevalence of these thiosulfate oxidizing α-Proteobacteria have also been reported from other marine sediments and hydrothermal vents (Teske et al., 2000). Though there was considerable difference in the microbial community of the sediment and the gill, uncultured fraction of certain bacterial group and Proteobacterial species were common. Their functions are yet cryptic. Preliminary experiments on carbon fixation rates at the expense of thiosulfate showed that the tissues were able to fix upto 1µM/hr/g dry wt. and sediment only about 0.2nM/hr/g dry wt.

Table 1. Range of Abundance of bacteria in gill, foot, mantle and sediment

Parameters Gill Foot Mantle Sediment (surface)

TC (/gm dry wt) 3.24x106-1.45x10

8 1.56x10

7-3.56x10

7 7.31x10

7-1.35x10

8 9.67x10

6-1.26x10

7

TVCa(/gm dry wt) 9.29x105-1.22x10

7 4.01x10

5-1.86x10

6 3.22x10

6-2.91x10

7 3.56x10

6-8.08x10

6

TVCan(/gm dry wt) 2.14x106-3.66x10

7 1.80x10

6-5.75x10

7 4.04x10

6-1.60x10

7 3.15x10

6-8.13x10

6

SO (/gm dry wt) 8.11x105-1.50x10

7 0-3.69x10

6 0-1.26x10

6 Not Present

MPN (/gm dry wt) 1.35x105-4.00x10

5 1.45x10

5-1.48x10

5 1.24x10

5-1.85x10

5 0.89x10

2-6.81x102

TC: Total count; TVCa: Total viable aerobic count; TVCan: Total viable anaerobic count; SO: Sulfur oxidizers like coccoid cells; MPN: Most probable number of thiosulfate oxidizers

The present study shows the thiosulfate utilization potential of the bacterial associates of the mangrove clam P. erosa which reflects their role in sulfide oxidation. Since the bacterial community in the gill, foot and mantle tissues are capable of thiosulfate utilization, they could serve in the detoxification of sulfide in the ambient mangrove sediment. Both sediment and tissue with their bacterial associates could potentially act as sink of CO2 as carbon fixation couples with thiosulfate oxidation.

References: Kuhn, E. et al. (2014), Brine assemblages of ultrasmall microbial cells within the ice cover of Lake Vida, Antarctica, Applied and environmental microbiology, 80, 3687–98. DeLorenzo, S. et al. (2012), Ubiquitous dissolved inorganic carbon assimilation by marine bacteria in the Pacific Northwest coastal ocean as determined by stable isotope probing, PloS one, 7, e46695. Cao, Y. et al. (2014), Novel psychropiezophilic Oceanospirillales species Profundimonas piezophila gen. nov., sp. nov., isolated from the deep-sea environment of the Puerto Rico trench, Applied and environmental microbiology, 80, 54–60. Thomas, F. et al. (2014), Rhizosphere heterogeneity shapes abundance and activity of sulfur oxidizing bacteria in vegetated salt marsh sediments, Frontiers in Microbiology, 5, 1-14. Teske, A. et al. (2000), Diversity of Thiosulfate-Oxidizing Bacteria from Marine Sediments and Hydrothermal Vents, Applied and environmental microbiology, 66, 3125.

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MULTIPLE ANTIBIOTIC RESISTANCES AMONG VIBRIO CHOLERA ISOLATED FROM COCHIN ESTUARY, SOUTHWEST COAST OF INDIA

Vijitha Vijayan1, Abdulaziz Anas1*, Sneha K.G1 , Anila Chandran1, Jasmin C1, Shanta Nair2

CSIR- National Institute of Oceanography Regional Centre, Cochin, Kerala 682018; [email protected] CSIR- National Institute of Oceanography (NIO), Dona Paula, Goa 403004

Vibrios form an important group of microorganisms in marine environment owing to their diverse ecological functions, ranging from participation in nutrient cycles to metamorphosis of organisms. There are at least twelve Vibrio species known to be pathogenic to human beings, amongst which V. cholerae remains the principal diarrhoeal human pathogen. Notably, the last decade has witnessed a 50 % rise in the incidence of cholera. In 2011 alone, WHO recorded 37 cholera outbreaks in 30 countries across the world predominantly in Africa [WHO, 2012]. Health risks evoked by these organisms are further aggravated by their multiple antibiotic resistances which make the therapy difficult. Recent studies have proposed that these organisms have evolved from an oral-faecal transmission linear model of a waterborne pathogen and human host, to a more complex ecological model of an infectious disease due to the effect of anthropogenic climate changes[Sedas, 2007]. This has become a grave environmental concern as it can influence the human and environmental health adversely.

In the present study we report the antibiotic resistance profile and presence of virulence genes in V. cholerae isolated from the Cochin estuary (CE) during the monsoon and post monsoon seasons. V. cholerae was isolated on TCBS agar medium and the identity was confirmed through fatty acid profile analysis. Antibiotic resistance profile was analyzed in Mueller Hinton solid medium following standard disc diffusion (Kirby-Bauer) method. Representative antibiotic discs belonging to inhibitors of cell wall synthesis (Ampicillin 25mcg and Vancomycin 10mcg), nucleic acid synthesis (Azithromycin 15mcg, Chloramphenicol 15mcg, Gentamycin 30mcg, Oxytetracycline 30mcg and Tetracycline 10mcg), and protein synthesis (Ciprofloxacin 30mcg, Nitrofuratoin 100mcg, Nalidixic acid 25mcg and Trimethoprim 10mcg) were used. Multiple Antibiotic Resistance Index (MAR index) was expressed as a ratio of number of antibiotics to which an isolate was resistant to total number of antibiotics tested. The presences of toxigenic genes toxR in the isolates were studied by standard PCR technique using gene specific primer. The comparison of fatty profile of V. cholerae resistant to cell wall synthesis class of antibiotics with sensitive isolates is also being reported.

The isolates were classified into low (MAR index < 0.25), medium (MAR index 0.25 – 0.5), high (MAR index 0.5 to 0.75) and extreme (MAR index 0.75 – 1.0) antibiotic resistant based on their MAR index. Majority of the V. cholerae isolated from monsoon (63 %) and post monsoon (56 %), showed high and medium (33 % of isolates from both monsoon and post monsoon) levels of resistance against the antibiotics tested. A low level of antibiotic resistance was observed among limited number of isolates. All the isolates showed resistance against cell wall synthesis inhibiting glycopeptidase class of antibiotic, Vancomycin, and 80 % were resistant against ampicillin belonging to β-lactamase class.

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More than 60 % of isolates from both seasons showed resistance against protein synthesis inhibiting class of azithromycin and tetracyclin. Interestingly resistance against protein synthesis inhibiting chloramphenicol was observed in less than 20 % of isolates. Resistance against nucleic acid synthesis inhibiting antibiotics, Nalidixic acid and trimethoprim, was observed among 20 % of isolates. Although there was no significant difference in the composition of signatory fatty acid profile between V. cholerae isolates resistant and sensitive to cell wall synthesis inhibiting antibiotics, we observed major changes in the proportion of fatty acids such as 16:1 ω7c/16:1 ω 6c (Palmitoleic acid / palmitic acid ) followed by 18:1 ω 7c ( Cis- Vaccenic acid). PCR results showed that all the V. cholerae isolates harbored toxR gene. Hence it is assumed that these isolates could be pathogenic to humans and animals. In short the present study reports multiple antibiotic resistances among V. cholerae isolated from CE. This may lead to a critical clinical dilemma, if the environmental conditions favor the outbreak of cholera by these organisms. The broad antibiotic resistance indicates that these organisms are of terrestrial origin and hence further studies are necessary to understand the prevalence of multiple drug resistant V. cholerae in CE and urgent control measures may be taken to prevent microbial pollution in the estuary.

References: 1. WHO (2012) Weekly epidemological record. Geneva: World Health Organization. 31 - 32 31 - 32. 289 - 304 p. 2. Sedas VTP (2007) Influence of environmental factors on the presence of Vibrio cholerae in the marine environment: a climate link. Journal of Infections in Developing Countries 1: 224 - 241.

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DYNAMICS AND DISTRIBUTION OF BACTERIA AND VIRUS IN KRISHNA GODAVARI BASIN, BAY OF BENGAL

Aswathy Vijaya Krishna, Anwesha Sarkar, Jasna Vijayan and Parvathi A*

CSIR-National Institute of Oceanography - Regional Centre, Kochi, 682018; [email protected]

Microbial dynamics, especially viral dynamics has been rarely investigated in the Krishna-Godavari (KG) basin of Bay of Bengal. We report dynamic patterns of free living viruses and heterotrophic bacteria in response to a variety of environmental parameters in coastal and offshore waters of KG basin. All in all, we observed that there were marked seasonal and vertical variations in abundances of bacteria and virus. Environmental factors varied significantly with depth and distance from the shore that strongly influenced the biological interactions between bacteria and virus. The culturable bacteria was mainly constituted by Vibrio sp., Aeromonas sp., Staphylococcus sp., Corynebacterium sp., Streptococcus sp., Pseudomonas sp., and Neisseria sp. This poster gives a first insight on viral and microbial ecology of KG basin during spring inter monsoon period.

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MULTIPLE ANTIBIOTIC RESISTANT VIBRIO HARVEYI ISOLATED FROM PENAEUS MONODON LARVAL REARING SYSTEMS OF SOUTH INDIA

Somnath S. Pai1,2, R. Preetha1,3, N.S. Jayaprakash 1,4, A. Anas1,5, I.S. Bright Singh1* 1National Center for Aquatic Animal Health, Cochin University of Science & Technology, Fine Arts Avenue,

Kochi, 682016, Kerala, India; [email protected] 2Current Address: Amity Institute of Virology & Immunology, Amity University, Sector 125, Noida, 201313,

Uttar Pradesh 3Current Address: Department of Food Process Engineering, School of Bioengineering, SRM University,

Kattankulathur, 603203, Tamil Nadu 4Current Address: Center for Bioseparation Technology, Vellore Institute of Technology, Vellore, 632014, Tamil

Nadu 5Current Address: National Insitute of Oceanography, Regional Centre, Kochi, 682014, Kerala, India

Vibrio harveyi is a principal pathogen of shrimps in culture and antibiotics are used for its control. The aim of this study was to assess the extent of antibiotic resistance in wild strains of this bacterium isolated from shrimp larval rearing systems. Eighty seven strains of V. harveyi of luminescent bacteria were isolated from rearing water, larvae and other points of shrimp hatchery from two shrimp larval rearing units located in Kakinada, Andhra Pradesh and one in Kochi, Kerala. Their sensitivity to 81 antibiotics encompassing various classes was evaluated by disc-diffusion assay and their resistance profile was evaluated by Multiple Antibiotic Resistance (MAR) index. The average MAR index for all isolates obtained

was 0.63 and they were highly resistant to antibiotics belonging to the classes -lactams, macrolides, tetracyclines, sulfonamides, and quinolones/ fluoroquinolones. They were most sensitive to aminoglycosides. The high MAR index of the isolates indicated that they were being exposed to sub-lethal levels of antibiotics in shrimp hatcheries leading to the selection of MAR strains of V. harveyi. The study shows that MAR variants of V. harveyi are dominant in shrimp hatchery environment and are associated with larval mass mortality. This information coupled with the ban on the use of certain antibiotics in shrimp culture, considerably limits the choice of antibiotics for use against these organisms thereby necessitating an urgent requirement of alternative therapeutics.

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ADENOSINE TRIPHOSPHATE IN THE WATERS OF WEST COAST OF INDIA-AN INDICATOR OF LIVING MICROBIAL BIOMASS

Anindita Das1,2, Christabelle EGF-C1, Sheryl OF1, Sunita Pandey1 Dhillan Vellip1 and LokaBharathi PA1*

1 CSIR- National Institute of Oceanography, Dona Paula, Goa-403004; [email protected]

2 Dass Scientific Research Laboratory Pvt. Ltd., Ahmedabad, Gujarat

The west coast of India is affected by various coastal forces like seasonal hypoxia and anthropogenic inputs. Many parts are rich in placers and are targets of mining. Constant changes in landscape are drastic and result in altering changing the activity patterns of biota. These changes are even discernible at the microbial level Adenosine triphosphate (ATP) is a biological energy currency and an excellent indicator of living and active microbial biomass. The measurement of microbial ATP indicates the energy equivalent of all the living microbiota in a given natural system. It is important in itself and in combination with other microbial and biogeochemical parameters. We hypothesize that the distribution of ATP in the waters of west coast of India could throw significant light on the seasonal layering patterns and might relate to secondary or tertiary levels of production. In this paper we report the ATP distribution in the coastal waters of Goa and Ratnagiri along the west coast of India. The samples were collected and analysed from Sagar Sukti cruises SaSu138 (Goa, April 2007), SaSu155 (Goa, October 2007), SaSu174 (Ratnagiri, May 2008) and SaSu176 (Goa, May 2008). Samplings were done at depths of 1, 5, 15, 25, 50 and 100m below sea surface. Water samples (500ml) were filtered immediately on-board on 0.22µm white cellulose nitrate filter papers. These filter papers were subjected to extraction in TRIS-HCl buffer of pH 7.8 and stored at -15 to -20°C till analyses in the laboratory. The analysis of ATP was done by luciferin-luciferase reaction in a BMG Optima Luminometer. The relative light units (rlu) obtained were converted to equivalents of ATP expressed as ng l-1. ATP was detected in all the samples and ranged from 103-104 ng l-1. Variations among depths were arithmetical during October 2007 (post-monsoon) off Goa. They showed one order higher value at deeper depths during April 2007(pre-monsoon) compared to October 2007 (post-monsoon). Higher ATP in deeper waters during pre-monsoon indicated higher live biomass at relatively cooler sub-surface layers. It could also mean lack of predators at deeper depths and/or sub-euphotic maxima of tertiary producers. Such stratifications were absent or minimal in October 2007, post-monsoon. The annual variation from post-monsoon 2007 to 2008 was significant (p<0.05) in case of Goa. The values increased by an order in the year 2008. Ratnagiri and Goa did not differ significantly in 2008, and were in the same 104th order in both cases. Thus pre-monsoons could be marked by higher microbial biomass and clear layering in the distribution of ATP unlike the post-monsoon marked by a lower living microbial load more homogenously distributed. This could be due to the seasonal hypoxia/anoxia prevailing along the shelf during September-October. During a single season there was no significant variation between Goa and Ratnagiri. Seasonal variations seem to surpass annual variations. It is suggested that ATP could be an important parameter that could be used not only as a direct indication of microbial biomass but also an indirect indicator of potential tertiary production in different layers.


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AUTHOR INDEX ABHAY FULKE 259

ABHILASH S. 71 ABHISHEK NAGAR 254 ABHISHEK TAVVA 183 ACHYUTHAN H. 253 153

ADITI DESHPANDE 248 ADITYA PEKETI 167 211

AFREEN HUSSAIN 239 AHMED S. A. 54 57

AJAY YADAV 32 39 AKHIL P. S. 35

ALBERTINA DIAS 248 ALI M. M. 112 ALMEIDA ANSELMO 214 ALOK KUMAR MISHRA 73 AMARA B. M. 276 AMARENDRA P. 225 222

AMARNATH REDDY N. 191 AMEY DATYE 153 AMIT PRATAP 256 ANAND BABU AMERE 90 ANANDITA DAS 292 ANANT PAREKH 62 64 90 249 251 255

ANANYA KARMAKAR 251 ANAS A. 283 288 291

ANDHARE V.V. 243 245 ANDREW A MENEZES 126

ANIL A. C. 262 265 266 269 278 279 280 281 ANIL KUMAR 235

ANIL KUMAR K. 210 ANIL SONI 275 ANILA CHANDRAN 288 ANIRUDH RAM 32 39 258

ANJALI R. 223 ANJALY C. GOPI 129 ANJU S. 85 ANKIT GUPTA 220 ANOOP S. MAHAJAN 42 ANSHATH HUSSAIN 135 ANSHIKA SINGH 263 ANTONIO MASCARENHAS 140 ANUPAM KUMAR DIXIT 74 ANWESHA SARKAR 290 APARNA K. 47 APPUKUTTAN V. SHEEBA 283 AQLEEMA SHAH 226 233

ARAUJO J. 27 ARCHANA KAMBLE 39 ARCHANA N. 117 ARCHANA NAIK 268 ARINDAM SARKAR 166 ARULALAN T. 84 ARULMUTHIAH M. 120 132 137

ARVIND SAHAY 203 248 ARYA PAUL 12

ASHA USAPKAR 163 ASHALATHA K 116 ASHOK K. 47 82 85 88

ASHOKAN M. 118 ASHWINI KUMAR 160 ASHWINI R. 285 ASWATHY VIJAYA KRISHNA 290 ASWINI K. K. 164 ASWINI NAYAK 242


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ATCHUTHAN P. 280 ATHIRA P. RATNAKARAN 52 ATMANAND M. A. 120 AUMONT O. 23 AYAZ AHMED 38 275

AZIZ-UR-RAHMAN SHAIK 19 BADESAB F. K. 157 163

BALACHANDRAN K. K. 285 BALAJI R. 134 BALAKRISHNAN NAIR T. M. 225 BARNES N. 279 BARPHE ANIKET 87 BASAVAIAH N. 163 BEHERA M. R. 226 229 233

BENJAMIN S. 174 BEPARI K. F. 27 31

BHAGYASHRI N. 276 BHANUMURTHY P. 225 BHARAT HARMALKAR 115 BHARATHI G. 90 222 225

BHASKARARAO DOKALA 22 BHAT U. G. 247 BHATT N. P. 63 186

BHATT N. Y. 146 BHAVANI T. S. D. 222 BHUPENDRA BAHADUR

SINGH 48 BINSIYA T. K. 52 BISHWAJIT CHAKRABORTY 126 127

BISWAPRAJNA MOHANTY 242 BOBADE K. B. 193 BOROLE D. V. 155 BRAHMANAND SAWANT 167 BRAJOGOPAL SAMANTA 282 BRIGHT SINGH I. S. 291 CARVALHO M. A. 165 CHAKRABORTY A. 3 58 60

CHAKRABORTY KUNAL 12 CHAKRABORTY S. 153 CHANDRASEKHARA RAO 276 CHARLS ANTONY 231 CHAUDHURI DIPANJAN 67 CHOUDHURY P. S. 145 CHOWDARY J. S. 62 64 89 90 96 252

CHRISTABELLE E. G. F. C. 292 DA SLIVA RHEANE 169 DAYAKARAN P. 278 D BANDYOPADHYAY 13 17 19

DELCY ROSY NAZARETH 277 DESAI D. V. 263 278 280

DEVIKA V. GHATGE 115 DEWANGAN P. 163 DEY M. 259 DHILLAN VELLIP 292 DHRUVA KUMAR PANDEY 71 DIANA MATHEW 283 DILEEP KUMAR M. 10 DIPTI RAUT 242 DRASTI GANDHI 146 185

ELAINE SABU 268 ELANGO S. 120 ESWARAN R. 281 ETHÉ C. 23 FEBY PAULOSE 113 FEMY PAULOSE 113 FERNANDES G. Q. 215 FERNANDES R. 217


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FERNANDO V. 214 217 FOUSIYA A. A. 153

FOUSIYA T. S. 249 90 GAJANAN NAVELKAR 140

GAJBHIYE S. N. 32 258 272 GANESAN P. 213

GAONKAR M. 217 GAONKAR S. S. 157 GARDADE L. 281 GAUTHAM S. 83 GAWADE L. 16 GAYATRI VANI D. 214 GEETHA N. 2 GIBIES GEORGE 69 113

GIREESH T. R. 283 GIRISHKUMAR M. S. 21 GLEJIN JOHNSON 130 187

GNANASEELAN C. 62 64 81 87 89 90 91 95 96 108 248 249 250 251 252 254 257

GOKULAVASAN 124 GOPALA KRISHNA V. V. 112 GOPALA REDDY K. 225 GOPIKA S. 86 GOSWAMI B. N. 88 GOVIND RANADE 115 GOWTHAM D. 120 GOWTHAMAN R. 178 180

GUJAR A. R. 157 GUPTA G. V. M. 34 254 257

HAIMANTI BISWAS 13 17 19 HANI TALAMALA 213

HARDIKAR R. 259 HAREESH KUMAR P. V. 92 HARIKRISHNA SHARMA YG 180 HARIPRASAD P. 222 HARIS K. 126 HATKAR P. 243 HEDE N. 281 HEMA NAIK 23 29 31 38 41 44 276

HIMADRI TANAYA PANDA 242 HIMANSU K PRADHAN 184 ILANGOVAN D. 226 INDRAJEET GHOSH 124 INGOLE B. S. 255 257 258 261 267

IVY PEREIRA 267 IYER S. D. 215 JADHAV G. N. 145 JAGADEESH KADIYAM 137 JAGDALE S. P. 250 JANANI P. 117 JASMIN C. 288 JASNA VIJAYAN 290 JASTI CHOWDARY 251 JAYA KUMAR SEELAM 191 178 196 232 189 226

JAYAPRAKASH N. S. 291 JAYU NARVEKAR 18 93

JENA B. K. 134 133 208 218 223 224 JINEESH V. K. 197 205

JISHAD M. 178 196 JISMY POULSE 185

JITHIN ABRAHAM.K 217 JIYALAL RAM M. JAISWAR 32 39

JOSHI R. K. 169 JOSHILKAR V. R. 273 JOSSIA JOSEPH K. 223 224

JYOTHIBABU R. 285 JYOTI JADHAV 82 85

KAKATKAR R. 108


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KALAVATI CHAGANTI 240 KALYAN DE 239 261

KAMALAKKANNAN K. 124 KAMANA YADAV 10 KAMESH RAJU K. A. 164 KANKONKAR A. 228 KANNAN R. 121 KAPIL MOHAN 146 KARISIDDAIAH S. M. 126 KARTHIKEYAN M. 209 KARUNAKAR KINTADA 133 KARUPASAMY M. 270 KHALAP S. 217 KIRAN A. S. 208 KIRAN GOVIND V 135 KIRAN GURUNG 2 KIRANMAYI S. 164 KRISHNA K. S. 163 KRISHNA M. S. 15 16 20 22

KRISHNAN R. 81 KUCHI N. 281 KUDALE M. D. 193 209

KULKARNI V. A. 250 KUMAR B. S. K. 20 KUMAR RAVI PRAKASH 111 KURIAN SIBY 29 KURIEN E. K. 52 LALLU K. R. 197 LATHA G. 65 109 118 121 122 123

LENGAIGNE M. 23 80 LENKA SREENU 15

LEVY M. 23 LIDITA KHANDEPARKER 279 281

LINA FERNANDES 149 150 LIPIKA PATNAIK 242

LOBSANG TSERING 239 LOKABHARATHI P. A. 36 174 285 291

LOKESH KUMAR PANDEY 51 LOTLIKER ANEESH 8 LUIS R. A. A. 157 LYDIA KIRUBA R. 132 MADHAN R. 226 MADHU N. V. 285 MAHALAKSHMI P. 169 MAHANTY M. M. 122 MAHENDER K. 215 MAJITHIYA D. 32 MAKSYUTOV S. 5 MAMATHA S. S. 174 MANEESHA K. 78 MANGESH GAUNS 24 31 38 41 247 275

MANI MURALI R. 226 MANI SANKAR 133 MANISH SINGH 140 MANJU NAIR P. 7 MANJULA R. 195 MANJUNATHA S. G. 193 MAPARI K. E. 281 MAQBOOL YOUSUF 167 MARIA J GONSALVES 268 277

MASSON S. 88 MATTHIEU LENGAIGNE 83 MAZUMDAR A. 211 163 165 167 169

MEHRA P. 115 226 MICHAEL G. S. 228

MIHIR KUMAR DASH 255 MILIND MUJUMDAR 81


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MODI A. 88 MOHANAKUMAR K. 49 MONTEIRO M. C. 278 MORAJKAR S. 27 MUDRA LEKSHMI B. 76 MUGILARASAN M. 207 MUKHERJEE JAYATI 11 MULIK J. T. 271 273

MURALEEDHARAN K. R. 197 205 285 MURALEEDHARAN P. M. 49 110

MURTUGUDDE R. 5 88 MURTY T. V. R. 116

MURTY V. S. N. 78 213 214 MURUMKAR P.K. 54

MUTHUVEL A. 124 NAGARAJAN G. K. 129 NAGARJUNA RAO D. 69 NAGENDER NATH B. 155 162 166

NAGESWARARAO G. 256 NAIDU C. V. 89 NAIDU S. A. 16 NAIK B. G. 169 NAIK D. K. 157 NAIK G. P. 115 NAIK R. 27 NAQVI S. W. A. 23 27 29 31 38 41 44 275

NARAYAN S. 115 217 NASEERA K. 268

NAVEEN GANDHI 153 NAVEEN KUMAR K. R. 205 NAYAK G. N. 211 NEETU S. 23 80 83

NISARG MAKWANA 63 NISHA V. 253 NITESH SINHA 153 NITHEESH THOMAS 138 NITHYANANDAM K. 118 NOUFAL K. K. 123 NOYEL V. 280 NUPUR THAKKER 140 ONKAR CHAUHAN 202 PABITRA SINGHA 164 PADALKAR P. P. 160 PANDEY SUNITA S. 36 PANKAJAKSHAN T . 83 PAREKH A. 89 P CHAKRABORTY 159 162

PARTHIBAN G. 150 PARVATHI A. 290 PARVATHI V. 23 PATIL J. S. 262 266

PATTAN J. N. 150 PAVAN KUMAR N. 5 108

PAWAN DEWANGAN 164 PEDNEKAR P. S. 178 PERIASAMY R. 239 257 261

PHANINDRA REDDY A. 109 PHILIP L. WOODWORTH 231 PRABHAKAR NAYAK 119 PRACHI NAIK 24 PRADEEP KUMAR P. 87 PRAJITH A. 152 PRAKASH CHAUHAN 203 248

PRAKASH N. 124 PRAKASH T. A. 214 PRAKASHBABU C. 151 156 160 173

PRAMOD MAURYA 140


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PRASAD K. V. S. R. 95 96 116 PRASANNA KUMAR S. 18 49 83 88 93

PRASANTH A. PILLAI 53 89 PRATIHARY A. K. 27 38 41

PRATIMA M. KESSARKAR 149 150 152 212 PREETHA R. 291

PRINCE PRAKASH 253 PRINCE PRAKASH J. 270 PRIYA RAUTH 203 PRIZOMWALA S.P. 63 146 186

PUNYASLOKE BHADURY 282 PURNACHANDRA RAO V. 149 150 152 212

RADHARANI SEN 58 RAGUMARAN S. 270 RAGURAMAN G. 121 RAHUL NAGESH 239 255 261

RAHUL S. 91 254 RAI A. K. 119 144 RAI SHAILENDRA 71

RAJ KUMAR 60 RAJANEESH M. 269 RAJAWAT A. S. 199 RAJEEV SARASWAT 170 RAJITH K. 210 RAJKUMAR J. 224 RAJU ATTADA 64 R MADHUSOODHANAN 240 RAMADASS G. A. 141 RAMAIAH N. 268 RAMAN V. AKKUR 240 RAMASWAMY V. 156 151 160 171 173

RAMESH K. 65 RAMESH KUMAR M.R. 86 RAMESH KUMAR YADAV 48 RAMPRASAD T. 163 RANADIP BANERJEE 168 RANGANATH L. R. 209 RAO A. D. 84 184 185

RAO A. R. 210 RAO P. S. 151 171

RAO R. R. 83 RASHITH P. 44 RASHMI KAKATKAR 62 RASHMI SHARMA 60 RASTOGI B. K. 63 146 186

RATHEESH R. 199 RATIRUPA BARDHAN 38 RAVIBABU MANDLA 223 224

RAVICHANDRAN M. 21 55 67 88 RAVINDER M. 134

REDDY N. P. C 16 20 22 REMSIYA V. R. 229

RESPLANDY L. 23 REVADEKAR J. V. 50 54 57 66

REVICHANDRAN C. 197 205 RITESH VIJAY 219 220 RITIKA K. 88

ROKADE M. A. 32 ROXY M. K. 81 88 94

RIYANKA R CHOWDHURY 3 ROY RODRIGUES 266 RYAN LUIS 115 SABEERALI C. T. 69 SABIN T. P. 81 SABU SEBASTIAN M 135 SABYASACHI SAUTYA 239 261

SACHIDANANDAN CHINNU 110


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SACHIKO MOHANTY 184 SADHURAM Y. 78 SAHAI A. K. 53 71

SAHU K. C. 8 SAKTHIVEL MURUGAN S. 117 SALVI S. M. 271 SAMBHAJI MOTE 239 261

SAMSON G. 80 SANDEEP 85 SANDEEP K. K. 84 SANDEEP N. 47 SANGEETA MISHRA 240 SANGEETA NAIK 155 SANIL KUMAR V. V. 130 180 187

SANITHA SIVADAS 255 257 258 SANJANA M. C. 123

SANJIBA K BALIARSINGH 8 SANJO JOSE V. 52 SANKAR S. 183 SANTOSH KUMAR SINGH 275 SARAVANAN S. 195 SARKAR D. 60 SARMA V. V. S. S. 10 11 14 15 16 20 22

SAROJ K. DASH 144 SATARDEKAR P. 27 SATHIBABU Y. 26 SATHISH K. 266 SATHISH KUMAR D. 218 SATISH R. WATE 219 220

SATYA PRAKASH 12 252 SATYAM SRIVASTAVA 77

SATYANARAYANA Y 147 SAUMYA NAIR 283 SAURABH RATHORE 255 SAYANTANI OJHA 250 257

SENGUPTA D. 55 67 SHAILESH SALVI 39

SHAJI A. 169 SHAKUNTALA V. M. 57 SHAMAL MARATHE 82 SHANTA NAIR 288 SHENOI V. S. 129 SHENOY D. M. 27 29 31 38 41 44

SHERIN C. K. 14 SHERYL O. F. 292 SHINDE N. 32 SHIVA PRASAD S. 55 S. N. SANAGOUDRA 247 275

SHREYA S. JOSHI 235 SHYNI T. N. 92 SHYNU R. 212 SIBY KURIAN 38 41 153 275

SIJIKUMAR S. 49 SIMI MATHEW 109 SIMONTINI SENSARMA 168

SINGH A. K. 209 SINGH H. N. 76 SINGH P. 252 SINGH SHIKHA 75 SINGH T. 174 SIVAGAMI A. 132 SIVAKHOLUNDU K. M. 133 134 183 208 218 223

SIVAKUMAR K. U. 49 SIVARANJANI S. 195 SMITA MITBAVKAR 265 269

SMITA PANDEY 185 SMITHA R. 199


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SMRATI GUPTA 42 SNEHA K. G. 288 SOJA LOUIS 6 SOMAYAJULU Y. K. 83 SOMNATH S. PAI 291 SONI S. 243 245

SONIYA SUKUMARAN 271 273 SREE HARSHA H. 89

SREELEKHA J. 55 SREENIVAS PENTAKOTA 95 96 108

SREEPADA R. A. 268 SRIDHAR IYER 157 SRINIVAS G. 62 SRINIVAS T. N. R. 26 SRINIVASA KUMAR T. 8 SRIRAM K. 6 SRIVASTAVA ATUL 73 STEEVEN PAUL Y. 214 SUBBARAO 189 191

SUBEESH M. P. 217 221 SUBIR MUKHOPADHYAY 168

S CHAKRABORTY 162 SUDHAKAR M. 34 SUDHARANI P. 26 SUDHEESH V. 34 SUDHIR KUMAR SINGH 77 SUJA S. 212 SUJATHA C. H. 6 7 35

SUJITH P. P. 174 SUMI A SAMAD 129 SUNDAR D. 228 SUNDAR R. 120 SUNDARARAJAN.S 270 SUNEET DWIVEDI 51 73 74

SUNITA PANDEY 292 SUPRIYA G. KARAPURKAR 150 SURESH I. 23 83

SURESH K. 160 173 SURESH T. 203 235 248

SURYACHANDRA RAO A. 69 SURYAKUMAR S. 124 SURYANARAYANA A. 214 SUSEENTHARAN V. 133 134

SWAPNA P. 47 81 82 85 88 TANUJA NIGAM 182

TATA SUDHAKAR 141 TEESHA MATHEW 49 80

TEMJENSANGBA IMCHEN 252 TERRAY P. 88 THAKUR N. L. 263 THANGAPRAKASH V. P. 21 THIRUNAVUKKARASU A. 122 THOMAS T. R. A. 286 THORAT B. R. 32 THULASIDAS K. R. 135 TRUPTI MARDIKAR 219 TYSON SEBASTIAN 155 UDAY GAONKAR 257 UDAYA BHASKAR T. V. S. 21 ULLAS N. 285 UMESH KUMAR SINGH 51 UNNI V. K. 138 UNNIKRISHNAN A. S. 217 221 228 231

USHA NATESAN 218 UTHAMAN C. P. 138 VAIGNAKAR D. 174 VARIKODEN H. 50 54 57 66


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VEERASINGAM S. 207 VENGATESAN G. 137 VENKATACHALAPATHY R. 207 VENKATESAN R. 67 65 109 120 132 137

VENKATESH RAGHAVAN 130 VENUGOPAL REDDY 112 VETHAMONY P. 207 VIALARD J. 23 80

VIJAPURE TEJAL V. 271 273 VIJAY KUMAR 188

VIJAY KUMAR K. 115 VIJAYA RAVICHANDRAN 133 183

VIJITHA VIJAYAN 288 VIKAS M. 189 191

VIKASH K. KUSHWAHA 220 VIMALA J. 65 137

VIMLESH PANT 84 111 182 VINAYARAJ POLIYAPRAM 130

VINITA J. 197 VINU VALSALA 5 75 88

VISHAL PATIL 239 257 261 VIVEK KUMAR PANDEY 77

VIVEK S. 95 VIVEK SHILIMKAR 94 VOLVOIKAR S. P. 211 VYAS D. U. 145 VYSHNAVI P. 224 WASIM EZAZ 252 WILLIAM FERNANDES 126 127

YADHUNATH E. M. 178 232 YATHEESH V. 164

YOGESH AGARVADEKAR 115 217


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OSICON-15 - Ocean Society of Indiaoceansociety.in/osicon/osicon2015/osicon2015_abstracts.pdf · OSICON-15 OCEANIC PROCESSES ALONG THE COASTS OF INDIA 22-24 March 2015 ... Vasant Kunj