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2012 BIENNIAL 3rd
WAQUA INTERNATIONAL WORKSHOP
2009
WAQUA
WESTA
FR
ICA
NQ
U
ATERNARYRESEARC
HA
SS
OC
IATION
WEST AFRICAN QUARTENARY RESEARCH ASSOCIATION
Book of Abstracts
West African Quaternary Research
Association (WAQUA)
Third International Workshop
Accra – Ghana
October 8 – 12, 2012.
THEME
Implications of paleoclimatic and sea level changes on coastal evolution, Are Humans
Adapting?”
.
Sponsors
Contact: Sowah Wahab Laryea, [email protected]
Page 2 of 24
Table of Contents
BACKGROUND .................................................................................................................................... 4
SCIENTIFIC PROGRAM ...................................................................................................................... 4
LOCAL ORGANIZERS ......................................................................................................................... 5
SCIENTIFIC COMMITTEE .................................................................................................................. 5
PROGRAMME OF ACTIVITIES .......................................................................................................... 6
Day 1 ....................................................................................................................................................... 7
OPENING CEREMONY, INAUGURAL SESSION & ACADEMIC SESSION I ............................... 7
DAY2 ...................................................................................................................................................... 8
ACADEMIC SESSION II& III .............................................................................................................. 8
DAY 3 ..................................................................................................................................................... 9
GUIDED FIELD TRIP ........................................................................................................................... 9
DAY 5 ..................................................................................................................................................... 9
WORKSHOP APPRAISAL & CLOSING CEREMONY ...................................................................... 9
ABSTRACTS ....................................................................................................................................... 10
Paleoclimatic Studies of Lake Chad Basin and its Implication on Lake Level Fluctuation Using
Isotope Geochemistry ........................................................................................................................... 10
Late Quartenary Vegetation Dynamics in Aghalokpe Grassland Delta State: From Pollen Taxa to
Ecoregion. ............................................................................................................................................. 10
Palaeoclimate and Lake Level Changes in TheTangraYumco, Tibet: An Ostracods Perspective ........ 11
Indigenous Knowledge on the Use of a Vegetable, Telfairia Occidentalis .......................................... 13
Palynological and Organic Geochemical Records of Quaternary Sediments of Some Parts of Lagos
Lagoon, Southwestern Nigeria .............................................................................................................. 13
Quaternary Stratigraphy and Geochemical Indices of the Lagos Lagoon Coastal Sediments,
Southwestern Nigeria, with Reference to Marine Transgressions ........................................................ 14
Simulation of Cross Shore Beach Change to Storms ............................................................................ 15
Coupling Physics – Biogeochemistry in the Gulf of Guinea ................................................................ 16
A Contribution to the Holocene Vegetation Changes of Nigeria: Palynomorphs from a 200 cm Core
from Ohe Pond Nsukka, Nigeria. .......................................................................................................... 16
Predictability, Prediction and the Linkage Between Sea Surface Temperature Analysis along
Coastline of Lagos, Nigeria. ................................................................................................................ 17
Preparing for Climate Change in Ghana, Through Coastal Monitoring ............................................... 17
Abrupt climatic changes in the Gulf of Guinea during the past 52 kyr. ............................................... 18
HISTOIRE RECENTE DE LA VARIABILITE PLUVIOMETRIQUE EN AFRIQUE DE L’OUEST :
EXEMPLE DU BENIN ........................................................................................................................ 18
Recent History of Rany Variabilite Pluviometrique in West Africa: ¶Example of the Benin ¶ ........... 19
Page 3 of 24
Palaeoclimatic and Palaeoecological Significance of Montane Pollen Assemblage from the Neogene
Formations of Eastern Nigeria .............................................................................................................. 20
Climatic oscillations during Holocene in West Africa: Palaeoclimatic Hypothesis of the Quaternary
Aquifer System Formation in the Coastal Sedimentary Basin in Benin ............................................... 20
Analyse séquentielle des dépôts du bassin sédimentaire côtier du Togo : implication
paléogéographique ................................................................................................................................ 21
Linkages between Sea-Level Rise and Groundwater Quality: Livelihood Implications and
Interventions ......................................................................................................................................... 22
Projection of extreme events of climate change on reservoir water storage in the Volta basin of Ghana
.............................................................................................................................................................. 23
ANALYSIS OF THE MEASURED TIDE DATA FROM TAKORADI–GAUGE STATION ........... 23
IMPACT OF SEA LEVEL RISE ON COASTAL TOURISM DEVELOPMENT IN ACCRA –
GHANA ................................................................................................................................................ 24
Page 4 of 24
BACKGROUND
Established 2009 through the INQUA Project 0904 entitled “West African Quaternary
Paleoclimate/Sea level Changes and Human Responses”, WAQUA formed 4 working groups
namely Lake Sediments as Archives for Paleoclimatic Changes; Coastal Sea Level Changes;
Ecosystem Changes and Livelihood of Human Development; Archaeology and Paleontology.
The previous workshops held in Ibadan and Cotonou (2010) focused mainly on Quaternary
Paleoenvironment/climate changes, Anthropogenic influences and Geoarcheology of West
African subregion.
The aims of the workshops are to enhance the growth of Quaternary Paleosciences in the
West African subregion through capacity building, mentoring and motivation of young
scientists and fostering collaborative research, exchange of information and networking
among Quaternary Paleoscientists.
The 3rd
international workshop will be hosted by University of Ghana, Legon, in Accra from
October 8 – 12, 2012. The primary objective of this workshop among others is to promote
awareness of the role of Paleoclimate and sea level rise in environmental research; and to
further enhance active communication on Quaternary Paleosciences in West Africa. Hence
the workshop theme: “Implications of paleoclimatic and sea level changes on coastal
evolution, are humans adapting?”
In order to appreciate the evolution of the climate during the 1.8 to 2 million years in West
Africa, there is the need to take inventory and to study the paleoclimate sequences during the
Quaternary. Continuous and reliable weather data exists only since the middle of the 19th
century. Therefore, to better understand the negative impact of the natural and anthropogenic
mechanisms on the past climatic condition, it is necessary to relate paleoclimatology and
paleontology with archaeology.
This workshop will provide a forum for professionals to meet, interact, and make updates on
recent developments, products and emerging trends in Paleosciences. It will also create
unique opportunity for sharing information and knowledge among young Quaternary
Paleoscientists and fostering network and capacity building between professionals, NGO’s
and policy makers in the development of the past climatic systems During the conference
there will be a mid-workshop guided tour of interesting coastal geological and archeological
locations up country in Ghana.
Thus, the conference is expected to bring together West African Quaternary senior and young
career scientists and students for exchanging information and to assess the opportunities and
challenges in research, training and capacity building
SCIENTIFIC PROGRAM
The workshop includes invited review presentations, contributed papers in thematic sessions
based on the themes of the four working groups. The workshop subthemes include:
Climatic oscillations during Holocene in West Africa
Coastal Sea Level Changes
History and dynamic of West Africa Lakes: indicators of climate change
Paleo- botany in West Africa
Ecosystem and Human Livelihood
Page 5 of 24
Climate and civilisations during the Quaternary in West Africa: Report on
paleontological research
LOCAL ORGANIZERS
Chairman Dr. Kwasi Appeaning-Addo
University of Ghana
Co-chairman SowahLaryea
University of Ghana
Secretary Bennet Atsu Foli
University of Ghana
Organizer Lloyd C. Allotey
University of Ghana
Member Kate Sago
Ghana Tourism Authority
Dr. A. M. Mensah
University of Ghana
B. Botwe
University of Ghana
Eunice K. Asamoah
University of Ghana
SCIENTIFIC COMMITTEE
Dr. Kwasi Appeaning Addo Department of Marine and Fisheries Sciences,
University of Ghana, Legon
Dr. Izuchukwu M. AKAEGBOBI (NIGERIA) Department of Geology, University of Ibadan,
Ibadan-Nigeria.
Prof. Roland Gehrels School of Geography, Earth and Environmental
Sciences
Plymouth University
Plymouth PL4 8AA
United Kingdom
Sowah Wahab Laryea Department of Marine and Fisheries Sciences,
University of Ghana, Legon
Prof. Ampah Kodjo Christophe JOHNSON
(TOGO)
Faculte Des Sciences - Department de Geologie,
Universite de Lome
Prof. M.L OYEDE (Bénin) Faculté des Sciences et Techniques, Laboratoire
de Géologie, UAC (Bénin)
Dr. Ibouraima YABI (Benin) Laboratoire Pierre PAGNEY "Climat, Eau,
Ecosystème et Développment " (LACEEDE),
Département de Géographie, Université
d'Abomey-Calavi (République du Bénin
Dr. Lizzy OKORO (NIGERIA) Department of Geological Sciences, Nnamdi
Azikiwe University, Awka – Nigeria.
Page 6 of 24
3RD
BIENNIAL WEST AFRICA QUATERNARY RESEARCH ASSOCIATION
(WAQUA) WORKSHOP
Accra, Ghana
October 8 – 12, 2012.
OPENING CEREMONY
PROGRAMME OF ACTIVITIES
1ST
SESSION
08:30 –09:30 am Arrival and registration of participants
09:30 –09:45 am Arrival of guest of honour, invited guests and dignitaries
09:45 – 11:00 am Opening Ceremony
Activities
Introduction of invited guests (Sowah W. Laryea)
Introduction of Chairman / Chairman’s response (Mrs. E. K Asamoah)
Introduction of participants
Welcome Address by Head, Department of Marine and Fisheries
Sciences, University of Ghana, Legon.
Keynote address by the Honourable Minister for Environment, Science
and Technology
Address by International Union for Quaternary Research (INQUA)
representative
Address by West Africa Quaternary Research Association (WAQUA)
representative
Statement by Chairman Local Organising Committee
Chairman’s closing remarks
Vote of thanks
11:00-11:30 am Cocktail
INAUGURAL SESSION FOLLOWS PROMPTLY
Page 7 of 24
Day 1
OPENING CEREMONY, INAUGURAL SESSION & ACADEMIC SESSION I
Time Activity Title Speaker
OPENING CEREMONY
08:30 – 09:30 Arrival and registration of participants
09:30 – 09:45 Arrival of guest of honour, invited guests and dignitaries
09:45 – 11:00 Keynote address Message by INQUA Message by WAQUA Statement by Organising Committee Closing remarks
Honourable Minister for Environment, Science and Technology Chairman
11:00 – 11:30 Opening Ceremony Cocktail
INAUGURAL SESSION
11:30 – 11:45 Messages
Messages and Information pertaining to workshop Message from Sponsors
Organising Committee PASS, INQUA, PAGES
12:20 Inaugural lecture
“Sea Level rise and coastal change: Causes and implications for coastal communities”
Dr. Thomas Kwasi Adu (Deputy Director, Ghana Geological Survey)
12:20 – 14:00 Lunch break / Heure du déjeuner
ACADEMIC SESSION I: QUATERNARY RESEARCH IN WEST AFRICA
CONVENER: Dr. Izuchukwu Mike Akaegbob 14:00 – 14:25 Paper 1 Late Quartenary Vegetation Dynamics in Aghalokpe
Grassland Delta State: From Pollen Taxa to Ecoregion. J.K.Ebigwai* , E.A Edu. and O.A. Orhoghere
14:25 – 14:50 Paper 2 Quaternary Stratigraphy and Geochemical Indices of the Lagos Lagoon Coastal Sediments, Southwestern Nigeria, with Reference to Marine Transgressions
*Olugbenga A. Boboye and Okezie R. Nwosu
14:50 – 15:15 Paper 3 Recent History of RanyVariabilitePluviometrique in West Africa: Example of the Benin
Yabi Ibouraïma*, Afouda Fulgence and Boko Michel
15:15 – 15:35 Coffee break / Pause café
15:35 – 16:00 Paper 4 Palaeoclimatic and Palaeoecological Significance of Montane Pollen Assemblage from the Neogene Formations of Eastern Nigeria
*Obianuju P. Umeji and C.O.C. Agwu
16:00 – 16:25 Paper 5 Climatic oscillations during Holocene in West Africa: Palaeoclimatic Hypothesis of the Quaternary Aquifer System Formation in the Coastal Sedimentary Basin in Benin
Henri S. Totin V., Moussa Boukari, Michel Boko
16:25 – 16:50 Paper6 Analyse séquentielle des dépôts du bassin sédimentaire côtier du Togo : implication paléogéographique
Pauline Y. Da Costa, Sani M. Tairou, Pascal Affaton
Page 8 of 24
DAY2
ACADEMIC SESSION II& III
Time Activity Title Authors
ACADEMIC SESSION II: PALEOCLIMATOLOGICAL RESEARCH IN WEST AFRICA Convener:Dr. YabiIbouraïma
09:30 – 09:55 Paper 7 Paleoclimatic Studies of Lake Chad Basin and its Implication on Lake Level Fluctuation Using Isotope Geochemistry
Izuchukwu M Akaegbobi
09:55 – 10:20 Paper 8 Palaeoclimate and Lake Level Changes in The TangraYumco, Tibet: An Ostracods Perspective
Akita Gifty Lailah, Frenzel Peter, Börner Nicole, Wang Junbo, Peng Pingand Torsten Haberzettl
10:20 – 10:45 Paper 9 Palynological and Organic Geochemical Records of Quaternary Sediments of Some Parts of Lagos Lagoon, Southwestern Nigeria
* O.A. Boboye and O.T. Ogunbameru and I.M. Akaeigbobi
10:45 – 11:05 Coffee break / Pause café
11:05 – 11:30 Paper 10 A Contribution to the Holocene Vegetation Changes of Nigeria: Palynomorphs from a 200 cm Core from Ohe Pond Nsukka, Nigeria.
Njokuocha, Reginald C
11:30 – 11:55 Paper 11 Indigenous Knowledge on the Use of a Vegetable, TelfairiaOccidentalis
*Taiye R. Fasola, Tolulope O. Beckley and I.O. Azeez
11:55 – 12:20 Paper 12 Coupling Physics – Biogeochemistry in the Gulf of Guinea
Apetcho Koku Eyram
12:20 – 14:00 Lunch break / Heure du déjeuner
ACADEMIC SESSION III: CLIMATE, SEA-LEVEL RISE AND COASTLINE CHANGES Convener: Mrs EK Asamoah
14:00 – 14:25 Paper 13 Projection of extreme events of climate change on reservoir water storage in the Volta basin of Ghana
Etornyo Agbeko, George Wiafe, Barnabas A Amisigo, & Francis K. E. Nunoo
14:25 – 14:50 Paper 14 IMPACT OF SEA LEVEL RISE ON COASTAL TOURISM DEVELOPMENT IN ACCRA – GHANA
Kate Sagoe-Addy
14:50 – 15:15 Paper 15 Abrupt climatic changes in the Gulf of Guinea during the past 52 kyr.
Adesina Adegbie and Ralph Schneider
15:15 – 15:35 Coffee break / Pause café
15:35 – 16:00 Paper 16 Linkages between Sea-Level Rise and Groundwater Quality: Livelihood Implications and Interventions
Nyamedor Felix H.
16:00 – 16:25 Paper 17 ANALYSIS OF THE MEASURED TIDE DATA FROM TAKORADI–GAUGE STATION
Tsei Senam
16:25 – 16:50 Paper 18
Page 9 of 24
DAY 3
GUIDED FIELD TRIP
Time Activity Resource person
GUIDED FIELD TRIP Convener: LC Allotey
06:30 – 06:45 Gathering and departure LC Allotey
06:45 – 16:00 Lover Volta Basin and Catchment Mrs EK Asamoah, LC Allotey, Sowah W.Laryea
Erosion hot spots Sowah W.Laryea
Keta Sea Defence Structure Sowah W.Laryea
DAY 4
ACADEMIC SESSION IV(CONTINUED)& WAQUA GENERAL ASSEMBLY
Time Activity Title Authors
ACADEMIC SESSION IV Convener: Mr Sowah W. Laryea
09:30 – 09:55 Paper 19 10. Predictability, Prediction and the Linkage Between Sea Surface Temperature Analysis along Coastline of Lagos, Nigeria.
Ediang Okuku Archibong, Ediang Aniekan Archibong, Benson Levi
09:55 – 10:20 Paper 20 Simulation of Cross Shore Beach Change to Storms Joseph Pabby*, Selorm D. Ababio and Bennet A. Foli
10:20 – 10:45 Paper 21 Preparing for Climate Change in Ghana, Through Coastal Monitoring
Sowah Wahab Laryea
10:45 – 11:05 Coffee break / Pause café
11:05 – 12:20 WAQUA GENERAL ASSEMBLY Convener: WAQUA PRESIDENT
12:20 – 14:00 Lunch break / Heure du déjeuner
14:30 – 16:00 Visit to University of Ghana (Geology, Archaeology, Marine & Fisheries Science departments and museums)
DAY 5
WORKSHOP APPRAISAL & CLOSING CEREMONY
Time Activity
09:30 – 12:20 (Strategies to improve WAQUA workshops)
12:20 –1400 Closing Ceremony and Cocktail
14:00 Department
Page 10 of 24
ABSTRACTS
Paleoclimatic Studies of Lake Chad Basin and its Implication on Lake Level
Fluctuation Using Isotope Geochemistry
Izuchukwu M Akaegbobi
Department of Geology, University of Ibadan, Ibadan – Nigeria
Email: [email protected]
The geodynamics along with the fluctuation of lake level and its implication on fishery and
other ecological resource management within the Lake Chad cannot be overemphasized.
During the Quaternary the Chad Basin experienced fluctuations of severe aaridity and
wetness events, This resulted in ca. 600m thick sediment deposition within the Megachad
area,. The present Lake Chad is a closed lacustrine systems with depths on the average of >
10 m and All waters draining the Mega Chad basin empties into the Lake Chad covering an
area of ca. 30000sq Km. Acurate records of lake level changes in the lake chad through
limnological study of sediment coring is missing.
Therefore, a set of 8 samples (derived mainly from interbeds of clay, silty clay and sands)
collected through two 5 meter deep pits in Duguri Island of Lake Chad were
limnologicallyanalyzed to see evidence of repeated changes in lake level, Another set of 20
samples of mainly clayey sand and calcerousshales and derived from 2 wells located within
the Megachad basin were also analysed. Samples containg fossilized fragments of shells were
subjected to isotopic studies on C, O, H and spore and pollen analysis. Also trace elements
were analyzed for provenance of sediment into the present day lake chad
Based on this study, isotopic baseline provenance data for Lake Chad is established.
Variations on the isotopic values of O and H reveals slternation of dry and wet periods which
complies with movement of the Intertropical Convergence Zone (ITCZ) which controls the
West African Monsoom climate. The Lake Surface Temperature though influenced by
atmospheric condition varies from 25 to 28.6*C
Late Quartenary Vegetation Dynamics in Aghalokpe Grassland Delta State: From
Pollen Taxa to Ecoregion.
J.K.Ebigwai1* ,
E.AEdu.1
and O.A. Orhoghere. 2
Department of Botany, University of Calabar, Calabar, Nigeria
Department of Geology, Delta State University, Abraka.
Corresponding author J.k. Ebigwai ([email protected])
This paper integrates recent efforts to map the distribution of habitats for the late quaternary
with the detailed evidence that plant species have responded individualistically to climate
change. Detailed palynological analysis of Sixty-eight cuttings recovered from a grassland
habitat surrounded by a lowland forest vegetation was recovered in Aghalokpe, (Delta state;
South southNigeria) provides information on the botanical history of the area during the last
Page 11 of 24
20,000 yr before present. Rich and well documented pollen counts exhibit changes in the
vegetation community related to climatic factors. Vegetation distribution and composition
was relatively stable during full glacial times (20,000 -15,000 yrBP) and changed slightly
during the mid to late Holocene (7000 -600yr BP) but changed significantly and rapidly in
habit and taxa during the late glacial period and early Holocene (16,000-8000yrBP) and after
600yrBP. Shift in plant taxon distributions were characterized by individualistic changes in
population abundances and ranges. For instance, pollens of moraceae, bignoniaceae,
urticaceae, bursaraceae and sterculiaceae dominated the pollen record of the late glacial
period while the pollen record of mid-late Holocene recorded pollens of asteracee, poaceae,
cucurbitaceae, araliaceae and cyperaceae . These pronounced changes are indicative of
catastrophic climatic regimes.
Key words: Aghalokpe, glacial, Holocene, pollen, before present
Palaeoclimate and Lake Level Changes in TheTangraYumco, Tibet: An Ostracods
Perspective
Akita Gifty Lailah1, Frenzel Peter
1, Börner Nicole
2, Wang Junbo
3, Peng Ping
3 Torsten
Haberzettl4
1Institut fuerGeowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749
Jena, Germany 2InstitutfürGeosysteme und Bioindikation,TechnischeUniversitätBraunschweig,Langer Kamp
19c, 38106 Braunschweig,Germany 3Institute of Tibetan Plateau Research, Chinese Academy of Sciences,No.18 Shuangqing Rd.
Haidian District, Beijing, 100085, China 4 Institutes of Geography, Friedrich-Schiller-University Jena, 07743 Jena, Germany
The Last glacial cycle is characterized by the large body of seawater that extends into large
lakes forming closed lakes. It is assumed that during some season the lake was fresh and
other times it become shallow and segmented into a series of saline swamps and pools, or
even dry and subaerially exposed. Marine waters transgressed the lake margins during
periods of high sea level, forming a shallow marine embayment through to open marine
conditions. A large brackish lake remained as the waters again receded. Fluctuations in the
extent and nature of this waterbody through the last glacial cycle are preserved in lake
sediment and shorelines.
In the ancient large lake stage, a large number of large, medium-sized and small, modern
lakes in the southeast of the northern Tibetan Plateau such as Nam Co, Siling Co, Zhari
Namco Co and TangraYumco were joined together to form a single great lake, whose areal
extent might overstep the watershed between the northern Tibet endorheic drainage system
and exorheic drainage (Nujiang River) system.
Ostracods are small bivalved crustaceans found in almost every aquatic habitat. Ostracods
have been used in palaeoclimate, paleolimnology, palaeooceanography, and sea level change,
because of their sensitivity to changes in salinity, anionic composition, temperature,
substrate, food supply, pH levels, dissolved oxygen content, also sensitively affected by a
Page 12 of 24
range of other habitat variables (water depth, microhabitat structure, water retain time,
aquatic macrophyte cover etc). Hence, qualitative and quantitative ecological studies on
modern ostracods are of great importance in palaeolimnology. Individual species have
different ranges of salinity tolerances; some are restricted to low-salinity conditions
(stenohaline) and others may be capable of tolerating varying salinity conditions (euryhaline).
The application of ostracods for studying lake level changes on Tibetan Plateau is increasing
during the last decade. Ostracods proxies provide past changes in effective moisture and
hydrological conditions in response to Asian monsoon dynamics. This knowledge is critical
for the understanding of long-time climatic processes and for assessing human impacts on
aquatic ecosystems changes and its sustainable management.
We report quantitative studies on ostracod fauna in the TangraYumco area, central Tibet,
carried out in September 2011. Modern ostracod samples were collected with a hand net or an
Ekman grab scraping max 2 cm of the surface sediment. The sediment samples were
preserved in 95% Ethanol. Thirty five samples were examined quantitatively for ostracods
(dead + living) from >200 µm size fraction. Aquatic habitats and water parameters for
ostracod samples were monitored simultaneously. All the samples contained ostracod valves
and twenty eight yielded living ostracods.
The investigations revealed that there are at least ten Recent ostracod species in the
TangraYumco area. Within the lake, the typical species are Leucocytheredorsotuberosa,
Leucocytherellasinensis, Limnocythereinopinata, Fabaeformiscandondagyirongensis, and
Candonaxizangensis.Eucypris spp. and Ilyocypris sp. are characteristic for small streams and
temporary waters also dwelled by Heterocyprisincongruens. Candona candida occurs both in
the lake and in flowing waters. A very rare genus is Potamocypris found in a modern stream
with a single valve only. Water depth indicator species identified include
Leucocytheredorsotuberosa and Fabaeformiscandonagyirongensis in medium and deeper
water; shallow water species are Leucocytherellasinensis and Eucyprisgyirongensis.
The applicability of Recentostracod analysis to fossil associations was tested using a short
core taken in 223 m water depth in TangraYumco (central part of the northern basin). The
core covers the last approximately 3500 cal yrs BP and yields all typical Recentostracod
species. The composition of the fossil ostracod association confirms sedimentation in a
deeper water environment. The lower part of the core is dominated by L. sinensis and partly
L. dorsotuberosa. There is a trend change to a drier climate starting earlier, around 2000 cal
yrs BP, when L. dorsotuberosa increased in proportion. The upper part of the core represents
a lowered lake level. It is dominated by L. inopinata, tolerating high salinity. This points to a
high evaporation/precipitation ratio during the last approximately 1000 cal yrs BP. The last
centuries are an exception when the proportion of L. inopinata decreases probably due to a
rising lake level.
Key words:Palaeoclimate, Micropalaeontological, Palaeoenvironmental Analysis, Ostracoda,
Tangra Yumco
Page 13 of 24
Indigenous Knowledge on the Use of a Vegetable, Telfairia Occidentalis
*Taiye R. Fasolaa, Tolulope O. Beckley
a and I.O. Azeez
b
aDepartment of Botany, University of Ibadan, Oyo State, Nigeria.
bDepartment of Veterinary Medicine, University of Ibadan, Oyo State, Nigeria.
Telfairiaoccidentalis is an important staple vegetable grown in Nigeria which produces
luxuriant edible green leaves, which are rich in iron and vitamins. Recent studies have shown
that Telfairiaoccidentalis leaf is rich in minerals (such as iron, potassium, sodium,
phosphorus, calcium and magnesium), antioxidants, vitamins (such as thiamine, riboflavin,
nicotinamide and ascorbic acid), and phyto-chemicals such as phenols. Anemia describes the
condition in which the numbers of red blood cells in the body is low, or a common blood
disorder that affects people of all ages, although the people at greater risk are the elderly,
young women of child-bearing age and the infants. Traditionally, there are set rules attached
to its harvesting periods. Therefore harvesting of the plant done at various stages and
subjected to scientific comparison in relation to the set out rules are discussed. The best
harvesting period of 120 t0 150 days is in support of the set out rules by the traditionalist.
Key words: Telfairiaoccidentalis, Indigenous knowledge, Vegetable, Planting
Palynological and Organic Geochemical Records of Quaternary Sediments of Some
Parts of Lagos Lagoon, Southwestern Nigeria
* O.A. Boboye and O.T. Ogunbameru and I.M. Akaeigbobi
*Department of Geology, University of Ibadan, Nigeria.
E-mail: [email protected]
The Quaternary period in the most recent geological intervals, represent the last 1.8 million
years.It was a period of major environmental changes that were possibly greater than at any
other time in the last 60 million years. Quaternary paleoclimatic investigations play a key
role in the understanding of the possible future climate change on our planet. For this reason,
studies were carried out on the Quaternary sediments which integrated geochemical and
palynological techniques on some samples retrieved from the Lagos coastal environment
within the Dahomey Basin; this is aimed at determining the age, paleoclimatic conditions, as
well as re-evaluating the depositional paleoenvironment.
Samples were collected from twenty different locations in the Lagos Lagoon. Laboratory
analyses involved the palynological study, which entails the identification of an age
diagnostic species, and organic geochemical studies, to determine the provenance of the
organic matter of the Quaternary sediments.
The palynological analysis results revealed the abundant occurrences of
ZonocostitesramonaeLaevigatosporitessp., Crassoretitriletesvanraadshooveni,
Sapotaceoidaepollenitessp. andsome few long ranging forms. This suggests that the
vegetations developed under a humid climate and the sediments were deposited during cooler
and wetter conditions. The Total Organic Carbon (TOC) values are generally high ranging
Page 14 of 24
from 1.14% to 4.65% and Carbon-Nitrogen (C/N) ratio for each of the sample analyzed is 10.
These conditions also indicate a wet climate and that algal source have dominated organic
input to the sediments suggesting they are protein-rich and cellulose-poor. The presence and
abundance of Zonocostitesramonae, Canthiumiditessp., Crassoretitriletesvanraadshooveni,
Sapotaceoidaepollenitessp. andPachydermitesdiederixi forms indicate an age range from
Late Pliocene (Zanclian) to Early Pleistocene (Emilian)
The dominance of theZonocostitesramonaedepicts a mangrove swamp environment which
was the most prevalent environment of the Lagos Lagoon.
The palynological and organic geochemical analyses revealed that the sediments were
deposited during a wet climate and the organic matter is from an algal source as indicated by
the C/N ratios.
Keywords: Quaternary, Dahomey Basin, paleoenvironments, palynology, paleoclimate,
Quaternary Stratigraphy and Geochemical Indices of the Lagos Lagoon Coastal
Sediments, Southwestern Nigeria, with Reference to Marine Transgressions
*Olugbenga A. Boboye and Okezie R. Nwosu
*Department of Geology, University of Ibadan, Nigeria.
E-mail: [email protected]
The Lagos lagoon, part of the barrier-lagoon geomorphic zone of the Nigerian coastal system,
is underlain by Quaternary Coastal Plain sands of the Dahomey Basin. Due to its
physiographic, geologic, geographic and coastal dynamic nature, it is susceptible to sea level
variations. Thus, this study involves sedimentological and geochemical study of the three
georeference Well LL-1(Iddo), Well LL-2(Mid-lagoon) and Well LL-3(Ajah), was carried
out to evaluation the lithofacies distribution, provenance, environment of deposition and the
resulting marine transgression from previous sea level rise.
A total of twenty nine core samples were analyzed for lithostratigraphic from three
georeferenced wells. Eighteen of these samples (sandstones) were subjected to granulometric
analysis, heavy mineral studies, thin section petrography, and Inductively Coupled Plasma -
Mass Spectrometry (ICP-MS). Geochemical facies criteria are established based on combined
diagnostic indices: Sr> 160ppm, B > 90ppm, Sr/Ba > 0.35, B/Ga > 4.0 and Sr< 90ppm, B <
50ppm, Sr/Ba < 0.2, B/Ga < 2.5 for the shallow marine and terrigenouslithofacies
respectively
The Quaternary lithofacies indicates the presence of clay, siltstone, sandstone and
conglomerate. The sandstones are fine to coarse grained, poorly sorted to moderately well
sorted, negatively to positively skewed and mesokurtic to leptokurtic. Heavy mineral
assemblage is characterized by zircon, rutile, tourmaline, garnet, staurolite, sillimanite,
apatite, epidote, hornblende and kyanite. This assemblage suggests sediments derived from
both igneous and metamorphic provenance probably from the Ibadan Craton. The average
ZTR index is 27.84 % which is indicative of mineralogically immature sediments.
Petrographic analysis shows that the most abundant detrital mineral is quartz (average of
88.7%), feldspar (average of 4.37%) and rock fragment (average of 7.3%). The QFR Ternary
plots revealed that the sands are super-matured quartz arenite derived from uplifted
Page 15 of 24
continental block under humid climatic setting which have experienced medium
transportation history and have been subjected to medium mechanical and chemical
weathering. The ratios of K2O/Na2O and SiO2 suggest passive and active continental margin
settings. Linear discriminant function revealed that the sediments were deposited within
fluvial to shallow marine environment. This corroborated the bivariant plots of the statistical
parameter. Trace-element (Sr, Ba, B, GA, V) content and ratios of Sr/Ba and B/GA are
considered with regard to their distribution in the various lithofacies. The results show: Sr,
50 – 120 ppm, Ba, 180 - 340 ppm, Ga, 5 – 14 ppm, B, 25 -48 ppm, V, 53 – 125 ppm, Sr/Ba,
0.20 – 0.39 and Ba/Ga 1.86 – 7.00, indicating lithofacies ranging from terrigenous to shallow
marine.
Conclusively, the lithofacies are derived from a mixed provenance which have undergone
chemical weathering in the course of transportation and are deposited in the fluvio-marine
environment. The geochemical indices indicate the occurrence of weak marine
transgressions.
Keywords: Depositional environment, provenance, tectonic setting and sea level rise.
Simulation of Cross Shore Beach Change to Storms
Joseph Pabbya*
, Selorm D. Ababioa and Bennet A. Foli
a
aDepartment of Marine and Fisheries Sciences, University of Ghana, Legon
*Corresponding author: [email protected]
Globally, coastal communities are becoming increasingly exposed to a wide range of
potential hazards including shoreline retreat and coastal resource degradation. Significant
coastline retreat can occur in a short period of time due to episodic storms endangering
people, property and thus defining the local susceptibility to erosion.
The problem is heightened by rapid urbanization and the human induced beach changes
which affect coastal processes. The lack of proper long term prediction and planning tools as
well as lack of basic disaster warning mechanisms makes the situation daunting.
This study therefore investigated the vulnerability of the coast to periodic extreme wave
events using models and estimated erosion prone area widths using the American EPA
guidelines. Simulation using the SBEACH model was employed for estimating coastal
vulnerability to storms. Beach fill options were also tested to determine the most effective
approach to reduce vulnerability of the coast. Problems related to beach profile response
during storms, seasonal changes in profile shape, and the influence of water levels on profile
evolution were conveniently predicted through simulation of potential storms.
The findings of this study revealed that beach fill options as a method of reducing coastal
vulnerability provided only a short term protection hence revealing retreat as the best option.
It was also found out that beaches with medium sized sediment were highly vulnerable to
storms. Information gathered from this study is significant for developing pragmatic coastal
environment policies for sustainable management of the coastal areas. It also provides a
framework for developing coastal projects, identifying problems and appropriate solutions,
evaluating alternative designs, and optimizing the selected design to reduce human
vulnerability.
Page 16 of 24
Coupling Physics – Biogeochemistry in the Gulf of Guinea
Apetcho KokuEyram
International Chair in Mathematical Physics and Applications
ICMPA - UNESCO Chair
Benin
A simple biogeochemical model with Nutrients (N), Phytoplankton (P), Zooplankton (Z),
Detritus (D) and Dissolved Organic Nitrogen (DON) compartments is used in order to study
coupling physics -biogeochemistry in the Gulf of Guinea. After an analytical study of the
equilibrium and stability of the model, a sensitivity study demonstrates the strong impact of
parameter values linked to hydrolysis of particulate organic nitrogen and remineralisation of
dissolved organic nitrogen on surface biogeochemical tracers concentrations. Using EGEE-3
data obtained in June 02, 2006, an analysis of the equilibrium state of the model was
performed at 10°W 0°N both without and with an external forcing such as equatorial
upwelling.
Keywords Biogeochemical model, equilibrium, stability, coupling, phytoplankton, Gulf of
Guinea.
A Contribution to the Holocene Vegetation Changes of Nigeria: Palynomorphs from a
200 cm Core from Ohe Pond Nsukka, Nigeria.
Njokuocha, Reginald C., Department of Plant Science and Biotechnology, University of
Nigeria, Nsukka, Nigeria
A 200cm core from Ohe pond Nsukka, Nigeria was analysed palynologically and the results
provided evidence of a possible vegetation change and human impact in the environment
spanning as far back 6,416 ± 20 BP. There was a discernable change in vegetation marked by
a gradual but progressive dominance of the savanna over the lowland rainforest species. The
forest components were represented by Elaeisguineensis, Berliniagrandiflora and members
of the Moraceae complex (Milicia excels, Toxicariaafricana, TreculiaafricanaandFicusspp),
while the savanna elements were dominated by Alchorneacordifolia,
Antidesmasp,SyzygiumguineensisandPhyllanthusmuellerianus. The transition from vegetation
dominated by lowland rainforest species to that dominated by savanna elements may be
attributed to the opening up of the forests and bushland tickets by human activities dated as
far back as 4005 ± 40 BP in the area. The impact could have accentuated the effect of climate
in the vegetation thereby favouring the expansion of savanna species.
Page 17 of 24
Predictability, Prediction and the Linkage Between Sea Surface Temperature Analysis
along Coastline of Lagos, Nigeria.
EdiangOkukuArchibong, EdiangAniekanArchibong, Benson Levi
Nigerian Meteorological Agency
PMB 1215 Oshodi Lagos
Nigeria.
+2347033466011
Marine weather observers have since 1988 been making sea surface temperature observations
at East mole station, about 2 kilometers from the Coast. The station uses the rubber sea –
temperature bucket thermometer and makes observations on hourly basis, sea surface
temperature has influence on Lagos coastal weather and it is important especially for coastal
fishermen, offshore oil and gas industries, shipping vessels, coastal recreational and port
handling facilities. Some evidences of global warming in Nigeria have been observed using
sea surface temperature (SST) for the period of 1989 – 2007 which statistically analyzed,
results shows that the Nigerian coastal waters is warmest in April and Coldest in August. The
period 1989 – 2007 and 1993-2010 mean yearly data of sea surface temperature (SST) show
some of the Teleconnections with global warming.
The attempt in this paper is however to highlight the features of sea surface temperature over
the Lagos coastal waters. Indicating the global warming is evident in the environment of
Nigeria Coastal line, Since the Sea Surface Temperature(SST) graph plotted shows that the
Temperatures for the past two decades are really changing.
Preparing for Climate Change in Ghana, Through Coastal Monitoring
Sowah Wahab Laryea
Department Of Marine and Fisheries Science, University Of Ghana
Climate change and related issues have dominated world debate and the scientific community
for many years. This is as a result of the impact of climate change on society, economy and
livelihood. Coastal habitat degradation, erosion, flooding and inundation are major
consequences of climate change resulting from global sea level rise and changing global
weather patterns. To mitigate the impact of climate change on coastal communities, a coastal
monitoring programme has been instituted in Ghana by the Department of Marine and
Fisheries Science, University of Ghana to establish baseline maps for the coastline and
coastal habitats; and to provide understanding into the processes driving coastal changes. The
programme seeks to build and develop capacity to monitor and examine coastal responses
climate change. Various forms of data used include topographic maps, bathymetric maps,
sediment sample, measured wave data, aerial-photographs and satellite imageries.
Preliminary results show various degrees of coastline erosion, degrading habitats, and farm
lands and communities being inundated under different scenarios of sea level rise.
Keywords: Coastal erosion, Coastal inundation, Sea level rise, Climate change, Coastal
habitat degradation.
Page 18 of 24
Abrupt climatic changes in the Gulf of Guinea during the past 52 kyr.
AdesinaAdegbiea and Ralph Schneider
b
aNigerian Institute for Oceanography and Marine Research (NIOMR), P.M.B. 80108,
Victoria Island, Lagos, Nigeria. ([email protected]).
bInstitute for Geosciences, University of Kiel, Ludewig-Meyn-Strasse 10, 24118 Kiel,
Germany.
Evidence of rapid climatic oscillations like those observed in the Greenland ice cores and
sediments from high latitudes of the northern Atlantic have been recognized in the pulses of
terrigenous material to continental margin sediments off Cameroon. Fe/Ca ratios used as a
parameter to quantify the relative proportions of terrigenous fluxes versus marine carbonate
monitor the variability of the west African monsoon. They reveal the history of abrupt
changes in precipitation over western and central Africa during last 52 kyr. These rapid
changes are particularly pronounced during the last glacial period and occur at timescales of a
few thousand years. Stable oxygen isotope (δ18O) records of Globigerinoidesruber(pink)
show high negative values reflecting periods of high monsoon precipitation. The Fe/Ca
pattern is very similar to the Dansgaard-Oeschger cycles from the Greenland ice cores. The
good correspondence between the warm interstadials of the Dansgaard-Oeschger cycles from
the Greenland Ice Sheet Program (GISP2) ice core records and the high pulses of Fe/Ca
sedimentation in our core suggest a strong teleconnection between the low latitude African
climate and the high latitude northern hemisphere climate oscillations during the last glacial.
This climatic link is probably vested in the west African monsoonal fluctuation that alters
tropical sea surface temperatures, thermohaline circulations and in turn net export of heat
from the south to the north Atlantic, coupled with the variability of the low latitude southeast
(SE) trade winds.
Keywords: Climate oscillation; Fe/Ca; last glacial period; stable oxygen isotopes; monsoon
precipitation; Dansgaard-Oeschger cycles
HISTOIRE RECENTE DE LA VARIABILITE PLUVIOMETRIQUE EN AFRIQUE
DE L’OUEST : EXEMPLE DU BENIN
YabiIbouraïma, Afouda Fulgence et Boko Michel
Laboratoire Pierre Pagney ‘’Climat, Eau, Ecosystème et Développement’’ (LACEEDE),
Département de Géographie et Aménagement du Territoire, Université d’Abomey-
Calavi (République du Bénin)
L’Afrique de l’Ouest est une des régions les plus vulnérables au système pluvio-
hydrologiques du monde dans la mesure où tout le tissu socio-économique et les
composantes environnementales en dépendent largement. Dans ce contexte, les anomalies
pluviométriques positives ou négatives provoquent des crises pluvio-hydrologiques aux
retombées parfois graves. Dans la perspective du développement durable, il convient de
mieux connaître l’histoire récente de ces anomalies en vue de définir des mesures
prospectives adéquates.
Les données utilisées sont relatives aux hauteurs saisonnières et annuelles de pluie extraites
du fichier de l’ASECNA-Cotonou. Ces données se rapportent à 16 stations réparties sur toute
Page 19 of 24
l’étendue du territoire et remontent jusqu’en 1921 (années de création). La recherche
documentaire et les investigations de terrain ont permis de compléter les données
pluviométriques. L’utilisation des outils statistiques a permis de caractériser les anomalies
pluvio-hydrologiques récentes aux Bénin.
Les résultats attestent qu’après les décennies 1970 et 1980 caractérisées par une fréquence
d’anomalies négatives, les années 1990 et 2000 sont plutôt marquées par une tendance à
l’augmentation des pluies notamment de la grande saison. Les déficits pluviométriques
s’accompagnent de sécheresses hydrologiques, de la détérioration des rendements agricoles et
des pertes importantes de récolte qui engendrent de graves crises alimentaires. A l’opposée,
les années excédentaires sont marquées par le débordement des cours et plans d’eau qui
engendrent des inondations à l’origine des dégâts socio-environnementaux tels la dévastation
des champs et cultures, l’envahissement et ou la destruction des habitations, des ponts, etc.
Probablement ces anomalies pluvio-hydrologiques vont se multiplier et s’intensifier
davantage au cours des années à venir dans le cadre des changements climatiques et les
futures politiques d’aménagement du territoire devront en tenir compte.
Mots clés : Bénin (Afrique de l’ouest), déficits et excès pluviométriques, incidences socio-
environnementales, changements climatiques, mesures prospectives
Recent History of Rany Variabilite Pluviometrique in West Africa: ¶Example of the
Benin ¶
YabiIbouraïma, Afouda Fulgence and Boko Michel
Laboratory Pierre Pagney `' Climat, Water, Ecosystem and Development ''
(LACEEDE), Department of Geography and Regional planning, University of Abomey-
Calavi (Republic of Benin)
West Africa east one of the areas most vulnerable to the rainy and hydrological system of the
world insofar as all the socio-economic and environmental components largely depend on it.
In this context, the positive or negative rainy anomalies cause the rainy and hydrological
crisis with the serious repercussions. From the point of view of the sustainable development,
it is advisable to understand the recent history of these anomalies in order to define adequate
prospective measurements.
The data used relate to the seasonal and annual heights of rain extracted the file of
ASECNA-Cotonou. These data refer to 16 stations distributed on all the extent of the territory
and go up until 1921 (years of creation).The information retrieval and the socio-economic
investigations are made to supplement the rainfall records. The use of the statistical tools is
put at contribution to characterize the recent rainy and hydrological anomalies.
The results attest that after decades 1970 and 1980 characterized by a frequency of negative
anomalies, years 1990 and 2000 are rather remembered by a tendency to the increase in the
rains in particular of the great season. The rain deficits are accompanied by hydrological
dryness’s, of the deterioration of the agricultural outputs and the significant losses of harvest
which generate serious food crises. With the opposite one, the rain surplus years are
remembered by the overflow of the courses and water levels which generate floods at the
origin of the socio-environmental damage such devastation of the fields and cultures, the
invasion and or the destruction of the dwellings, bridges, etc.
Page 20 of 24
Probably these rainy and hydrological anomalies will multiply and to more intensify during
years to come in the framework from the climate changes and the future policies from
regional planning will consider this context.
Key words: Benin (West Africa), rainy deficits and excesses, socio-environmental
incidences, climate changes, prospective measurements
Palaeoclimatic and Palaeoecological Significance of Montane Pollen Assemblage from
the Neogene Formations of Eastern Nigeria
*Obianuju P. Umeji
Department of Geology
University of Nigeria
Nsukka
E-mail: [email protected]
And
C.O.C. Agwu
Department of Botany
Kogi State University
Ayangba
E-mail: [email protected]
Abundance of extant Alnus pollen in sediments is commonly associated with orogeny and
uplift while the decrease is ascribed to the gradual leveling of mountains. Alnus was earlier
thought to be absent in Nigeria because its stratigraphic distribution in the tropics was related
to the presence of mountains which provided the temperate climate required by the plant and
to the connections with more northerly mountain ranges which created the migration routes.
Recovery of an assemblage of montane species comprising saccategymnospermous
pollenPodocarpiditesmilianjianus, the non-saccategymnospermous pollen
Inaperturopolleniteshiatus and I. dubius, andthe fossil angiosperm, Alnipollenitesverus, from
the Oligocene-Pliocene Ogwashi-Asaba Formation and its correlateableMpu Formation
further inland, indicates the Neogene tectonic uplift affected the entire eastern Nigeria rather
than only the Cameroon Highlands. The effect of Neogenetectonism on the palaeoclimate is
also discussed.
Climatic oscillations during Holocene in West Africa: Palaeoclimatic Hypothesis of the
Quaternary Aquifer System Formation in the Coastal Sedimentary Basin in Benin
Henri S. Totin V. 1, Moussa Boukari
2, Michel Boko
3
1. Laboratory of Climatology, University of AbomeyCalavi, Benin, 03 BP1122 Cotonou,
Benin ([email protected]; [email protected])
2. Laboratory of Applied Hydrology, University of AbomeyCalavi, BP 526 Cotonou, Benin,
3. Interfaculty Centre of Training and Research in Environment for Sustainable
Development, University of Abomey-Calavi, Benin
Page 21 of 24
The coastal sedimentary basin is situated in southern Benin, covering an area of
approximately 12 377 km2. Coastal sedimentary deposits belong to the vast sedimentary
basin of the Gulf of Benin, which extends from Ghana to Nigeria. This study aims to
highlight climatic variations which contribute to quaternary aquifer formation in the coastal
sedimentary basin of Benin. The study is carried out using existing literature,
palaeoenvironmental tracers of palaeoclimate and palaeohydrology effects in the coastal area
of Benin and stratigraphic indicators collected through boreholes profiles and
hydrogeological cross section. In the coastal sedimentary basin of Benin, successive
variations in sea level establish eight major stratigraphic units. Hydrostratigraphical
classification shows four aquifers (Continental Terminal aquifer (Units V, VI and VII);
Cretaceous aquifer (Unit I); Palaeocene aquifer (unit IIb) and Quaternary aquifer (unit VIII).
These aquifers are linked by argillaceous and marly strata. They have been created in various
palaeoclimatic contexts as Holocene climate for the Quaternary aquifers. The Quaternary
aquifer is identified in the coastal sand and in the sand deposits of the Rivers Mono and
Oueme valleys and of the Lake Nokoue, where water table shows lentil of fresh water at the
top of salt water from lagoon or sea. This aquifer (Unit VIII) is supposed to be formed in
Holocene by alternation of glaciations and interglaciations with its associated climate since
2.4 Ma. The Quaternary aquifer is the most exploited for groundwater in the coastal area of
Benin.
The understanding of the climatic context of the Quaternary aquifer could help to best
manage its water resources with the regards of the coastal basin population rapid growth.
Key words: Benin, Coastal sedimentary basin, Quaternary aquifer, Holocene climate, Sea
level.
Analyse séquentielle des dépôts du bassin sédimentaire côtier du Togo : implication
paléogéographique
Pauline Y. Da Costaa, Sani M. Tairou
a, Pascal Affaton
b
aDépartement de géologie, faculté des sciences, université de Lomé, BP 1515, Lomé, Togo
bCNRS, Cerege, Aix-Marseille Université, Europôle méditerranéen de l’Arbois, BP 80,
13545 Aix-en-Provence cedex 04, France
∗Auteur correspondant : Pauline Y. Da Costa ([email protected])
Résumé - Les formations du bassin togolais, interprétées pour la première fois à la lumière
des concepts de la stratigraphie séquentielle montrent que la série sédimentaire est mise en
place sous l’action conjuguée des variations relatives du niveau marin, des apports
sédimentaires et de la tectonique. Trois cycles transgressifs successifs y ont été identifiés,
notamment au Campanien-Maastrichtien, Paléocène-Eocène et Oligocène supérieur-Miocène.
Les cortèges sédimentaires (IT, IC PBP, PHN) identifiés sont séparés par des limites des
séquences soit de type 1 ou de type 2. L’étude des variations de l’indice de pélagisme jointe
à l’analyse séquentielle permet d’y retrouver les marqueurs des grandes variations eustatiques
définies par Haq et al. (1987) notamment, ceux des variations eustatiques de l’intervalle
Crétacé terminal-Miocène inférieur.
Page 22 of 24
Le dernier épisode transgressif est suivi d’un cycle essentiellement continental couvrant
l’intervalle Miocène supérieur-Quaternaire basal.L’étude des dépôts du proche plateau
continental (Blivi, 1993) a permis de mettre en évidence deux cycles transgressifs au
Quaternaire. Le premier cycle a eu lieu au Pléistocène supérieur (40 000-18000 ans BP) avec
un niveau marin proche de l'Actuel et le second, au Pléistocène terminal-Holocène (18000-
Actuel). L’analyse de ces différents cycles transgressifs anté-quaternaires montre que la ligne
de rivage s’est déplacée progressivement du nord vers le sud. La présence de deux
générations de beach-rocks situées à quelques mètres de la ligne de côte actuelle traduit les
variations du niveau marin eustatique durant le Quaternaire.
Mots clés : Bassin côtier, Togo, Stratigraphie séquentielle, Crétacé, Tertiaire, Cycle
transgressif, Minéraux argileux, Indice de pélagisme, Tectonique, Ligne de rivage.
Linkages between Sea-Level Rise and Groundwater Quality: Livelihood Implications
and Interventions
NYAMEDOR Felix H.
Regional Institute for Population Studies, Box LG 96, University of Ghana, Legon.
Email: [email protected]@yahoo.com
Sea-level rise and groundwater linkages affect drinking groundwater and livelihood in
general. The present study examines the linkages using 350 quantitative data, focus group
and 60 groundwater samples for laboratory analysis according to WHO 2008 guidelines. The
Brun’s rule and its modification were used to assess local data for sea level measurements
using mean tide data. The result shows that sea-level rise has occurred in the study area and
affects groundwater for irrigation using sodium absorption ratio techniques.
Proximity to the coastline and the quality of groundwater was used to examine linkage using
least mean square level (LMSL) methodology. The analysis revealed four major groundwater
groups: low salinity, acidic groundwater contaminated with phosphorus; low salinity,
moderate to neutral pH in ground waters from communities away from the coastline; very
high salinity waters which are not suitable for most domestic and irrigation purposes, and two
intermediaries of moderate pH and ionic metals.
Responses to impacts are more burdensome to women than their male counterparts. Preferred
sea defence methods, sensitisation as well as equitable distribution of potable water and
livelihood empowerment through pump irrigation for agriculture will help alleviate poverty
and empower coastal rural communities to meet Ghana's MDG1.
Page 23 of 24
Projection of extreme events of climate change on reservoir water storage in the Volta
basin of Ghana
Etornyo Agbeko1, George Wiafe
2, Barnabas A. Amisigo
1, & Francis K. E. Nunoo
2
1 CSIR-Water Research Institute, P.O. Box AH 38, Achimota, Accra,
Ghana([email protected]) 2
University of Ghana, Marine & Fisheries Science Department, P.O. Box LG.99, Legon,
Ghana
The northern part of Ghana could be considered as most vulnerable zone in terms of water
shortage resulting in an arid condition. However, the global trend in climate change has
created extreme events of precipitation and drought in this part of the country. This paper
assesses the trend in extreme high rainfall in the Vea Reservoir catchment area in the Volta
basin of Ghana under future climate change scenarios. Future extreme high rainfall values
were projected based on IPCC, worst case scenarios (SRES A1FI) and best case scenarios
(SRES B2) with climate mid sensitivity and General Circulation Model (GCM: HADCM3).
These climate scenarios were run on SimCLIM extreme event analyzer using historic climatic
time series data over 1979-2009 for the 21st century. A forecast of rainfall pattern up to 2100
revealed that extreme high rainfall will increase under both climate change scenarios and
high runoff events like floods could intensify. More multi-purpose reservoirs are needed to
harness the water from the expected extreme high rainfall.
ANALYSIS OF THE MEASURED TIDE DATA FROM TAKORADI–GAUGE
STATION
TSEI SENAM
University of Ghana, Legon, Accra
Tide gauges provide enough information on the rate of sea level rise (SLR). Based on such
data, the IPCC estimated sea level to be rising at a rate of 2.0 mm/yr. The analysis of the
measured tide gauge data from Takoradi gauge station had revealed that the sea level is rising
at a rate of 2.6 mm/yr in Ghanaian waters. On monthly bases, the sea level is observed to be
increasing in the months of February, April, July and October at the rate of 0.12 mm/month.
Tidal potential energy along the coast of Ghana was identified to be increasing at the rate of
178.56 KJ/year. Moreover, a bi- annual cycle of high tidal heights was observed. Hence,
policies and activities within the coastal zone of Ghana should be geared towards adaptations
of the effects of sea level rise.
Page 24 of 24
IMPACT OF SEA LEVEL RISE ON COASTAL TOURISM DEVELOPMENT IN
ACCRA – GHANA
*Kate Sagoe-Addy
Department of Natural Resources, Kwame Nkrumah University of Science and Technology,
Kumasi
Recent sea-level rise has mostly been attributed to global warming and this process is
expected to continue for centuries. The extent of the impact of sea level rise on tourism in
Ghana is unknown though there are predictions that some prominent tourism facilities are at
risk. This paper assessed the potential impact of enhanced sea level rise (ESLR) for different
IPCC scenarios on tourism facilities along the coast of Accra. Shorelines for 1974 and 2005
were extracted from orthophotos and topographic maps, and vulnerability for tourism
facilities estimated. Mean sea level measurements indicated an average rise of 3.3mm/yr,
while the shoreline eroded by as much as 0.86m/yr. Predictions for Ghana showed 10cm,
23.4cm and 36.4cm sea level rise for 2020, 2060 and 2100 respectively with 1990 as base
year. Modelled predictions for the years 2020, 2060 and 2100 based on A2 (enhanced
regional economic growth) and B2 (more environmentally focused) IPCC scenarios indicated
that 13 tourism facilities are at risk to sea level rise. Out of the total number of tourism
facilities at risk, 31% cannot physically withstand the event of sea level rise hazard. In terms
of socio-economic vulnerability, accommodation facilities are the most susceptible.
Salinization and sanitation problems along the coast will adversely affect tourism.
Keywords
Mean Sea Level, Vulnerability, Coast of Accra, Tourism Facilities, Coastal Erosion.
