ECASA methods workshop, Dunstaffnage Laboratory, Oban

24-25 January 2006

Methods for the determination of Eh, OC, TN, and TP in surficial sediments

University of Veniceand ICRAM – STS Chioggia

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1 cmEh, OC, TN, TP

Eh

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Eh, OC, TN and TP mesurements - Sediment sampling

Sediment is sampled by means of a Box corer (15 x 17 x 26.5 cm)

2. The measure of Eh is performed in situ;Sediment samples from the first =~ 1 cm layer are transported to the laboratory, to perform OC, TN and TP measurements.

Performing Eh (mV) measurement

This combination electrode consists of a platinum ring indicator electrode and a silver/silver chloride reference electrode.

Electrode calibration: The ZoBell’s is used as reference in the checking routine. This solution has an Eh value of +430 mV at 25°C.

The measurement is performed in situ, by means of a portable pH/ion meter, coupled with the combination electrode.

Lars Erik Bågander, 1978. An evaluation of the use of redox measurements for characterizing recent sediments. Estuarine and coastal Marine Science, 6: 127-134.

OC determination in surficial sediment

Samples are homogenised, centrifuged to remove interstitial water, and stored at − 20 °C;

Sample processing: Sediments are dryied and sieved at 200 µm;6-10 mg of sediment are taken for the analysis; Carbonates are removed by treating the sediments with concentrated HCl 1 N (Verardo, 1990);

Analysis:Organic carbon concentration is determined by using a CHNS-O elemental analyser Fison (Italy) mod. EA1108, calibrated with acetanilide as standard.

TN determination in surficial sediment

TN concentrations are determined following the same procedure as for OC, but without acidification.

A reference marine sediment BCSS-1 (NRC, Canada) is periodically used to assess the accuracy of the analytical data.

TP determination in surficial sediment

Samples are homogenised, centrifuged to remove interstitial water, and stored at − 20 °C;

Sample processing: Sediments are dryied and sieved at 200 µm;About 100 mg of sediment are taken for the analysis;Total phosphorus is extracted from sediments with 1 N HCl after ignition at hight temperature (550°C for a 4 hours time);

Analysis:TP concentration is determined using an inductively coupled plasma atomic emission spectrometer (Spectro Modula) at 177.500 nm wavelength;

Aspila, K.I., Agemian, H., Chau, A.S.Y., 1976. A semiautomatedmethod for the determination of inorganic, organic and total phosphate in sediments. Analyst, 101, 187– 197.

THANK YOU!

UnitsBoth OC and TN concentrations are expressed as percentage of the element on the dry weight.

ECASA methods workshop, Dunstaffnage Laboratory, Oban

24-25 January 2006

14 – University of Veniceand ICRAM – STS Chioggia

Visma Site - characteristics

Location: 5 miles off-shore Chioggia (Venice council)

Farming area =~ 1 x 106 m2 (could be extended up t 4 x 106 m2)

Bathymetry =~ 21m (without strong gradients)

Type of gear: long-lines

Annual production: 600 MT, 6 x 105 kg

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Adriatic sea

Visma farm – layout of the study site

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Visma site – historical dataset

ICRAM-Chioggia, MAV datasetSamples collected on a monthly basis, during a three years period, from Lug-99 to Aug-02.

1. Mussel length, DW, Condition Index;2. Benthic macrofauna beneath the farm and in a reference station;3. CTD profiles;

Physico-Chemical and Water quality variables are monitored on a monthly basis nearby the farming area (Italian Ministry of the Environment, SiDiMar dataset). Monitored variables are:T, S, O2%, pH, Chl-a, trasp., NH4+, NO2, NO3, PO4, Si(OH)4, TP and TN.

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Visma site - current data

Aanderaa RCM-9 current meter, positioned 1 m above the bed, Module and direction of water current are recorded every 20 minutes.Data are available:From Oct to Dec 2000From Feb 2001 to Aug 2002

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Visma Site – presurvey

December 2005

SURFACE SEDIMENT 0-1 cm

Parameters Samples n. Station n. Tot analyses n.Eh 1 20 20pH 1 20 20

Grain size 1 20 20Water content 1 20 20

Ash 1 20 20Total Carbon 1 20 20Total Nitrogen 1 20 20

Organic Carbon 1 20 20Inorganic Carbon 1 20 20Total Phosphorus 1 20 20

Inorganic Phosphorus 1 20 20Total Sulfide 1 20 20

THANK YOU!

VERTICAL PROFILES IN THE CORESParameters Samples n. Levels n. Tot analyses n.

Eh 2 15 30pH 2 15 30

Grain size 2 15 30Water content^ 2 15 30

Ash 2 15 30Dissolved oxygen at interface water/sed 2 15 30

Total Carbon 2 15 30Total Nitrogen 2 15 30

Organic Carbon* 2 15 30Inorganic Carbon 2 15 30Total Phosphorus 2 15 30

Inorganic Phosphorus 2 15 30Radiodatation** 2 15 30

^to use two temperatures:450°C and 800°C*derived parameter**Make to ISMAR (check the cost)

INTERFACE WATER/SEDIMENT IN THE TWO CORESParametri Samples n. Station n. Tot analyses n.

Eh 1 30 30pH 1 30 30T 1 30 30

Dissolved oxygen 1 30 30

Visma Site – vertical profiles

Visma Site – bimontly samplingWATER

Parameters Sample n./year Station n. Level n. Tot analyses n.Temperature 6 2 vertical profile 12

Salinity 6 2 vertical profile 12Dissolved oxygen 6 2 vertical profile 12

Particulate organic carbon 6 2 5 60Particular total nitrogen 6 2 5 60

Suspended matter 6 2 5 60Particular phosphorous 6 2 5 60

Chlorophyll 6 2 5 60

SUPERFICIAL SEDIMENTParameters Sample n. Station n. Replicates n. Tot analyses n.

Eh 6 2 3 36pH 6 2 3 36

Grain size 6 2 3 36Water content 6 2 3 36

Ash 6 2 3 36Interface Oxygen water/sed 6 2 3 36

Total Carbon 6 2 3 36Total Nitrogen 6 2 3 36

Organic Carbon 6 2 3 36Inorganic Carbon 6 2 3 36Total Phosphorus 6 2 3 36

Inorganic Phosphorus 6 2 3 36Total Sulfide 6 2 3 36

MUSSEL Mytilus galloprovincialisParameters Sample n./year Individual n. Replicates n. Tot analyses n.

Length 12 100 1200Thickness 12 40 480

Height 12 40 480Total wet weight 12 40 480

Wet weight of soft tissue 12 40 480Dry weight of soft tissue 12 40 480

Shell weight 12 40 480Ash of tissue 12 40 480

AFDW 12 40 480Weight of faecal and pseudofaecal pellets 6 10 3 180Org.C of faecal and pseudofaecal pellets 6 10 3 180

Total Phosphorus of faecal and pseudofaecal pellets 6 10 3 180Inorganic Phosphorus of faecal and pseudofaecal pellets 6 10 3 180

Total Nitrogen of faecal and pseudofaecal pellets 6 10 3 180Ash of faecal and pseudofaecal pellets 6 10 3 180

Org.C of tissue 6 10 3 180Total Phosphorus of tissue 6 10 3 180

Inorganic Phosphorus of tissue 6 10 3 180

fine

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Italy

PO river

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Site 2:Water quality,mussel growth

& farm structuredata

Adriatic Sea

Italy

PO river

P:7.5 .103 T y-1

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data

Site 2:Water quality,mussel growth

& farm structuredata

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3a) Dati sperimentali – Temperatura, irradianza e …

Data Italian Ministry of the Environment & National Research Council

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FR IU LI V. G IULIA VENET OEM ILIA R .

Field data -Year 2003

Data Italian Ministry of the Environment

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