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Coastal Lagoon Eutrophication and Anaerobic processes

Objectif

The goal of the project is to study eutrophication and dystrophy in coastal lagoons exhibiting production of toxic sulphide and release of volatile organic sulphur compounds to the atmosphere. Two sampling lagoons will be investigated through common field trips twice a year : Etang du Prévost (Mediterranean) which is highly eutrophic and displaying dramatic dystrophic crisis, and Arcachon Bay (Atlantic) where eutrophication is slowly increasing but still at a relatively low level. The specific objectives are :

1. To identify the key processes involved in lagoon eutrophication and dystrophy. Several environmental factors, nutrients, element cycles (with special emphasis on nitrogen and sulphur cycles), bacterial community structure (selected chemo-organotrophs, chemo-lithotrophs and phototrophs), algal (microphytes and macrophytes) and faunal (zooplankton, meio- and macrobenthos) components will be measured over different time scales (seasonal cycles and more detailed studies over diel cycles), in the water column and surface sediments of the lagoons.

2. To determine the impact of dystrophy on the dynamics of biological communities. The biodynamics of algal and faunal communities will be estimated in situ in relationship with sulphur bacteria dynamics, changes in biogeochemical cycles during dystrophic crisis, and estimation of the emission of volatile organic sulphur compounds to the atmosphere.

3. To compare a heavily polluted (Etang du Prévost) with a relatively clean lagoon (Arcachon Bay) and then to produce simple models with selected parameters in order to describe the interactions between biological processes and groups of organisms.


In general, research will be focused around eight joint field campaigns (four in each site). Both Prévost and Arcachon lagoons will be sampled intensively by the whole group during one week in spring and one week in summer 1993, and one week in spring and one week in summer 1994. During these campaigns two sampling stations will be investigated in each lagoon. Furthermore, four routine campaigns will be made in both lagoons by local teams, throughout the line of the project. Lagoon waters will be sampled and analysed for physical, chemical and biological parameters. Sediment cores will be subsectioned and subsequently biological and chemical parameters will be determined.

High resolution in situ measurements will be done at the sediment surface by microsensor techniques. Seasonal variation will be followed throughout the routine sampling. Diel variation of selected chemical and biological parameters will be followed during the intensive joint field campaigns in spring and summer. Measurements of physical and chemical parameters, in the water column and at the water-sediment interface (temperature, salinity, pH, dissolved oxygen, major nutrients and sulphur compounds, POC, DOC), (b) Determination of total bacterial biomass, (c) Determination of chlorophyll a content in water and sediment; biomass and specific composition of macrophytobenthos, macro- and meiobenthos; abundance of dominant groups in zooplankton.

Champ scientifique

Programme(s)

Thème(s)

Appel à propositions

Data not available

Régime de financement

CSC - Cost-sharing contracts

Coordinateur

Université de Bordeaux I
Contribution de l’UE
Aucune donnée
Adresse
2 rue Professeur Jolyet
33120 Arcachon
France

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Coût total
Aucune donnée

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Dernière mise à jour: 2 Avril 1996

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Permalink: https://cordis.europa.eu/project/id/EV5V0080/fr

European Union, 2024