Royal Belgian Institute of Natural Sciences; Marine Ecosystem Management; Management Unit of the North Sea Mathematical Models; Brussel (KBIN-BMM)
Pichot, Georges
Abstract
OAERRE aims to understand the physical, biogeochemical and biological processes, and their interactions, involved in eutrophication in coastal marine Regions of Restricted Exchange (RREs), especially lagoons and fjords. The scientific issues addressed include the controls on horizontal and vertical exchange in RREs and the response of coastal ecosystems to nutrient enrichment. Studies that help to define safe loadings of an RRE with nutrients are relevant to the EC Urban Waste Water Treatment Directive and similar directives, soon to be consolidated in a Water Framework Directive. They are also relevant to aquacultural aspects of the Common Fisheries Policy. OAERRE relates to key action 3 (Sustainable Marine Ecosystems) of Framework V, especially to the themes concerned with: better assessment of naturally occurring mechanisms of ecosystem functioning; transport pathways and impacts of pollutants and key elements in the marine environment; reducing the effects of anthropogenic activities on the marine environment and recovering degraded marine systems; and integrated studies of land-ocean interaction. The project will contribute to the aims of ELOISE, including the objective-foci concerned with interactions between pollution, eutrophication, and physical disturbance and development of mathematical models aimed at prediction and upscaling.
Scientific Objectives and Approach
OAERRE's objectives are:
1. Observations of the physics of vertical and open boundary exchange in RREs, leading to improved parameterisation of these processes in research and simplified models.
2. Study of the phytoplankton and pelagic micro-heterotrophs responsible for production and decomposition of organic material, and of sedimentation, benthic processes and benthic-pelagic coupling, in RREs, with the results expressed as basin-scale parameters.
3. Construction of closed budgets and coupled physical-biological research models for nutrient (especially nitrogen) and organic carbon cycling in RREs, allowing tests of hypotheses about biogeochemistry, water quality and the balance of organisms.
4. Construction of simplified 'screening' models for the definition, assessment and prediction of eutrophication, involving collaboration with 'end-users', and the use of these models to analyse the costs and benefits of amelioration scenarios.
OAERRE is a collaboration amongst physical, chemical and biological oceanographers, and coastal resource managers, with intensive studies relating to eutrophication at sites that exemplify a range of hydrographic and enrichment conditions. Four of these sites are fjords:
Two are bays:
-Golfe de Fos (French Mediterranean);
-Ria Formosa (Algarve).
Research cruises to fjords will using standard shipborn instrumentation (ADCP and CTD with optical sensors and water sampling bottles), plus turbulence probes, towed undulating CTD, and benthic sampling devices. Bays will be sampled using small boats and divers. Moorings will be equipped with a range of physical, acoustic, chemical and (bio-) optical sensors. The Gullmaren mooring will contain a profiling sensor package. Process studies will provide estimates of key ecosystem parameters, especially concerning physical exchange, nutrient cycling, the relative importance of autotrophic and heterotrophic processes, and the 'balance of organisms' amongst the benthos and the smaller plankton. Remote sensing will be used to study larger RREs and to provide boundary conditions.
Research models, involving 1D, 2D and 3D representations of physical, biogeochemical and biological processes in RRE, will draw on and advance the state of the art, and will be tested against historic and new data. One model will be used for trial 'real-time' simulations. The research models, and the process studies, will underpin the development of 'screening' models for eutrophication and related aspects of water quality. These 'screening' models are simplified representations of RREs in terms of a few boxes, in which the major processes are described in terms of a few system parameters. They will be designed to be safe through use of the precautionary principle, and to be transparent to a range of end-users, especially those responsible for maintenance of water quality. Output will be subjected to socio-economic scenario analysis to demonstrate the use of these models in evaluating options for ameliorating environmental impact.
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