Physical and biological models coupling: Application to the Bay of Vilaine (South Brittany)

Two models have been set up in order to study an eutrophicated coastal ecosystem, the Bay of Vilaine (South Brittany, France). The hydrodynamical model simulates real years with the joint effects of winds, tides and Loire and Vilaine Rivers discharges. The biological model reproduces phytoplankton, nitrogen and phosphorus cycles and oxygen concentration in a box model of the Bay. Coupling the two models consists in introducing calculated water circulation by the physical model into the biological box model. Then results are compared to datas. This coupled model not only improves the understanding of the ecosystem but it allows to test different hypothesis about the eutrophication of the Bay.