Nearshore areas and GIS; sensitivity to eutrophication in Brittany, France

Periodic proliferation of macrophyte seaweeds and phytoplankton occur every year along the French coast, especially in Brittany. The main scopes of the present multi-disciplinary programme are to identify the factors of coastal eutrophication and their relative contribution along with mapping the observed and potential eutrophication-sensitive zones. The study demonstrates that proliferation factors are both natural (seawater currents and temperature, nearshore sediments, rainfall, on-land geology and soil types) and man-made (nitrogen and phosphorus inputs). These data are now organized into a Brittany Nearshore Information System. A quantitative approach through multivariate spatial analysis and multivariate statistics leads the authors to elaborate an index of coastline vulnerability to eutrophication