| Eutrophication was studied in the coastal waters of Vilaine Bay (VB) in relation to that in the Loire and Vilaine rivers, by analyzing long-term trends of phytoplankton biomass and nutrient concentrations during the past decades. The reduction in dissolved riverine inorganic phosphorus concentrations (DIP) during the last two decades led to the significant decrease in chlorophyll a concentrations. However, dissolved inorganic nitrogen concentrations (DIN) decreased only slightly in the Vilaine and actually increased in the Loire, especially during summer. Simultaneously, phytoplankton in VB has undergone the following changes: 1) increase in biomass, 2) change in timing of the annual peak of biomass from spring to summer, 3) modification in seasonal course... |
