Anthropogenic influences on a mediterranean Nature Reserve: modelling and forecasting

The Lagoon of Biguglia (northeastern Corsica) is one of a number Nature Res erve. Anthropogenic activities are increasing over its watershed however. T he present study aims to examine the state of health of the lagoon with the example of two pollutants (Cd and Cu). Water samples were collected in spr ing and summer 1997. The trace metal fluxes between the various compartment s were measured. Transfer processes from the watershed to the lagoon were a lso examined. The temporal evolution of Cd and Cu content is assessed on th e one hand by comparing the present data with former reference work (1992). On the other hand, a 5-box model is implemented in order to reduce the com plex functioning of the lagoon to a system of differential equations. With the help of a numerical resolution method, the increase of metallic concent ration levels is estimated since 1992. On the basis of 1997 data, two hypot heses are compared. The hypothesis that takes into account a growing increa se of anthropogenic activities on the watershed gives, by extrapolation, re sults that are closer to field measurements. However, even with this hypoth esis, the cadmium content in the lagoon is underestimated. This may signify that for this metal the evolution of the lagoon pollution is more importan t than a Linear increase.