Evolution des peuplements des fonds cotiers au large du bassin d'Arcachon

This study deals with the evolution of a fine sand benthic community located in shallow water off Arcachon Bay in an area which receives effluent from domestic and industrial sources. Comparison between 1974 and 1979 samplings shows trophic structure fluctuations. In 1979, the community is characterized by a dominance of deposit feeders with a decrease of suspension-feeders and carnivores. An effects of the sewage is not proved. The sedimentation of fine elements is proposed to explain the changes of trophic structure. It is suggested that these fluctuations are governed either by water movements or by long period sedimentary cycles.