The influence of the Western Scheldt on the meiobenthos of the Belgian coastal area

A difficult aspect of pollution research is that of assessing the chronic, ecological effects os small amounts of pollutants discharged over long periods of time. These effects have to be distinguished from the natural variability of the populations. The spatial and temporal variability of the meiobenthos of six subtidal stations along the Belgian coast are examined seasonally from 1977 onwards. The sediment of the western part is characterized by fine to medium sands, the eastern zone is characterized by very fine to fine sands with a high mud content. The bulk of these fine materials emanates from the load in pollutants in the Western Schelde waters. The mud content in the eastern zone shows significant seasonal fluctuations; the fluctuation has no effect on the structure of the meiobenthic communities in this area. Despite the strong relationship between the characteristics of the meiobenthic communities and the sediment structure, the influence of the Western Schelde is reflected in a clear decrease in trophic, family and species diversity of meiobenthic communities. The eastern zone of the Belgian coast is one of the most impoverished areas in benthic life so far known