SOFT-SEDIMENT MEIOFAUNA COMMUNITY RESPONSES TO ENVIRONMENTAL-POLLUTION GRADIENTS IN THE GERMAN BIGHT AND AT A DRILLING SITE OFF THE DUTCH COAST

During the Bremerhaven Workshop, the meiofaunal communities along 2 supposed North Sea pollution gradients, one at a drilling site off the Dutch coast and the other across the German Bight, were analysed by a variety of univariate and multivariate techniques and the changes on community structure related to a suite of measured environmental variables. At the drilling site the only evidence of change in community structure was a slight reduction in the abundance of nematodes in the deeper parts of the sediment (2 to 10 cm) close to the drilling site. Otherwise, there were no significant differences between sites using any other measure of community structure. It is concluded that sufficient time had elapsed since the cessation of drilling activity for a complete recovery of the copepod communities. Any differences which may still have been detectable in the nematode communities had been confounded by the scale of sediment disturbance caused by recent storms. Significant differences were found in the meiofauna communities along the German Bight transect but these are mainly correlated with corresponding changes in sediment granulometry and water depth. Although the addition of zinc improved the correlation between environmental variables and copepod community structure, it is argued that heavy metal contamination on this gradient is not likely to influence meiofaunal communities because (1) there is little variation in concentrations and (2) these concentrations are not particularly high when compared to other unpolluted (and polluted) areas of the North Sea.