Macrobenthic and meiobenthic communities of an area off the Belgian coast of the North Sea were studied from 1970 until 1975 at 74 stations. On the basis of both macro-and meiobenthos, three zones can be distinguished in the area. The coastal zone is characterized by the macrobenthic Abra alba community, corresponding to the meiobenthic Microarthridion littoraleHalectinosoma herdmani community, and the open sea zone by the macrobenthic Venus gallina community and the meiobenthic Leptastacus laticaudatus -Paramesochra helgolandica community. In between is a transient zone where elements of both other zones mix. The distribution of these zones is governed by the hydrodynamical regime of the region, especially by the residual and tidal current system of the Southern Bight. Within the coastal zone, the composition of the community is influenced by pollution which especially affects the epibenthic detritus-feeders of the meiobenthos. The spatial stability of parameters describing community structure can be used for monitoring changes. Temporal characteristics of these parameters could not be investigated properly, but diversity seems to be much stabler than biomass.

Meiofauna composition, abundance, biomass, distribution and diversity were investigated for 31 stations in summer. The sampling covered the whole Oosterschelde and comparisons between the subtidalintertidal and between the western-central -eastern compartment were made .Meiofauna had a community density ranging between 200 and 17500 ind 10 cm -2, corresponding to a dry weight of 0 .2 and 8 .4 gm-2 . Abundance ranged between 130 and 17 200 ind 10 CM-2 for nematodes and between 10 and 1600 ind 10 cm -2 for copepods . Dry weight biomass of these taxa was between 0 .5-7 .0 gm-2 and 0 .008-0 .3 gm -2 for nematodes and copepods respectively .The meiofauna was strongly dominated by the nematodes (36-99%), who's abundance, biomass and diversity were significantly higher intertidally than subtidally and significantly higher in the eastern part than in the western part . High numbers were positively correlated with the percentage silt and negatively with the median grain size of the sand fraction . The abundance and diversity of the copepods were highest in the subtidal, but their biomass showed an inverse trend being highest on the tidal flats .The taxa diversity of the meiofauna community and species diversity of both the nematodes and the copepods were higher in subtidal stations than on tidal flats . In the subtidal, the meiofauna and copepod diversity decreased from west to east, whereas nematode diversity increased .The vertical profile clearly reflected the sediment characteristics and could be explained by local hydrodynamic conditions . Seasonal variation was pronounced for the different taxa with peak abundance in spring, summer or autumn and minimun abundance in winter .Changes in tidal amplitude and current velocity enhanced by the storm-surge barrier will alter the meiofauna community structure . As a result meiofauna will become more important in terms of density and biomass, mainly due to increasing numbers of nematodes, increasing bioturbation, nutrient mineralisation and sustaining bacterial growth . A general decrease in meiofauna diversity is predicted . The number of copepods is expected to decrease and interstitial species will be replaced by epibenthic species, the latter being more important in terms of biomass and as food for the epibenthic macrofauna and fishes .

Meiofauna composition, abundance, biomass, distribution and diversity were investigated for 31 stations in summer. The sampling covered the whole Oosterschelde and comparisons between the subtidalintertidal and between the western-central -eastern compartment were made .Meiofauna had a community density ranging between 200 and 17500 ind 10 cm -2, corresponding to a dry weight of 0 .2 and 8 .4 gm-2 . Abundance ranged between 130 and 17 200 ind 10 CM-2 for nematodes and between 10 and 1600 ind 10 cm -2 for copepods . Dry weight biomass of these taxa was between 0 .5-7 .0 gm-2 and 0 .008-0 .3 gm -2 for nematodes and copepods respectively .The meiofauna was strongly dominated by the nematodes (36-99%), who's abundance, biomass and diversity were significantly higher intertidally than subtidally and significantly higher in the eastern part than in the western part . High numbers were positively correlated with the percentage silt and negatively with the median grain size of the sand fraction . The abundance and diversity of the copepods were highest in the subtidal, but their biomass showed an inverse trend being highest on the tidal flats .The taxa diversity of the meiofauna community and species diversity of both the nematodes and the copepods were higher in subtidal stations than on tidal flats . In the subtidal, the meiofauna and copepod diversity decreased from west to east, whereas nematode diversity increased .The vertical profile clearly reflected the sediment characteristics and could be explained by local hydrodynamic conditions . Seasonal variation was pronounced for the different taxa with peak abundance in spring, summer or autumn and minimun abundance in winter .Changes in tidal amplitude and current velocity enhanced by the storm-surge barrier will alter the meiofauna community structure . As a result meiofauna will become more important in terms of density and biomass, mainly due to increasing numbers of nematodes, increasing bioturbation, nutrient mineralisation and sustaining bacterial growth . A general decrease in meiofauna diversity is predicted . The number of copepods is expected to decrease and interstitial species will be replaced by epibenthic species, the latter being more important in terms of biomass and as food for the epibenthic macrofauna and fishes .