PHYSICAL AND BIOTIC ASPECTS OF FINE-SEDIMENT IMPORT IN THE OOSTERSCHELDE TIDAL BASIN (THE NETHERLANDS)

The distribution of fine sediments inside the Oosterschelde (Eastern S cheldt) throughout the year has been investigated. The results have be en interpreted in terms of physical transport processes and activity o f biotic components. Evaluation of the mechanisms that may induce land ward transport of fine sediment shows that an asymmetry in maximum ebb and flood currents is probably mainly responsible for the observed la ndward transport of fine sediment in the Oosterschelde. A theoretical formulation is presented which fits long-term sedimentation. Transport is higher during winter than during summer. Despite a lower transport rate during summer, filter feeders do not clear Oosterschelde water. Most of the biodeposits of filter feeders are resuspended by waves and currents, probably stimulated by bioturbation and fishery.