Influence of currents and waves on the whirling up of benthic diatoms living on intertidal flats

Summary Experimental observations showed that the presence of relatively dense populations of benthic diatoms in the water can be caused by water currents of relatively low velocity. However, field observations showed that wave action can strongly increase the whirling up of these populations. Observations done in the laboratory and in the field showed that benthic diatoms reached the water column together with resuspended sediment. The field observations indicated that, in contrast with the fine sediment fraction, bare parts of sand grain particles are relatively insignificant as a substrate for benthic diatoms. It is suggested that in turbid areas with extensive flats the benthic diatom populations are an important additional food source for the pelagic fauna.Publication no. 47 of Biological Research Ems-Dollard Estuary.