EXPERIMENTAL-STUDY OF MICROPHYTOBENTHOS R ESUSPENSION

The aim of this study was to determine the critical free-stream veloci ty required to resuspend the microphytobenthos, a specially designed r ecirculating flume. Sediments were collected at 2 sites representative of Northern Mediterranean shallow coastal waters: the Gulf of Fos and the Thau Lagoon. Critical free-stream velocity was between 15 and 20 cm.s(-1) for samples from Thau lagoon and 16.5cm.s(-1) for sediments c ollected in Gulf of Fos. At velocities greater than the critical flow rate, bent hic diatoms were resuspended as indicated by microscopic an alyses and increased fluorescence in the water column. About 7% of the benthic algae in the surficial Thau sediment were resuspended when th e velocity was increased fr om 10 to 30 cm.s(-1).