Distribution of mesozooplankton resting eggs in seabottom sediments of Thermaikos gulf (NW Aegean Sea, Greece) and possible effects of sediment resuspension.

The distribution of mesozooplankton resting eggs was studied in the bottom sediments of Thermaikos Gulf (Aegean Sea, Greece), to study possible effects of sediment resuspension on egg assemblages, due to physical forcing (storm events) and/or anthropogenic activity (trawling). The total abundance of eggs in sediments was higher at stations located close to the rivers’ mouths, with muddy sediments, and with the water column richer of zooplankton, than at stations located at greater depths and with muddy-sand bed sediments. At the former stations the vertical distribution of eggs has revealed a trend of homogenization within the sediment column, from September to February. This is related probably to the sediment re-suspension. At the latter stations, no clear temporal variability in the vertical distribution was detected. The eggs found in the bottom sediments of Thermaikos Gulf were assigned to 16 morpho-types. Amongst these, those assigned to Paracartia latisetosa and Labidocera wollastoni (as well as one type called Calanoida 3), were found to be dominant at all the stations and during all the sampling periods, both as full and empty eggs.