The biotic plankton community and eutrophication in coastal regions of the Gulf of Genoa.

Information of the results of the sampling carried out from May to September 1989 for the study of the biotic plankton community at three fixed stations in the Gulf of Genoa, locations affected by discharges from urban purification plant and rain water, are shown. The zooplankton sampling was performed using a standard net (WP2, mesh size 200 um), the phytoplankton and nutrient samples were taken with reversing water bottles and the bacteria sampled with a sterile bottle fitted with a closing mechanism. The catches were supported by hydrological data (Temperature, salinity, dissolved oxygen, pH) obtained using a multiparameter probe. The plankton community was studied both for quantity and quality, determining the most representative group of the zooplankton and the phytoplankton. The phytoplankton biomass was evaluated by measuring chlorophyll “a” while the total bacteria count was performed using the marine agar on plate count method. Bacteria resistant to mercury and chrome were investigated, as an indirect indication of pollution from these heavy metals, with negative result. Self-purifying test were performed on samples of water from the three sample stations, these tests have produced dispersion times for 90% of total Escherichia coli load from 6.9 to 20.9 hours.