Long term response of six dia tom species to eutrophication

An investigation has been made on the abundance and annual periodicity patterns of six diatom species, using samples collected during the period 1977-1981 from Saronicos Gulf, Aegean Sea. The data comprised counts of the species Chaetoceros affine, Chaetoceros curvisetum, Chaetoceros didymum, Rhizosolenia fragilissima, Rhizosolenia stolterfothii, and Skeletonema costatum in samples collected from eutrophie and oligotrophic waters. The frequency distribution for abundance and the autocorrelation analysis were used for explaining the intraspecific and interspecific differences in growth and annual periodicity patterns of the above species. It is postulated that this procedure cao be followed for defining on a quantitative basis the sensitivity of phytoplanktonic species to water enrichment.