Phytoplankton Composition of Turkish Offshore Water – October 2000

In order to determination of phytoplankton characteristics of the offshore waters of turkish seas were studied species composition, abundance and biomass of phytoplankton were comparatively investigated for october 2000. a total of 97 phytoplankton samples collected from the black sea, the marmara sea, the aegean sea and the mediterranean were analysed. during the study, a total of 111 phytoplankton taxa were found and 102 of them have been identified at the species level. there were 6 different phytoplankton groups in october 2000 in all seas. from these, dinoflagellates displayed the highest species diversity. diatoms had the highest contribution to the phytoplankton biomass of all seas. besides, the most abundant phytoplankton groups were coccolithophores (mainly e. huxleyi) in the black and the aegean seas, diatoms in the marmara sea and small flagellates in the mediterranean-levantine basin. average surface phytoplankton abundance and biomass values of each seas were estimated as 172x10^3 cells l^-1, 826 mg l^-1 in the black sea; 14x10^3 cells l^- 1, 159 mg l^-1 in the marmara sea; 2x10^3 cells l^-1, 10 mg l^-1 in the aegean sea; and 7x10^3 cells l^-1, 13 mg l^-1 in the mediterranean, respectively. there was a similarity in the dominant species between the black and aegean seas. the coccolithophorid e. huxleyi has been dominant phytoplankton species in both seas; especially in the black sea, its contribution to the total abundance reaching to 89%. based on the extensive sampling, phytoplankton seem to have a rather homogenous abundance distribution in the black sea compared to other seas investigated.