p. 251 - 273 DYNAMIQUE QUALITATIVE ET QUANTITATIVE DE LA MICROFLORE PLANCTONIQUE DES EAUX DU LAC SINOE PENDANT LA PERIODE 1971-1980 Anca Roban Institut Roumain de Recherches Marines Constanta Abstract The structure and dynamics peculiarities of the phytoplankton from the Sinoe Lake are presented in the paper Cyanophyta was the dominant systematic group in the last four years, when a strong decre- asing of salinity - tp the fresh water, have been registered. The fresh species are also prevalent, both qualitatively and quantitatively, in whole studied period.