Dynamics of physiologically active cells of pico- and nanophytoplankton in the coastal waters of Black Sea

Abstract

The dynamics of the abundance and viability index (VI) of pico- and nanophytoplankton in the coastal waters of Black Sea near Sevastopol were investigated by regular monthly monitoring using flow cytometry and fluorescein diacetate vital dye (FDA), as a marker of intracellular enzyme activity. Directed seasonal changes in the fraction of physiologically active cells in the study groups of algae in coastal waters was not identified. It is noted that, in the warm season and during vegetative growth of algae in the composition and pico nano-phytoplankton predominate living cells, the percentage of which varies from 70 to 100 %. Low values of the VI (30 %) picophytoplankton were obtained at individual stations in September, October and December, possibly due to the presence of this kind of cell size group Synechococcus, which are very sensitive to fluctuations of environmental factors. Refs 28. Figs 7.