Home – Home – Jornals – Contemporary Problems of Ecology 2019 number 5

The results of studying the structural and functional characteristics of phytoplankton in the coastal region of the Black Sea with the help of flow cytometry are presented. Data of the seasonal variability of the biomass of three algal groups (Synechococcus, pico-eukaryotic phytoplankton, nano-phytoplankton), chlorophyll a content, percentage of living cells, and fluorescence FDA (diacetate fluorescein), which characterizes the functional state of algae were obtained. A significantly positive relationship between the values (biomass, autofluorescence of chlorophyll), determined on the flow cytometer and the total content of chlorophyll a , calculated using standard methods, was revealed. Influence of environmental factors such as temperature, illumination and content of nutrients in the medium on biomass and fluorescence of the FDA of three isolated groups of algae is shown. It was noted that the nitrate content and temperature had no significant effect on the abundance of pico and nano-phytoplankton, while a reliable relationship was established between the biomass of nano-phytoplankton and the concentrations of dissolved forms of mineral phosphorus. An inverse statistically significant correlation was established between the intensity of light and the biomass of pico-eukaryotic phytoplankton. It was noted that the abiotic environmental factors considered in the study did not significantly affect the FDA fluorescence value, except for temperature: in the warm period of the year in the Black Sea the picophytoplankton are most active, while the cold period of the year s favorable for the development of nanophytoplankton.