Phytoplankton adaptation strategies under the influence of climatic changes and anthropogenic pressure on the Black Sea coastal ecosystems on the example Sevastopol Bay

Abstract

Some ways of the Black Sea coastal waters phytoplankton community adaptation to changes in water temperature, nutrients concentration and anthropogenic pollution have been identified on the example of the Sevastopol Bay. The increase in water temperature and decrease in nutrient content in the studied waters during 2000 — 2014 caused a gradual decrease in the chlorophyll a concentrations, total phytoplankton biomass and its re-composition, predominantly in the summer and autumn periods. The phytoplankton restructuring was predominantly reflected by a decrease in relative diatoms contribution in the total phytoplankton biomass and an increase in dinoflagellates contribution. Among the dominant diatoms species, the share of resistant species to high temperatures, pollution, low nitrate content in the water and microzooplankton grazing was increasing. An increase in nitrate concentration in the studied waters in 2020 led to increase in total phytoplankton biomass and a predominance of diatoms species, which under the stated conditions did not lead to bloom emergence as were regularly observed earlier in the Sevastopol region.