Phytoplankton Indicators in the Assessment of the Ecological Status of Two Reservoirs with Different Purposes in Southern Ukraine

A comparison of two closely located reservoirs on the Southern Bug River and its tributary in the southern region of Ukraine is carried out. One of them (Tashlyk reservoir on a small river, tributary of the Southern Bug River) is a cooling reservoir (pond) for the nuclear power plant, the other (Alexandrovskoye reservoir, on the Southern Bug River) is used for agricultural purposes, for the production of electricity at a hydroelectric power plant, and as a lower reservoir for a pumped storage power plant. Comparison of the main indicators of phytoplankton in the reservoirs was carried out together with its spatial distribution. It was found that the distribution of coenotic groups of plankton in the cooling reservoir corresponds to thermal conditions. In the Alexandrovskoye reservoir, separate communities of plankton are formed along its length. The description of indicator species of algae in two reservoirs is given. The important role of the catchment basin was demonstrated with statistical maps. It was shown that a significant increase in temperature in the cooling pond did not lead to the depletion of phytoplankton.