Abstract
N.Ya. Rudyk-Leuska*, N.Yu. Yevtushenko, M.I. Khyzhniak, M.V. Leuskyi, R.V. Kononenko, N.I. Tson and O.Y. Dumych
Detailed analysis of temperature indicators of Kremenchug reservoir in August showed a tendency to increase the coefficient of their variation (Cv=10.69–13.97%). This is indicated the unstability and stress of the temperature conditions of the aquatic environment for the living organisms. First of all, it affected the organisms of near-flood layers of water which are in direct contact with unstable air masses (Cv=28.45–31.45%). Blue-green algae species which were the most resistant to temperature fluctuations were Microcystis aeruginosa Kutz. emend. Elenkin and Anabaena flos-aquae sp. Their maximum values were recorded in the water area near the village Chervona Sloboda. An impact of a temperature factor and a number of other abiotic factors leads to intensive water “bloom” and subsequent mass extinction of algae Cyanophyta. Hot sunny days with the air temperature up to 18-32 °C and water temperature of 21.0–25.8 °C are the most dangerous to aquatic biota. As a result of lethal consequences, significant amounts of the most sensitive species of aquatic living organisms fall out of the ecosystem: Noble сrayfish (Astacus astacus) and Zander (Sander lucioperca). The obtained results could be partially explained by the global warming.