Влияние повышения температуры поверхностного слоя моря на потенциальную пополняемость популяции мидии у берегов юго-западного Крыма

Abstract

The article discusses the possibility of a connection between an increase in the temperature of the surface layer of water and a decrease in the potential replenishment of the Black Sea population of the mussel Mytilus galloprovincialis recruitment off the southwestern coast of Crimea in recent decades. The considered biological parameter is characterized by the number of mussel post-larvae, formed planktonic larvae that settled on the experimental substrate per unit of time (usually a month). The study of water temperature variability in the region showed that from the 80s of the last century to the present, there has been an increase in the average annual temperature of the surface water layer by about 2 ° C. The maximum increase in water temperature was noted during the warm period of the year, especially in June, July and September – during these months it was about 5°C. This ecological change took place against the background and, very likely, due to the previously noted processes of global warming, freshening of the surface layer of the Black Sea, a decrease in its vertical mixing, a decrease in the frequency and duration of coastal upwellings, and an increase in the eastern component in the surface wind speed in the region, contributing to the intensification of surge phenomena off the coast of Crimea. All these processes can lead to a decrease in the productivity of the surface layer of the sea, and, consequently, in the reproductive potential of the mussel population, as well as to a decrease in the probability of its larvae appearing in mass number at the stage of settling in the coastal zone during upwellings. In addition, a significant increase in the temperature of surface water in the Black Sea in the warm season can contribute to the food and reproductive activity of the predatory Rapana, feeding mainly on mussels, as well as to the survival of its juveniles. Thus, an increase in the temperature of the surface layer of the sea and the processes leading to this increase can directly or indirectly contribute to a decrease in the potential recruitment replenishment of the mussel and a decrease in reproduction of its population in the Black Sea.