Transformation of Gulf Sivash (the Sea of Azov) in Conditions of Growing Salinity: Changes of Meiobenthos and Other Ecosystem Components (2013-2015)

Abstract

In April 2014, Ukraine has stopped the supply of Dnieper river water in the North Crimean Canal, bringing began to a salinity increase in the Gulf of Sivash (the Sea of Azov). Expeditions, which were conducted on Sivash in 2013-2015, have made it possible to evaluate the occurred changes in salinity, the concentration of total suspended solids (TSS), dissolved organic matter, as well as in macro- and meiobenthos, and plankton. Particular attention was paid Harpacticoida taxocene. In the 2014-2015, salinity was 40-70 g/L, it is significantly higher than in previous years (average 22 g/L). In 2014-2015, the concentration of TSS was three times higher than in 2013. Significant changes have occurred in benthos and plankton. Floating mats of green filamentous algae have developed intensively along coast, which noted the high number of meiobenthic Harpacticoida. In 2014-2015, species composition of Harpacticoida taxocene in the Sivash was differed from that in 2013; all of the marked species (8) were observed only in the plankton, there were only 2 species in mats, and 3 – on soft bottom. The authors conclude that the Sivash ecosystem moves into a new state

Keywords

• long-term changes
• lagoons
• salinity
• the Sea of Azov