Anthropogenic Transformation of Kyzyl-Yar Lake in Crimea: Multiyear Research Findings

Resumo

Most of the hypersaline lakes located in the arid part of the Crimea have been undergoing anthropogenic transformations. We concentrate on the impact of the established water storage reservoir on the marine Kyzyl-Yar Lake (Western Crimea) over the period from 1985 to 2017. As a result of water seepage from the reservoir, the lake salinity decreased from 162 g/L in 1985 to 2–3 g/L in 2005 and subsequently remained steady at this level. Over 20 years, the lake changed from a hypersaline to freshwater lake. The accompanying changes included an altered ratio of ion concentrations in the water column and interstitial waters and increased Ca²⁺/Na⁺ and \({{{\text{SO}}_{4}^{{2 - }}} \mathord{\left/ {\vphantom {{{\text{SO}}_{4}^{{2 - }}} {{\text{C}}{{{\text{l}}}^{ - }}}}} \right. \kern-0em} {{\text{C}}{{{\text{l}}}^{ - }}}}\) indicators. Substantial shifts occurred in the structure of the biological diversity and conditions of the bottom deposits, such as the disappearance of branchipoda crustaceans of the genus Artemia, which had been practically the only representative of the local fauna before, and the dominance of new species Cladocera and Cyclopoida in plankton.