Distribution and Population Dynamics of the Highly Halotolerant Species Eucypris mareotica (Fischer, 1855) (Crustacea, Ostracoda) in Hypersaline Lakes of Crimea

The distribution and population dynamics of Ostracoda and their response to environmental factors have been analyzed in Crimean hypersaline lakes based on data from a long-term monitoring study (2005-2016). Only one representative of this class, Eucypris mareotica (Fischer, 1855), occurs in these lakes. The species was recorded in the Crimean lakes at a maximum salinity of 300 g/L. The frequency of occurrence of this species correlated negatively with salinity. This species reached high abundances in plankton (650000 ind./m(3)), benthos (565000 ind./m(2)), and floating mats of filamentous green algae Cladophora spp. (9900000 ind./kg of wet weight of the mat). Ostracods were shown to reduce the concentration of calcium and magnesium in the water as a result of using these elements for the construction of their shells. The possibility of using the shells of ostracods for paleoclimatic and palaeolimnological reconstructions was discussed.