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Measuring the linear characteristics of chironomid larvae is easier and faster than measuring their mass. The relationships between them are approximated by parabolic equations. Generalized equations are provided for all chironomid larvae. However, these relations vary in different water bodies. Measurements of 1424 chironomid larvae representing several species were taken in Crimean waters with salinity ranging from 0 to 280 PSU. There was a high correlation between three traits. In the case of Baeotendipes noctivagus and Cricotopus gr. sylvestris, dimorphism was found in the "head capsule length– width" relationship. Salinity affects the head capsule. The exponent "b" varied from 1.43 to 3.06 in the "body length-mass" equation for B. noctivagus, and from 1.943 to 2.592 for C. gr. sylvestris. It is inappropriate to use only one coefficient "b" for all chironomid larvae. In B. noctivagus and Paratanytarsus confuses, the mass of one-size larvae decreased with increasing salinity. Salinity is not the only factor affecting the size and mass of chironomid larvae. [ABSTRACT FROM AUTHOR]

Summary: Sivash Bay is the largest hypersaline lagoon in the world. In 1963-1975 the North Crimean Canal was constructed, with water from the River Dnieper and discharge of drainage water collected from agricultural lands into Sivash Bay. Salinity in Sivash Bay began to drop, resulting in a new brackish water ecosystem. The political decision to stop supplying water from the River Dnieper to the Canal was made in 2014, and the discharge of fresh water into the lagoon ended, resulting in an increase in salinity up to 60-75 g l−1. This study showed that the abundance of meiobenthos increased, with Nematoda dominating. The composition of nematode species in the lagoon has not previously been studied. Using samples from 1979, 2013 and 2015, 50 nematode species and forms were identified in 1979, 32 in 2013 and 21 in 2015. The species composition of nematodes at different periods was significantly different. The average abundance of nematodes was 134 198 ind. m−2 in 2013 and 606 660 ind. m−2 in 2015. [ABSTRACT FROM AUTHOR]

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Political and economic decisions have led to more drastic changes of aquatic ecosystems, than those caused by hydrological extremes (drought, floods). Examples of this are two transformations of the Sivash Bay (Sea of Azov); a review and analyses of them are given in the paper. Sivash Bay was a hypersaline lagoon before 1963. The North Crimean Canal was built to improve water supply to the Crimean peninsula by using the waters of the Dnieper River. After the initiation of Dnieper water via the North Crimean Canal and the subsequent development of irrigated agriculture, runoff waters from the fields began draining into Bay Sivash. The salinity began to drop. Pre 1997 the average salinity in Sivash Bay was 140 g L −1 ; in 1997 it had dropped to 17 g L −1 . A fundamentally new brackish water ecosystem gradually formed in Sivash Bay. In April 2014, Ukraine made a political decision to stop supplying Dnieper water via the North Crimean Canal. Discharge of fresh water to the bay almost ceased. Salinity began to increase, and a new transformation of the Sivash ecosystem started. Six complex expeditions were conducted in the Sivash region; their results are described and analyzed in the article. The salinity of the lagoon has now risen to 55–75 g L −1 , and drastic changes have occurred in the plankton, benthos, and aquatic vegetation. [ABSTRACT FROM AUTHOR]