Non-Biting Midges (Diptera, Chironomidae) in the Benthic Communities of Saline Rivers in the Lake Elton Basin: Diversity, Salinity Tolerance, and Distribution

Physicochemical characteristics of the Dombrovska pit lake (Ukraine) formed in an opencast potassium salt mine and the genome response of Chironomus salinarius Kieffer (Chironomidae, Diptera) to these conditions

“…In experimental studies, Cartier et al ( 2011 ) found that for a salinity over 35 g dm -3 very few individuals of C. salinarius survive. The dominance of C. salinarius among benthic fauna in saline, especially hypohaline water, has also been found by other authors (Arias and Drake 1994 ; Gascon et al 2007 ; Zinchenko et al 2019 ; Zorina et al 2014 ). Both the water salinity and the percentage share of C. salinarius (from 47 to 85%) in zoobenthos in the Dombrovska pit lake was similar to those found in the saline (13–31.9 g dm −3 , density 49–66%) rivers of the Lake Elton basin (Volgograd region, Russia) (Zorina et al 2014 ).…”

“…The biodiversity of benthic fauna of the pit lake was relatively small compared with other saline water ecosystems (Arias and Drake 1994 ; Zinchenko et al 2019 ; Zorina et al 2014 ), indicating the stressed conditions in the pit lake. The pit lake was inhabited mainly by species typical for saline waters: Chironomidae such as euryhaline C. salinarius and halophilic Cricotopus (C.) cfr salinophilus , or eurytopic (with wide ecological spectrum) taxa Coleoptera such as Hydrotus and Heteroptera– Sigaria.…”

“…This species inhabits aquatic ecosystems (rivers, lagoons, seas, and lakes) with a salinity from 6 to 80‰ (Arias and Drake 1994 ; Drake and Arias 1995 ; Gascon et al 2007 ; Hiebaum 2007 ; Michailova 1973 , 1974 ; Ponti et al 2007 ; Zinchenko et al 2019 ; Zorina et al 2014 ). For example, C. salinarius (together with C. salinophilus ) was extremely abundant in the rivers of the Lake Elton basin (Volgograd region, Russia) which has a salinity above 26 g dm −3 (Zinchenko et al 2017 ; Zinchenko and Golovatyuk 2010 ) but does not exceed 41.1 g dm −3 (Zinchenko et al 2019 ). In experimental studies, Cartier et al ( 2011 ) found that for a salinity over 35 g dm -3 very few individuals of C. salinarius survive.…”

“…A preliminary study of benthic fauna in 2018 showed that the Chironomus ( Chironomus ) salinarius Kieffer were dominant in the Dombrovska pit lake. C. salinarius inhabit aquatic ecosystems with a wide salinity spectrum and tolerate important variations in salinity (Arias and Drake 1994 ; Cartier et al 2011 ; Drake and Arias 1995 ; Gascon et al 2007 ; Hiebaum 2007 ; Michailova 1973 , 1974 ; Ponti et al 2007 ; Zinchenko et al 2019 ; Zorina et al 2014 ). This species appears in Palearctic regions and is very abundant in saline waters, as well as mesotrophic and eutrophic rivers and lakes (Cartier et al 2011 ; Zorina et al 2014 ).…”

“…In terms of water mineralization, in 2015 the deepest central part of the pit lake had two distinct layers: the surface layer (0-5 m) was well oxygenated with mineralization of 50-134 g dm −3 , and the underlying layer (up to a depth of 85 m) was poorly oxygenated with a mineralization 179-420 g dm −3 (Zurek et al 2018). It is known that the salinity is the main parameter governing the biological biodiversity (Mirabdullayev et al 2004;Zinchenko et al 2019). The high levels of water mineralization of the Dombrovska Responsible editor: Philippe Garrigues pit lake creates unsuitable conditions for most biota, thus regarding zooplankton only three living taxa have been found: the rotifer Brachionus plicatilis and the ciliates Paradileptus elephantinus and Tindinnidium.…”