Assessment of water quality and state of waterbasins of different types from characteristics of benthic animal communities

Abstract

Studies on waterbasins of different type have shown the impact of eutrophication and pollution by toxic and organic matter on the structural and functional characteristics of zoobenthos. A major factor determining quantitative development of non-predatory zoobenthos in lakes is, undoubtedly, the level of development of primary producers. Relationship of zoobenthos biomass and primary production is particularly pronounced in shallow lakes. Analysis of relationship of zoobenthos with abiotic and biotic factors in shallow hyperhaline lakes of Crimea has shown that the most significant parameters determining the values of biomass of macrozoobenthos were salinity and primary production, second in significance were oxygen concentration and depth. The changes in structure and quantitative characteristics of benthic communities of the Neva River estuary occur under impact of a complex combination of organic and toxic pollution. For the assessment of water quality and state of ecosystem in the Neva River estuary we used IP' integrated index specially devised by us for water-bodies and watercourses of north-western Russia. It is based on structural parameters of zoobenthic communities and makes it possible to take into consideration pollution with toxic and organic substances. On average the water quality of the Neva Bay judging from IP' values was relatively stable during 1982–2014. It was assessed as “polluted” with exception for abnormality in 2006 (“polluted–dirty”) caused by large-scale dredging work. As a result of stronger pollution, species diversity of benthic animals in the Resort District of the eastern part of the Gulf of Finland is lower than in the Neva Bay.