The use of zoobenthos to characterize the ecological state of aquatic ecosystems

© SGEM 2019. The water quality assessment on chemical and biological indicators of the Kuibyshev reservoir (Middle Volga, Russia) and the rivers - tributaries of 1 and 2 orders was carried out. Based on the results of hydrobiological research, modal intervals of the total number of zoobenthos were calculated, as well as the proportion of oligochaetes in the community and the Woodiwiss index. The Woodiwiss index was used as the indicator of water quality on the base of characteristics of benthos community. The method of redundancy analysis (RDA) and principal component analysis (PCA) were used for the search of correlation between an abiotic characteristic and the chemical composition of water. Inclusion in the analysis of a factor " Woodiwiss index" showed that the dominated role in the formation of the division of water bodies was played by a chemical factor at relative uniformity of biotic characteristics. In this regard, all biological data were divided into two classes: The 1st “clean” (the 1 and 2 classes on Woodiwiss) and the 2nd “dirty” (3,4,5 classes on Woodiwiss) that gave the division of water bodies according to the Woodiwiss index (modified) on two groups. The regression model of correlation between the number of a zoobenthos and the chemical composition of the water showed the existence of significant correlation between number of a zoobenthos and the content of suspended substances. As well as mineralization, ammonium ions, chrome and petroleum hydrocarbons content and negative correlation with the content of chloride ions, sulfate ions and iron ions. Thus, the indicators of macrozoobenthos, including the Woodiwiss index are good markers of water quality and can be used for classification of water quality and identification of intervals of the chemical compounds corresponding to an ecological system state on the response of benthos community