Ecological Status of the Chusovaya River by Its Epilithon and Hydrochemical Indices (near the Chusovoy Town)

Abstract

As a result of our study, data were obtained on the structure of the epilithon and the physicochemical parameters of the waters in the Chusovaya river near the town of Chusovoy for 2017–2018. The taxonomic structure, quantitative characteristics, dominant species, features of the distribution of the main groups of algae were studied. The algal flora includes 191 infrageneric algal taxa (168 species) from 6 divisions, 10 classes, 24 orders, 51 families and 86 genera. The taxonomic spectrum is based on diatoms (67.5% of the total numbers), green algae (21%), and cyanobacteria (9%). In the environmental and geographical aspects, the epilithon is mainly represented by widespread salinityindifferent benthic and plankton-benthic species, having an optimum in slightly alkaline or neutral waters. The epiliton of the Chusovaya river has reached a fairly high level of development. The values of the total biomass varied from 1.46 to 46.32 g/m², and the abundance did from 1.5 to 31.7 billion cells/m². The species diversity index (an average of 3.22±0.18) indicates species-rich and balanced algocenoses of the Chusovaya river, while in summer the indices are 1.9–2.2 times lower than in autumn. The dominant algae species differed in seasons, they were represented by diatoms or cyanobacteria in terms of their number, and by diatoms in terms of their biomass. In water samples with epilithon flushing, higher concentrations of chemical substances (NH₄⁺, NO₃^-, PO₄^3-, and Fe_tot) were noted than in river water, indicating the ability of the epilithon to accumulate substances. Significant changes in the biomass and/or abundance of epilithon as a function of the content of chemical substances in water and fouling washes were revealed. By the value of the saprobity index (from 1.34 to 2.27), the sanitary-biological state of the water in the Chusovaya river is assessed as satisfactorily pure (II–III water quality classes), the saprobity zone is ο-β-, β-mesosaprobic.