Results of zoobentos research in river Sotka, PINEZHSKY STATE RESERVE (Arkhangelsk region, Russia)
The article considers the qualitative composition (species and taxonomic diversity) and quantitative indicators (occurrence, number and biomass) of zoobenthos of river Sotka in the spatial aspect. The sections of the river with the minimum and maximum abundance and biomass were identified. The dominant groups of benthic animals were determined by their numbers (chironomid larvae and small-bristle worms) and biomass (dipterans, oligochaetes and bivalve mollusks). Comparison of quantitative indicators in the annual aspect revealed a significant increase in biomass and relative stability of abundance over a 20-year period at the Filippovskoye site, as well as a decrease in numbers and biomass at the Moiseev Nos site. Based on cluster analysis (by species similarity), benthic sampling stations are combined into 2 groups. Water quality is assessed as conditionally pure, slightly polluted. Studies of zoobenthos in a unique river on the territory of the Pinezhsky reserve will be used to conduct a comprehensive monitoring of water quality and the biotic part of its ecosystem (phyto- and zooplankton, zoobenthos, ichthyofauna), including the inflow system.