THE LONG-TERM DYNAMICS OF ZOOBENTHOS COMMUNITIES IN THE LAKE UNDER CONDITIONS OF WASTEWATER POLLUTION FROM APATITE- NEPHELINE PRODUCTION

The changes in the composition and structure of zoobenthos of Bolshoi Vudyavr Lake were analyzed in the long-term dynamics. Benthic fauna is characterized by low taxonomic diversity. Zoocenosis consists of eurybiont species of oligochaetes (Tubifi cinae), chironomids (Chironiminae, Tanypodinae), and mollusks (Pisidiidae) in the deep-water zone. Chironomids Orthocladiina dominated in the littoral zone. Communities are complemented by bivalves, oligochaetes and invertebrates typical for the littoral zone of the lakes (gastropods, caddisfl y, beetles, mayfl ies, stonefl ies). In the structure of deep-water biocenoses there is a tendency of increasing of mollusks Pisidiidae. Their share in the total number of invertebrates increased from 30 % in 2001 to 66 % in 2022. Zoobenthos are characterized by relatively high values of abundance number and biomass. The average level of biomass of zoobenthos in the lake varies from “moderate” (5,0–10,0 g/m2) to “elevated” class (10–20 g/m2).