Dynamics of benthic communities state and the sediment chemical composition in Lake Onega under the influence of anthropogenic and natural factors

Large Russian Lakes Ladoga, Onega, and Imandra under Strong Pollution and in the Period of Revitalization: A Review

“…The analysis of the literature [22,24,25,28,43,44,60,61] indicates that during the period of a reducing anthropogenic load, a new species structure of communities is formed that is different from the natural one: (i) nutrients are involved in biogeochemical cycles, as evidenced by their low concentrations of bioavailable forms in relation to high total contents; (ii) a number of species characteristic of the natural state are not recovered or are found in single-unit abundance; (iii) dominance changes in communities, e.g., species that are single in their natural state, develop in high abundance; and (iv) new introduced species are emerging that are actively exploring new ecological niches.…”

“…Research in 1998-2016 [24] showed that large-scale transformation of the deep-water benthic communities occurred in various areas of Lake Onega. In the northwestern bays (Kondopoga) and deep-water areas, the abundance and biomass of benthic communities decreased, and their production has reduced by 2-4 times in the last 25 years.…”

“…Significant areas of technogenic deposits in this zone still do not contain macrobenthos organisms. The reason for the decrease in the benthos indicators may be the inhibitory effect of iron, whose accumulation in the sludge is associated with an increase in the supply of this element in the composition of humus substances with river waters due to climatic changes in the catchment area [24].…”

“…This paper is based on an analytical review of published studies characterizing the natural state of the lakes before industrial activity [13][14][15][16][17][18]; changes in the main indicators of the polluted bays, which occurred in the mid 1960-1970s of the last century up to the 2000s [19][20][21]; and the state of the ecosystems in the same bays after stopping the pollution [22][23][24][25]. In this review, attention is focused on the main parameters of water chemistry and indicators of phytoplankton, zooplankton, benthos, and fish condition, which reflect ecosystem changes during different periods for Volkhov Bay of Lake Understanding the impact of anthropogenic contamination on aquatic ecosystems and their subsequent recovery as a result of decreasing anthropogenic stress is important for successful environmental management.…”

Modern changes in the ecosystem of Lake Onego with climate warming

“…The change in runoff into the Petrozavodsk Bay caused an increase in the content of iron and phosphorus in its waters. In the same period, there was the iron accumulation in bottom sediments of the Petrozavodsk Bay and a 4-fold decrease in the biomass of macrozoobenthos, Oligochaeta and Amphipoda (Kalinkina and Belkina, 2018) (Fig. 1).…”