Changes in biocenoses of Kondopoga Bay, Lake Onego, under the effect of effluents from a pulp and paper mill

Long-term changes in the quantitative and structural characteristics of bacterio-, phyto-, zooplankton, and macrozoobenthos are studied in a water body subject to pollution by effluents of pulp and paper production. The key effect on the state of biocenoses is shown to be due to anthropogenic load and the qualitative changes in the composition of industrial wastes after nature protection measures taken at the plant. Differences are revealed in the character, stages, and direction of transformations in planktonic and benthic communities. The most significant changes in biota have taken place after the commissioning of biological treatment facilities and diffusing wastewater discharge, resulting in accelerated eutrophication of the basin and redistribution of transformed biocenoses over areas within the water body. A decrease in the load during production decline demonstrated the possible deeutrophication of the ecosystem.