Home – Home – Jornals – Contemporary Problems of Ecology 2020 number 2

The development of principles and methods for restoration of ecological systems that have undergone intense anthropogenic impacts is one of the most important tasks of modern ecology. The work is devoted to the study of the regularities of the influence of organic pollution on the structure and functional characteristics of zoobenthic communities and the degree of restoration of the pristine communities of bottom animals and the quality of the waters of the small Izhora River by bioindication characteristics. For this, the results of studies of the 1970s and 2000s were compared. Intensive organic matter pollution influenced the structure and functioning of zoobenthos, increasing biomass and energy flow through the bottom animal communities. At the same time, the role of oligochaete worms in the bottom communities sharply increased, the role of larvae of amphibiotic insects decreased, the species richness and biological diversity of zoobenthos declined, and the efficiency of energy transfer between trophic levels of primary and secondary consumers fell down. Water quality in accordance with the values of the integrated index IP′ corresponded to the fifth highest class of pollution (“dirty”). Downstream, due to self-purification processes, the water quality and ecosystem state improved slightly, but this improvement was not very significant, which indicated that the river’s ecosystem was not able to process excess organic matter entering the river. The introduction of wastewater treatment from organic pollutants at sewage treatment plants contributed to the restoration of the structural and functional organization of zoobenthic communities and significantly improved the state of the river ecosystem. However, a complete restoration of water quality did not occur: it improved to “moderately polluted”.