CURRENT STATE OF PLANKTON COMMUNITIES OF THE LOWER VYCHEGDA RIVER AND ITS TRIBUTARIES

Abstract

The work is a part of the comprehensive studies of the rivers and lakes of the south-east of the Arkhangelsk region, carried out in 2021 for the purpose of development of aquaculture of inland water bodies. The data on the species diversity and structure of plankton communities of freshwater bodies belonging to the Vychegda River watershed were obtained. Taxonomic composition of phytoplankton in summer period of 2021 was shown. Species diversity was estimated using Shannon index based on relative abundance of species, Menchinic index to determine species abundance, and Jaccard's similarity coefficient. Pantle-Bucca saprobicity index was calculated to assess pollution of natural waters. Evaluation of watercourses trophicity based on the obtained indicators of phytoplankton and zooplankton was carried out. We have identified 192 taxa of microalgae from 8 divisions and 15 species of zooplankton from three systematic groups. Green and diatom algae were found to be the basis of the algoflora. The zooplankton community was cladoceric-copepodic. New data on the state of the phytoplankton community can serve as an informational and methodological basis for the development of ecological monitoring programs for the aquatic ecosystems of the region. The results of the research can be used to assess the fish productivity of the Arkhangelsk region water bodies and to calculate the damage to aquatic bioresources from economic activities.