Composition and structure of algocoenosises in the estuary of right bank Volga’s tributary Kudma river

Abstract

Present work provides information on the taxonomic composition and structural parameters of algocoenosises of the Kudma river, a right-bank Volga tributary. Data was obtained during the analysis of samples of plant plankton taken in the mouth of the river in 2019. The Kudma river is characterized by an irregular water regime, high salinity and relatively strong anthropogenic impact. Analysis of the algal flora of the studied water body revealed 248 species and intraspecific taxa, as well as algae identified to the genus, which belonged to 8 divisions. The flora was characterized as green-diatom-blue-green, with a significant predominance of green algae. The biomass during the period from May to October were quite high and corresponded to the eutrophic level. The biomass reached values of 18.80 g/m3. The complex of structure-forming species was mainly formed by centric diatoms. In Kudma river’s algocoenosises during summer period the presence of an invasive species, the dinophytic alga Unruhdinium kevei (Grigorszky & F.Vasas) Gottschling is noted.