Phytoplankton in the Lake Otstoynik (Samara Oblast) Different Ecotopes

This article presents the results of the study of the species composition and main indicators of the quantitative development of phytoplankton in various ecotopes (pelagic zone, phytal zone) of Lake Otstoynik. It is a small pond belonging to the system of Vasilievsky lakes of Togliatti, Samara Oblast. Initially it served as a receiver of nitrogen fertilizer production waste. In the 90s of XX century, the technological use of this lake was terminated but the rehabilitation works to restore the ecosystem of the reservoir was not carried out. Modern condition of the ecosystem is entirely the result of self-purification and self-healing. Therefore, the materials presented in this article may be of interest to experts on environment, especially those who work in the field of cost-benefit analysis in predicting the development of a "zero" scenario, i.e. without interference through recreational activities in the recovery processes of disturbed aquatic ecosystems. The study deals with the species composition of the plankton algoflora in various ecotopes of the reservoir (open pelagic zone and phytal zone formed by reed), its floral and ecological/geographical analysis. In addition, it considers seasonal succession of phytoplankton in different ecotopes in the period from 2014 to 2016, analyzes quantitative indicators of development (abundance, biomass) of phytoplankton, the role of the major divisions of algae in their formation. We estimated the level of species diversity in different ecotopes of the reservoir with the use of the Shannon-Weaver index. In terms of quantitative development of phytoplankton, the level of water trophies was estimated. Based on the data of sapro/biological analysis, the pollution level has been established and the class of water quality in the investigated water body has been determined.