Estimation of indicators of phytoplankton development and water quality of the Peipus-Pskov Lake in modern conditions

Abstract

Currently, there is an acute problem of pollution of the hydrosphere, which results in a drop in the stability of ecosystems, destruction of the signaling links of biocenoses, and food pyramid violation. This paper presents the results of our monitoring the current state of phytoplankton communities and water quality of the Peipus-Pskov Lake, a large transboundary reservoir located in the northwest of the Pskov region. During the growing season of 2022, 221 phytoplankton taxa with ranks below the genus from 8 divisions were identified. The average abundance of phytoplankton over the entire period of our study was 11.6 million cells/L, the average biomass was 1.6 g/m3. An ecological and geographical analysis was carried out, according to which widespread freshwater planktonic forms of microalgae predominated in the lake, preferring stagnant-flowing weakly alkaline waters. According to the Sjörensen–Chekanovsky index, the degree of commonality of the species composition of the planktonic algal floras in the Pskov and Peipsi Lakes was 73.2%. Saprobiological analysis showed that the waters of the study area in 2022 were slightly polluted (class II of water quality).