Phytoplankton as a bioindicator of the water quality of Lake Malenets (Pskov Region)

This paper shows the use of planktonic algae in determining the ecological state of the reservoir. Phytoplankton is an important link in the aquatic ecosystem, which is the first to react to the slightest fluctuations in environmental conditions by changing its structure and quantitative characteristics, and therefore is very convenient in bioindication studies. In the summer of 2017, the planktonic algaflora of Lake Malenets, located on the territory of the Mikhailovskoye Museum-Reserve in the Pushkinogorsk District of the Pskov Region, was studied for the first time. In total, 87 species and intraspecific taxa of phytoplankton were identified from 8 phylums, 12 classes, 20 orders, 35 families, and 58 genera. The dominant algaflora complex is characterized as diatom-chlorophytic with the presence of golden algae. Using the Sierensen-Chekanovsky index, the degree of similarity of the phytoplankton species composition of Lake Malenets with the nearby Lake Kuchane was estimated. The calculation of quantitative indicators of phytoplankton – abundance and biomass was carried out, the ecological and geographical characteristics of microalgae were presented, and the water quality class of Lake Malenets was established. The obtained results are of practical importance, since they allow to establish the ecological state of the water body as well as to develop methodological recommendations for its improvement and stabilization.