摘要

The results of the study of phytoplankton of the Tvertsa River, the biggest tributary of Ivankovo Reservoir, are presented. Species composition, taxonomic structure, and ecological and geographic characteristics of plankton algae are discussed. A total of 381 taxa below the rank of genus were identified. It was found that the Chlorophyta and Bacillariophyta complex with the addition of Euglenophyta and Cyanoprokaryota form the basis of species diversity. The similarity of different sections of the river in the species composition of algae, and dependence of species richness of algae from different taxonomic groups on the abiotic parameters were revealed. The hydrochemical characteristics of the river is given. Discrete continuity in changing plankton flora from the source to the mouth of the river due to hydrochemical factors was demonstrated.