Vertical distribution of phytoplankton at the section in front of the hydroelectric damnear of Kuibyshev reservoir dam during the period of massive development of Cyanoprokaryota

Data are presented on the vertical distribution of autotrophic plankton near the dam of the Kuibyshev Reservoir in the summer of 2023 during the massive development of Cyanoprokaryota and the “blooming” of water. 41 species from five systematic groups were identified in plankton: Cyanoprokaryota - 14, Bacillariophyta - 9, Chlorophyta - 16, Cryptophyta - 1, Dinophyta - 1. The limits of changes in abundance were: 0.35-158.95 million cells/l, biomass - 0.05-16.83 mg/l; the greatest values are noted in the surface horizon (0-2 m). The dominant species were mainly Cyanoprokaryota species: Aphanizomenon flos-aquae, Microcystis aeruginosa, Dolichospermum flos-aquae. Species diversity in algocenoses varied from 0.38-0.86 bits/ind. in the horizon where Cyanoprokaryota are concentrated, up to 1.47-2.48 bits/ind. at a depth of 3 to 7-9 m, where species of other systematic groups of algae developed: mainly Bacillariophyta and Chlorophyta. The vertical distribution of these species was characterized by an increase in the concentration of cells at deeper horizons compared to surface ones, which is associated with their adaptation to the massive development of Cyanoprokaryota.