Ratio between living and dead cells and the size structure of the Yenisei River phytoplankton downstream of the Krasnoyarsk Hydroelectric Power Station

Resumo

Based on a daily examination of phytoplankton in the Yenisei River downstream of the Krasnoyarsk Hydroelectric Power Station (HPS) within a 4-year period, the ratio between living and dead cells is estimated and the size fractions of phytoplankton are described. It is found that, despite the certain negative effects of passing through the turbine blades of the high-head dam, high current speed, and influence of water discharges from the HPS, living algae cells dominate over dead ones in the water column of the studied reach of the Yenisei River during almost the entire year, except for several dates in late autumn and winter. It is shown that microphytoplankton (20–64 μm in size) and nanophytoplankton (2–20 μm), which make up 83% of the total algae count, pass through the turbine blades of the HPS and mostly remain undamaged, with the fraction of living cells varying from 21% in the winter period to 96% in the spring–summer period.