Structure and dynamics of phytoplankton in the Oka River mouth at the beginning of the 21th century

Abstract

Data on the species composition, abundance, and biomass of phytoplankton in the lower reaches of the Oka River are presented. The floristic and cenotic role of centric diatoms is shown. The dynamics of com� position and abundance of some Centrophyceae species is analyzed using light and electron microscopy. The expansion of brackishwater diatoms has increased, but th e eutrophic status of the stream is maintained against the background of drastic changes in abiotic conditions in the river at the beginning of the 21th century.