Новые и редкие виды водорослей в планктоне нижнего течения реки Иртыш

According to studies of phytoplankton of the Irtysh River downstream (from Tobolsk to Khanty-Mansiysk)in August 2017, a taxonomic list of algae was compiled from 259 species and intraspecific taxa (sit), including thenomenclature type of species. Compared with previous studies of the middle XX and early XXI centuries, an increasein the abundance of species of Euglenophyta, Dinophyta and Chrysophyta has been established. 115 new ones sit wereidentified for this part of the river, among which Chlorophyta (60 sit) and Euglenophyta (27 sit) predominate. Thesechanges indicate the spread of the process of anthropogenic eutrophication from the middle to the lower flow of the IrtyshRiver and the increasing pollution of its waters with organic substances.