The first information about the phytoplankton of the Chernoye lake (Omsk region)

The author presents the first data on the species composition and abundance of the phytoplankton of the deepwater Chernoye Lake, located in the forest area of the Omsk region. Phytoplankton samples were selected in August 2015. The 51 taxa of specific and intraspecific ranks of 8 phylum have identified in the composition of the phytoplankton, including: Cyanoprokaryota - 9, Euglenophyta - 2, Dinophyta - 2, Chrysophyta - 7, Bacillariophyta - 12, Xanthophyta - 1, Chlorophyta - 9, Streptophyta - 9. In the lake plankton have found 11 taxa from Dinophyta, Chrysophyta, Bacillariophyta and Streptophyta, that are new for the Omsk Priirtyshye. The author estimates the ecological and geographical characteristics of the identified species of algae and cyanobacteria, whose structure is dominated by the indifferented to water salinity and an active reaction of the environment cosmopolitan organisms, species with wide tolerance to water pollution by an readily oxidizable organic substances (χ-β-, β-o-, o-β-, o-α-mezosaprobionts). Aphanocapsa delicatissima, Merismopedia tenuissima, Aphanothece sp., Cyanobium parvum (Cyanoprokaryota), Peridinium umbonatum (Dinophyta) and Trachelomo- nas volvocina (Euglenophyta) have been reaching the greatest abundance in the lake phytoplankton. Low similarity coefficient of the species composition by Czekanowski-Sеrensen (0.19-0.26) has set in comparison of the phytoplankton of the Chernoye Lake with other examined lakes of the forest zone. The trophic status of the lake corresponds to oligotrophic category with mesotrophic features. The facts indicate that the Chernoye Lake, like most of the lakes in the region, is in the process of natural eutrophication, but the lack of intense anthropogenic pressure gives the special features to its phytoplankton. The findings will be important in the biomonitoring of the water bodies of the Omsk Priirtyshye as an example of a lake in the natural undisturbed state.