Habitat and Features of Development of Plankton Communities in the Unique “ Round ” Lakes of the Nadym River Basin (Western Siberia)

The article discusses mo rphometry, hydrochemistry, zooplankton and macrophytes of three unique “round” lakes of the Nadym River basin (Western Siberia, Yamal-Nenets Autonomous Okrug). Significant depths, weak lakeshore angularity, zero color of water and predominance of sulfates in the ionic composition are atypical for the northern taiga lakes of Western Siberia. Coastal aquatic vegetation is characterized by extremely low species richness with dominance of Sparganium angustifolium , which is an indicator of high-transparent ultrafresh oligotrophic waters. Dominant complexes were formed in planktonic communities represented by 1–2 species with a high level of dominance. According to the level of development of total zooplankton biomass the lakes belong to the ultra- and oligotrophic types.