Hydrobiological characteristics of a tundra river of the East European Arctic region

Species composition, quantitative development and community structure of zooplankton and zoobenthos of the Chernaya River Basin were studies in 2013. Studies covered the main channel of the Chernaya River in the lower reaches, its tributaries, lakes and small tundra water bodies. In the composition of zooplankton in the Chernaya river basin 52 species were identified. The most diverse in the water bodies were rotifers - 36 species and forms. Cladocera and Copepoda were less significant, and presented by the similar number of species and forms. The basis of the fauna of copepods made Cyclopoidae, among which the most interesting is Cyclops sibiricus, arctic species characteristic of small cold-water bodies. Among Calanoidae the usual for arctic zone Heterocope borealis, and Arctodiaptomus (Rh.) bacillifer, eurytopic species, reaching high abundance in cold-water bodies and in water bodies with high water salinity were met. Cladocerans were represented mainly by species of the families Daphniidae, Chydoridae and Bosminidae. The most rich planktonic fauna was in lakes and small water bodies, the leastin one of the tributaries.The most abundant zooplankton communities developed in small, overgrown water bodies, in which abundance and biomass reached significant values.Benthic communities of streams also were not rich in quantitative development. The average number and biomass of zoobenthos in water bodies were higher than in streams. The most diverse benthic fauna was registered in shallow tundra ponds, in which 22 major taxa of aquatic organisms were met. On larger lakes, tributaries and the Chernaya River number of taxa did not exceed 18-19. Amphibiotic insects, primarily dipterans (chironomids and black-flies) were the main share in aquatic communities. Only on the sandy bottom in the Chernaya riverbed nematodes dominated. Higher share of chironomids in the biomass of the zoobenthos of the river was observed when moving from the top point of research to the mouth. In the mouth section of the Chernaya River the bottom fauna is enriched by polychaetes and isopods. The availability of Phyllopoda - Polyartemia forcipata and Branchinecta paludosa, Conchostraca Cyzicus tetraceus is the characteristic feature of the Arctic waters.