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For the first time, we investigated species composition, phytoplankton community structure, and hydrochemical parameters in the artificial cooling reservoir of a major thermal power plant (TPP) in northeastern Europe located in the Pechora River basin (Komi Republic). Our research, conducted during June and August, revealed a total of 81 species of algae and cyanobacteria, with cyanobacteria predominating. Among these cyanobacteria and microalgae (Bacillariophyta and Chlorophyta), algae that serve as reliable indicators of water quality were identified. The assessment of water quality based on abundance and species composition of indicator phytoplankton species revealed that the waters of the Pechorskoe Reservoir belong to the III class (β-mesosaprobic or moderately polluted). This indicates that water quality is satisfactory, and the reservoir retains the ability to self-purify. The power plant's discharges heat the surface layers, increasing plankton communities' diversity, abundance, and biomass. Such stable warming in the upper layers throughout the season, uncommon for natural water bodies in the north, results in a slight increase in the trophic status of the studied reservoir, supported by hydrochemical analysis. These results provide valuable information about ecosystem functioning under temperature increasing for predicting changes in the phototrophic biota of small northern reservoirs facing the impacts of climate change. [ABSTRACT FROM AUTHOR]

The algae which cause snow blooming remain poorly studied in the northern regions of the Eastern Europe. However, the process is widely observed, especially, in the mountain regions. The growth of cryophilic algae has a strong fascilitating effect on melting of the glaciers, thus, the comprehensive study of snow algae species would help to foresee and model interrelated processes of climate change in the ecosystem. The red snow blooming in the Subpolar Urals was investigated. The ecological characteristics of habitats where blooming occurred, as well as, chemical parameters of the meltwater were studied. The snow contained important elements for algal development, including N, P, Ca, Mg and other biogenic compounds. The density of algal cells in samples reached 0.33 × 104 cells per ml-1. A Chloromonas reticulata strain isolated from the red snow with massive development of biflagellate algae was studied in detail. The algal strain is stored in a collection of living algae in Institute of Biology Komi Scientific Center (SYKOA Ch-054-11). Based on analysis of ITS2 sequences, morphological and ultrastructural characteristics, the studied biflagellate strain has been placed to Chloromonas clade, Reticulata group with a high bootstrap support. The set of ultrastructural characters detected in isolated strain matched with that of previously described for other Chloromonas reticulata strains. Minor morphological deviations that were observed in Chloromonas reticulata strain from SYKOA Ch-054-11 in comparison with the strains SAG 29.83, SAG 32.86 and SAG 26.90 could be attributed to a latitudinal gradient differences and ecological conditions. [ABSTRACT FROM AUTHOR]

Biological N2 fixation in high-latitude ecosystems usually exhibits low rates but can significantly contribute to the local N budget. We studied N2 fixation in three habitats of East European subarctic tundra differing in soil N stocks and fluxes: N-limited vegetated peat plateau (PP), frost formations of bare peat called 'peat circles' (PC) with high availability of soil N, and vegetated upland tundra (UT) with low to intermediate N-availability. Nitrogen fixation was measured at field conditions twice during summer 2011 by acetylene reduction assay, and N2 fixation rates were verified by 15N2 fixation assay. Response to variation in nutrients, carbon, and temperature was studied in complementary laboratory experiments. Further, we aimed to link N2 fixation rates to N deposition and major N transformation rates (gross and net mineralization, plant N uptake) including high N2O emissions recently found from PC. We hypothesized that N2O emissions in PC were fueled partly by biologically fixed N. Contrary to that hypothesis, N2 fixation was found solely in PP (0.01-0.76 mg N m-2 d-1), where N2 was fixed by moss-associated cyanobacteria and heterotrophic soil bacteria. The low N and high P availability corresponded with the occurrence of N2 fixation in these soils. Nitrogen fixation represented only a small portion of plant N uptake in PP. Conversely, bare PC (as well as vegetated UT) lacked N2 fixation and thus N2O efflux is most likely fueled by release of mineral N to the soil through internal nutrient cycling. [ABSTRACT FROM AUTHOR]

Ten rare species of macroscopic algae were found in freshwater ecosystems of the Pechora and Vychegda River basins, belonging to four divisions: Cyanoprokaryota - 1 species, Rhodophyta - 3, Chrysophyta - 1, Charophy-ta - 5. Some of these were included in the regional Red Data Books of Nenets Autonomous District and Komi Republic, others were recommended to be included. Areas of distribution were marked; algae development conditions and limiting factors were described. [ABSTRACT FROM AUTHOR]

For the first time, we investigated species composition, phytoplankton community structure, and hydrochemical parameters in the artificial cooling reservoir of a major thermal power plant (TPP) in northeastern Europe located in the Pechora River basin (Komi Republic). Our research, conducted during June and August, revealed a total of 81 species of algae and cyanobacteria, with cyanobacteria predominating. Among these cyanobacteria and microalgae (Bacillariophyta and Chlorophyta), algae that serve as reliable indicators of water quality were identified. The assessment of water quality based on abundance and species composition of indicator phytoplankton species revealed that the waters of the Pechorskoe Reservoir belong to the III class (β-mesosaprobic or moderately polluted). This indicates that water quality is satisfactory, and the reservoir retains the ability to self-purify. The power plant's discharges heat the surface layers, increasing plankton communities' diversity, abundance, and biomass. Such stable warming in the upper layers throughout the season, uncommon for natural water bodies in the north, results in a slight increase in the trophic status of the studied reservoir, supported by hydrochemical analysis. These results provide valuable information about ecosystem functioning under temperature increasing for predicting changes in the phototrophic biota of small northern reservoirs facing the impacts of climate change.