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To estimate conditions for the stability of iron carbide under oxidation and to assess the possibility of formation of elemental carbon by interaction between iron carbide and oxides, experimental modeling of redox interaction in the systems Fe ₃C-Fe ₂O ₃ and Fe ₃C-Fe ₂O ₃-MgO-SiO ₂ was carried out on a “split-sphere” high-pressure multianvil apparatus at 6.3 GPa and 900-1600 °C for 18-20 h. During carbide-oxide interaction in the system Fe ₃C-Fe ₂O ₃, graphite crystallizes in assemblage with Fe ³⁺-containing wüstite. Graphite forms from carbide carbon mainly by cohenite oxidation: Fe ₃C + 3Fe ₂O ₃ → 9FeO + C ⁰ and FeO + Fe ₃C → (Fe ²⁺, Fe ³⁺)O + + C ⁰. At above-solidus temperatures (≥1400 °C), when metal-carbon melt is oxidized by wüstite, graphite and diamond crystallize by the redox mechanism and form the Fe ³⁺-containing wüstite + graphite/diamond assemblage. Interaction in the system Fe ₃C-Fe ₂O ₃-MgO-SiO ₂ results in the Fe ³⁺-containing magnesiowüstite-olivine-graphite assemblage. At ≥1500 °C, two melts with contrasting f _O2 values are generated: metal-carbon and silicate-oxide; their redox interaction leads to graphite crystallization and diamond growth. Under oxidation conditions, iron carbide is unstable in the presence of iron, silicon, and magnesium oxides, even at low temperatures. Iron carbide-oxide interaction at the mantle temperature and pressure leads to the formation of elemental carbon; graphite is produced from carbide carbon mainly by redox reactions of cohenite (or metal-carbon melt) with Fe ₂O ₃ and FeO as well as by interaction between metal-carbon and silicate-oxide melts. The results obtained suggest that cohenite is a potential source of carbon during graphite (diamond) formation in the lithospheric mantle and the interaction of iron carbide with iron, silicon, and magnesium oxides, during which carbon is extracted, is a process of the global carbon cycle.

The soils of the study area function in different temperature regimes: under the influence of permafrost (turbic histic cryosol and cryic eutric histosol) and long-term seasonаl freezing (Albic Podsol). Sporadic permafrost defines the differences in temperature regimes. All soils were characterized by low values of carbon dioxide effluxes (an average of 160 mgCO₂/(m²⋅h)) indicating their low biological activity. The lack of easily accessible carbon for microorganisms was detected in all investigated soils by the C_mic : C_org ratio despite the high stocks of organic matter. The value of CO₂ emission and the C_mic : C_org ratio were “site-specific” for the region of investigation and may be used as indicators of environmental changes. Peat cryogenic soils represent a unique natural object and provide functional diversity and integrity of northern taiga ecosystems of West Siberia.

Data on the species composition and distribution of ferns in the present-day periglacial zone of the Aktru, Karagemsky, Akkem, Sophiysky, Gebler and Taldurinsky glaciers in the Central Altai were presented. Sixteen species of ferns were found and confirmed by herbarium specimens. Botrychium lunаria (L.) Sw., Cystopteris dickieanа R. Sim, C. fragilis (L.) Bernh. and Polystichum lonchitis (L.) Roth were the most tolerant to the severe conditions of the high mountains. The distribution of ferns in the centers of present-day glaciation was related mostly to the occurrence of rocks. Colonization of the periglacial zone by ferns occured only by means of spores, initially by their dispersion from the locations far from the periglacial zone. Further colonization and migration of species following the retreating glaciers were possible by means of spores produced by sporophytes growing in the periglacial zone. Germination of spores and development of gametophytes and sporophytes in severe conditions of the periglacial zone occured mainly in local micro-niches providing protection in the cold season and sufficient amount of moisture in the warm season.

The diet of the American mink near the lakes and mountain rivers of the Southern Urals was studied. The structure and dynamics of the minks’ feeding near the lakes and mountain rivers differed significantly. On mountain rivers the minks’ diet depended on the abundance of small mammals on the river bank. The abundance of small mammals in each season was determined by the peculiarities of the hydrological regime.

The article presents the results of an experimental study on the bream Abramis brama L. exposed to polychlorinated biрhenyls (PCBs) administered with food. Responses of the components of hepatic biotransformation system (activity of ethoxyresorufin-O-deethylase and glutathione-S-transferase), antioxidant system (superoxide dismutase and catalase activity) and lipid peroxidation system (conjugated dienes and malonic dialdehyde contents) were studied. It was determined that the 2 mg/kg dose of PCBs did not cause permanent physiological alterations in the bream exposed to such feed for 14 days. Apparently, at these exposure conditions hepatic protection systems of the bream were able to suppress effects of xenobiotics and keep destructive processes on a stable moderate level.

The study area covered the West Siberian plain from the Urals to the Yenisei River, and the same lane further southwards to the borders of the former USSR in 1991, including a part of the Altai-Sayan mountain country, Kazakhstan, Uzbekistan, Turkmenistan, Kyrgyzstan and Tajikistan. On this site we analyzed the results of ornithogeographic surveys carried out on routes with a length of 63 thousand km in 3140 habitats from May 16 to July 31 in the period from 1936 to 2013. More than 100 specialists participated in the study. The collected data were averaged according to the contours of natural-geographical maps. The subsequent cluster analysis revealed the presence of 3 systems (rows) of bird communities of undeveloped and developed land, and water and riparian communities. Within the first system 8 types of communities were determined: 1 - Tundra; 2 - Forest-tundra; 3 - Forest; 4 and 5 - West Siberian: 4 - Meadow-steppe and 5 - Semidesert-steppe; 6 and 7 - Asian: 6 - North-desert-steppe and 7 - South desert; 8 - High-mountain. The borders of their distribution did not coincide with the zonal borders. In the second and third systems 7 and 6 types of communities were allocated respectively. A part of them was divided into 29 subtypes. The heterogeneity of bird communities was determined by 12 environmental factors. The greatest impact was detected for forest cover, building cover and watering cover. The correlation of the bird population variability with all the identified environmental factors amounted to 54 % ± 1 percentage of variance in the similarity matrix. It corresponded with the correlation coefficient of 0.74.

The elemental composition, the content of pigments, proteins, liрids, free amino acids and antioxidants of 5 wild halophyte species in Prieltonye were investigated. Plants differed in systematic location (Chenopodiaceae, Plumbaginaceae, Asteraceae), the type of regulation of salt metabolism (eu-, cryno- and glycohalophytes), life form (annual grasses, shrubs), the water regime (mesoxerophytes, xeromesophytes). A decrease in the ion content of K, Na, Ca among Suaeda linifolia > Salicornia perennаns > Halocnemum strobilaceum > Limonium gmelinii > Artemisia santonica was noted. The reversed pattern was observed for the content of C. The increase in the total content of C in glyco-, cryno- and euhalophytes was accompanied by increased content of total and membrane liрids, proteins and pigments. Halophytes varied considerably in terms of components of the antioxidant system - the content of endogenous proline, soluble protein, liрid peroxidation and the level of total SOD activity. Cluster anаlysis revealed that the differentiation of the studied halophyte species by the type of regulation of salt metabolism was mostly determined by biochemical parameters.

The ecology of the meadow piрit was studied in nаture in the Lower Ob region and on the Yamal Peninsula. Laboratory investigations were carried out under natural and artificial photoperiods. The factors affecting the distribution of the species in the north-eastern limit of its range were analyzed. The meadow pipit is wide-spread in the taiga zone and it does not need any special adaptations for the conditions of forest-tundra and southern tundra. But the species is not adapted to the north tundra environment. Current climate changes define the northern border of its range. The species has no obvious obstacles to spreading to the east.

Succession stages of epixylic lichens in relation to decomposition of fallen deadwood were studied in Eastern Baikal region. It was found that lichens passed through four stages of epixylic succession: from epiphytic and epixylic to the epigeic stage. It was also determined that lichens could inhibit decomposition of the higher layer of deadwood which served as the substrate to them.

Transformation of ecological environment on coal dumps under the influence of Pinus sylvestris L. lead to formation of three-zone phytogenous fields. The undertree zone was characterized by smoothed temperature conditions, low illumination, accumulation of the forest floor and formation of plentiful undergrowth. The crown zone with high moisture content was characterized by the developed moss cover and low occurrence of undergrowth. The external zone served as a transitional space to background meadow communities and was characterized by the developed grassy cover, high abundance of species and group distribution of undergrowth of P. sylvestris L. Positive, adaptive and negative reactions of grassy plants to phytogenous fields of Scots pine were noted. The majority of species expressed negative reaction.