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Large stocks of soil organic carbon (SOC) have accumulated in the Northern Hemisphere permafrost region, but their current amounts and future fate remain uncertain. By analyzing dataset combining >2700 soil profiles with environmental variables in a geospatial framework, we generated spatially explicit estimates of permafrost-region SOC stocks, quantified spatial heterogeneity, and identified key environmental predictors. We estimated that Pg C are stored in the top 3 m of permafrost region soils. The greatest uncertainties occurred in circumpolar toe-slope positions and in flat areas of the Tibetan region. We found that soil wetness index and elevation are the dominant topographic controllers and surface air temperature (circumpolar region) and precipitation (Tibetan region) are significant climatic controllers of SOC stocks. Our results provide first high-resolution geospatial assessment of permafrost region SOC stocks and their relationships with environmental factors, which are crucial for modeling the response of permafrost affected soils to changing climate.

See the retraction notice BIO Web of Conferences 84, 00001 (2024), https://doi.org/10.1051/bioconf/20248400001

The purification of perfluoro(7-methylbicyclo[4.3.0]nonane) industrial fractions with a component content above 0.950 in mass fraction is not effective and requires the use of special separation methods. According to experimental data, the separation factor of the initial mixture during distillation with no additional substances is close to 1. At the same time, the addition of acetone (Ac) makes it possible to significantly intensify the process. Ac allowed for obtaining MBCN with a purity higher than 0.998 in mass fraction in one separation cycle, and the degree of recovery was more than 0.85 by weight. The paper presents data on the distribution of components (target product, identified and unidentified impurities of electrochemical fluorination of decalin) between the distillate and bottom product fractions, separation factor, liquid–liquid phase equilibrium in the MBCN-Ac system, and characteristics of the MBCN-Ac heteroazeotrope.

Structure of arctic peatlands with massive ice and structure-forming ice were studied in drained lake («khasyrey») of the Pur-Taz interfluves (the north of West Siberia). The period of accumulation of two-meter thickness of the peat was established to be changed from 8413±90 to 897±90 years BP. Composition of the peat deposits is represented by Betula nana, Sphagnum sp., Vaccinium oxycoccos, Eriophorum sp., Equisetum sp. The massive ice is represented by ice wedges with large shoulders and young ice wedges. The central part of the ice wedge is composed by recrystallized crystals of ice veins. Melting zones (elongated crystals of segregated ice and closed-cavity ice) were found in the shoulders of the ice wedge and in the upper part of the young ice wedge. Young ice wedges in the central and lateral parts the main wedge have a similar structure in the cross-section, but they are built by different genetic types of ice: the ice veins or closed-cavity ice with segregated ice. Ice-rich peat contains different types of ice inclusions and subhorizontal ice belts and ice lenses. Ice lenses in the peat can be formed by the segregated ice and/or infiltrated-segregated ice. The hydrochemical composition of the ice wedges, ice lenses, surface water samples and the aqueous extract from peat was analyzed. Hydrochemical analysis did show that polygonal-core ice has basically similar composition with the present-day atmospheric precipitation and surface waters of the polygonal bath; in the area of the shoulder – the composition is intermediate between the ground waters of peat and the central part of the vein. The hydrochemical composition of the ice lenses is similar to the composition of the lake water and peat underlying the active layer. The methane concentrations and its distribution within the ice wedges, peat and lens ice were determined. The closed-cavity ice doesn’t contain methane; the ice wedges with ice veins have minimal methane concentrations; large ice lenses have differentiation of methane concentrations. High concentrations of methane are typical for the frozen peat with inclusions of closed-cavity ice in the uppermost part of permafrost layer; the maximum methane concentration was determined inside the peat with ice lenses. The heterogeneous ices inside the ice wedges, distribution of hydrochemical compounds and methane distribution were conditioned by dynamics of the melting depth during the peatland formation under changing climate of the Holocene in the Arctic.

The process of crystallization separation of an industrial mixture of perfluorinated cycloalkanes was considered. The content of target products, cis- and trans-isomers of perfluorodecalin (PFD), in all initial fractions of the investigated samples of the reaction mixture was at least 70 wt.%. Based on the experimental data, the dependences of the crystallization (partition) coefficients between the solid and mother liquor (Ds/l), the enrichment factor (ηs), and the separation factor (Fs) on the ratio of trans-PFD to cis-PFD, the ratio of mother liquor to solid, and crystallization temperature in the range −50–15 °C were obtained. It was shown that the values Ds/l and ηs depended significantly on the concentration of trans-PFD in the initial solution, and that the value of Fs decreased as the process temperature rose.

Soils of the Arctic sea coasts are one of the least studied due to the complex logistical accessibility of the region, as well as the severe climatic conditions. The genesis of these soils is determined by several factors of soil formation simultaneously—cryogenesis, the influence of river alluvial processes, as well as the tidal influence of the sea. The paper presents data on the morphological structure of soils formed on the seacoast of the East-Siberian Sea (Kolyma Lowland, North Yakutia). Under the influence of cryogenesis and sea water tidal input, marsh soils are formed, with a relatively high level of salinity and the development of gleyization. Autochthonous and allochthonous soil organic matter play a leading role in marsh soil formation here, including the possible accumulation and biochemical transformation of incoming pollutants (e.g., hydrocarbons). The main objective of the study was to evaluate the soil organic matter genesis and alteration under the influence of tidal processes in coastal permafrost-affected soils as well as to obtain the previously unknown characteristics of the structural and elemental composition of different fractions of organic matter. The elemental composition and 13C NMR spectroscopy of humic acids were analyzed. It was revealed that humic acids extracted from the studied marsh soils accumulate up to 50% C and 4% N. Active processes of dehydrogenation are noted in HAs molecules, which indicates a relatively low degree of aliphatic structure development. According to 13C NMR spectroscopy, it was revealed that up to 45% of aromatic structural fragments accumulate in marsh soils, indicating a relatively high degree of organic matter stabilization and resistance to biodegradation.

The syngenetic ice and ice-ground composite veins in khasyrey (alas) and interalas plateaus were studied on the second lake-alluvial terrace located in the North of the Gydan Peninsula near the village of Gyda. On the basis of the radiocarbon dating, the time of formation of deposits containing veins from was established – from 16 640 to 854 BP. The peat deposits are mainly represented by the following species: Carex sp., Eriophorum sp., Betula nana, Equisetum sp., Calamagrostis sp., Vaccinium vitis-idaea, Drepanocladus sp., Empetrum sp., Vaccinium uliginosum, Rubus arcticus, Petasites sp. It is established that the polygonal-veined ice of khasyrey and interalas plateaus, except for vertical-striped «clean» ice, contain areas with vertical wavy streaks of ice-ground. Ice of elementary veins and segregation ice were revealed in the composition of veins according to structural and textural features in polarized light. Elementary ice veins compose «clean» ice sections of veins and segregation ice which are their ice-ground sections. Elementary veins are indicative of the predominance of the process of frost cracking during the formation of polygonal-vein ices. The presence of inclusions of ice-ground in the structure of veins points is evidence of a manifestation of local thermokarst processes under the growth of polygonal-vein ice. Ice-ground veins were formed by repeated thawing of the initial ice veins. The formation of ice-ground veins during syngenetic freezing of sediments of the second lake-alluvial terrace is related to uneven manifestation of thermokarst in different facies situations and and climate changes at the Early Pleistocene and Holocene.

Background: To adapt quickly to changes in the environment, significant functional changes occur in the human body exposed to various negative factors (including extreme occupational stress). The endocrine system, with the activation of the sympathoadrenal and pituitary-adrenocortical axis, plays an important role in this process. The aim of our investigation was to study the features of interhormonal relationships between the sympathoadrenal and pituitary-adrenocortical axis and the thyroid and gonadal hormones among professional, at-risk staff. Materials and Methods: A total of 156 police officers stationed in the Archangelsk region were examined. Depending on their professional activity, 3 groups were formed. Group 1 included 48 police officers who were sent to the conflict regions to maintain law enforcement – combatants. Group 2 included 52 duty officers who had never been in a territory with military conflict. Group 3 was formed from 56 students of the Police Training Center. Spearman’s rank correlation coefficient was calculated to measure the strength and direction of the relationship between two variables. Results: Among the studied groups of police officers, we found that the severity of interhormonal correlation depended on the intensity of professional activity. The highest number of significant interhormonal correlations was registered in the group of combatants, and these correlations were recorded between the hormones of all parts of the endocrine system: pituitarysympathoadrenal and thyroid-gonad hormones. Conclusion: The revealed multiple significant intersystem hormonal correlations among combatants, as compared with duty and student policemen, indicate that the functional intensity of the endocrine system is due to the extreme state of the professional environment.