Ensuring the Sustainability of Arctic Industrial Facilities under Conditions of Global Climate Change

Global climate change poses a challenge to the mineral development industry in the Arctic regions. Civil and industrial buildings designed and constructed without consideration of warming factors are beginning to collapse due to changes in the permafrost structure. St. Petersburg Mining University is developing technical and technological solutions for the construction of remote Arctic facilities and a methodology for their design based on physical and mathematical predictive modeling. The article presents the results of modeling the thermal regimes of permafrost soils in conditions of thermal influence of piles and proposes measures that allow a timely response to the loss of bearing capacity of piles. Designing pile foundations following the methodology proposed in the article to reduce the risks from global climate change will ensure the stability of remote Arctic facilities located in the zone of permafrost spreading.

Typological diversity and ecological-geographical characteristics of the forest cover of southern part of the Evenki region

The article presents the results of preliminary comprehensive ecological and geographical studies of the forest cover of the middle taiga subzone of Central Siberia. The higher syntaxa of forests were identified using the ecological-floristic classification of vegetation (Braun-Blanquet approach). All forest communities in the region are classified as Vaccinio – Piceetea Br.-Bl. in Br.-Bl. et al. 1939 and are represented by the following orders: Ledo palustris – Laricetalia gmelinii Ermakov in Ermakov et Alsynbayev 2004 – coniferous (mainly larch) forests of Northern Eurasia on permafrost soils characterized by stagnant moisture and low heat supply; Piceo obovatae – Pinetalia sibiricae Ermakov 2013 – typical Siberian dark coniferous forests; Lathyro humilis – Laricetalia gmelinii Ermakov et al. 2002 – boreal forests with the participation of xeromesophilic moderately thermophilic species, widespread in the ultracontinental climate of East, South Siberia and Mongolia. The features of their ecology and geographic regularities and the participation of order communities in the formation of forest cover in different parts of the studied region were considered.

Changes in the microbial community structure triggered by permafrost peat thawing

An increase in permafrost temperature, accompanied by the melting and release of buried organic carbon, is one of the elements of the global warming scenario. To understand the way ecosystems respond to environmental changes, it is necessary to elucidate the factors affecting the distribution and activity of microbes in permafrost soils, which have been poorly studied so far. Meanwhile, they can have significant implications for nutrient cycling and related processes. Our research is devoted to assessing changes in the structure of the microbial community due to the melting of the palsa permafrost layer caused by the fire in 2007. The ecological-trophic groups of microorganisms of the territories changed under the influence of a natural fire in comparison with undisturbed analogs have been studied. It was revealed that the number of microorganisms in most groups on the palsa, affected by fire, is statistically significantly higher than the number of microorganisms in the undisturbed area.

Modeling the Process of Thawing of Tailings Dam Base Soils by Technological Waters

The storage of wastes from mining and mineral processing plants in the tailing dumps in regions with cold climates has a number of environmental consequences. Interactions of water with tailings in cold climates often lead to the thawing of permafrost soils, formation of technogenic thawing zones, and leakage of drainage waters. In the case of fault zones development in these areas, technogenic solutions are often filtered outside the tailing dump, promoting further development of filtration channels. In order to prevent leakage of solution from tailing dumps over time, it is necessary to determine the thawing zones and prevent the formation of filtration channels. In the case of the formation of a filtration channel, it is necessary to know what rate of rock thawing occurred near the formed filtration channel. In this study, for the tailing dump of a diamond mining factory, we calculated two exothermic effects: (1) due to physical heating of dump rock by filtering industrial water with temperatures from 2 to 15 °C through the rock; and (2) due to the chemical interaction of industrial water with the dam base rock. The amount of energy transferred by the water to the frozen and thawed rock over 10 years was calculated using thermophysical modeling and was 207.8 GJ and 8.39 GJ respectively. The amount of energy that the rock received during the ten-year period due to dissolution of the limestones and equilibration of solutions was calculated using thermodynamic modeling and was 0.37 GJ, which is 4.4% of the average amount of energy, expended on heating the thawed rock (8.39 GJ).

THE EFFECT OF ALFALFA INOCULATION BY NODULE BACTERIA STRAINS ON HE AGROCHEMICAL COMPOSITION OF PERMAFROST SOILS OF CENTRAL YAKUTIA

The long-term experimental data of studies on the influence of nodule bacteria strains on alfalfa yield, improving the quality of the resulting product, increasing agrochemical indicators of permafrost soils of Central Yakutia are presented.

The Influence of Hydrogeological Factors on the Railway Stability in the Areas of Island Permafrost Distribution (by the Example of the Trans-Baikal Railway, Russia)

Changes in the geocryological situation at the road base and in the adjacent territory should be predicted based on an analysis of regional features of the “climate – landscape – cryolithozone – construction” system. These relationships are manifested in various ways across various cryolithozone regions, with these differences being rather poorly understood. In this regard, in 2019, the Melnikov Permafrost Institute (Yakutsk, Russia) and the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences signed an agreement on joint research work in order to elucidate the evolution of frozen soils, as well as to justify the application of certain measures to stabilise the permafrost environment. These projects aim to study the cryolithozone response along the routes of projected high-speed highways and existing railway tracks. Since 2019, the Institutes’ representatives along with specialists from the Tynda permafrost station (the branch of Russian Railways), North-Eastern Federal University (Neryungri, Russia), Zabtransproekt (Chita, Russia) and the Institute of Natural Resources, Ecology and Cryology of the Siberian Branch of RAS (Chita, Russia) have been investigating individual sections of the Far Eastern and Trans-Baikal railways in Russia. Some areas here are characterised by the continuous distribution of permafrost soils, while others – by island permafrost distribution. These areas share such common features, as the significant lifetime of linear structures (lasting for several tens of years) and the presence of deformations of the railway track, which appeared in the first years after construction. Railway track sections installed in high-temperature frozen soils are of particular interest for monitoring. However, the construction deformations are not always caused by frozen soil degradation. This article presents the results of surveys at one of such objects – a section of the track confined to the Chernovskaya station of the Trans-Baikal railway.

Nutrient Inputs Stimulate Mercury Methylation by Syntrophs in a Subarctic Peatland

Climate change dramatically impacts Arctic and subarctic regions, inducing shifts in wetland nutrient regimes as a consequence of thawing permafrost. Altered hydrological regimes may drive changes in the dynamics of microbial mercury (Hg) methylation and bioavailability. Important knowledge gaps remain on the contribution of specific microbial groups to methylmercury (MeHg) production in wetlands of various trophic status. Here, we measured aqueous chemistry, potential methylation rates (kmeth), volatile fatty acid (VFA) dynamics in peat-soil incubations, and genetic potential for Hg methylation across a groundwater-driven nutrient gradient in an interior Alaskan fen. We tested the hypotheses that (1) nutrient inputs will result in increased methylation potentials, and (2) syntrophic interactions contribute to methylation in subarctic wetlands. We observed that concentrations of nutrients, total Hg, and MeHg, abundance of hgcA genes, and rates of methylation in peat incubations (kmeth) were highest near the groundwater input and declined downgradient. hgcA sequences near the input were closely related to those from sulfate-reducing bacteria (SRB), methanogens, and syntrophs. Hg methylation in peat incubations collected near the input source (FPF2) were impacted by the addition of sulfate and some metabolic inhibitors while those down-gradient (FPF5) were not. Sulfate amendment to FPF2 incubations had higher kmeth relative to unamended controls despite no effect on kmeth from addition of the sulfate reduction inhibitor molybdate. The addition of the methanogenic inhibitor BES (25 mM) led to the accumulation of VFAs, but unlike molybdate, it did not affect Hg methylation rates. Rather, the concurrent additions of BES and molybdate significantly decreased kmeth, suggesting a role for interactions between SRB and methanogens in Hg methylation. The reduction in kmeth with combined addition of BES and molybdate, and accumulation of VFA in peat incubations containing BES, and a high abundance of syntroph-related hgcA sequences in peat metagenomes provide evidence for MeHg production by microorganisms growing in syntrophy. Collectively the results suggest that wetland nutrient regimes influence the activity of Hg methylating microorganisms and, consequently, Hg methylation rates. Our results provide key information about microbial Hg methylation and methylating communities under nutrient conditions that are expected to become more common as permafrost soils thaw.

Ecology of microorganisms in the conditions of permafrost

The results of research into the ecology of pathogens of infectious diseases in permafrost conditions are presented. The work was carried out in laboratory conditions and horse breeding farms of the Republic of Sakha (Yakutia), located in the permafrost zone. Isolation and identification of pathogenic and conditionally pathogenic microorganisms were carried out by generally accepted methods used in microbiological practice. The survival rate of microorganisms was studied by methods of veterinary sanitation. The studies conducted showed that the survival time of some microorganisms on the objects of the environment in permafrost conditions is 2-3 times longer than the survival time of similar microorganisms in the southern and European territories of Russia and abroad. When studying microbial contamination and the survival time of microorganisms, a significant content of aerobic spore-forming bacteria (more than 2 x 106 CFU/g) in permafrost soils of Central Yakutia was established. Isolation of viable bacteria of the genus Bacillus from representatives of mammoth fauna preserved in permafrost soils (age 30-40 thousand years) proves the role of permafrost in the preservation of bacteria of the Pleistocene period. Permafrost contributes to the long-term preservation of foci and transmission factors of pathogens of infectious diseases. Isolation of pathogens of yersiniosis from the surfaces of glaciers and from wild animals indicates the danger of contamination of food during storage and consumption. The establishment of the circulation of pathogens of viral diseases among reindeer suggests the role of migratory birds in the spread of infectious diseases. The study of the epizootology of anthrax remains relevant. Knowledge of the survival time of microorganisms on the objects of the environment in the extreme conditions of the Far North and the study of the microbiota of wild animals and migratory birds are necessary to optimize antiepizootic and epidemiological measures in the prevention or elimination of infectious diseases in humans and animals.

Biological activity of meadow-chernozem and sod-taiga permafrost soils of the Yeravninsky basin

The biological and biochemical parameters of two types of permafrost soils of the Yeravninsky basin (the carbon content of the microbial mass, different groups of microorganisms, protease, catalase and the intensity of cellulose decomposition) were studied, depending on the water-thermal properties and the type of soil formation. It is established that permafrost soils do not have an optimal combination of potential and real (actual) enzymatic activity. It is also noted that the acidic reaction of the soil solution and the low availability of nutrients in sod-taiga soils increases the development of fungal microflora. The most significant soil-ecological factor that determines the microbiological activity of meadow-chernozem and sod-taiga permafrost soils is humidity, as evidenced by a direct correlation. In turn, these microbiological indicators can be used for diagnostic assessment of the biological state of soils, and also, along with other soil properties, should be taken into account when developing methods to increase the productivity of existing hayfields and pastures on them.