The studies conducted as part of the KNI-2 regional complex scientific research in the Republic of Sakha (Yakutia) focused on analyzing both global and domestic markets for rare metal raw materials. The findings revealed that, in addition to the well-known group of rare earth metals (REM) and rare earth elements (REE) from the unique “Tomtor” deposit, lithium extracted from hydromineral brines and tungsten sourced from the Agylkinskoye deposit are also highly sought after. To improve project efficiency and facilitate the production of high-quality products in Yakutia, we propose a model for the establishment of a consolidated rare metal cluster within the Republic of Sakha (Yakutia). This model includes three principal initiatives: the extraction of lithium from hydromineral resources, particularly the brines associated with the “Udachnaya” pipe; the extraction of rare earth metals, such as niobium and scandium (and potentially manganese), from the ores located at the Tomtor deposit; and the development of the Agylkinskoye deposit for the production of tungsten concentrate. The first two projects are planned for implementation in the Mirninsky and Oleneksky districts of the Republic of Sakha (Yakutia). These projects will focus on the production of various chemical reagents, including caustic soda, chlorine, or hydrochloric acid, utilizing local resources. Selective sorbents, either of domestic origin (such as Axionite) or produced in China, may be employed for the extraction of lithium. The resultant commercial product will be lithium carbonate, which is intended for future distribution within the Russian Federation (for instance, to the KhMZ in Krasnoyarsk) or for export to China. The primary chemical treatment of Tomtor ore to produce commercially viable industrial products, such as pyrochlore concentrate and solutions enriched with REM and scandium, can be achieved through alkaline opening using locally produced reagents. This process is followed by the application of selective sorbents to extract rare earth compounds. The proposed metallurgical cluster in the southern region of the Republic of Sakha (Yakutia) represents a substantial opportunity for the advancement of rare metal production. The establishment of pyrometallurgical facilities within this cluster could significantly enhance the production of various ferroalloy products, including ferrotungsten, ferroniobium, and ferromanganese. These materials are essential for the production of high-quality steel, particularly in the Republic of Sakha (Yakutia).

This article presents findings from research conducted on the Mesozoic intrusive magmatism within the ChokhchuroChekurdakh zone (CCZ). This zone extends in a submeridional direction across the Primorskaya (Yano-Indigirka) lowland, from the Bakyn massif of the Northern batholith belt in the south to Cape Svyatoy Nos on the Laptev Sea in the north. All granitoid massifs of this series intrude upon the folded strata of the Late Jurassic and Early Cretaceous periods. Their location is controlled by a regional deep fault zone, indicating that the massifs formed during the postcollision stage of the tectonic stretching process. Available data suggest a close timeframe for their formation, estimated at 105–109 million years ago, as determined by the ³⁹Ar–⁴⁰Ar dating method. Petrography, mineralogy and petro-geochemical features of rocks, forming the massifs of the zone and their associated dikes are examined. The P–T parameters of the generation for parent melts and the crystallization of granitoids are calculated. It has been determined that the granitoids of the massifs of the northern part of the zone belong to I type granitoids, which formed in a suprasubduction environment. In contrast, the massifs of the southern part of the zone and the postgranitic dikes of rhyolite-porphyry are defined as A-type granites, formed under the conditions of the continental margin (granites of massifs) and close to the continental rift-related one (dikes of rhyolite-porphyry). The temperatures and pressures during magma generation are close for all massifs in the zone, indicating a change in the composition of magma-forming substrates along the zone from north to south. Geochemical criteria correspond to the crustal origin of the granitoids, whereas the high temperatures of magma generation (1000–1200 °C) and the beginning of crystallization (900– 1150 °C) require the inflow of juvenile heat to begin melting crustal substrates.

Since the last century, the monitoring of permafrost rocks, which involves observing changes in the depth of seasonal thawing and temperature, has been conducted across a wide geographical area. However, an increase in the cumulative average daily positive air temperatures and the average annual air temperature has significantly activated cryogenic processes in the northern part of Western Siberia. Since 2016, extensive and thorough research on permafrost polygonal peatlands has been undertaken in the Pur-Taz interfluve area. In 2021, a study was initiated to observe changes in polygonal relief and the upper layers of permafrost, which are affected by natural processes occurring in peatlands near lake shores. An assessment of changes in polygonal relief in the peatland–lake interaction zone of polygonal peatlands has been conducted as a result of exogenous processes against the background of modern climatic fluctuations. This study used field methods and approaches, including the establishment of monitoring sites to observe geocryological conditions and the use of unmanned aerial vehicles to assess changes in relief and manifestations of cryogenic processes along lake shores. The results of the field observations were analyzed using both classical statistical methods and specialized software for processing orthophotoplans and digital terrain models obtained from unmanned surveys. These findings were subsequently compared with satellite images. Several climatic and landscape factors affecting polygonal peatlands in the peatland-lake interaction zone were identified. Thus, the accumulated monitoring data from multiple sites within this zone, combined with results from key peatlands in the research area, allowed us to draw preliminary conclusions regarding the general dependence of polygonal peatland degradation along lake shores on the wave action of lake water, which is influenced by the wind rose of the research area. This degradation occurs against the background of contemporary climatic fluctuations and the differentiation of other contributing factors, including the landscape-geomorphological conditions of the monitoring sites.

Regional scenario-based projections require a comprehensive understanding of baseline climatic conditions, particularly the spatial distribution of total mean annual precipitation within the region. Precipitation data from 40 meteorological stations across the Republic of Sakha (Yakutia) for the period from 1961 to 2020 were used to evaluate the performance of modern reanalyses: CRU TS, ERA5-Land, GPCC, NCEP-NCAR, PREC/L, and JRA55. The performance of each model was assessed by comparing the observed mean annual precipitation to the reanalysis field values in pixels corresponding to the locations of the observation points. The statistical assessment employed Lin’s coefficient of concordance, Wilmott’s index of agreement, Kendall’s tau, and the root mean square error. Interpolation-based models (CRU TS, GPCC, PREC/L) demonstrated a superior ability to reproduce observed total precipitation, whereas modeling-based reanalyses tended to overestimate it by more than 100 mm/year, or by 30% to 50%. The GPCC reanalysis exhibited the best performance when compared to observations; however, it appeared to be significantly overfitted, as evidenced by a substantial negative spatial correlation between total precipitation coverages for the periods from 1961 to 1990 and 1991 to 2020. Consequently, the interpolation uncertainty associated with overfitting precludes the use of GPCC data as a reliable benchmark. Ultimately, the CRU TS 4 reanalysis was determined to be optimal as a baseline for total precipitation coverage. According to CRU TS 4 data, the mean annual precipitation across the Republic of Sakha (Yakutia) was 285 ± 81 mm for the period from 1961 to 1990 and 293 ± 92 mm for 1991 to 2020, indicating an insignificant change of 8 ± 18 mm. Thus, between the two climatic periods, the annual precipitation in the Republic of Sakha (Yakutia) increased by 8 ± 18 mm, a change that is not statistically significant.

Central Yakutia is distinguished by the widespread presence of highly ice-rich permafrost dating back to the Pleistocene epoch, commonly known as the Ice Complex. In the context of global climate warming, it is essential to evaluate the sensitivity and response of permafrost-dominated landscapes to projected climatic changes. The Ice Complex sediments are primarily found in the interalas terrain type. Disruptions to the surface energy balance, particularly those associated with human activities, often lead to destructive cryogenic processes, such as thermokarst and thermal erosion. Alases are prevalent in the region, most of which formed during the Holocene Optimum as a result of the thawing of the Ice Complex. In this study, we analyzed climatic data from weather stations and the thermophysical characteristics of soil samples collected from interalas sites to develop predictive models and compile maps of future soil temperatures under projected climate warming scenarios. Moreover, we conducted model verification. The simulations were based on climatic data from seven meteorological stations and a cryolithological profile representative of the interalas terrain. The study area is a well-drained, forest-covered upland. The simulation results project the dynamics of ground temperatures and active layer thickness in the Ice Complex under three climate warming scenarios for the year 2100: an increase of +2 °C, +3 °C, and +4 °C per century, along with increases in snow cover of 10% and 30%, with no change in precipitation. The findings indicate that thawing of the Ice Complex will commence at a warming of 4 °C with no change in precipitation, at 3 °C with a 10% increase in precipitation, and at 2 °C with a 30% increase in precipitation. Additionally, we classified the terrain into two categories based on susceptibility to Ice Complex degradation due to climate change: unstable and stable. In unstable areas, thawing of the Ice Complex is projected to begin with a +3°C increase in mean annual air temperature.

Climate change, characterized by increased temperature fluctuations and alterations in precipitation and soil moisture conditions, can significantly impact ecosystems that experience both moisture deficits and excesses. Even small changes in precipitation and air temperature can significantly affect tree growth. This paper examines the statistical parameters of the width of annual rings and the results of dendroclimatic analysis of larch (Larix cajanderi Mayr.) and pine (Pinus sylvestris L.) growing in the zone of continuous permafrost. The forest areas where larch and pine samples were collected are located near the village of Magan and the urban-type settlement of Nizhny Bestyakh in the central part of the Republic of Sakha (Yakutia). Woody plants are characterized by a longlife cycle, the annual rings of which are able to store information about their growth. This important resource allows obtaining valuable information about the climate and environmental changes in a given area. To understand how trees respond to climate change, Pearson correlation coefficients were calculated between the width of tree rings and average monthly air temperature, annual precipitation, and the SPEI aridity index using data from the Yakutsk weather station. To identify the response of different tree species to climate change over the past 30 years, each year was considered as a separate period. We assume that air temperature, which tends to increase, is one of the limiting factors that affects precipitation and dry periods. Due to the lack of moisture in the form of rain, tree species experience difficulties. They mainly receive moisture from the active layer of permafrost, which accumulates autumn precipitation of the previous year. Overall, we observe a negative response to the increase in air temperature in the surface layer of the atmosphere. On one hand, this suggests a decline in the radial growth of larch and pine; on the other hand, tree species are adapting to the changing climatic conditions in the central region of Yakutia.

The microbial communities of cryogenic meadow-steppe soils in Central Yakutia, developed within the Yakut Botanical Garden (YBG), have not been previously investigated. This study aimed to analyze soil properties, the composition of microbial communities, their abundance, and their distribution within soil profiles. Data were collected from five soil profiles of the examined cryogenic soils using a combination of soil and microbiological methods, along with standard laboratory analytical techniques. The abundance of microorganism groups studied ranged from 8.2 ± 3.3 × 10¹ to 2.4 ± 0.8 × 10⁶ CFU/g of soil. The soils exhibited an increasing sequence of total microorganisms: saline solonetz, meadow-chernozem, ordinary chernozem, chernozem-meadow, and meadow-chernozem. The highest concentration of azotobacter was identified in the chernozem, which was the only unsalted soil among those studied. The dominance of specific microbial groups was found to be influenced by the chemical composition of the soils and their hydrothermal parameters. A strong correlation was established between the number of microorganism and the content of humus and nitrogen, as well as soil temperature, which decreased with depth. The microbiological findings of cryogenic meadow-steppe soils in the cryolithozone region can be utilized to bioindicate soil fertility and assess anthropogenic and agrogenic transformations of cryogenic soils.

Loess-like loams in the Selenga Middle Mountains are formed within a layer of soils that experience prolonged seasonal freezing. The permafrost in this area is characterized by a low ice content. This study aims to explore the genetic characteristics of soils derived from loess-like loams under the long-term seasonal permafrost conditions prevalent in the Selenga Middle Mountains. The research focuses on Eutric Retisol and Eutric Cryosol, which are located in eluvial and transeluvial positions on the watersheds of the primary ridges in the region. A profile-genetic approach was employed, and the physical and chemical characteristics of the soils were evaluated using standardized methodologies. The total organic carbon (C_org) content was measured in accordance with the Tyurin method, while the analysis of oxalate-extractable iron was conducted utilizing the Tamm method. The particle-size distribution was assessed through the pipette method. Soil classification adhered to the standards set forth in the Classification and Diagnostics of Soils of Russia and the World Reference Base for Soil Resources. The genesis and characteristics of the soils under investigation are predominantly influenced by cryogenic processes. Eutric Retisol exhibits a differentiation consistent with eluvial-illuvial processes, while the podzolic horizons are characterized by a thin-plate structure with a skeletal surface on the peds. This research represents the first examination of Eutric Cryosol, which displays minimal differentiation in terms of color, structure, soil texture, and elemental composition. The practical implications of this study are significant for the sustainable management of soil resources within the permafrost zone of the Selenga Middle Mountains. The presence of charcoal particles within the soil profile suggests a history of frequent ground fires, highlighting the necessity for monitoring forest fires and implementing environmental protection measures to safeguard natural resources.

An assessment of landscape resilience and hydrobiological research on watercourses was conducted for the first time in the Kular gold-bearing region within the Yana River basin of the Republic of Sakha (Yakutia). This study was prompted by the increasing interest in resuming placer gold mining in these areas, which could potentially harm the natural environment and exacerbate existing ecological issues. To address these potential negative impacts, it is essential to implement effective environmental protection strategies. A key component of this effort involves assessing the current state of the natural environment and thoroughly evaluating the resilience of its ecosystems. The hydrobiological research employed both quantitative and qualitative samples collected from the Suor-Uyalaakh River streams. We assessed landscape resilience using a methodology aimed at understanding how key factors affect landscape stability in the cryolithozone. Additionally, we conducted field and laboratory analyses of algae to identify indicators of species composition, abundance, and biomass in the watercourses of the Suor-Uyalaakh River. The findings revealed low diversity and underdevelopment of algal populations, with diatoms being the dominant group in the phytoplankton and phytoperiphyton communities. In contrast, green algae showed lower diversity, followed by yellow-green algae and Euglena. The evaluation of landscape stability in the region indicated extremely low to low resistance to human impacts, which varied based on the ratio of permafrost to bioclimatic factors. The data collected can serve as a basis for creating a biomonitoring database, particularly in light of the increasing human pressures on the aquatic ecosystems of the Suor-Uyalaakh River in Northeast Yakutia. Assessing the resilience of landscapes in the Kular goldbearing deposits may be practically significant for formulating ecological regulations and implementing environmental protection measures to mitigate adverse effects on the natural environment.

Anthropogenic influences have emerged as significant ecological drivers affecting the survival of various animalspecies in the 20th century. Numerous researchers have demonstrated that climate warming and anthropogenic disturbances – including the degradation of ecological barriers – have facilitated the northward expansion of new avian and mammalian species. Concurrently, these anthropogenic pressures exert several detrimental effects. We conducted a comprehensive study on the population trends of some game mammal species in Yakutia. Data collection has been ongoing since 1962 and employs standardized ecological methodologies, including transect surveys, short-term observational protocols, and stationary work, which are typically conducted simultaneously at three to four sites. Ecological monitoring encompassed all seasonal cycles. Aerial censuses of moose, tundra populations of wild reindeer, and brown bears were conducted throughout the entire territory of Yakutia. Furthermore, structured interviews with commercial hunters and analyses of hunting statistics spanning from 1935 to 1985 were undertaken. Throughout the 20th century, fluctuations in population abundance and demographic dynamics were observed among key game mammal species, including the mountain hare, Eurasian red squirrel, wolf, brown bear, moose, and wild reindeer. The population density of the river otter remains critically low, while the red fox, Eurasian lynx, and wolverine maintain low but stable populations, with no discernible contraction in their distribution ranges. A disturbance in the sex and age structure of the wild reindeer population has been identified. The primary factor regulating the population dynamics of the mountain hare, large carnivores, and ungulates has been determined to be hunting pressure. The underlying causes of the population decline of the Eurasian red squirrel remain unresolved. This research has facilitated the refinement of species distribution maps, including the northernmost range limits of the brown bear. The absence of rigorous conservation measures presents a significant threat to certain mammalian taxa, such as the Sundrun population of wild reindeer.

The second part of the paper presents the results of studies that examines species diversity, structure, biotopic occurrence, and spatial distribution of orthopteran communities in grasslands of the Abalakh terrace located in the LenaAmga interfluve. A total of 18 species from three families were identified throughout the research. Biocenological studies have shown that, in terms of species richness and general diversity, the Orthopteran communities on alas of the Abalakh terrace in 2019 exhibited similarities to those of the Tyungyulyun terrace; however, they were distinct in terms of total abundance. Thus, in the middle belt of the alas meadows, the maximum total abundance reached 670 specimens/100 sweeping, while in the steppe belts up to 790 specimens/100 sweeping. The cluster analysis of the data collected from the northeastern part of the Lena-Amga interfluve in 2019 revealed two main classes of Orthopteran communities. The first class was characterized by the absolute dominance of Chorthippus albomarginatus, where the contribution of the species to the structure varied from 70 to 100%. The second class was subdivided into a subclass of xeromorphic habitat communities with the dominance of Omocestus haemorrhoidalis and Chorthippus albomarginatus, and a subclass of wet meadow communities that feature a specific complex of hygromesophilic species. Chorthippus albomarginatus, recognized as the most pest grasshopper species in Central Yakutia, was recorded in all alas hydrothermal belts, from wet meadows to forest edges and steppe slopes; in the majority of communities, this species dominated or was a subdominant. The cryoarid climate of Central Yakutia and the widespread taiga-alas landscapes necessitate a tailored approach to managing pest grasshoppers. In our opinion, the RAAT method (Reduced Agent and Area Treatments) represents the most viable strategy as its implementation could substantially decrease financial costs and mitigate damage caused to ecosystems during chemical treatment of farmland.

A common practice for determining the safe service life of polymer composites is to assess their climatic resistance. This evaluation is based on experimental studies that examine the effects of aggressive climatic factors on the physical and mechanical properties of materials used in various climatic zones. This article presents the results of climatic aging tests conducted on glass-carbon plastic samples under extremely cold conditions. Microstructural analysis, dynamic mechanical analysis (DMA), and assessments of elastic-strength characteristics were used to evaluate the climatic and nutrient impacts on these polymer composites. The samples underwent two years of climatic exposure, during which provocative phenomena were introduced to investigate changes in their properties and structural features. As a result of the studies, a decrease in the tensile strength of a fiberglass (FG) by 57% and of the carbon fiber-reinforced plastics (CFRP) by 8% was observed. The obtained results are supported by studies of DMA, profilometry and open porosity. The findings regarding surface degradation, porosity, and DMA confirm the aging of the material in the surface layer, an increase in porosity, and changes in the degree of polymerization of the polymer matrix in layered plastics. Furthermore, the introduction of microorganisms significantly reduces the elastic-strength characteristics of the materials. The identified changes are confirmed by a decrease in the dynamic modulus of elasticity and an increase in the glass transition temperature. The results obtained regarding the influence of biogenic microorganisms on the aging processes of polymer composites, under simultaneous exposure to UV radiation and low temperatures, can be applied to address issues related to reducing the polymer aging.

The practical application of carbon nanomaterials drives the search for new methods of efficient synthesis. One promising approach is the production of graphene-like materials through fast (flash) Joule heating (or Ohmic heating) of a carbon-containing precursor. In this study, we investigated the effects of flash Joule heating on amorphous carbon films formed by deposition in methane plasma on Si/SiO₂ substrates. Joule heating was conducted via electric discharge through samples from a capacitor block with a total capacitance of 180 mF, charged to voltages ranging from 100 to 300 V. We used various methods, including Raman spectroscopy, scanning electron microscopy, X-ray energydispersive spectroscopy, and current-voltage characteristics. The findings revealed that the most ordered structure is the carbon film subjected to fast Joule heating at a discharge voltage of 160 V. Furthermore, flash heating significantly enhances both the electrical conductivity and hydrophobicity of the material. The highest values were observed for carbon films after the discharge of a capacitor bank charged to 160 V. These results can be attributed to the transition of the initial amorphous carbon film to a crystalline structure characterized by a predominance of sp²-hybridized bonds, which exhibit low electrical resistance. The emergence of water-repellent properties can be explained by the “lotus effect, the formation of spherical particles up to 1 μm in size and their larger conglomerates on the film surface. These findings can be used to synthesize graphene-like nanomaterials with high hydrophobicity and electrical conductivity from amorphous carbon. Such materials are particularly relevant for the development of designs for all-weather unmanned aerial vehicles.