The article presents the data on the structural control of the first kimberlite body in the Syuldyukar field of the Ygyatta diamondiferous region in Western Yakutia. We applied a new approach to processing geological and geophysical data. Threedimensional computer interpolation technology used for processing primary data indicate high efficiency of this approach and make it possible to correct prospecting within the new kimberlite field and the entire Ygyatta diamondiferous region. 

We studied petroand geochemical features of the compositions of magmatic formations in the Taezhny massif. The massif is located in the central part of the Nimnyr block of the Aldan shield within the Leglier ore cluster in the Evotinsky gold bearing region. For the first time, according to our field and petrographic observations, the two-phase structure of the massif has been established. The first phase was represented by syenite-porphyry, and the second, by leucocratic syenite. At the later stages of magmatism development, the intrusion of bostonite and 

vogesite dikes took place. According to various classification data, we distinguish two groups of rocks in the Taezhny massif: quartz syenites (phase I) with ambiguous petrochemical characteristics, which make them close to both high-potassium calc-alkaline and shoshonite petrochemical series; leucocratic syenites (phase II) of the shoshonite petrochemical series; bostonite dikes, similar to syenites and corresponding to rocks of the shoshonite petrochemical series only; vogesite dikes (syenite-monzonite lamprophyre) correspond to rocks of the shoshonite petrochemical series. All rocks are geochemically specialized for lithophilic elements: Rb, Ba, Sr, B, Cr, V, Nb,  Sc. According to the ratios of trace elements, all studied rocks bear both crustal and mantle marks. We conclude that all the rocks involved in the structure of the massif could be considered as part of the monzonite-syenite formation type.

In this article we investigate the problems of the mineral deposits development in the Republic of Sakha (Yakutia). Moreover, the relevance of the strategy revision for the development of mineral resources in Russia is discussed. We justify the methodology for the integrated development of the solid mineral deposits, taking into account the changing requirements of the world market and domestic needs. The demand for the program development of the mineral resources in the Republic of Sakha (Yakutia) for the period 2030–2050 is validated.

The Arctic deltas represent the scene for active permafrost formation and, at the same time, the place for talik zones development. Due to the wide distribution of shallow waters in the Arctic deltas under channels freezing to the bottom in winter, the area of newly formed underwater permafrost significantly exceeds the area of thawed under-channel massifs. During the field research in the Lena River Delta we have revealed features and patterns of formation of both 

newly formed permafrost within the channels and under-channel taliks. On the basis of drilling, geophysical and bathymetric data obtained in the course of expedition research in 2014–2020, we have found that permafrost under the channels almost always forms at low water depths of less than 2–2.5 m, but can also occur at depths of 3–5 m. The depth of thawing of underwater permafrost in shallow waters in summer reaches from 1 to 3 m. Under-channel taliks develop under channels with a depth of more than 3 m, where talik zones are formed. The results obtained can be used by river fleet specialists to clarify changes in the position of river fairways in the Arctic deltas

We studied the bottom sediments of the lakes in Yakutsk in the period of 1998–2021. During the monitoring period, we observed that the chemical composition of the bottom lake sediments remained constant. The analyses showed their sulfate composition, with mixed cations, where calcium predominated, and significant changes in their salinity. Against the general background of salinity decrease in these deposits (0.018 % per year), we have noted a formation of short-term positive anomalies of salinity and long periods of desalination. The latter is determined by a decrease in the density of atmospheric fallout. Though the atmosphere in the city was under a relatively constant value of technogenic emissions, sharp changes in the volume of atmospheric precipitation were associated with the climatic factors. They affected the dynamics of salinity fluctuations in the bottom sediments of the lakes under study. Cryogenic metamorphization of the bottom sediments occurred unevenly in different parts of the lakes. In the deep parts they were poorly mineralized. Their composition was predominantly sulfate-hydrocarbonate. In the shallow parts of the lakes, they were more of saline sulfate or hydrocarbonate-sulfate composition.

Previously published lists of the mammal fauna of the region date back to the 1930s to 1970s; they present information on 59–63 species (by different sources). Over the past 50 years, significant changes have taken place, both due to 

additional research of the mammal fauna and due to the introduction of several species by man. According to the current studies, the faunistic list of the orders covered in this article embraces a total of 42 species: Insectivores (Eulipotyphla; 2 families, 3 genera, 10 species), Chiropterans (Chiroptera, 1 family, 3 genera, 5 species), Lagomorphs (Lagomorpha, 2 families, 2 genera, 3 species), and Rodents (Rodentia, 3 families, 19 genera, 24 species). In the 1970s, the faunistic list of the same orders included 36–37 species. The reasons for the expansion of the list are a better current knowledge of the regional fauna (four species new for the fauna of Yakutia have been found: two chiropterans and one species of insectivores and rodents each) and changes in the taxonomic rank of species and subspecies belonging to the genera of Ochotona, Urocitellus, and Alexandromys (Microtus). Some changes in the fauna composition (with no changes in the amount of species) are associated with the revision of 13 species names. The major part of the population of the discussed orders on the terrtory of Yakutia is composed of indigenous species (approximately 93 %); one species, Ondatra zibethicus, has appeared as a result of intentional introduction measures in the 1940s; and two species, Mus musculus and Rattus norvegicus are invasive eusynanthropes that expanded widely in the second half of the 20th century.

The first part of the article presents the results of many years of research on the biotopic confinement, structure and spatial distribution of orthopteran insect communities on the Tungyulyunskaya terrace of the Lena-Amga interfluve. 

In total, 21 orthopteran species were identified in herbaceous phytocenoses during the study period, including the steppe species Montana eversmanni (Kittary, 1849) and Arcyptera albogeniculata (Ikonnikov, 1911). These are rare for the fauna of Yakutia. With the help of the index of biotopic confinement, species of orthopteran insects were identified that determine the appearance of communities living in natural and anthropogenic phytocenoses. The most diverse and original communities, which include a significant number of stenobiont species, were found on the humid belts of the alas, tussocked meadows, and forest edges. In 2019, the total abundance of Orthoptera was very low, while not a single specimen was caught in the middle belts of alas meadows. Compared with the initial period of research, a marked decrease in the taxonomic diversity of orthoptera insects is currently observed in alas meadows, due to increased anthropogenic influence.

The article presents the data on the scale samples of lichenobiota obtained from the Alazei River basin. We have collected lichens from the various plant communities (larch forests and woodlands, willows, yerniki and tundra). The list of the studied lichenobiota includes 16 species of lichens. Among them we have identified Lecanora circumborealis as a new species for Yakutia. Furthermore, 14 species were indicated as new for the Alazei River basin. We specify a single location in Yakutia for the species: Biatora subduplex, Cyphelium inquinans, Lecanora saligna. While Cyphelium inquinans, Lecanora circumborealis belong to the rare species in Yakutia and adjacent territories. The studied lichens species supplement the data on the lichenobiota in the Arctic Yakutia.

The article presents the results of studies of indicators of mesostructure in the ontogeny of leaves of dwarf birch (Betula nana L.), which grows under the influence of emissions of industrial enterprises of the city of Murmansk. Signs of xeromorphism of B. nana leaves were revealed: thickening of the upper and lower epidermis, leaf blade, spongy parenchyma. In the leaf ontogenesis, the thickness of the palisade mesophyll and the palisade index decreases. As a result of data processing by analysis of variance, it was found that technogenic pollution effects on the length of palisade cells of the leaves of B. nana in June and July (p ≤ 0.0005) and does not affect in August (p ≤ 0.1).There were no significant differences in the sizes of cells of the spongy mesophyll in the samples, which indicates an increase of the thickness of the spongy layer and leaf blade due to the number of periclinal cell divisions and increase of the volume of intercellular spaces. The obtained data confirm the nonspecific reaction of the assimilation apparatus of birch trees on the influence of stress environmental factors. The ontogenetic reactions of indicators of the mesostructure of B. nana are considered as adaptive responses to technogenic stress, providing the decrease in transpiration and optimal photosynthesis under conditions of environmental pollution of the Arctic city. Dwarf birch can be used as an object for biomonitoring of environmental quality in the industrial areas of the Arctic and Subarctic.

The article provides the data on composition of the non-native fresh water species in the basin of the Lena River. We indicate the years they have been discovered and describe the vectors of their invasion into the water reservoir. In different years, 9 non-native freshwater species have been introduced into the Lena River ecosystem: sterlet, European cisco, Arctic cisco, bream, Chinese carp, Amur carp, silver carp, European pike-perch and Amur sleeper. In general, the invasion of fish species in the Lena River basin is characterized by the following vectors: 1 – deliberately introduced (sterlet, European cisco, Arctic cisco, bream, Chinese carp, Amur carp, silver carp, European pike-perch); 2 – selfdispersing (bream, Amur carp). In recent years, Amur carp and bream have been encountered in the river’s middle and lower reaches; 3 – accidentally introduced (Amur sleeper). We identify deliberate introduction as the key invasion vector in the basin of the Lena River. Bream and carp have acclimatized successfully. Moreover, Amur sleeper has spread to the estuary of the Olyokma River (November 2021), having passed 1350 km in 10 years. Its migrant capacity made 135 km/year. Thus, being a highly invasive species, Amur sleeper can naturalize successfully. Current downstream dispersal of bream, Amur carp, Amur sleeper, as well as pike, ide, roach and perch is associated with general 

climate warming in the Arctic area, which creates favorable conditions for the fish dispersal. Self-dispersal of nonnative species in the Lena River basin meets the definition of biological invasion and may create complications in interspecies competitive food relationships, bring new pathogenic organisms and rearrange parasitic communities. We conclude that the formation of the Lena River basin ichthyofauna is in progress.

The use of high-modulus fibers with improved technological and operational properties in production of the composite elastomers is an urgent task in Materials Science. The widespread reinforcing fillers are basalt, glass and carbon fibers, which have a high chemical inertness. Therefore, the introduction of these fillers into the elastomer requires an increase of their adhesion to the rubber matrix, which further improves the reliability and durability of the material in operation. This paper presents a method for increasing the adhesion between the adhesive and the substrate due to the surface treatment of reinforcing fabrics with a rubber mixture previously dissolved in phenylmethane (toluene). We investigated the obtained materials for elastic-strength properties, wear resistance, hardness and adhesion. We also studied the microstructure in the volume of the material, the friction surface and the place of delamination. The results of the tensile tests showed a general tendency in increasing of the tensile strength values up to 1.6 times and decreasing of the relative elongation values up to 2 times. The tests for wear resistance showed a decrease in values by 10–20 % for samples with the surface treatment of fabric with a dissolved mixture, along with an increase in their hardness values. Surface treatment of fabrics by proposed method before vulcanization increased adhesion values from 1.2 to 3 times. 

The industrial development of the Arctic has increased interest in the use of the most common natural materials (snow and ice) for the construction of temporary buildings in northern regions. The technical characteristics of the snow and ice (strength, thermal conductivity) correspond to similar properties of other construction materials. These characteristics allow to use them in the Arctic conditions for a long period of time. We studied the strength characteristics of building blocks made from natural raw materials (snow), which are sufficient for the construction of temporary lowrise buildings (warehouses, garages, hangars, caponiers, etc.). The strength of frozen snow-water blocks is provided at 3.1–6.4 MPa, while heat content at 1.38 W/(m·°С). Full-scale tests of the externally reinforced snow blocks prove their sufficient strength for the construction of one-story buildings. Technological features of the blocks allow their production without specialized equipment. We determined technological modes for blocks forming, their thermophysical and strength characteristics. The units were tested for their resistance to the warming in spring. We also tested one-story building model (size 3×4,2×2,3 m). The results of both tests showed the possibility of widespread use of the technology in the North and the Arctic.

Monolayer transition metal dichalcogenides (TMD) as new two-dimensional semiconductor materials open new possibilities for optoelectronics due to their excellent light capture and photodetection capabilities. TDM-based photodetectors have become important components of sensing, visualization and communication systems, capable of receiving and converting optical signals into electrical ones. An urgent and unsolved task is the development of high-quality single-layer and heterolayer electronic devices based on transition metal dichalcogenides with a long service life, such as optoelectronic devices and field-effect transistors. The control of the band gap in heterostructures is one of the necessary steps in this development. We studied the band gap in the MoS₂/WS₂ heterostructure depending on the distance between the MoS₂ and WS₂ layers. Ab initio calculations showed that, in contrast to homogeneous bilayers, the MoS₂/ WS₂ heterojunction has an optically active band gap smaller than that of single-layer MoS₂ and WS₂. With an increase in the interlayer distance in the MoS₂/WS₂ heterostructures, the interaction between the layers weakens. Thus, it results in a shift of the Fermi level to a state of higher energy.