Magma models calculated for the first time show that under the deep conditions the fluid phase is absent in them as a consequence of its dissolution in the melt under high pressure. This points to the absence of fluid torrents in the regions of magma formation. Under these conditions, the content of solid phases in magmas increases sharply, which contradicts the hypothesis concerning magma formation as a result of partial melting and points to its origin as a result of friction and decompression remelt of the rocks of identical composition. These rocks originated from the fractionation of the global magma ocean at the early stage of the Earth’s evolution. Relatively low-temperature magmas at the late stage of lifting were solidified as a result of decompression release of the fluid phase in them. The high pressure of this phase, conserved due to solidification, caused disintegration of the upper parts of magmatic columns and explains the nature of volcanic explosions. With pressure rise, the fluid phase appears at later stages of magma crystallization, when the residual melts accumulate ores and volatile components carrying them. This explains the genesis of ore-bearing hydrotherms.

Erosion section of kimberlite bodies and host rocks is one of the prognostic and search criteria of the primary diamond deposits of Western Yakutia. The depth of erosion and the intensity of kimberlite weathering determine the scale and quality of placer diamondiferousness and the contrast of the halos of satellite minerals – direct exploratory signs of deposits. The material for the retrospective analysis of the Alakit-Markhinsky ore field was the available information on the geology of the area: stratigraphy, tectonics, paleogeography, isotopic and paleontological dating of kimberlites, well logging etc. The procedure of investigations and analysis of specialized tectonic maps and schemes is considered, allowing determination of erosion section of buried kimberlite fields and deposits. It is shown that paleogeological reconstructions based on large-scale cartographic materials using logging data make it possible to calculate the level of erosion cut of kimberlites and host rocks with an accuracy of ± 5 to ± 100 m (up to 10–20 % of the denudation value). As a result of investigation, it was found that the kimberlite bodies of the AlakitMarkhinsky ore field are eroded to a depth of 325 to 500 m, increasing eastward. The existence of two epochs of kimberlite magmatism in the Middle Paleozoic is confirmed, while the Late Devonian-Early Carboniferous kimberlites differ from Late Silurian-Early Devonian ones in larger denudation comparable with the reconstructed thickness of the Devonian deposits.

It is established that in the Middle Jurassic (Aalenian – Callovian), the paleogeography of the Earth was represented by two Supercontinents – Pacifida and Arasia, and four continents: Atlantida, Lemurida, Hyperborea and Antarctida, which were separated by shallow shelf sea basins, about 2000–3000 km wide. The Boreal basin was connected to the Alpine-Melanesian-Chinese (Tethys) by western, eastern straits, and the Russian sea. Based on the study of spatial-temporal distribution of the Early Jurassic brachiopods, Equatorial, Boreal, and Nоtal superrealms were differentiated. The Equatorial Superrealm is represented by the Alpine-Melanesian-Chinese (Tethian), New Zealand-New Caledonian, West-SouthAmerican realms. Within the Alpine-Melanesian-Chinese Realm, the provinces are distinguished: the European, North-African, Russian, Arabian, Ethiopian, Caucasian-Crimean, Iranian, Central-Middle-Asian, Pamirian, Tibetan, Thai-Chinese-Japanese. In the structure of Boreal Superrealm, the Siberian-NorthAmerican realm is distinguished, divided into Siberian, West-Canadian, Nevadan and Greenlandian Provinces. The Antarctic Realm is established in the composition of the Notal Superrealm.

The main physicochemical properties (content of chemical elements, mineralogical and granulometric composition) of suspended solids in the atmosphere of Yakutsk sampled in the summer of 2019 were determined on the territory of the city, a geochemical study of suspended solids (SS) in the surface atmosphere, soil and snow cover was carried out. SS entering the surface atmosphere are polydisperse and comprise a combination of solid particles of different sizes. About 70 % of the amount of SS in the atmosphere is related to dust itself, aerosuspensions account for 20 %, and medium-finely dispersed suspended particles accout for about 10%. Polydisperse SS contain toxic elements: Mn, Co, Cu, Cd, Pb, Zn. The most environmentally hazardous particles are medium-finely dispersed ones with a high content of elements of the 1st and 2nd classes of toxicity: Cd, Pb, and Cu. The average annual concentration of SS in the air of the city is 1.8 times higher than the sanitary standards. Suspended substances (dust and aerosols) adversely affect human health.

The phosphate status of five types of permafrost soils in Southern Yakutia is studied for the first time: the content and intra-profile distribution of total phosphorus, as well as mineral and mobile phosphates determined according to Chang-Jackson and Ginsburg-Artamonova methods, respectively. The study revealed that the weighted mean content of total phosphorus in examined soils was not very high, and varied from 290 to 474 mg/kg. According to the total phosphorus content, these types of soils were arranged into the following descending sequence: pale-brown (474 mg/kg) > podzolic alpha-humus (429 mg/kg) > muck-calcareous (320 mg/kg) ≈ podzolic typical (318 mg/kg) > sod-calcerous (290 mg/kg). At the same time, the intra-profile distribution of total phosphorus in podzolic alpha-humus soils had an eluvial-illuvial pattern, podzolic typical and sod-calcerous soils had an accumulative eluvial distribution pattern, palebrown soils were characterized by an eluvial distribution, and muck-calcerous soils had an accumulative distribution pattern.
It was demonstrated that landscape and climatic conditions of southern Yakutia favor the development of primarily acidic permafrost soils unsaturated with exchangeable bases, as well as long-seasonal permafrost soils of eluvia row, which are characterized by low biological activity. These soils are also characterized by the low content of mobile phosphates, with the average value of 2,5–6,7 mg P₂O₅/100 g of soil and not higher than 1–2 % of its total content.
It was also shown that the total content of loosely linked phosphates and calcium phosphates, which are more readily utilized by plants, is generally low in the examined soils and is mainly less than 5 % of their total content. At the same time, aluminum phosphates (Al-P) and iron phosphates (Fe-P) that are hardly available for plants prevail in the mineral phosphatecomposition of the soils of Southern Yakutia, with the dominance of the latter fraction. The content of Al-P and Fe-P in these soils varied significantly, with the maximum variations of 40 and 60 % of their total content, respectively.

The work is devoted to the study for temperature regulation of hibernation rhythms in wintersleeping species of Sciuridae family. The data on observations of hibernation course on body temperature and temperature in the nest litter of 34 individuals from four species were used. For the first time graphical dependences of body temperature on the environment temperature and the dependence of the torpor duration on body temperature in squirrels in a state of hypothermia were obtained. All species have a relatively small interval of body temperature (from +1 to –1 °С), in which the longest periods of hibernation are marked, the dependence of body temperature on the environment temperature is clearly expressed. The hibernation temperature optimum zone, in all species, is close to the soil temperature regime of their native habitats during most of the wintering. Hibernators from Sciuridae and Erinaceus families, during their hibernation, demonstrate a number of similarities in the overall organization of hibernation processes, and temperature regulation of its rhythm.

Based on the data of route census conducted in 2016, the number and density of the stray dog population (Canis lupus familiaris) in Magadan were calculated; the spatial distribution of these dogs in urban areas was revealed. All stray dogs were included in censuring: ownerless (stray) and semi-free dogs (having a master, but leaving the household territory without an accompanying person). The total number of animals according to the census was 500–800 individuals, the average population density was 45 ind./km² . The population density of stray dogs was established to depend on the type of building development and was determined by the presence of food and shelters. The highest population density was detected in the low-rise housing zone (102 ind./km² ), and the lowest – in the high-rise residential area (32 ind./km² ). The population density at the industrial and warehouse territory occupied an intermediate position (42 ind./km² ). The data obtained can be used to plan the work aimed at the regulation of the number of stray dogs.

In connection with the expert assessment of the pasture suitability of the territory for breeding musk oxen (Ovibos moschatus Zimm.), in the summer of 2018, an express assessment of the productivity of 3 species of dominant herbaceous plants of Zavyalov Island, located in the sea of Okhotsk, not far from Magadan, was carried out. By the method of model plants developed by V.N. Andreev, the stock of aerial phytomass of Hierochloe alpina, Aconogonon tripterocarpum, Oxytropis evenorum was determined. Since the rhizomes of Oxytropis evenorum are used in the diet of many species of herbivores, a reserve of underground phytomass at a depth of 22–25 cm was determined for this species. It was found that the resource of the above-ground phytomass of model plants Hierochloe alpina, for which the height of generative shoots reached 33–34 cm on the record day (30.06.2018), varies from 9,2 to 12,3 g of air-dry mass (10,7 g on average). The fraction of dead grass in this species accounts for about 10 % of the total phytomass. For Aconogonon tripterocarpum, the average height of shoots varied from 33 to 48 cm. The resource of the phytomass of a single generative shoot in this species ranged from 0,89 to 1,59 g (1,25 g on verage). A significant part of the phytomass (from 30 to 66 %; 45 % on average) in this species is located at an altitude of up to 20 cm above ground. The total phytomass of model plants Oxytropis evenorum, including rhizomes, varies from 68,3 to 162,2 g (115,3 g on average). The average resource of the green mass of O. evenorum model plants was 23,4 g, living branches of the caudex – 57,9 g, rhizomes – 16,2 g, mort-mass – 17,7 g. Presumably, the resource of above-ground phytomass of the studied plants may increase by 15-20% by the end of the growing season. Our results can be evaluated as a primary assessment of the productivity of the most promising forage plants of this territory. These data can serve as a preliminary indicator of the productivity of the species considered. For a deeper and objective determination of the forage potential of the vegetation on the Zavyalov Island and its pasture capacity for herbivorous animals, it is necessary to accumulate statistical data, expand the range of observed plants, observe the dynamics of phytomass, etc. This report is part of a series of publications devoted to the adaptation of the musk ox to Zavyalov Island conditions.

The possibility to use the methods and approaches of higher plant biotechnology for in vitro clonal micropropagation of the genus Hemerocallis (Krasodnev) of the varieties ʻWine and Rosesʼ was investigated. The use of generative organs (flower buds) as primary explants allowed them to be introduced into an in vitro culture without any harm to donor plants grown in the nursery. The specific features of the induction of callus formation on the nutrient medium of Murashige and Skoog in the presence of naphthylacetic acid and/or 6-benzylaminopurine are determined. The conditions for obtaining regenerated plants from embryogenic callus cultures were tested. The use of a biocomposite obtained as a growth regulator by means of mechanochemical treatment of the biological product from fir branches and needles (100 mg/l) containing water-soluble salts of triterpene acids revealed its high efficiency in the processes of morphogenesis and regeneration in the callus culture of Hemerocallis in vitro. During the three passages of callus, the development of meristematic and embryonic cells was noted, from which the kidneys and embryoids formed as a result of repeated divisions. Further cultivation led to the formation of regenerated plants. The study allowed us to obtain a sterile culture and select the composition of a nutrient medium for the successful propagation of Hemerocallis in vitro. In vitro clonal micropropagation protocol was developed for the genus Hemerocallis of the ʻWine and Rosesʼ variety, which can be an effective method for successful reproduction.

On the territory of Yakutia, lichens are an essential component of vegetation in both tundra and taiga zones. They are highly resistant to adverse environmental conditions, which leads to the accumulation of various biologically active substances that perform adaptive functions in lichens. The climate of Central Yakutia is sharply continental, which manifests itself in a long, cold, low-snow winter and a short, hot dry summer. According to climatic conditions, Central Yakutia ranks second in the Republic in terms of the lowest temperatures in winter, and the first in terms of high temperatures in summer. The annual dynamics of lichen acid accumulation in thallomas of Cetraria laevigata Rass and Flavocetraria cucullata (Bellardi) Kärnefelt &Thell in the conditions of Central Yakutia was studied by means of HPLC. It was shown that the maximum content of fumarprotocetraric acid in the thallomas of Cetraria laevigata was observed in February and March, and the minimum values in May. It is suggested that fumarprotocetraric acid may have cryoprotective properties due to the formation of a hydrophobic layer in the cell wall of the hyphae of the inner part of the lichen. It was found that the maximal concentrations of usnic, allo-protolichesterinic and protolichesterinic acids in the thalli of Flavocetraria cucullata was in June and July, and the minimal one was in January and February. It was revealed that Cetraria laevigata and Flavocetraria cucullata exhibit a species-specific response to changes in weather conditions, which may be associated with different adaptation strategies and functions of lichen acids in lichen thallomas. The studied species of lichens are part of the feed of reindeer (yagel). The species Flavocetraria cucullata is well eaten all year round, especially in winter. Taking into account the antimicrobial activity of usnic acid, part of the thalluses of this lichen, and a high proportion of this species in the fodder base of deer, it may be stated that Flavocetraria cucullata has special significance not only in feed but also in veterinary-pharmaceutical respect to reindeer husbandry.

The article considers problems of operation of elastomers and elastomeric products in cold climates. There are also studies the behavior of elastomeric sealing materials during their operation in extreme climatic conditions and suggestions of the ways of new frost-resistant elastomers development. Based on these ways, elastomeric composites based on mixtures of propylene oxide rubber (SKPO) and fluorine-containing polymers were obtained. SKPO has a unique frost resistance (T_G = –74 °C). Following standard methods of rubber technology, polymer composites based on SKPO and polytetrafluoroethylene (PTFE) or ultrafine polytetrafluoroethylene (UPTFE), which differ in the preparation method and degree of dispersion, were studied. These fluoropolymers selected for rubber modification have a low coefficient of friction, resistance in most known liquids, and heat resistance. Using electron microscopy, we studied the structure of elastomeric composites and the features of their phase morphology, depending on the nature of the fluoropolymer used. We revealed the effect of particle size of the dispersed phase and the content of the fluorine-containing component on the phase morphology and properties of elastomeric composites. It was shown that as the content of PTFE (UPTFE) in the mixture increases, the wear and oil resistance of rubbers increases as well, but frost resistance decreases. The addition of UPTFE powder, which has smaller particle sizes, was preferable to obtain elastomeric composites with a high level of low-temperature characteristics and wear and oil resistance. As a result, we obtained frost-resistant elastomeric composites with a balanced set of properties. The developed compositions were patented and recommended for use.

The paper presents the results of the study of the efficiency of sorption treatment of oily wastewater using nonwoven sorbing material «Ecosorb» as a filter load. The tests of the filter unit showed that the highest purification efficiency of oily wastewater in a given operating mode is achieved with four layers of sorbent in the filter. The most optimal density of the sorbent in the filter corresponded to four layers or 2.4 cm in total thickness. With an excessive increase in the number of layers, and accordingly the density of the packing, it leads to a decrease in the filtration efficiency due to both the overlap of the fibers and the decrease in its porosity. The results of cleaning oil-containing waste water when placing the sorbent in four layers show that the cleaning efficiency is 79 and 97 %, and the concentration of petroleum products in the treated water is 0.17 and 0.25 mg/l, respectively. The tests have shown that «Ecosorb» has a sufficiently high sorption capacity in relation to oil and can be used as a effective sorbing load for filters for pretreatment of oil-containing wastewater.