Search Results (88)

The rocks of the Burpala alkaline intrusion contain a wide range of rare minerals that concentrate rare earth elements (REEs), Nb, Th, Li, and other incompatible elements. One of the examples of the occurrence of such mineralization is albite–aegirine rocks located at the contact zone between the intrusion and the host terrigenous–sedimentary rock. In albite–aegirine rocks, cubic crystals of “metaloparite”, partially or completely substituted by bastnäsite-(Ce) and polymorphic TiO₂ phases (anatase and rutile) mainly represent the rare metal minerals. In albite–aegirine rocks, trace element minerals are predominantly represented by cubic crystals of “metaloparite”, which are partially or completely replaced by bastnäsite-(Ce) and polymorphic TiO₂ phases such as anatase and rutile. Additionally, Th-bearing zircon (up to 17.7 wt% ThO₂) and a variety of unidentified minerals containing REEs, Th, and Nb were detected. The obtained data indicate that bastnäsite-(Ce) is the result of the recrystallization of “metaloparite” accompanied by the formation of Th-bearing zircon and Nb-bearing rutile (up to 9.9 wt% Nb₂O₅) and the separation of various undiagnosed, unidentified LREE phases. Our studies show that remobilization of LREEs, HFSEs, and local enrichment of rocks in these elements occurred due to the effects of residual fluid enriched in fluorine and carbon dioxide. Full article

The Baikal region, including areas with poor environmental conditions, has significant clean background zones. In the summer of 2023, we analyzed the physical and chemical parameters of aerosol particles with different size fractions at Irkutsk and Listvyanka monitoring stations. Reduced wildfires and minimal impact from fuel and energy industries allowed us to observe regional and transboundary pollution transport. A large data array indicated that, during the shift of cyclones from Mongolia to the south of the Baikal region, the concentrations of Na⁺, Ca²⁺, Mg²⁺, K⁺, and Cl⁻ ions increased at the Irkutsk station, dominated by NH₄⁺ and SO₄²⁻. The growth of the ionic concentrations at the Listvyanka station was observed in aerosol particles during the northwesterly transport. When air masses arrived from the southerly direction, the atmosphere was the cleanest. The analysis of 27 elements in aerosols revealed that Al, Fe, Mn, Cu, and Zn made the greatest contribution to air pollution at the Irkutsk station, while Fe, Al, Cu, Cr, Mn, and Ni made the greatest contribution to air pollution at the Listvyanka station. The dynamics of the investigated elements were mainly due to natural processes in the air under various synoptic situations and weather conditions in the region, although anthropogenic factors also affected the formation of aerosol composition wth certain directions of air mass transport. Full article

A multimethodic approach based on infrared, Raman, electron spin resonance and photoluminescence spectroscopy, absorption spectroscopy in near infrared, visible and ultraviolet regions, single-crystal X-ray diffraction as well as electron microprobe analyses was applied to the characterization of a new commensurately modulated cubic haüyne analogue with the modulation parameter of 0.2 and unit-cell parameter of 45.3629(3) Å (designated as haüyne-45Å) from the Malobystrinskoe lazurite deposit, in the Baikal Lake area, Siberia, Russia, as well as associated SO₃²⁻-bearing afghanite. Haüyne-45Å is the second member, after vladimirivanovite, of the sodalite group with a commensurately modulated structure. The average structure is based on the tetrahedral aluminosilicate sodalite-type framework with sodalite cages of different sizes. The simplified formula of haüyne-45Å is Na₆Ca_2−x(Si₆Al₆O₂₄)(SO₄²⁻,HS⁻,S₂^●−,S₄,S₃^●−,S₅²⁻)_2−y. The structural modulations of the haüyne-45Å framework are presumably related to the regular alternation of SO₄²⁻ anions with polysulfide S₂^●−, S₃^●−, S₄, and S₅²⁻ groups detected by the spectroscopic methods. Mechanisms of thermal conversions of S-bearing groups in haüyne-45Å under oxidizing and reducing conditions at temperatures up to 800 °C are studied, and their geochemical importance is discussed. Full article

In this study, a large portion of data on the chemical composition of precipitation falling in the South Baikal region shows the main factors determining their formation in 2017–2024. Taking into account the high variability of meteorological conditions in the region, both in time and in space, a method of observing the chemical composition of atmospheric precipitation has been developed, which makes it possible to determine its composition depending on the conditions of air mass formation. Using statistical analysis, marker substances characterizing the main groups of sources influencing the composition of atmospheric precipitation were identified. Joint analysis of air mass trajectories and data on chemical composition of precipitation allowed for establishing the areas of location of potential sources of precipitation pollution. All precipitation events were categorized based on the similarity of air mass formation conditions and chemical composition. Precipitation composition data collected on the shores of Lake Baikal reflect the influence of different types of pollutants such as industrial emissions, motor vehicles, dust storms, and forest fires. The results of the study are relevant for air quality assessment in the region and demonstrate the potential of using precipitation chemistry data to understand the long-range transport of pollutants, which contributes to sustainable development by increasing the availability of air quality data in ecologically significant regions such as Lake Baikal. Full article

The aim of this study was to expand the monitoring network and evaluate the accuracy of inexpensive WoMaster ES-104 sensors for monitoring particulate matter (PM) in temperate latitudes, using the example of the Southern Baikal region. The research methods included continuous measurements of PM_2.5 and PM₁₀ concentrations, temperature, and humidity at three stations (Listvyanka, Patrony, and Tankhoy) from October 2023 to October 2024, using the LCS WoMaster ES-104. ERA5-Land reanalysis data and the HYSPLIT model were used to analyze meteorological conditions and air mass trajectories. The results of this study showed a high correlation between the WoMaster ES-104 and the DustTrak 8533; the correlation coefficient was 0.94 (R² = 0.85) for both fractions. The seasonal dynamics of PM_2.5 and PM₁₀ were characterized by a dual-mode distribution with maxima in summer (secondary aerosols, high humidity) and winter (anthropogenic emissions, inversions). The diurnal cycles showed morning/evening peaks associated with transport activity and atmospheric stratification. Extreme concentrations were recorded in anticyclonal weather (weak north-westerly winds, stable atmosphere). This study confirms the suitability of the LCS WoMaster ES-104 for real-time monitoring of PM_2.5 and PM₁₀, which contributes to sustainable development by increasing the availability of air quality data for ecologically significant regions such as Lake Baikal. Full article

The article addresses the problem of increasing the capacity of the Baikal–Amur Mainline, which is part of the Northern Eurasian Corridor and provides the shortest route from Europe to the countries of the Asia-Pacific region via the ports of the Russian Far East. A key focus of the study is the Severobaikalsk section, which currently operates as a single-track system and is located in a specially protected natural area. In this regard, it is a limiting element since its reconstruction projects require environmental expertise. To tackle this issue, we develop a mathematical model based on semi-open queuing networks as a research tool. This modeling apparatus allows us to describe the features of the considered transport system, including single-track traffic, long sections between stations, which leads to the appearance of additional sidings, the presence of through and ring routes, and the significant influence of random factors on train operation. Based on the results of a numerical study of the model, we evaluate the current and maximum permissible section loads and point out bottlenecks in its structure. We compare two alternative ways of increasing the section capacity: creating a double-track connection on the most problematic sections and using a partially batch train schedule. Based on the results of the calculations, we conclude about the possibility and conditions of their implementation. Full article

In the past 42 years from 1980 to 2021, 103 regional strong cooling events (RSCEs) occurred in winter in Northeast China, and the frequency has increased significantly in the past 10 years, averaging 2.45 per year. The longest (shortest) duration is 10 (2) days. The minimum temperature series in 60 events exists in 10–20 d of significant low-frequency (LF) periods. The key LF circulation systems affecting RSCEs include the Lake Balkhash–Baikal ridge, the East Asian trough (EAT), the robust Siberian high (SH) and the weaker (stronger) East Asian temperate (subtropical) jet, with the related anomaly centers moving from northwest to southeast and developing into a nearly north–south orientation. The LF wave energy of the northern branch from the Atlantic Ocean disperses to Northeast China, which excites the downstream disturbance wave train. The corresponding LF positive vorticity enhances and moves eastward, leading to the formation of deep EAT. The enhanced subsidence motion behind the EAT leads to SH strengthening. The cold advection related to the northeast cold vortex is the main thermal factor causing the local temperature to decrease. The Scandinavian Peninsula is the primary cold air source, and the Laptev Sea is the secondary one, with cold air from the former along northwest path via the West Siberian Plain and Lake Baikal, and from the latter along the northern path via the Central Siberian Plateau, both converging towards Northeast China. Full article

The dispersal of plant pathogens is a threat to the global economy and food industry which necessitates the need to discover efficient biocontrol agents such as bacteria, fungi, etc., inhibiting them. Here, we describe the Bacillus mycoides strain b12.3 isolated from the soil of Olkhon Island in Lake Baikal, Russia. By applying the co-cultivation technique, we found that the strain inhibits the growth of plant pathogens, such as the bacteria Xanthomonas campestris, Clavibacter michiganensis, and Pectobacterium atrospecticum, as well as the fungus Alternaria solani. To elucidate the genomic fundament explaining these activities, we leveraged next-generation whole-genome sequencing and obtained a high-quality assembly based on short reads. The isolate bore seven known BGCs (biosynthetic gene clusters), including those responsible for producing bacillibactin, fengycin, and petrobactin. Moreover, the genome contained insecticidal genes encoding for App4Aa1, Tpp78Ba1, and Spp1Aa1 toxins, thus implicating possible pesticidal potential. We compared the genome with the 50 closest assemblies and found that b12.3 is enriched with BGCs. The genomic analysis also revealed that genomic architecture corresponds to the experimentally observed activity spectrum implying that the combination of produced secondary metabolites delineates the range of inhibited phytopathogens Therefore, this study deepens our knowledge of the biology and ecology of B. mycoides residing in the Lake Baikal region. Full article

Plants are sessile organisms and any changes in environmental factors activate various responses and defense mechanisms. Artemisia plants widely inhabit harsh conditions of arid and semiarid ecosystems. Using two species—a subshrub, Artemisia frigida, and an annual–biennial herb, Artemisia scoparia—the functioning of the antioxidant system of plants in semiarid territories have been examined. The activity of enzymatic antioxidants and the content of non-enzymatic antioxidants in both species as well as the antiradical activity of their extracts have been shown. Although the plants were collected in areas differing in moisture supply, the activity of enzymatic antioxidants and the content of non-enzymatic antioxidants corresponds to their physiological level, within the range of the norm of reaction, in wormwood. Consequently, conditions of differing moisture deficiency do not cause a specific biochemical response at the level of the antioxidant system in the studied species, which confirms their adaptability to these conditions. Meanwhile, A. frigida plants show greater morphological and biochemical plasticity than A. scoparia under changing growth conditions. Both species contain tissue monoterpenoids and sesquiterpenoids, the emission of which provides additional protection against high temperatures and drought. Their composition and contents of phenolic components illustrates the differences in adaptation between perennial and annual plants. Full article

This article presents the results of the automatic monitoring of the concentrations of gaseous impurities of sulfur and nitrogen oxides in the ground-level atmosphere of the urban and rural areas in the Southern Baikal region (East Siberia, Russia). The study was conducted from 2020 to 2023 at the urban Irkutsk station and the rural Listvyanka station located at a distance of 70 km from each other. We calculated the main statistical characteristics of the variations in the concentrations of nitrogen oxides and sulfur dioxide in the ground-level atmosphere and determined a nature of variability in their concentrations on various time scales: annual, weekly, and daily. Annual variabilities of gaseous pollutants in the ground-level atmosphere above the Irkutsk city and the Listvyanka settlement were similar and showed the highest values in winter and the lowest in summer. The daily and weekly dynamics of the nitrogen oxide concentrations in the urban area clearly depended on the increase in the road traffic during rush hours (morning and evening). In the rural area, there was no such dependence. In this area, the daily and weekly variability in the concentrations of nitrogen oxides and sulfur dioxide mainly depended on natural meteorological processes. The work systematizes the meteorological parameters at which the largest amount of anthropogenic impurities enters the air basin of Lake Baikal. The maximum values of acid-forming gas concentrations were observed when the air masses were transferred from the northwest direction, which corresponds to the location of sources in the territory of the Irkutsk–Cheremkhovo industrial hub—the largest concentration of anthropogenic objects in the Irkutsk region. Full article

In recent years, the role of the atmosphere in the formation of the chemical composition of water in Lake Baikal and its tributaries has been increasing. In this regard, the study of equivalent black carbon (eBC) in the air above the lake and its coast has an important practical application. This paper presents the results of the mass concentration of eBC and submicron aerosol in the air above the water area of Lake Baikal, which were obtained during expeditions onboard research vessels in the summer of 2019 and 2023. We analyzed the data from the coastal monitoring station Listvyanka. To measure eBC, an MDA-02 aethalometer was used in the water area of the lake, and a BAC-10 aethalometer at the Listvyanka station. The background level of the eBC concentration in the air at different areas of the lake ranged between 0.15 and 0.3 µg m⁻³. The results of the two expeditions revealed the influence of the coastal settlements and the air mass transport along the valleys of the lake’s large tributaries on the five- to twentyfold growth of the eBC concentration in the near-water atmosphere. In the diurnal dynamics of eBC near settlements, we recorded high values in the evening and at night. In background areas, the diurnal dynamics were poorly manifested. In the summer of 2019, there were smoke plumes in the water area of Lake Baikal from distant wildfires and a local fire site on the east coast of the lake. The eBC concentration increased to 5–6 µg m⁻³, which was 10 to 40 times higher than the background. The long-range transport of plumes from coal-fired thermal power plants in large cities of the region made the major contribution to the eBC concentration at «Listvyanka» in winter, which data on aerosol, gas impurities, and meteorological parameters confirmed. Full article

In this study, the new data of experimental studies of the atmospheric particulate matter (PM) on the south-eastern coast of Lake Baikal (station Boyarsky) were analyzed in summer 2021. High-altitude measuring sites were arranged in the forest massif (mast, 16 m) and above the meadow vegetation (mast, 30 m). By the Giardina M. model and based on the measurements data the calculations of the deposition flux density of aerosol particles on forest and meadow vegetation were made. Our preliminary results of prediction obtained by Giardina M. model good agrees with measured dry deposition velocities across particle sizes. In the forest, the mass concentration of aerosol particles differs slightly from the mass concentrations in the grasslands and is equal on average 7.9 × 10⁻³ mg m⁻³ for the size particles below 200 nm (PM_0.2) and 6.7 × 10⁻⁴ mg m⁻³ for particles in the size range from 0.2 to 10 μm (PM_0.2–10). However, we found that mass flux density of aerosol particle is almost 4.8 times higher under forest canopy than in meadow vegetation. In addition, the leaf area index (LAI), which characterize the effective area of particle deposition, is also significantly higher in the tree canopy (5.6) compared to the grassland vegetation (2.4). Full article

Influenza A viruses (IAVs) pose a serious threat to global health. On the one hand, these viruses cause seasonal flu outbreaks in humans. On the other hand, they are a zoonotic infection that has the potential to cause a pandemic. The most important natural reservoir of IAVs are waterfowl. In this study, we investigated the occurrence of IAV in birds in the Republic of Buryatia (region in Russia). In 2020, a total of 3018 fecal samples were collected from wild migratory birds near Lake Baikal. Of these samples, 11 were found to be positive for the H13N8 subtype and whole-genome sequencing was performed on them. All samples contained the same virus with the designation A/Unknown/Buryatia/Arangatui-1/2020. To our knowledge, virus A/Unknown/Buryatia/Arangatui-1/2020 is the first representative of the H13N8 subtype collected on the territory of Russia, the sequence of which is available in the GenBank database. An analysis of reassortments based on the genome sequences of other known viruses has shown that A/Unknown/Buryatia/Arangatui-1/2020 arose as a result of reassortment. In addition, a reassortment most likely occurred several decades ago between the ancestors of the viruses recently collected in China, the Netherlands, the United States and Chile. The presence of such reassortment emphasizes the ongoing evolution of the H13N8 viruses distributed in Europe, North and East Asia, North and South America and Australia. This study underscores the importance of the continued surveillance and research of less-studied influenza subtypes. Full article

Lake Baikal is the largest freshwater lake in the world, accounting for about 20% of the world’s fresh surface water. The lake’s outflow to the ocean occurs only via the Angara River, which has several hydroelectric power plants (HPPs) along its watercourse. The first such HPP, Irkutsk HPP, was built in 1956 and is located 60 km from the Angara River’s source. After two years, the backwater from this HPP expanded to the lake shores and began raising the Baikal Lake level. Currently, there is a dynamic balance between the new lake level, the lake inflow from its tributaries, and the Angara River discharge through the Irkutsk HPP. However, both the Angara River discharge and the Baikal Lake level were distorted by the HPP construction. Thus, to understand the changes to the lake basin over the past century, we first needed to estimate naturalized lake levels that would be if no HPP was ever built. This was an important task that allowed (a) the actual impact of global changes on the regional hydrological processes to be estimated and (b) better management of the HPP itself to be provided through future changes. With these objectives in mind, we accumulated multi-year data on the observed levels of Lake Baikal, and components of its water budget (discharge of main tributaries and the Angara River, precipitation, and evaporation). Thereafter, we assessed the temporal patterns and degree of coupling of multi-year and intra-annual changes in the lake’s monthly, seasonal, and annual characteristics. The reconstruction of the average monthly levels of Lake Baikal and the Angara River water discharge after the construction of the Irkutsk HPP was based on the relationship of the fluctuations with the components of the Lake water budget before regulation. As a result, 123-year time series of “conditionally natural” levels of Lake Baikal and the Angara River discharge were reconstructed and statistically analyzed. Our results indicated high inertia in the fluctuations in the lake level. Additionally, we found a century-long tendency of increases in the lake level of about 15 cm per 100 years, and we quantified the low-frequency changes in Lake Baikal’s water levels, the discharge of the Angara River, and the main lake tributaries. An assessment of the impact of the Irkutsk HPP on the multi-year and intra-annual changes in the Lake Baikal water level and the Angara River discharge showed that the restrictions on the discharge through the HPP and the legislative limitations of the Lake Baikal level regime have considerably limited the fluctuations in the lake level. These fluctuations can lead to regulation violations and adverse regimes during low-water or high-water periods. Full article

In order to deepen the understanding of the occurrence mechanism and water vapor transport characteristics of the heavy rain process in the extreme arid region of Xinjiang, a rare heavy rain process in the Tarim Basin during the period of 18–22 July 2021 was comprehensively analyzed by using multi-source data. The results show that the upper tropospheric South Asian high was distributed in a “west-high-east-low” pattern during the rainstorm process, and the rainstorm area was located on the right side of the upper jet stream entrance area, while the middle-level Iranian high pressure, Baikal high pressure and Central Asian low pressure formed a “two-highs and one-low” circulation situation. The coupling of the high and low air jets and the strong vertical upward motion provided favorable dynamic conditions. Rainstorm water vapor mainly comes from the Mediterranean Sea, Central Asia and the Indian Ocean, and it enters the basin in four paths: west, east to west, west to east, and southwest and south. The water vapor mainly flows into the middle layer of the western boundary and the southern boundary and the lower layer of the eastern boundary, and it flows out from the middle and upper layer of the eastern boundary. The negative moist potential vorticity region at a low level has a strong indicator significance for the occurrence and development of heavy rain, and the superposition of positive and negative moist potential vorticity regions at vertical height is conducive to the occurrence and development of heavy rain. Full article