Home – Home – Jornals – Atmospheric and Oceanic Optics 2023 number 6

Model estimates of the concentrations of black carbon (BC) in the surface air at four sites located on Kola Peninsula, in Arkhangelsk region, and on the territories of Nenetz and Gydansky nature reserves were carried out for winter and summer 2000-2016 based on satellite data. The long-range atmospheric BC transport is analyzed by the author's methodology for calculating the function of sensitivity to potential sources of submicron aerosol for the sites under study based on the statistics of back trajectories of air mass transport. The contribution of anthropogenic sources to BC concentration in every region generally prevails over the contribution of natural fires. The BC concentration in surface air is maximal over the Nenets Nature Reserve and, hence, over the Pechora Sea, where the main sources of this impurity all year round are gas flares at the Russian largest oil and gas provinces. The average, median, and maximal values of BC concentrations in the surface air in winter and summer are calculated from its interannual variations due to differences in air mass circulation, as well as from spatial and interannual variations in BC emissions from wildfires.

The results of the analysis of seasonal and interannual variability of the aerosol optical depth of the atmosphere (AOD), the aerosol volume concentration, and the mass concentration of black carbon in the surface layer obtained at observations in Barentsburg (Spitzbergen archipelago) in 2011-2021 are presented. The annual behavior of all parameters is characterized by two maxima: spring (or winter-spring) and summer, apparently due to the transport of pollutants from the middle latitudes in the winter-spring period and smoke aerosol in summer. In the interannual variability, there are significant negative trends in the fine AOT component (-0.012 over 11 years) and the mass concentration of the absorbing substance (by 46.7 ng/m³ over 10 years).

The new coronavirus pneumonia has rapidly spread around the world. The World Health Organization emphasized that the SARS-CoV-2 coronavirus spreads mainly between people who are in close contact with each other, as well as in the case of touching contaminated surfaces followed by touching the eyes, nose, or mouth without first cleaning the hands. Possible permanent sources of the spread of the virus can be gathering of patients in hospitals in the case of non-compliance with the requirements for organizing the functioning of a hospital. Meteorological conditions can be a key factor influencing the spread of the virus in the case of an accidental release of virus-containing aerosol from such a hospital. Simulations are carried out with modern methods for solving a system of differential equations of the atmospheric boundary layer, which are adapted to describe the distribution of harmful atmospheric impurities over a real complex terrain considering urban buildings of various heights, forests, reservoirs, changing meteorological conditions, and many other factors.

The paper presents the results of studies of the content of particulate matter PM₁ - PM₁₀ in the atmosphere of the western coast of South Baikal with high temporal resolution. It has been established that PM are emitted into the atmosphere of Southern Baikal from both anthropogenic and natural sources. In winter, the influence of thermal power engineering increases, as evidenced by synchronous increases in the concentrations of submicron aerosol PM₁ and sulfur dioxide. In summer, remote forest fires make a significant contribution to atmospheric pollution with particulate matter. The relationship between the increase in the concentration of PM₁ in the atmosphere in the region under study and mesometeorological features (temperature inversions and mesoscale transfer of plumes from large thermal power plants) has been revealed. Increases in PM₁ concentrations in most cases occur during the night and morning hours, which is associated with a decrease in the thickness of the atmospheric boundary layer.

This paper represents an approach based on analysis techniques (statistical, microscopic, verification) of data provided by aerosol optical sensors, diffusion aerosol spectrometer, aspirating air sampler, and optical microscopy. The particulate matter size distribution and PM_2.5 mass concentration are studied. The low-cost measurement tools are verified with expensive precise equipment. The results show a high correlation (from 0.92 to 0.98) between different tools. The combination of considered devices can become a basis for a multipoint aerosol monitoring network for a wide urban territory with relatively low expenses.

A comparative assessment of the concentrations of PM_2.5 in the surface atmosphere over the territory of the city and over the water area of the Yenisei River was carried out. It is shown for time periods from several days to two years that, with rare exceptions, pollution over the river is lower than over the territory of the city. This pattern persists during periods of unfavorable meteorological conditions and during pollution of the urban atmosphere by the smoke of forest fires.

The results of experimental determination of near-surface aerosol density for particles of different composition and size have been published over many years. Based on the generalization of these data, as well as the results of our own field observations of microphysical characteristics and composition of Moscow aerosol, an algorithm and parameters for numerical estimation of mass concentration of submicron and micron urban aerosol are suggested. Using this algorithm, on the basis of experimental data on the size distribution function of aerosol particles in the diameter range 0.3-10 microns obtained during regular observations at IAP RAS in Moscow in 2020-2022, the mass concentration of near-surface aerosol of various fractions was calculated. A comparative analysis of the results of such an assessment and the data of synchronous measurements of mass concentration of aerosol particles using a portable aerosol spectrometer GRIMM 1.108 over the past two years has shown a good correspondence between the calculated and measured values. Density values for four ranges of aerosol particle sizes are selected for more correct numerical estimation of the mass concentration of urban aerosol of fractions PM_2.5 and PM₁₀.

Methods for estimating the buoyancy and rise characteristics of atmospheric pollutant emissions from high sources are discussed. They are based on the application of the relations of the theory of similarity and dimension for smoke plumes. Aerological sounding data and satellite images of plumes and their shadows on the earth's surface are used as additional information. The proposed approach to assessiment of the buoyancy flows of smoke plumes and the height of their rise was tested for three large thermal power plants in Siberia. A satisfactory agreement between the results and the normative characteristics of buoyancy flow for the chimneys under consideration has been established.

The paper considers changes in the state of the environment in Krasnoyarsk and its environs during the existence of the smoke of large-scale Yakut fires in August 2021. The appearance of smoke aerosols in the atmosphere led to a weakening of the passage of solar radiation to the Earth's surface and, accordingly, to a decrease in the temperature of the active soil layer and the surface air layer. Advection of cooled air with high relative humidity over the surface of the Yenisei River in the lower reaches of the Krasnoyarsk HPP formed cooling mists.

The outcome of the first tests of a measuring system designed for the monitoring of atmospheric aerosol content and meteorological parameters is considered. Based on the measurement results from August 2022, the data of the system prototypes, a calibrated optical aerosol sensor, and the on-site meteorological station are compared. The revealed drawbacks of the system design are described. The plans to improve and extend the system capabilities are discussed. A blueprint of a future multipoint aerosol monitoring network in Yekaterinburg and its neighborhood is presented.

The ecological state of the Arctic hydrocarbon deposit territories over the period 2013-2022 is estimated. Vegetation cover is considered an indicator of the ecological state of the territories under study. Based on the Terra/MODIS satellite data, the state of the vegetation cover of hydrocarbon fields in the Purovsky district of the Yamal-Nenets Autonomous Okrug is studied: Urengoyskoye, Vostochno-Tarkosalinskoye, Gubkinskoye, Vyngayakhinskoye, Komsomolskoye, and Tarasovskoye. Using the ArcGis geographic information system, the average values of EVI (Enhanced Vegetation Index) of the field vegetation cover for the full growing season from May 25 to September 20, 2013-2022, are calculated. The EVI minima and maxima for the territories are determined. Tendencies towards an increase in EVI in the final growing season over the 10-year period under study are found.

Artemisia jacutica Drob. is an East Siberian endemic, biennial plant. It is distributed within the Republic of Sakha-Yakutia and the South of Central Siberia. The typical habitats are saline mesic and semi-dry meadows, steppes, salt marsh, abandoned fields and ruderal habitats. The south-eastern border of the species area of distribution is located in Buryatia. The essential oils were obtained by hydrodistillation from air-dry raw materials in the year of collection. The composition of the essential oils was analyzed by chromato-mass spectrometry. The main component of the essential oils of A. jacutica was chamazulene, which showed anti-inflammatory effect. According to the literature and own data it was found that the formation of essential oils’ composition was influenced by climatic conditions, which, obviously, provided the best adaptation of plants to environmental conditions. Climatic conditions determined the composition of essential oils of A. jacutica, resulting to the formation of two chemotypes - “Buryat” and “Yakut”. It has been established that the formation of these chemotypes generates due to differences in the level of heat and moisture supply of habitats, which is expressed by the hydrothermal coefficient (HTC). The temperature-humidity extremeness coefficient calculated on the basis of annual data influenced the ratio of components in the essential oils in a greater degree. Climatic factors (air temperature, precipitation, etc.) and their integral characteristics affected the content of individual components in the essential oils directly or in combination with each other, enhancing or diluting the influence of each other.

Here, we present the results of long-term monitoring (2002-2017) of epiphytic lichen Hypogymnia physodes in the influence zone of the Middle Timan Bauxite Mine (Komi Republic). The main environmental pollutant in this area is dust with a predominance of Al and Fe. Three periods of the reaction of lichen to dust pollution are identified: shock, maximum changes, and adaptation. Dust pollution significantly decreased the projective cover of the species under study, increased the frequency of thallus necrosis and decreased thallus linear dimensions. In ten years after we started our monitoring studies, the vital state parameters of H. physodes began to stabilize and then to improve due to adaptation of the lichen to chronic environmental pollution with dust. The study of changes in the content of main pollutants showed that, during the mine operation, they accumulate in the thalli of the lichen H. physodes in the following order: Al > Fe > Ni > Cu > Pb.

The distributions of bioorganic components, as well as compounds of anthropogenic and mixed origins, have been studied in the sediments and water of the Parshikha Bay of the brackish Lake Chany (the Novosibirsk Region). The contribution of the main sources of organic matter in water and bottom sediments was estimated relying on the compositions of identified compounds (acyclic, aromatic and naphthenic hydrocarbons, acyclic and alicyclic oxygenated organic compounds, steroids, bicyclic sesquiterpenoids and pentacyclic triterpenoids). The composition of these objects has been established to be formed mainly due to the compounds of biogenic and mixed origin. The ratio of odd to even alkanes is equal to unity, the presence of cyclohexanes and drimanes, which are not characteristic of recent precipitation, indicates the presence of petroleum products. Household compounds - triphenylphosphates and phthalates, which are used as plasticizers in the production of polymer materials, have also been identified.

In this work, the samples of α-fractions isolated from the pitches of different grades (B, B1, V) obtained from an industrial sample of coal tar are studied. The main numerical characteristics obtained from the Raman spectra of the isolated α-fractions are calculated and analysed. A direct relationship is established between the content of defects in graphite-like crystallites and the pitch softening temperature.

The production of high-purity lithium hydroxide (LiOH) solution by electrochemical conversion of soluble lithium salts (membrane electrolysis) was tested on semi-industrial scale. Stainless steel (cathode) and lead (anode) were used as electrode materials. Lithium sulphate solution was utilised as anolyte and water - as catholyte. During membrane electrolysis, water oxidation takes place in the anode compartment with the formation of gaseous oxygen and protons. Lithium ions permeate through the cationic membrane into the cathode compartment, where gaseous hydrogen and hydroxide ions are formed as the products of water decomposition on the cathode, so lithium hydroxide gets concentrated up to 33-36 g/dm³ with respect to lithium oxide. Electrolysis efficiency is 50-55 % for one process cycle. Sulphuric acid formed in the anode compartment may be then neutralised by adding lithium carbonate, and the formed lithium sulphate may be re-used in membrane electrolysis, which means anolyte recycling. Five successive electrolysis cycles with recycled anolyte allow an increase in the degree of lithium ion transfer from the anode to cathode compartment to 95-98 %. It is established that, in addition to lithium, other metal ions (sodium, potassium, calcium, etc. ) and sulphate ions migrate through the cation-exchange membrane into the cathode compartment from anolyte solution. To evaluate the quality of the obtained lithium hydroxide monohydrate (LiOH · H₂O), lithium hydroxide solutions obtained both by membrane electrolysis and by the traditional lime causticisation process were evaporated. Comparison between the concentrations of impurity ions in lithium hydroxide monohydrate samples obtained using different methods shows that the product of better purity may be synthesized from lithium sulphate solution by membrane electrolysis.

A compact mechanism based on elementary radical reactions is proposed for the temperature conversion of methane-ethane mixtures. The kinetic model relying on this mechanism describes the literature data on the conversion of methane and ethane at millisecond time intervals in the temperature range 600-1400 °C. Within the kinetic model, the time dependences of the concentrations of hydrogen, ethylene, acetylene and benzene on the temperature and on the methane/ethane ratio in the initial mixture are determined in the isothermal approximation. Using the proposed mechanism for the calculations of axisymmetric gas dynamic flows of reagents mixture, the yields of hydrogen and valuable unsaturated hydrocarbons in a non-isothermal tubular reactor are determined.

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The results of studies on changes in the chemical composition and structure of doped titanium hydroxide during thermal treatment are analysed. It is shown that anatase is formed at first under heating in all cases, and with further increase in temperature or in the duration of thermal treatment it is transformed into rutile. The temperature of the start of anatase-rutile transition depends on the type of doping component. The transition proceeds not abruptly at a certain temperature but gradually over a wide temperature range, while both compounds can exist simultaneously. At a constant temperature, the proportion of rutile increases with an increase in the duration of thermal treatment. It is concluded on the basis of the conducted studies that the samples of titanium dioxide in the presence of doping components represent the broad classes of non-stoichiometric compounds with different crystal structures, and the transition of anatase to rutile is not a polymorphic transformation of the 1^st kind but it is a consequence of various chemical processes involving the release of anionic and/or cationic impurities into the gas or solid phases.

The influence of the concentration of cobalt introduced into HZSM-5 on its acidic and catalytic properties in the transformation of ethanol into high-octane components of motor fuels has been studied in the plug-flow unit within the temperature range of 300-450 °С. The unmodified НZSM-5 zeolite is shown to be highly selective to aromatization products (27.5-47.6 %) and С₁-С₃ alkanes (25.8-37.1 %). A significant increase in selectivity to isomerisation products (from 17.2-19.8 to 34.0-42.7 %) is established for cobalt-modified (1.0-3.0 wt. %) zeolite catalysts within the temperature range 300-350 °C. The highest increase in the selectivity of modified catalysts to aromatisation products (32.7-40.7%) is observed within the temperature interval of 400-450 °С. The effect of modification on the acid properties of HZSM-5 zeolite has been studied using the temperature-programmed desorption of ammonia. It is shown that the changes of the catalytic properties of HZSM-5 zeolite are connected with a considerable decrease in the concentration of strong Brensted acid centres (from 538 to 317 µmol/g), with the formation of new stronger Lewis acid centers (37-80 µmol/g) including cobalt ions and acid-base Co^δ+-O^δ- type pairs capable of strong polarization and activation of C-H bonds in the intermediates. Selectivity to the products of isomerisation and aromatization on the modified catalysts is regulated by cobalt concentration and process temperature. The highest selectivity to isomerisation products (42.7 %) is achieved over the 2 % Co/HZSM-5 catalyst at a temperature of 300 °C. The catalysate obtained over the 2 % Co/HZSM-5 catalyst at 300 °С corresponds to Euro-5 standard in the content of isoparaffin (56.4 %) and aromatic (29.8 %) hydrocarbons, benzene (0.6 %) and olefins (1.1 %).

The increasing concern for environmental sustainability and the need for efficient and green chemical synthesis have driven the development of alternative methods for producing new compounds. In this study, we have synthesized a series of novel 2H-chromene derivatives using a one-pot multicomponent reaction under ultrasound sonication. The use of ultrasound sonication is a green and efficient synthetic method that utilizes sound waves to initiate chemical reactions. We optimized various reaction parameters, such as solvent, temperature, catalyst amount, and reaction time, to identify the best reaction conditions for the synthesis of the derivatives. The synthesized compounds were characterized using analytical techniques such as IR, mass, ¹H and ¹³C NMR spectra, which confirmed the molecular structures of the derivatives. Furthermore, the antioxidant activities of the synthesized derivatives were evaluated and compared to those of ascorbic acid. The IC50 values of the derivatives were promising, indicating their potential as antioxidants. Overall, this study demonstrates the effectiveness of ultrasound sonication as a green and sustainable approach to the synthesis of novel compounds with potential biological activities. The use of one-pot multicomponent reactions also adds to the efficiency and simplicity of the synthesis method. These findings may have important implications for the development of new and sustainable chemical synthesis methods in the future.

Ferulic acid (FA) is a phenolic substance widespread in plants and exhibiting a wide range of potential therapeutic effects, such as antimicrobial and anti-inflammatory, and useful in the treatment of diabetes, lung and cardiovascular diseases. Methanol extracts from the fresh leaves of 40 species from the Lamiaceae family growing in the outdoor collections of the Botanical Garden of the Komarov Botanical Institute of the Russian Academy of Sciences (BIN RAS, Saint-Petersburg) and the experimental station "Otradnoye" BIN RAS (Leningrad region) have been investigated. Ferulic acid was detected in 18 species under investigation, related to the subfamilies Lamioideae Harley ( Betonica grandiflora Willd., Galeobdolon luteum Huds., Lamium album L., Sideritis taurica Steph. ex Willd., Stachys byzantine K. Koch) and Nepetoideae Kostel. ( Clinopodium vulgare L., Hyssopus officinalis L., Lavandula angustifolia Mill., Meechania urticifolia (Miq.) Makino, Melissa officinalis L., Mentha piperita L., Monarda didyma L., Nepeta bucharica Lipsky, Nepeta grandiflora M. Bieb., Origanum vulgare L., Prunella laciniata (L.) L., Salvia desertum L., Salvia officinalis L., Thymus serpillum L.). Ferulic acid was not detected in the representatives of Ajugoideae Kostel. и Scutellarioideae Caruel subfamilies. For 7 species, FA was detected for the first time. The content of FA in the representatives of Lamiaceae subfamily varied within a broad range from 0.01±0.00 mg/g ( Meechania urticifolia ) to 6.68±1.30 mg/g ( Melissa officinalis L.). The high ferulic acid content was established in the Nepetoideae subfamilty in the species Melissa officinalis (6.68±1.30 mg/g) and Origanum vulgare L. (6.07±1.90 mg/g).

The kinetics and mechanism of hydrogen evolution on the FeSi₂ electrode in 0.25-1.0 M NaOH solutions have been studied by polarisation and impedance measurements. The cathodic polarisation curves of iron disilicide in the studied solutions are characterized by a Tafel region with constants a and b equal to (-0.78)-(-0.72) and (-0.133)-(-0.128) V, respectively. The impedance spectra of FeSi₂ at the potentials of the Tafel region represent a capacitive semicircle with a displaced centre, which corresponds to an asymmetric maximum in the graph of phase angle dependence on the logarithm of the alternating current frequency; the magnitude of the electrode impedance in all solutions changes in accordance with the course of the polarization curves. To describe the hydrogen evolution reaction on iron disilicide, an equivalent electrical circuit was used, the Faraday impedance of which consists of series-connected charge-transfer resistances and a parallel circuit responsible for the adsorption of atomic hydrogen on the surface and its diffusion into the depth of the electrode material; the circuit also includes the electrolyte resistance and the double-layer capacitance impedance, which is modeled by a constant phase element. It is shown that the results of polarization and impedance measurements for the FeSi₂ electrode are in satisfactory agreement with the discharge-electrochemical desorption mechanism, in which both stages are irreversible and have unequal transfer coefficients; for adsorbed atomic hydrogen, the Langmuir adsorption isotherm is satisfied; simultaneously with the reaction of hydrogen evolution, the reaction of hydrogen absorption by the electrode material proceeds with diffusion control. It has been found that iron disilicide in an alkaline electrolyte is characterised by the low overvoltage of hydrogen evolution, and it is a promising electrode material for the electrolytic production of hydrogen.

High-molecular oil fractions exhibiting the initiating effect, nontypical for these oil objects, on the model reaction of cumene radical oxidation were investigated by means of microcalorimetry. It is shown for some objects that the initiators appear in the high-molecular fractions of oil in the course of their isolation from native oils by n-hydrocarbons. An insignificant correlation is established between the content of nickel, vanadium, and vanadylporphyrins and initiating activity. The initiators have been found in freshly isolated ‘acid resin’ fractions, which lose their initiating ability during storage due to chemical condensation processes. This method may be considered as a test for the content of inhibitors or initiators of radical oxidation in oil objects.

Intense coal mining at the territory of our country, related to the growing amounts of exported fuel, promotes the development of logistic infrastructure but at the same time causes a worsening of the environmental situation near coal mining enterprises. One of the ways to cope with the surfaces that generate dust, in particular fine coal dust particles, is surface treatment with hydrophobising organosilicon emulsion. However, the problem connected with enhancing the hydrophobicity of coatings formed by the emulsion has not been solved yet. This parameter is estimated by determining the wetting angle. The efficiency of modification and the coalescing ability of various additives in the aqueous emulsions of organosilicon liquid GKZh-94 are evaluated in the present work from changes in the wetting angle. The dependences of film wettability changes on the modifying and coalescing agents, and on their amount in the emulsion are demonstrated. The dependences of wetting angle changes on the amounts of the modifying and coalescing agents in the emulsion are plotted on the basis of the polynomial approximations of functions. It is established that preliminary modification of the emulsifier causes an increase in the hardness of polyvinyl alcohol, which hinders coalescence of particles in the emulsion. It is also determined as a result of a comparative analysis that the best wetting angle values are detected for the emulsions with the emulsifier modified with a small amount of glutaric aldehyde, with the high concentration of ethylene glycol as a coalescing agent. The use of glutaric aldehyde in the amount of 0.1-0.25 % and ethylene glycol in the amount of 3-6 % of the total mass of emulsion will allow an increase in the wetting angle of the formed coatings to 125°.

Currently, the chemical nickel plating process is one of the most popular electroplating methods compared to others due to a number of advantages. However, the production process generates a significant amount of spent chemical nickel plating solutions, which poses a threat of environmental pollution. To solve this problem, the possibility of regenerating the spent solution of chemical nickel plating from one of the industrial enterprises of Udmurtia by the reagent method was studied. Sodium carbonate was chosen as the precipitant for nickel ions, the amount of which was determined from potentiometric titration curves; the most complete precipitation of nickel ions occurs at pH 10. It has been established by IR spectroscopy that nickel hydroxide salts are formed as a result of the interaction of the spent electrolyte with the precipitant. The results of thermogravimetric and differential thermal analysis of the precipitate showed three endothermic effects: at temperatures up to 100 °C, it corresponds to dehydration; at 280±10 °C - to the removal of a part of chemisorbed water and carbonates; at 420 °C - to the final removal of water. As a result of heat treatment of the hydroxocarbonate precipitate, a black fine powder of nickel (II) oxide is obtained, the IR spectrum of which has a set of bands characteristic of this compound. Two variants of the technological scheme for the regeneration of spent electrolytes for the preparation of initial working solutions for chemical nickel plating from nickel (II) hydroxocarbonate and nickel oxide are proposed. The quality of the obtained solutions was checked by applying a nickel coating on brass products. The thickness of the coating was measured by scanning electron microscopy. It has been established that the highest quality coating is obtained using an electrolyte prepared from nickel hydroxocarbonate.

The morphology and mineral composition of cryogenic formations of the Malaya Nizhneudinskaya Cave have been studied by electron microscopy and X-ray powder diffraction. This cave is confined to permafrost. The temperature in the cave is near zero all year round, as a result of which ice formations are widely developed in the cave. When solution freezes, and the subsequent partial evaporation of ice occurs, a cryogenic residue composed of gypsum, calcite, and a rare mineral rapidcreekite Ca₂(SO₄)(CO₃)·4H₂O is formed. Rapidcreekite forms radial-radiant aggregates of acicular crystals of up to 200 μm in length. In our opinion, the source of sulfur is represented by the locally developed interlayers of gypsum in the non-karsting rocks overlaying the limestones. This is the second finding of rapidcreekite in the speleo-cryomineralogenesis environment in the world and the first discovery of this mineral in the caves in Russia.

Erosion plays an important role in removing permafrost degradation products. In order to identify the rates and mechanisms of erosion in degrading permafrost, fluvial landforms in small catchments at the foothills of the Kharaulakh Range were typified, and their morphology, formation conditions, and dynamics for 2019-2022 were characterized. The most dynamic landforms associated with melting ice wedges were thermokarst runoff troughs (water tracks), rills, and thermoerosional gullies. Thermoerosional gullies forming in sediments without wedged ice grow upon very high floods; in the rest of the time, their sides slowly slide down under the action of snowfields. Sediments from gullies and rills are deposited in the upper reaches of small rivers. The channels of small rivers are relatively stable, which is also typical of other permafrost regions. Differences in the dynamics of erosional landforms can be explained by an increase in the thermal rather than mechanical impact of water on frozen deposits, which is observed with the rise in air temperature against the background of relatively stable precipitation in the north of Yakutia.

The elaborated method of regional calculation of the hydrological regime of glaciation includes determination of long-term changes in glacial runoff and glacial feeding in river basins. For the Rhone River basin, monitoring data on glaciation parameters over the period of 1971-2016 and long-term data on precipitation and air temperature at weather stations of Switzerland were used for hydrological and glaciological calculations. The results of linear extrapolation of spatiotemporal changes in the altitude-area characteristics of the classified groups of glaciers proved to be sufficient for calculating the hydrological regime of glaciation. An adequate description of seasonal and long-term glacial feeding of rivers should take into account spatiotemporal variations in the ablation of glaciers depending on the five types of active glacier surface and their altitude-area characteristics. Satisfactory absolute and relative estimates of differences between the measured runoff and the amount of precipitation, evaporation, and glacial feeding in the upper Rhone River in 1971-2010 (Porte du Scex gauging station), as well as between the measured and calculated annual precipitation in the Rhone River basin for 1971-2016, were obtained.

The reasons and conditions for the formation and change of moulins are considered on the base of author’s own data and on published data. Moulins can form above the water level in crevasses in the ice column and cannot form below the water level. The cylindrical shape of moulins is associated with the spraying of water jets at a certain depth from glacier surface. Questions related to different mechanisms of moulin formation, their depth, age, water level fluctuations are considered. A possible connection between moulins and the internal drainage system of glaciers is shown. Since there are glaciers in which water does not penetrate to the bed through moulins, the question of the connection between moulins and thrusts in the ice thickness is being considered.

Changes in the Earth’s insolation by latitudes and seasons in certain periods of the Holocene are considered. A comparative analysis of insolation in boundary years of Holocene geochronological periods with modern insolation (2022) is carried out. The change in summer insolation in the hemispheres is analyzed separately. Quantitative estimates in the intensity of insolation’s changes in the Holocene are assessed with respect to the modern insolation. The extremes of summer insolation in the Northern hemisphere are synchronized with the global paleogeographic events of the Holocene: the transition from the cold Pleistocene epoch to the warm Holocene and the Little Ice Age. Characteristics of the Earth’s orbital motion have also been shown to control the Northern hemisphere summer insolation’s change, which is a factor of the noted global paleogeographic events.

The Priobskoe plateau is characterized by a high diversity of plant communities. It is associated with the specific features of the relief, hydrology and edaphic factors. Currently, a lot of separate works on the syntaxonomy of vegetation have been published for certain areas of the Priobskoe Plateau, but there is't unified checklist of communities. Its compilation will allow assessing the phytocoenotic diversity of the region and identifying “blind spots” in the study of the territory. A database of 1530 published geobotanical descriptions was created in the IBIS 7.2 program in order to analyze the syntaxonomic coverage of the vegetation in the Priobskoe plateau. Based on those, the prodromus of vegetation was compiled, which included 17 classes, 29 orders, 44 alliances and 103 associations. It covers the frequency of associations in the right-bank and left-bank parts of the plateau - separately for the steppe and forest-steppe zones (table). For each association, the position on the soil moisture and richness-salinization gradients was determined using phytoindication scales. This resulted in the creation of the ordination schemes of associations (Fig. 2). The vegetation of the forest-steppe zone on the left bank of the Ob is represented by 63 associations, 35 alliances, 24 orders and 16 classes. Steppes, meadows, forests, halophytic, aquatic and semi-aquatic communities are widespread here. The diversity of aquatic and semi-aquatic vegetation is associated with the large number of rivers and lakes. Forest coenoses are formed along the ravine and hollow systems and suffusion depressions. Natural meadows are found in small areas in the edges and clearings of small-leaved forests, ribbon forests, along the fields and idle lands. The tops and slopes of the ravine and hollow systems feature well-preserved steppes. The steppe zone vegetation of the Priobskoe plateau left bank is less diverse. It is represented by 22 associations, 13 alliances, 10 orders and 8 classes. Moisture deficiency results in the dominance of steppe communities and is the reason for the small number of associations representing meadows and forests. To date, complete information on the diversity of the forest, halophytic, aquatic and semi-aquatic vegetation in this area is not available. The right-bank part of the Priobskoe plateau is represented by 50 associations, 23 alliances, 14 orders and 6 classes. The vegetation of this territory is close to the left-bank forest-steppe. The main difference is the absence of halophytic communities. This is related to the good drainage of landscapes, which prevents the development of saline soils. Our studies have revealed the diversity of the Priobskoe plateau vegetation. The three areas of the plateau differ from each other markedly in terms of syntaxonomic diversity. This is associated with the differences in natural conditions and the degree of coverage.

We studied the seed set of the andromonoecious Oenanthe aquatica (Fine-leaved Water-Dropwort), a biennial or perennial mono- or oligocarpic herbaceous plant. Our survey was carried out in natural conditions of the Moscow region in 2021 according to generally accepted methods of studying plant seed sets. We showed that the seed set of individuals depends on the degree of synflorescences branching. Fine-leaved Water-Dropwort has two types of individuals with umbels on shoots of I-III and I-IV orders. O. aquatica has a high potential (number of ovules per individuals) and real (number of seeds per individuals) seed set (up to 21 490 seeds per individual) and the proportion of perfect flowers forming full seeds (95.8-96.8 % per individual). The potential and real seed set of terminal umbels is lower than that of individual umbels on shoots of the second orders. In Fine-leaved Water-Dropwort, the seed set of umbels on shoots of the same branching order naturally increases with an increase in the branching of the shoot system. The contribution of the seed set of umbels to the total seed set of O. aquatica individuals also depends on the degree of synflorescences branching. With an increase in the branching of the shoot system, the share of seed set of terminal umbels and umbels on second-order shoots gradually decreases. These characteristics of umbels on third-order shoots naturally increase due to both their numerical predominance.

The article presents the results of the analysis of the demographic structure of the coenotic populations of Hedysarum sangilense Krasnob. et Timoch. on the high-altitude Sangilen plateau (South-Eastern Tuva). The ecological-coenotic association, ontogenesis, ontogenetic and vital structure of 7 populations of this subendemic species were studied. It is established that in the studied territory the species is confined to the communities with Kobresia and dryad tundras within the alpine belt and to the shrubby thickets in the forest belt. Study of the demographic structure revealed that the majority of coenotic populations are characterized by left-sided age spectra with a predominance of juvenile, virginal and, most often, young generative plants. In conditions of disturbed phytocenoses (recovering from fires), left-sided spectra are formed with a maximum on generative young plants. Among the vitality of the types of populations of H. sangilense is dominated by depressive and equilibrium types. Sufficiently high real seed productivity and a long generative period ensure the self-maintenance of H. sangilense populations in the conditions of high-altitude plant communities of the Sangilen highlands.

The appearance of new collections from Eastern Siberia and the reanalysis of previously studied collections from Siberia and Mongolia stored in Herbariums LE, MW, NSK, as well as the analysis of virtual collections hosted in the international Jstor database, made it possible to describe a species new to science Lappula turczaninowii Ovczinnikova from the kinship L. redowskii (Hornem.) Greene from the Redowskianae Ovczinnikova series of the type section , validate the names of two varieties of L. anisacantha (Turcz. ex Bunge) Gürke var. sibirica Popov ex Ovczinnikova and L. anisacantha var. uniserialis Popov ex Ovczinnikova, proposed by M.G. Popov in “Flora of the USSR”, as well as to clarify the range of L. stricta (Ledeb.) Gürke in the Baikal region. L. turczaninowii is described from the Irkutsk region, found on stony and rocky steppe slopes in the Baikal region, Transbaikalia, Yakutia, and Mongolia. It differs from the closely related species L. redowskii in the sparse soft pubescence of all plant organs, more densely arranged fruits on the fruiting twigs, the ovoid shape of the eremocarp disc, and the number of glochids (13-15) along the edge of the disc. For all new taxa, a nomenclature citation is given, labels of type specimens are cited, information is given on ecological features and distribution, and a table of diagnostic characters of the new species and the species in which it was included is compiled. The main diagnostic features of the taxa are illustrated in the figures, and photographs of type specimens are given. The cited new localities of L. stricta from the Irkutsk region complement the natural range of this species.

For the first time for the flora of Omsk Region, a representative of the steppe halophyte complexes Camphorosma lessingii from the Chenopodiaceae family is indicated. The nearest findings of this species are known in Novosibirsk Region and in the north of the Republic of Kazakhstan. The article also contains data on the new locations of 7 rare and protected species of vascular plants for the territory of Omsk Region: Allium ramosum L., Campanula bononiensis L., Cleistogenes squarrosa (Trin.) Keng., Galatella divaricata (M. Bieb.) Novopokr., Nitraria sibirica Pall., Stipa praecapillata Alechin, Vincetoxicum sibiricum (L.) Decne., discovered during field studies in 2021-2022. The article justifies proposals to change or confirm the current security status for Allium ramosum, Camphorosma lessingii, Galatella divaricata, Nitraria sibirica, Stipa praecapillata - 1 (E), Campanula bononiensis - 2 (V). Due to poor knowledge and a small number of populations, it is proposed to include Cleistogenes squarrosa and Vincetoxicum sibiricum in the list of species that need special attention to their condition in the nature.

New localities of alien species rarely found in the Novosibirsk Region are reported: Acer tataricum L. subsp. ginnala (Maxim.) Wesm., Amelanchier ovalis Medik., Bromus tectorum L., Cornus alba L. f. argenteo-marginata (Rehd.) Schelle, Corylus heterophylla Fisch. ex Trautv., Hemerocallis fulva (L.) L., Iris × hybrida hort., Lamium galeobdolon (L.) L., Prunus fruticosa Pall., Rubus odoratus L., Schisandra chinensis (Turcz.) Baill., Sisymbrium volgense M. Bieb. ex E. Fourn., Symphytum caucasicum M. Bieb., Tilia cordata Mill., Veronica filiformis Sm., Viola tricolor L. Dispersal of 14 species, predominantly invasive or potentially invasive, was recorded in the Novosibirsk Region. Most of the discussed species are ergasiophytes - species that have left the culture.

The paper presents an analytical review of the multivolume floristic synopsis, “Conspectus Florae Asiae Mediae” (1968-1993), edited by the eminent Russian botanist, Professor Aleksei Ivanovich Vvedensky (1898-1972). Сheck-lists for new species as well as for new nomenclature combinations published in these books are compiled. Overall from 1968 to 1993, 10 volumes of synopsis of the Middle Asian flora were published with 8102 species, 1151 genera and 125 families. According to the materials published in the additional 11^th volume of the synopsis, the total number of vascular plants in Middle Asian flora is 9347 species.

The article is dedicated to the 90th anniversary of the birth of the famous Russian florist, algologist Tatiana Andreevna Safonova. Her work has made a great contribution to the study of the diversity, morphology and distribution of freshwater algae.

On February 15, 2023, Olga Dmitrievna Nikiforova, a well-known taxonomist of Siberian vascular plants, Doctor of Biological Sciences, a real ascetic of science and a person of great soul, passed away. All scientific activities of O.D. Nikiforova is associated with the Central Siberian Botanical Garden of the Siberian Branch of the Russian Academy of Sciences. For the multi-volume edition “Flora of Siberia” she studied the morphology, geography and ecology of more than 200 species from the families Poaceae, Fabaceae, Brassicaceae, Boraginaceae. She is the author of 114 scientific publications. In the study of the flora of Siberia and neighboring states, she described 24 new species and subspecies, 50 new sections, subsections and series in the system of genera Vicia, Mertensia, Myosotis.