Home – Home – Jornals – Geography and Natural Resources 2024 number 3

The generalized chemical composition data on the studied dolerites from the Vilyui-Markha dike swarm (Vilyui paleorift) allowed detecting geochemically anomalous areas among them. It has been found that percentage of TiO₂ and a number of heavy rare-earth elements (Th, Ta, Hf, Y, Nd) in the dolerites of dikes located within the kimberlite fields show almost twofold increase compared to the normal content for these elements in the Vilyui-Markha dolerites. Similar behavior of these elements is also observed in the dolerite dikes near the Kuoika kimberlite field (the Molodo dike swarm, Olenek paleorift). It is inferred that there is a connection between the increase in abundances of titanium and rare-earth elements in the dolerites and that the latter occur within the lithosphere blocks hosting kimberlite fields. The areas of lithospheric mantle roots linked with the formation of proto-kimberlites may have had bearing on the composition of tholeiite melt both in the processes of its generation and during its ascent to the Earth’s surface, which led to its local enrichment in titanium and a number of other elements. While the processes of the alignment of the geochemical composition between the high-titanium basites and the rest of the melt beyond the contours of the lithospheric blocks with kimberlite fields were weakly pronounced, they were responsible for appearance of zones enriched in titanium. Kimberlite fields that formed before or after basite magmas intrusion overlap with placements of high-titanium dolerite dikes. Thus, high-titanium dolerites in dike swarms (belts) can be used as one of the criteria for kimberlite searches. In view of the above, two new potential zones (Tenkelyakh and Kyulenke areas) for kimberlite exploration have been identified within the Vilyui-Markha dike swarm.

Understanding the origin of quartz veins of the mica-pegmatite formation is of great importance for deciphering the emplacement conditions for the of commercially prospective quartz targets. On the example of the Berkutinskaya vein, which is the typical metamorphogenic quartz deposit of the mica-pegmatite formation of the South Urals, we study the source and origin of the mineral-forming fluid, temperatures of quartz formation, the structure of intergranular boundaries, their morphometric feature, the fractal dimension of quartz grains and commercial characteristics of quartz grit. An integrated approach to the study of the typomorphic features of quartz allowed us to assess their impact on the technological characteristics of quartz concentrates. Comparison of data on the content of impurity elements in the Berkutinskaya quartz vein with quartz of the vein No. 175 of OOO Russian Quartz and IOTA-std (Sibelco) showed that the Berkutinskaya quartz vein is promising for commercial development.

Dinocyst assemblages are subjected to taxonomic typification based on a qualitative and quantitative assessment of their generic composition for the Northern Hemisphere during the Coniacian-Santonian time in order to identify correlation taxa. The typification is carried out using a cluster analysis according to the Jacquard calculation model (BioDiversity Professional, 1997). Three types of dinocyst assemblages have been identified in the Coniacian. As compared to the Turonian, the relatively cold-water West Siberian basin is characterized by a decrease in the number of cosmopolitan taxa and an increase in species endemism. The only taxa identified at present are those allowing for intrabasin correlations. Three types of dinocyst assemblages have also been established for the Santonian. Free interbasin connections in the Northern Hemisphere contribute to the equalization of the generic composition between the three identified types and to the identification of characteristic taxa that allow for interregional correlation.

The Permian-Triassic (P-T) boundary records the most dramatic events in Phanerozoic history. The character of the boundary differs greatly, so it has been the subject of great discussion. The Barents Sea separates regions having markedly different expressions of the P-T boundary, and it can give an insight into the conditions of formation of this boundary in different parts of the European North. This contribution is based on a combination of regional projects from the Russian and Norwegian sectors, including seismic data across the Barents Sea and well data in marginal zones. Application of new seismic data and the sequence stratigraphy concept provides a novel approach to correlation and interpretation of the P-T boundary beneath the Barents Sea. The study has revealed a distinct regional sequence boundary corresponding to the P-T boundary with conformable and unconformable bedding. Three major types of this stratigraphic boundary are recognized. The distinct “erosional” type of the P-T boundary, with a significantly reduced Permian section, exists in the southeast (Timan-Pechora Basin). The conformable “overcompensated” type of boundary with an additional Lower Triassic section is interpreted in the central part of the Barents Sea. Westward, beneath the Norwegian sector, a relatively conformable “condensed” type of P-T boundary predominates. In addition to these types associated with regional paleostructural and depositional trends, the superposed “structural” subtype caused by local growth of structures at the Permian-Triassic boundary is identified.

Erosion and sedimentary landforms are linked through sediment transport pathways, which forms a source-to-sink system (S2S). The coupling relationship of different components in the clastic sediment system is emphasized by the S2S concept. A new method for characterizing the sedimentary process of continental rift basins is also provided. It has been proven that there is rich exploration potential in the third member of the Shahejie Formation (Es₃) in the Shulu Slope of the Bohai Bay Basin in China but with relatively low production. With the complex structural background of the Es₃ of the Shulu Slope, conventional research methods are ineffective in guiding the current development strategies. Therefore, this study adopts the S2S theory, and its elements in the study are characterized using core, logging, and seismic data. The results suggest that the S2S in this study area was supplied by the Ningjin Uplift in the western region, and a fan delta and lake sedimentary systems were formed by the sand transported through valleys and fault troughs. The S2S coupling model, “the Ningjin Uplift sand supply-fault trough, valley transport-fan delta, and shore-shallow lake sedimentation,” is established. This research field permits prediction of sand bodies in continental rift basins with similar structural backgrounds.

Permeability is one of the most significant and challenging parameters to estimate when characterizing an oil reservoir. Several empirical methods with geophysical borehole logs have been employed to estimate it indirectly. They include the Timur model, which uses conventional logs, and the Timur-Coates model, which uses the nuclear magnetic resonance log. The first goal of this study was to evaluate porosity, because it directly impacts permeability estimates. Deterministic and stochastic inversions were then carried out, as the main objective of this work was to estimate the permeability in a carbonate reservoir of the Campos Basin, Southeastern Brazil. The ridge regression scheme was used to invert the Timur and Timur-Coates equations deterministically. The stochastic inversion was later solved using fuzzy logic as the forward problem, and the Monte Carlo method was utilized to assess uncertainty. The goodness of fit for the estimations was all checked with porosity and permeability laboratory data using the Pearson correlation coefficient ( R ), root mean square error (RMSE), mean absolute error (MAE), and Willmott’s agreement index ( d ). The results for the Timur model were R = 0.41; RMSE = 333.28; MAE = 95.56; and d = 0.55. These values were worse for the Timur-Coates model, with R = 0.39; RMSE = 355.28; MAE = 79.35; and d = 0.51. The Timur model with flow zones had R = 0.55; RMSE = 210.88; MAE = 116.66; and d = 0.84, which outperformed the other two models. The deterministic inversion showed, thus, little ability to adapt to the significant variations of the permeability values along the well, as can be seen from comparing these three approaches. However, the stochastic inversion using three bins had R = 0.35; RMSE = 320.27; MAE = 190.93; and d = 0.73, looking worse than the deterministic inversion. In the meantime, the stochastic inversion with six bins successfully adjusted the set of laboratory observations, because it provides R = 0.87; RMSE = 156.81; MAE = 74.60; and d = 0.92. This way, the last approach has proven it can produce a reliable solution with consistent parameters and an accurate permeability estimation.

Information on the distribution of earthquake hypocenters for many seismically active zones of Siberia remains insufficient, which is associated with sparse networks of seismological observations. The paper presents the results of determining the earthquake depths in several seismogenic areas in the Altai-Sayan region, Cisbaikalia, Transbaikalia, and Yakutia using the travel time of longitudinal refracted waves from the Mohorovičič discontinuity ( P_n waves) from earthquakes and the recently obtained information about the deep structure of these regions. The depth determination algorithm is tested using data from aftershocks of large earthquakes occurring in Tuva in 2011 and 2012 ( M_L = 6.7 and 6.8), recorded both by the regional seismological network and by a local group of seismic stations. Different methods are applied to reveal that some aftershock depths have a close match, including those for the main shocks - the Tuva-1 and Tuva-2 earthquakes. Another good match of earthquake depths is obtained using Р_n waves with materials from regional and detailed studies of the Baikal branch of the Geophysical Survey of the Russian Academy of Sciences in the Muyakan activation site in the Baikal rift zone. The resulting data complement the information on the hypocenter of the main shock and confirm the change of the Muyakan activation cluster from large depths to shallow ones since the onset of activation in 2014. New information on the earthquake depths using Р_n waves is obtained in Yakutia along the border of the largest Eurasian and Okhotsk tectonic plates. It is revealed that they decrease to 6-12 km as compared to higher depths of 20-30 km in adjacent areas. The resulting series of new information on the distribution of earthquake hypocenters using Р_n waves is extremely important mostly because it indicates the possibility of identifying and redefining earthquake hypocenters using previous seismological observations in seismically active zones of Siberia.

Earthquake focal mechanisms that are atypical for the South Baikal basin, which is under the extension of the Earth’s crust in the NW-SE direction, are analyzed. Atypical mechanisms are understood as focal solutions of strike-slip and reverse fault types, as well as solutions with normal fault movements along NW-trending planes transverse to the main structures of the basin. Whereas normal faults along NE-trending planes dominate, 29% of solutions from the sample of focal mechanisms are of non-normal fault type, of which 18% account for strike-slip faults and their combinations with other types of displacements (with a normal or reverse component) and reverse faults (with a strike-slip component) - 11%. Such displacements occur predominantly along NW-trending planes, as well as along submeridional and sublatitudinal ones, and strike-slip movements are characterized by right-lateral displacement along NW and submeridional planes, and, accordingly, left-lateral displacement along sublatitudinal and some NE planes. Earthquakes with atypical mechanisms are distributed almost throughout the entire basin, but it is necessary to note an increase in their number on its southwestern termination (the Kultuk segment) and on the eastern side of the Central Basin. In the current field of crustal extension, transverse shears play the role of transfer faults, accommodating differences in the rates and vectors of deformation of local blocks within the basin, and on a regional scale between neighboring rift basins.

The processes of spraying, spatial propagation, and deposition of aerosol particles generated impulsively using the energy of energetic materials. Such aerosols are produced for the purpose of decontaminating harmful gases or aerosol formations. A mathematical description of the evolution of the decontaminating aerosol cloud is proposed, and the results of experiments on spraying an aerosol of titanium oxide particles are presented.

New modifications of helical generators with meander shaped striplines have been proposed, which allow the inductive and capacitive parts of the generator to be separated in space. The proposed change allows separate regulation of the characteristic impedance of a double-bus helical line and the generator inductance and winding capacity. The characteristics of the generators have been studied experimental, and theoretical models adequately describing the operation of these devices have been proposed. The developed generators can be used to produce pulsed X-ray devices with explosive electron emission.

This paper presents the results of calculations of liner implosion without the formation of shock waves under the influence of a current up to 70 MA and a magnetic field induction up to 20 MGs (magnetic pressure up to 16 Mbar) in devices with a disk explosive magnetic generator. It is shown that during deep implosion of two-layer (Cu-W) and (Cu-Ta) liners, the shockless pressure in tungsten and tantalum can reach 40 Mbar (hydrodynamic cumulation). The inner part of the liner, whose mass is more than 32% of its total mass, may remain in a solid-state dynamically strengthened state at a temperature of its copper skin layer up to 38 eV.

The impact interaction of composite projectiles with thin metal plates is studied, and a method for evaluating the ballistic limit and residual velocity of the projectile is proposed. The composite cylindrical projectile consists of a deformable highly porous nose part and a hard non-deformable tail. The velocity of the projectile is considered in the range 200-850 m/s. The problem is solved numerically in a two-dimensional axisymmetric formulation. The motion of the medium is described using the Lagrange method. The calculation results are compared with experimental data. It is shown that the results obtained are in good agreement with the results of calculations using available analytical models and experimental data.

An analytical (exact) solution of equations of a two-dimensional boundary layer of a non-Newtonian viscous fluid in the case with mass transfer is obtained with the use of the Ostwald-Reiner power-law model in a particular case with n = 2 (dilatant fluid). It is noted that the apparent viscosity in this case is described by an expression that coincides with the equation for turbulent viscosity of a Newtonian fluid derived by the Prandtl mixing length model. For the particular case under consideration, it is found that there is an analogy between the flows of a non-Newtonian fluid and a Newtonian fluid with turbulent viscosity.

The laminar--turbulent transition in transonic flows is studied with the use of thin-film surface hot-wire probes. For determining oscillations recorded by the thin-film probe in the boundary layer, coherence spectra are constructed between the data obtained by the thin-film probe and by the hot-wire probe, which was used to perform measurements across the entire boundary layer. Based on the analysis of these spectra, it is demonstrated that the most accurate and complete data are obtained by the thin-film probe in the intermittency region.

The dynamics of an acoustic signal passing through a bubble curtain has been studied by mathematical modeling. The case is considered where the gas (methane) inside the bubbles is under hydrate formation conditions. The effects of the hydrate formation process, the initial radius of bubbles, and the volume gas fraction on the attenuation coefficient and phase velocity of the wave propagating in a deep-water sea (located at a large depth) bubble curtain are investigated. The reflection and transmission coefficients of acoustic waves at the boundaries separating single- and two-phase regions are obtained. It is found that the hydrate formation process increases the wave attenuation coefficient by more than two orders of magnitude at low frequencies (below 1 kHz).

Distributions of the amplitude of controlled disturbances in space and time and their frequency-wave characteristics are obtained from experimental results on weakly nonlinear development of the wave train in the region of a stationary wake inside the boundary layer on a flat plate at the Mach number M = 2. A stationary streamwise disturbance is generated by a pair of weak oblique shock waves. Controlled disturbances are inserted into the flow by a local high-frequency glow discharge located inside the model. The development of controlled disturbances is analyzed on the basis of the linear theory of hydrodynamic stability. Typical resonant wave triplets are identified. It is found that flow inhomogeneity suppresses the mechanisms of interaction of controlled disturbances.

The results of a numerical study of heat transfer in a gas-droplet turbulent flow behind a single square barrier with variations in the initial mass concentration and diameter of dispersed phase particles are presented. When flowing around a barrier, adding droplets to the flow leads to a significant intensification of heat transfer (almost twice) compared to a single-phase air flow. It is shown that when a two-phase flow flows around a transverse barrier, the coordinates of the maximum heat transfer intensity and the flow reattachment point differ by approximately 12%. An increase in the barrier height leads to a decrease in heat transfer intensity.

For a nonlinear parabolic reaction - diffusion system, solutions are constructed and investigated that have the form of a diffusion wave propagating in a medium at rest with a finite velocity. For the first time, for cases of spherical and cylindrical symmetry, the problem of initiating a diffusion wave by boundary conditions specified on a sphere (circular cylindrical surface) is considered. A theorem of existence and uniqueness of a solution in the class of analytic functions is proved. An exact solution is constructed, which is presented in the form of explicit formulas. A step-by-step iterative algorithm is proposed, based on the collocation method and expansion in radial basis functions. Numerical calculations are performed, for the verification of the results of which the exact solution is used.

The influence of spanwise-uniform roughness elements (streaks) on the transition to turbulence in the boundary layer on a swept wing with domination of crossflow instability in the presence of unsteady and steady free-stream vortices is studied. The measurements are performed for rectangular (in the plane parallel to the flow and normal to the wall) roughness elements shaped as streaks of different heights, which have two different widths in the chord direction. The experiments are performed in a low-turbulence wind tunnel at low subsonic velocities of the incident flow with the use of hot-wire anemometry. The studies are conducted in the range of unit Reynolds numbers (based on the streamwise component of velocity at the boundary layer edge at the beginning of the rough surface region) 0.687 ·10⁶ - 1.568 · 10⁶ 1/m. The results are obtained in 76 regimes of measurements for two types of free-stream vortex disturbances generated by two turbulizing grids: with domination of unsteady disturbances and combination of steady and unsteady disturbances.

Modern approaches to visualization and automatic identification of regions are discussed separation of three-dimensional boundary layers. The corresponding algorithms are implemented within the framework of the original LOTRAN software package, designed to calculate the position of the laminar-turbulent transition in boundary layers over surfaces of small curvature. Their work is demonstrated using two configurations: a swept wing and a prolate spheroid.

In this study, the thermal and fluid flow characteristics of a piezoelectric fan are experimentally evaluated by altering its height and distance from single-fin and plate-fin heat sinks. Based on the thermal resistance of heat sinks, the piezoelectric fan performance is assessed. Particle image velocimetry is used to study the flow velocity field generated by the piezoelectric fan.

This study is aimed at optimizing the design parameters (winding angle, fiber volume fraction, elasticity modulus of fibers, and radius-thickness ratio) of the fiber-wound pressure vessel for achieving a stable strength ratio based on a hybrid method of Particle Swarm Optimization and Grey Wolf Optimization (HPSOGWO). A three-dimensional linear elasticity theory is used to solve the problem numerically.

It is proposed to use a curvilinear triangular finite element with a small number of degrees of freedom to reduce the amount of calculations in solving problems of the numerical nonlinear dynamics of shells using step-by-step integration over time. The compactness of the finite-element formulation is achieved by applying strain-tensor invariants. This is done using natural deformation components which are determined in the directions of three coordinate lines parallel to the sides of the element. Solutions describing large displacements, rotation angles, and buckling dynamics are given to analyze the capabilities of the proposed finite-element model.

The influence of the main parameters of the nonlocal continuum model on the stress concentration was studied when solving the problem of stretching a plate with an elliptical cutout in its center, also called the Kirsch problem. The influence of thermal expansion of the medium on the stress-strain state of the plate was studied. The obtained results were compared with the classical ones. It was shown that the maximum stress and heat flux density decrease, and the deformation in the stress concentration zones increases.

The paper describes a methodology for the experimental study of a powerful heat release in a microsized probe immersed in a two-component solution with a lower critical solution temperature. Experimental data on overheating relative to the liquid - liquid spinodal and thermal impact on the stability of the system for a water - PPG-425 solution are presented. The following conclusion is made for a solution whose near-critical mass fraction of PPG-425 is 30%: despite the high density of the heat flux through the heater surface (9.2-13.7 W/m²), its temperature stabilizes at a value exceeding the equilibrium temperature of the liquid - liquid system by approximately 150 K. It is shown that the heat exchange process is stable against changes in the heating parameters: the nature of heat transfer by the solution remains the same. It is revealed that the heat transfer coefficient is several times greater than the corresponding value obtained for water.

For the spray of a single-component fluid (water) from a simplex atomizer, dependences of the mean size, mean velocity, and frequency of droplet registration on the pressure and method supplying the power fluid into the simplex channels were obtained by the local time-shift method using a SpraySpy device. Visual analysis of the effect of adding a fluid (kerosene) immiscible at the molecular level with water on the structure and decay of the spray cone was carried out by shadow photography. It was found that the two-component emulsion disintegrates in the close proximity of the atomizer outlet orifice almost at once, resulting in significant deformation of the spray cone.

A working concept of geosystem monitoring of forest ecosystems under modern global warming is outlined. It is planned to carry out a full cycle of monitoring in its classical triad of Izrael-Gerasimov triad: “observation (state assessment) - control (forecast) - management (adaptation, feedback, regulation)”. The program of scientific research involves developing empirical and statistical models of the state of forest ecosystems in the past, present and future as well as uncovering the mechanisms of forest forward and backward linkages with climate. The models should describe the spatial diversity of the local and regional responses of forest cover to climatic signals as well as the regulation patterns of the carbon cycle by forest biogeosystems. According to the Paris Agreement (2015) on climate change, it is planned to solve the two-pronged problem of “adsorption-adaptation”: quantify the ecological resources of boreal and nemoral forests in mitigating modern warming and calculate sustainability parameters of forests to a changing climate as a measure of their adaptive potential. In terms of solving this problem, a working algorithm for geosystem monitoring of forests is proposed, which describes a successive change in the stages of observation, forecasting and regulation, with the identification of mitigation and adaptation effects on the carbon balances of forest ecosystems. The working tool of analysis is represented by a sliding (pendulum) operating system where observation and forecasting are repeated many times, and the basic landscape-ecological relationships are regarded as mechanisms of the metabolic response of forest communities to climate change. The program presented describes one of the ways to solve the main scientific and practical task of monitoring, i. e. to establish the ecological potential of forest ecosystems in given zonal and regional conditions for the transition to adaptive forestry.

This paper presents the main results of comprehensive systems research into the issues of Lake Baikal level regulation. The research was conducted in 2021-2023 within the framework of State Assignment FWEW-2021-0009 on the theme “Influence of changes in the Lake Baikal water level on the lake’s ecosystem and assessment of the damage to economic facilities and infrastructure of the coastal territory of the Republic of Buryatia and Irkutsk oblast, in the context of the lake’s level and discharges of Irkutsk HPP” (final third stage of FWEW-2021-0009). The research involves analyzing the historical background for the emergence and evolution of the Lake Baikal regulation issue, considering the need to take into account environmental and socio-economic factors, and shedding the light on the reasons and relevance of this research. Critical intra-annual periods and components of the ecosystem are identified for the coastal part of the lake whose successful functioning largely depends on seasonal changes in the lake level. Environmental and fishery requirements are formulated for regulating the level of Lake Baikal. Socio-economic damage is assessed for various lake levels and flow rates of Irkutsk HPP. Critical levels and flow rates are identified. Projected changes in the components of the water balance and net inflow into Baikal are presented considering the expected climate changes for the period into 2060. A procedure (rules) for regulating the level of the lake is proposed with due regard for the environmental and socio-economic factors for various streamflow water conditions. The permissible maximum and minimum levels, ranges for the lake level fluctuations and flow rates of Irkutsk HPP, which could minimize potential environmental and socio-economic damage, are determined. Proposals are formulated to amend federal legislation related to the issues of Lake Baikal level regulation.

The uncertainty of the concept of the “BAM zone” and of its territorial composition and boundaries is indicated. The composition of the zone has been clarified and its following structural elements have been identified: 1) a subzone of direct influence in the form of a latitudinal chain of municipalities directly crossed by the highway, and consisting of three sections: the head Taishet-Ust-Kut, the middle Ust-Kut-Komsomolsk-on-Amur, and the final Komsomolsk-on-Amur-Sovetskaya Gavan; 2) a subzone of indirect influence in the form of municipalities adjacent to the first subzone. As a result, the BAM zone includes 31 municipalities (taking into account the addition of urban districts to the districts of the same name) and occupies 29.1 % of the total area of the six “BAM” regions: Irkutsk oblast, Republic of Buryatia, Zabaikalskii krai, Republic of Sakha (Yakutia), Amur oblast, and Khabarovskii krai. The results of the development of the zone are considered according to two main components: settlement and industrial. It has been established that due to the steady decline in the population of the zone at the post-Soviet stage, its number and share in the total population of the “BAM” regions (with the exception of the middle section) have now almost returned to their original state half a century ago, and the population of the base cities (Ust-Kut, Neryungri, Tynda, and others) turned out to be 2-3 times less than planned. The industrial development of the BAM zone was suspended until the early 2010s, the plans for the formation of 8-13 territorial production complexes and industrial hubs were not implemented, and in fact only Yuzhno-Yakutsk and Verkhnelenskii complexes were formed from the planned complexes. It is concluded that in the near future, more intensive industrial resource and raw material development of the mainline is expected, but its settlement development and demographic potential will continue to decrease due to the introduction of new low-labor-intensive technologies and the use of a shift method of labor organization.

This article is timed to the 300th anniversary of the Russian Academy of Sciences and is devoted to the scientific activity of Institute for Water and Environmental problems SB RAS. A brief description of its history of creation and development is given. The organization of the Institute was dictated by the need to conduct basic research on the study of environmental processes and phenomena, assessment of the state of water resources and study the issues of balanced nature management in the vast Siberian region. The main scientific directions of the institute’s activities are listed: formation, monitoring and use of water resources in Siberia (based on the basin approach); development of scientific bases for environmental protection and rational nature management taking into account anthropogenic factors and climate change. The structure of the institute, including 7 laboratories and 2 branches, is presented, the main research objects (the Ob and Irtysh Rivers, the Novosibirsk reservoir, the lakes: Teletskoye, and Chany and their catchment areas), scientific projects and their results are noted. Among the largest projects are: assessment of ecological consequences of construction of large hydroelectric power plants (Katun, Krapivinskii, Boguchansk, and Evenkiiskii); ecological assessment of consequences of nuclear tests at the Semipalatinsk nuclear test site; ecological support of rocket and space activity, including construction and operation of the Vostochny cosmodrome; research into the current state and scientific substantiation of methods and means to ensure sustainable functioning of the water management complex in the basins of the Ob and Irtysh Rivers; research into methods and means to ensure sustainable functioning of the water management complex in the basins of the Ob and Irtysh Rivers, and research on the environmental protection of the Ob and Irtysh Rivers.

This article summarizes the results of long-term integrated research performed by SIPPВ of SB RAS studying composition, structure and dynamics of biodiversity in Siberia and adjacent regions at the level of populations, species, biocoenoses, and ecosystems and revealing of responses of organisms and their coenoses to changes in environmental conditions caused by natural and anthropogenic factors. The sequestration of carbon dioxide by conifer forests growing on the territory of Baikal Natural Region was estimated. Forest fires in Transbaikalia were reconstructed on the basis of tree-ring chronology with an annual resolution of 351 years. The concept of paragenesis was justified as it characterizes the formation of phytocoenoses which by their structural-dynamic organization are not related to a zonal type (or altitudinal belt) of vegetation. The data obtained can serve as an information base while determining basic vectors of regional ecological policy, and they are important for the assessment of the present state of biodiversity in Baikalian Siberia and its changes under the conditions of anthropogenic factor press as well as for development of measures for its protection.

The stages of development of basic geographical research in the Russian Far East since 1971 to the present are considered. The main directions of scientific studies into the components of the landscape geosphere in the continent-ocean transition zone are shown, and an analysis is made of the natural resources management structures and socio-economic aspects of the region’s development, including in the transboundary context. Fundamental theoretical and applied research results obtained by Pacific Geographical Institute FEB RAS are presented. The direction of the studies on the geographical forecasts theory, dynamics of geosystems and territorial economic structures that was originally formulated in the 1970s by A.P. Kapitsa, corresponding member of RAS, the first director of PGI FEB RAS, has been developed at the institute till the present. The most important contribution to a further development of PGI FEB RAS has been made by P.Ya. Baklanov, academician of RAS, who headed the Institute from 1991 to 2016. In the 1990s, new relevant research directions, such as the studies of the sustainable development issues, dynamics and stability of geosystems of different ranks, and forecasting changes in forest vegetation appeared, which methodologically continued the forecasting and geographical topics. The study of the role of market-oriented reforms in the transformation of territorial economic structures, migration processes, foreign economic and geopolitical factors in the development of the Far Eastern region, problems of coastal-marine and transboundary natural resources management began. At the same time, the geographical scopes of the studies covered not only the Russian Far East, but also adjacent regions of Russia, neighboring countries and vast areas of the Pacific Ocean. The ‘eastward vector’ of Russia’s contemporary development influenced geographical research in the Far East as well. To form a balanced system of socio-economic development of the region, research efforts focused on the functional zoning of its territory, preparation of settlements master plans, setting up the priorities for transboundary cooperation in the field of sustainable natural resources management, transboundary economic corridors and “green” zones development in terms of the Northern Sea Route and the New Silk Road conceptions, are especially relevant at present.

Information on the history of the creation and development of the Institute of Water and Environmental Problems FEB RAS. It is one of the oldest scientific institutions of the Russian Academy of Sciences in the Far East. Information on the main scientific areas of research related to the study of the patterns of formation of land waters and the dynamics of ecosystems for the purpose of rational use of biological resources is summarized. The main scientific tasks of the institute’s laboratories: hydrology and hydrogeology, hydroecology and biogeochemistry, vegetation ecology, animal ecology, soil ecology, optimization of regional environmental management, and swamp and forest resources are described, and the most important results of research, mainly over the past ten years, are presented. Characteristics of the scientific bases located on the banks of the Amur and in the foothills of the Sikhote-Alin and the Center for Collective Use “Interregional Center for Environmental Monitoring” are given. Analytical studies of the state of the environment and monitoring of biogeochemical processes are carried out in this Center. Brief information on the institute’s herbarium, which has an International Herbarium Index (KHA), which presents rare and endangered plant species in the region, is given. The areas of expeditionary research carried out in recent years are pointed out, and information on the most important applied research commissioned by various organizations is given. In this paper, we especially noted the research carried out in connection with the need to quickly assess and solve particularly unexpected acute environmental problems that arise from dangerous manifestations of natural processes in the region. Information on the international scientific contacts of the institute, the participation of employees in teaching activities at universities and work with students in schools in Khabarovsk krai is presented.

This paper presents results from studying chemical contamination of soil and surface water in the area of the reclaimed solid waste landfill located within the boundaries of Vladimir Opolie. The study showed that the highest concentrations of bulk forms of heavy metals in soil cover, exceeding the MPC values, are observed near the solid waste landfill at a distance of 80-120 m. With distance from the landfill, the concentrations of metals in soil cover decrease to values below the MPC. The accumulation of heavy metals here was facilitated by factors such as spontaneous combustion of solid waste at the landfill, air transport of aeropollutants as well as the characteristics of gray forest soil, such as the content of organic matter, pH and granulometric composition. In surface waters flowing in the immediate vicinity of the solid waste landfill, an excess of MPC values for a number of heavy metals was established; for zinc and copper, by a factor of several tens. An analysis of the ionic composition of surface waters showed the presence of chemical contamination which is likely due to the ingress of seepage water from the solid waste landfill. The engineering inadequacy of this solid waste landfill and the lack of a clear mechanism for reclamation measures significantly increase the risk of contamination of soil cover of adjacent territories and surface watercourses with hazardous chemical compounds. To monitor the state of the environment in the interests of the safety of the population living here and the preservation of the unique ecosystem of Vladimir Opolie near this closed reclaimed landfill, it is recommended that regular environmental monitoring observations should be conducted.

The anthropogenic load on urbanized areas and their surroundings by monitoring the chemical parameters of waters of small rivers was assessed. Seventeen such watercourses draining the territory of Khabarovsk and its suburbs were considered. Sampling and measurements were carried out during the winter low-water period. The data obtained for 2017-2021 were used in this study. By means of cluster analysis, four groups of water bodies were identified, which differed in the degree of change in hydrochemical indicators and the presence of anthropogenic pollutants. Areas experiencing the greatest anthropogenic impact were identified as well as possible sources of pollutants. The first cluster includes rivers flowing in the southern and northeastern parts of Khabarovsk (Gnilaya Pad, Chernaya, Bezymyannaya and Matrenikha Rives). The second cluster mainly includes rivers in the central part of Khabarovsk (Osipovka, Lesopilka, Cherdymovka and Plyusninka Rivers) and less often in the eastern part (Polezhaevka and Gnilaya Pad Rivers). The third cluster, in addition to the rivers of the central part (Kurcha-Murcha and Cherdymovka), included rivers of remote districts of Khabarovsk (Berezovaya, and Krasnaya Rechka). The fourth cluster is represented exclusively by the rivers draining the territory of the Bolshekhekhtsirsky Reserve (Levaya, Pravaya, Osinovaya, Polovinka and Bykova Rivers). The samples in this cluster are characterized by the lowest values of chemical concentrations. This suggests that these rivers do not experience any significant anthropogenic influence. Therefore, they can be taken as background values of the contents of the substances in waters of small rivers draining the territory of the city of Khabarovsk and its populated neighborhood, and also be used to assess anthropogenic pollution.

Increased concentrations of pollutants in wastewater discharge zones of the Lake Baikal coastal waters and tributaries are detected. Green filamentous algae, an indicator of the local eutrophication, are shown to be present in wastewater discharge zones. The technical parameters of four wastewater treatment facilities located in the central ecological zone of the Baikal Natural Territory have been analyzed. The plants do not meet the requirements for key indicators and do not have the technical capacity to improve efficiency. The maximum permissible concentrations are exceeded hundreds of times for a number of parameters. The wastewater standards established for the Baikal Natural Territory are unprecedentedly strict and have no analogues in the world. For their implementation the cleaning efficiency exceeding 98-99 % in some cases must be achieved. The best available technologies allow to reach the efficiency within 85-97 %, but the wastewater treatment facilities under study operate with outdated technologies which are not designed for the extraction of biogenic compounds from wastewater. Since the introduction of regional standards, the plants in question have not come close to their implementation nor have been modernized. The frustrating requirements of regulatory framework presumably hampers the modernization processes. It is proposed to adjust the wastewater treatment standards to the realistic level of values corresponding to those actually achievable when using the best available technologies. The economic capabilities of the region must be taken into account as well. The model testing of adjusted standards should be preceded by the pilot modernization of wastewater treatment technologies.

By analyzing and integrating long-term experimental data, it was possible to formulate important theoretical and practical conclusions. The genesis of the process of flow formation is revealed and its theoretical justification is given. A pattern has been discovered, which implies that only three natural factors have a significant impact on spring overland runoff: snow reserves, freezing and the degree of soil moisture. At their certain (limiting) levels (freezing depth is less than 50 cm, moisture reserves in the soil layer of 0-50 cm are less than 70-120 mm in the zones, and snow reserves are less than the volume of free pores in the 0-30 cm soil layer), runoff is not formed. If the indicators of the levels of each of these factors are higher than the limiting ones, then the runoff is necessarily formed, and its size (layer) does not depend on the depth of freezing, as absorption occurs only in a layer from 3 to 30 cm (varying by zones and years), because a waterproof ice screen is formed in it, below which snow water does not arrive. The amount of runoff depends on the free porosity in this layer of soil and snow reserves. Free porosity, in turn, depends on the degree of soil moisture. The amount of runoff during deep freezing of the soil depends on its humidity and snow reserves before snowmelt. These factors are the main ones in the emergence of runoff formation conditions. The main role is played by soil moisture. Snow reserves play a passive role in the formation of runoff. Its value depends on snow reserves, but they do not directly affect water absorption, that is, part of the snow water drains after filling the free pores, and the more it is in the snow, the more it will drain. Knowledge of the genesis of the interaction of meltwater with frozen soil allows us to approach the prediction of the overland runoff of meltwater on a genetic basis.

An overview of the tourist and recreational potential of the Katun River valley and its left bank area in all its sections: upper, middle and lower is presented. The publications of these authors and other researchers who have highlighted similar issues in other regions of the country, and scientists who raise related issues of the tourism sector, recreational potential, organization of tourist space as well as the construction of networks of routes and tourist trails, including environmental ones, are considered. Specialized software tools were used in this study, on the basis of which methods of mapping the territories under study were applied, followed by the use of the modeling method, which made it possible to fully reflect the resource tourism and recreational potential of the left bank area of the Katun River and justify the design features of tourist routes. The features of the development of the tourism sector are considered not only in the valley of the Katun River. The fact of inaccessibility of certain places in the Altai Mountains is described, associated with the remoteness of the upper and middle sections of the river valley from the main highways and territories that represent a higher value for the tourist flow throughout the year. The software used in the study made it possible to display the main objects of tourist interest on the left bank of the Katun River as well as to simulate individual shooting situations when displaying trails, routes and their attractions as well as route networks where a further development of the tourist, recreational and excursion sphere of the Altai Republic and Altai krai, within the boundaries of which the largest transit waterway, the Katun River, flows.

The results from studying the specifics of the formation of rain floods in river basins of mountainous areas are presented. The features in the formation of dangerous hydrological events, such as floods and mudflows, are considered. An analysis of the rain floods characteristics on the rivers of the Eastern Sayan mountains was carried out, based on data from highly detailed monitoring of river flow parameters and atmospheric precipitation using automatic measuring devices. Water level measurements are carried out once every 15/30 minutes, and precipitation once per hour. The characteristics of floods for the flood season of 2022 on eight rivers are given as well as floods on the Belaya and Kyngarga Rivers from 2019 to 2022. For extreme floods that can cause significant damage, an assessment of flood-forming precipitation is made. The timing of passage, duration, height of the level rise and its amplitude, the rate of rise and fall, etc. are determined. It was established that during flood season, up to 10 rain floods of different sizes occurred on the rivers. There is a synchronicity in the high floods passage on the left tributaries of the Angara river. Most often, the maximum floods of the year occurred in July. The duration of a flood rise is on average 2-3 times less than its reduction, and the average rate of level rise is three times higher than the rate of reduction. The duration of the highest levels during floods is several hours. For small floods occurring in mid-summer, it is 15-30 minutes and is equal to the measurement step of the devices. Flood-forming precipitation during extreme floods can be long-lasting and widespread or intense and short-lived. The total amount of precipitation before the peak of the flood varied from 31,4 to 122,6 mm, and the average intensity of precipitation varied from 0,10 to 1,95 mm/h.

The Khankaiskiy State Naturfl Biosphere Reserve, located on the eastern, southern and western shores of Lake Khanka, includes five separate clusters. Since 2007, an extreme rise of the water level in the lake has been recorded, which reached a historical maximum in 2016. The study results of changes in the ratio of the main categories of habitat of flora and fauna species on the territory of the Khankaiskiy Natural Reserve in 2017 and 2020, after the rise of the water level, compared with 1990, when the nature reserve was founded. GIS layers were formed, displaying the distribution of habitat categories and their area characteristics for each period of time. The main source of information is remote sensing data for the corresponding periods. It was found that in 2020, water bodies occupied 42 % of the total area of protected areas, of which 33 % accounted for Lake Khanka, or by a factor of 4-5 times more than in 1990; swamps and meadows covered about 57 %, with a predominance of swamps; forest areas are confined to hilly terrain and, as before, occupied less than 1 % of the territory. It was found that the terrain portion of the Sosnovyi, Mel’gunovskii and Rechnoi clusters was almost completely covered with water; vast areas were flooded in the Zhuravlinyi and Chertovo Boloto clusters. Along the shores of Lake Khanka, death of plants, including shrubs and trees, has been noted. The multidirectional influence of changes in nesting habitats on the population of birds was noted.