The vertical and lateral distribution of iodine and selenium in the soils on different types of parent material, i. e. loess-like loams and fluvioglacial sands and sandy loams, was studied within associated landscapegeochemical systems of the Titovka River basin (Bryansk region, Russia). It was found that the content of both elements in particular genetic horizons of the studied soils under the contrasting environment varies widely, namely I: 0,22?7,93 mg/kg, n = 93, and Se: 0,001?0,668 mg/kg, n = 93, air-dry mass. Gray forest loamy soil on loess-like loams contains 2 times more iodine and almost 4 times more selenium than sod-podzolic sandy loam soil on binary deposits (1,67 / 0,81 mg/kg for I (p < 0,05); 0,453 / 0,120 mg/kg for Se (p < 0,05), respectively). This may be due to both the type of parent material and higher content of organic matter, and the lighter texture of gray forest soils. The content of iodine and selenium in bottom sediments of the Titovka River (0,59 and 0,36 mg/kg of air-dry mass) is most comparable with the upper horizon of sod-carbonate-gley soil sampled a few meters from the sampling site of bottom sediments (I ? 0,57 mg/kg; Se ? 0,35 mg/kg of air-dry mass). At the same time, the elements showed dissimilar differentiation in soil horizons, due to their affinity to geochemical barriers. Iodine is actively fixed on the alkaline-carbonate barrier and is mobile under reducing conditions, while selenium concentrates on the gleyic barrier and is mobile in an oxidizing environment. This should be taken into account when assessing the availability of these biologically significant chemical elements in soils and local food products, particularly in the areas exposed to radioactive isotopes of iodine.

The construction of the Tsimlyansk reservoir in 1952 and the actual climate changes led to significant reduction of spring water flow and the area of the Lower Don River spawning grounds. About 300 thousand hectares of spawning lands were flooded in 1963, while not more than 130 thousand hectares in 1979?1994. In later years water often didn’t rise to the floodplain at all. As a result, the fishing industry of the Lower Don River underwent degradation and the spawning grounds were ploughed or built over. The spawning grounds of the Lower Don were the basis for the reproduction of anadromous and semi-anadromous fish of the Azov ? Don basin, which has already lost its commercial value for sturgeon and herring. The article presents the results of mapping the modern structure of the floodplain lands of the Lower Don River within the flooding areas in different years. The areas of 1979?2018 floods were determined by processing the Landsat satellite images; the modern structure of their land use was mapped according to Sentinel-2 data. The types of land cover were also analyzed using the global data (GLC30 and ESRI). Within the area of 1979?1994 flooding there are 0,7 thousand hectares of built-up territories, about 30 thousand hectares of arable land and 10 thousand hectares of fallow lands. There is a threat of flooding the buildings and other infrastructure facilities, therefore the floods in the Lower Don River area are now perceived as a negative phenomenon. It is necessary to impose restrictions on the economic use of floodplain lands, and ban the construction activities and stocking of oil products, fertilizers and pesticides within the 1994 flooding area. Application of satellite monitoring technologies is a promising tool for assessing the economic development of floodplain lands and identification of flooded lands. In the future, it is possible to create an automated system for monitoring floodplains of the Don River and other rivers, basing among other on the satellite microwave radiometry data. The advantage of such data is the independence from the presence of clouds, which impedes satellite observations in the visible range.

The content, legends and methods of designing the basic soil maps in complex regional atlases published over the past 60 years were analyzed. The atlases were grouped in accordance with the time of publication and potential users. The main attention was paid to the content and conceptual background of maps, their compliance with the rules and experience of traditional soil mapping in Russia, as well as to the requirements for soil maps, i. e. completeness of information with new knowledge included, visual clarity and readability. The content of maps is assessed in the following aspects: natural soils, presence of human-modified soils, classification used, soil cover composition and pattern, relief, and soil texture. The legends were evaluated in terms of information on soils and presentation of the mapping concepts, namely, legend structure, the number of units and the order of soils in the legend; methods of cartographic presentation were discussed as well. Soil maps in the atlases dating from the second half of the last century were compiled in accordance with the zonality concept; the soils basically corresponded to the USSR soil classification (1977) with some additions. In the atlases of the latest period, there are several maps compiled according to the new classification of soils in Russia. Soil maps in the atlases mostly used standard cartographic techniques; at present a certain deviation from the rules and standards of traditional soil cartography is obvious, which affects the information content and visual clarity of maps.

The economic use of water bodies in many ways relies on the calculation of solid runoff at various scales, from momentary to annual. Estimation of the annual solid runoff and the degree of its reliability, as well as the estimation of statistical parameters of turbidity are extremely difficult in case of irregular and insufficient illumination for different phases of water regime. At the same time, the knowledge of the processes of natural water quality formation and the elaboration of sufficient calculation methods allow reproducing the main indicators of water quality with acceptable accuracy. The statistical analysis of water quality indicators could be expanded through a comprehensive approach to their evaluation using well-established deterministic and stochastic calculation algorithms with arguments that are observed regularly and for a long time. In this case, a composite method can be applied to estimate the parameters of sediment flow or water turbidity distribution. The method allows finding the parameters of the distribution curve of a function through the parameters of the distribution curve of its arguments. The paper presents a deterministic-stochastic modeling system “weatherrunoff- sediments”, based on a stochastic weather model, a model of runoff formation in the catchment and a model of annual solid runoff. The system makes it possible to estimate the parameters of the distribution of sediment load and turbidity daily values in case of insufficient observation data and changing conditions of runoff formation within the catchment resulting from natural causes or economic activities. The practical implementation of the modeling system for the Narva River showed a good correspondence between the distribution parameters of observed and calculated series of daily water turbidity values. The presented numerical implementation of the climate forecast showed that a decrease in river flow caused by increasing air temperature will lead to a significant increase in water turbidity.

Specific features of thermal regime of the rivers of the Debed River basin in the cold season (December – March) are considered, as well as the patterns of their temporal fluctuations. Characteristics of the space-time dynamics of air temperature are also presented in order to assess the response of thermal regime to climate change. Observations on water temperature of the rivers of the Debed River basin at 13 gauging stations and on air temperature at 6 meteorological stations were used as the initial data.

A correlation was obtained between the average values of water temperature and the air temperature for December – March in the basin of the Debed River. It is shown that water temperature in the cold season is almost always higher than the air temperature. The lowest average monthly water temperature on all rivers is observed at the end of January. And it mainly increases downstream the rivers. For the period from 1964 to 2018 the average water temperature in the cold season ranges from 1,1 to 4,4°С. To calculate water temperatures over the unexplored river sections correlations were obtained between its values for the cold season and the areas of river basins, as well as between the average monthly values of water temperature during the cold period and during other time periods.

During 1984–2018 there is a statistically significant increase in air and water temperatures at currently operating meteorological stations and gauging stations. And for the period 1964–1983, both an increase and a decrease in water and air temperatures were recorded, with a predominant increase.

The results obtained can be used to calculate the heat flow, to consider the thermal regime of unexplored river basins, and to assess the hydroecological safety of the Debed River basin.

Based on the results of geomorphologic surveys carried out in 2021–2022 with the involvement of published materials, an original large-scale (from 1:25 000 to 1:100 000) description of relief of urban areas of the Republic of Abkhazia (Gagra, Pitsunda, Gudauta, Noviy Afon and Sukhum) was compiled, and unprecedented general geomorphologic maps were prepared, with morphogenesis-based legends. According to their morphostructure position and geomorphologic structure, the cities are grouped as follows: 1) completely lying in the area of the coastal-marine relief (Pitsunda and Gudauta); 2) located mainly within the sea terraces and erosion-denudation hills (Sukhum and Gagra); 3) completely located in the low mountains with a predominance of strongly dissected structural-denudation, fluvial and slope relief (Noviy Afon). A field survey revealed about 300 areas with unfavorable and dangerous geomorphologic processes within the urban areas, 44% of them are in Sukhum, 26% in Gudauta, 11% in Gagra, 10% in Pitsunda, 9% in Noviy Afon. The leading geomorphologic hazards in all spectra are suffusion, erosion and biogenic processes. A list of other processes in a spectrum is predetermined by the geomorphologic position of cities. The widest range, which in addition to the above-mentioned processes, includes also karst, mudflows and landslide processes (i.e. the most dangerous ones), is typical for urban areas with a complex relief structure, abundant in steep slopes and located within a narrow strip separating the spurs of the Main Caucasian Range from the sea (Gagra, Noviy Afon). The risk of destruction of street infrastructure (roadbed, communications, etc.) by dangerous geomorphologic processes was qualitatively estimated and its high dependence on the geomorphologic position of a particular section of the city has been established. In particular, the distribution patterns of recorded unfavorable and dangerous geomorphologic processes made it possible to state that the most favorable conditions for the construction and operation of urban infrastructure and buildings in general are within the leveled surfaces of the Late Pleistocene marine terraces, as well as the upper levels of floodplain terraces in the valleys of large rivers. Other levels of relief have certain disadvantages that impede the development of territories. Thus, the construction on the surface of the Holocene marine terrace is possible only if the foundations are waterproofed and soil is dumped in the lower areas. The development of high sea terraces, erosion-denudation and structural-denudation relief is difficult because of the high density of erosion dissection.

Distribution of suspended matter and the volumes of its flows in the Kara and Laptev seas was studied during the Cruise 72 of the R/V Akademik Mstislav Keldysh (August-September 2018) using the filtration technique and the sediment traps, respectively. The organic component (C_org, lipids and hydrocarbons) and the inorganic lithogenic component (amorphous silica and calcium carbonate) were determined for the suspension. It was found that the content of suspended matter in surface waters varied from 0,2 to 5,9 mg/l (on average 0,90 mg/l) with maximum values in the Blagopoluchiya Bay, of lipids from 28 to 120 ?g/l (average 52 ?g/l), and of aliphatic hydrocarbons from 10 to 49 ?g/l (average 22 ?g/l) with maximum in the area of the Ob River discharge (6799 mg/m2day). The suspension flux decreased from the surface to the near-bottom horizon only in the Blagopoluchiya Bay (from 13 127 to 11 900 mg/m2day), but in most samples the flux increased in the near-bottom horizon. The maximum flux in the Ob River discharge water area coincides with the maximum of the C_org flux (682 mg/m2day). The allochthonous components basically prevailed over autochthonous ones in the composition of suspended matter, as well as in organic compounds, including hydrocarbons.

The long-term interannual and seasonal variability of the chemical runoff along the main branches of the Kuban River delta was investigated. We analyzed the data of systematic observations on water runoff and the concentrations of the main ions, biogenic and organic substances, phenols, oil products and heavy metals for the period from 2008 to 2018. The annual and seasonal runoff of dissolved chemicals in the main branches of the Kuban River delta, i. e. the Protoka branch and the Kuban branch, was calculated. The chemical composition of water in the main branches of the Kuban River delta is practically the same, and the greatest differences are characteristic of the concentrations of chlorides, iron compounds, copper and oil products. Multidirectional trends of changes in the ionic composition and content of biogenic elements were revealed. There was a synchronous increase in the concentration of sulphates and ammonium nitrogen in both deltaic branches of the Kuban River; the content of nitrates and nitrites in the Kuban branch practically did not change, while it was decreasing in the Protoka branch. At the same time, the maximum frequency of exceeding the MPC for all components is rather low, and a low level of water pollution is typical. The chemical runoff along the delta branches is rather similar, especially in terms of the runoff of sulphates, organic substances and biogenic elements. The greatest differences by 20–22% are observed in the runoff of chlorides, iron and copper compounds. It is shown that the runoff of chlorides and sulphates, as well as biogenic and organic substances, is interconnected with water runoff. In general, the distribution of chemical runoff along the delta branches is uniform, its seasonal variability corresponds to changes in water amount during the principal seasons, while some differences are observed only for chlorides and iron compounds. Under actual climatic changes and anthropogenic impact, the revealed features and trends of variability of chemical runoff along the main branches of the Kuban River delta are of great practical importance. The data obtained can be used for predictive estimates of the removal of chemicals into the coastal zone of the Sea of Azov.

The article analyses landscape factors that determine the runoff of small Arctic and Subarctic rivers in the far northeast of Asia. The paper considers hydrography, structure of permafrost landscapes and their hydrochemical characteristics, and the spatial dynamics of low-water runoff in the basins of the Ugolnaya-Dionisiya and Yanranayvaam rivers. It has been established that sustainable water intake depends on the ratio of landscapes generating and depositing the permafrost runoff, namely Arctic char gravelly shrub tundra, lowland tussock tundra and hummock swamps. The low-water runoff of 20–50 l/km2·sec is typical for the sources of rivers, where seasonal char ice melts in the slope deposits and condensation waters are formed. Melt water of seasonal intra-surface soil ice on the gentle slopes of tundra hummocks provides specific runoff of 10–20 l/km2·sec. Upland and lowland marshes deposit above-frozen waters, and their runoff is less than 10 l/km2 sec. Using the example of two catchment basins, it is shown that the decrease in precipitation in the north of Chukotka is almost completely compensated by the formation of condensation waters. At the same time, in-ground seasonal infiltration soil ice is replaced in Arctic landscapes by infiltration-condensation char ice, and its melt water makes up for the loss of surface runoff.

Four post-socialist countries of Eastern Europe (Poland, Hungary, Romania and Russia) were comparatively analyzed in terms of the relative position and dynamics of different types of territories over a ten-year period from 2010 to 2020. The author develops methodological ideas about the usage of individual typology to create a socio-economic profile of a territory in order to identify spatial inequality of the countries under study upon socio-demographic, economic and infrastructural indicators. The results of the analysis allowed concluding about dominant trends of socio-economic differentiation between rural, urban and peri-urban zones. It was found that the intraregional spatial convergence is not an obligatory consequence of the socio-economic development of a country. The transformation processes which accompany the post-socialist transition led to the formation of different models of spatial socio-economic differentiation in each country, i. e. relatively balanced development in Poland, zonal development in Hungary and differentiated development in Romania and European Russia. The author suggests a concept of main stages and directions of the socio-economic differentiation of territories, which helps to systematize statistically-obtained conclusions.

In 1922, a first-ever stationary general geographical field training for students of the Moscow University was held in the Moscow region. The paper is inspired by a hundred-year-old publication by a trainee, then student B. Shustov, which describes the reasons for organizing the students’ fieldwork at the geographical station in the Vereya district of Moscow Governorate, the place and the format of training, and the research program including mainly meteorological, geomorphologic, geodetic and biogeographic components. Due to various circumstances, the first experience of stationary training in the Moscow region went to nowhere. Later, there were further attempts to arrange a permanent base for training, but they became successful only after almost a quarter of a century. At the same time, the first experience of such training formed some initial principles for conducting general geographical research for educational and practical purposes in the Moscow area. The article also provides information about the author of the publication, B.S. Shustov, who after graduating from the university was for a decade and a half actively engaged in scientific and teaching activities at the Research Institute of Geography and at the geographical department (later – the faculty) of the Moscow State University, and then in the Ryazan oblast.

The results of model simulation of the phosphorus regime and balance in the Ivankovo, Mozhaisk and Istra reservoirs, which carries out seasonal regulation of the Upper Volga runoff and long-term regulation of the Moskva and Istra rivers, are presented. The components of phosphorus balance were calculated using 2-D box model of heat and mass transfer which provides for day-by-day calculation of spatio-temporal distribution of water quality parameters. Phosphorus balance equation accounts for phosphorus input along the rivers and from the side watershed area, phosphorus regeneration from the bottom sediments, water release to the lower pool, and phosphorus removal through water discharge from the Ivankovo reservoir to the Moscow Canal, as well as the annual increase or decrease of phosphorus mass. Calculations refer to an average water year. A comparative analysis of phosphorus balance components in the Ivankovo reservoir and in the reservoirs near Moscow shows that the processes of sedimentation and regeneration of phosphorus from sediments are more intensive in the Ivankovo reservoir. The main discharge of phosphorus to the lower pool is during the spring flood period in the reservoir of seasonal regulation and during the low-water period in the reservoirs of longterm regulation. Scenario calculations provided graphs of the values of phosphorus retention in a reservoir depending on the increasing external phosphorus load.

Методом прямой потенциометрии с фторидным ионоселективным электродом получены новые данные о содержании фтора в водах Северной Атлантики. Концентрация фтора по результатам измерений составила 1,27 ± 0,03 мг/кг при массовом отношении F/Cl, равном (6,59 ± 0,11) · 10?5, что близко соответствует обычному содержанию фтора в морской воде. Совокупность имеющихся данных по отношению F/Cl в разных районах Мирового океана позволяет предположить наличие слабой изменчивости содержания фтора в солях морской воды.

The present-day state, problems and shortcomings of the modern use of country estates in the areas of their concentration outside the large urban agglomerations are discussed using the example of suburban noble estates located near the town of Torzhok, the Tver region. Based on the results of the analysis of their state, an applied scheme for the formation of a tourist cluster which includes the estates of the former Novotorzhsky and Staritsky counties is suggested. Using the example of 17 estates, the authors present promising options for rationalizing the use and preservation of the estate heritage in the countryside of the Tver region. It is proposed to combine the considered estates into a single estate cluster named after architect Lvov, since the history of many estates in the area is associated with his name. The cluster could include three hierarchical and territorial “tiers”. The estates are attributed to one or another tier depending on the current state of their complex and their historical and architectural potential. On the one hand, such division within a single estate cluster makes it possible to form a common brand and facilitate the organization of connecting routes. On the other hand, the division of estate functions within a single cluster expands the possibilities of their use. The results of the analysis of the state of estates made it possible to consider the territorial organization of their complexes within the cluster. Besides, the authors focus on the problem of collapsing estates, which could become a resource for the economic and cultural development of rural areas, and offer specific solutions applicable to particular estates.