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Presented are the results of hydrochemical work on the Amur river done during the freeze-up period in 2006, 2008 and 2011-2015 at the city of Khabarovsk and the villages of Leninskoe and Amurzet. The source of information used was represented by data of a joint Russian-Chinese monitoring of the water quality of the transboundary water bodies. We examine changes in the chemical composition of the Middle Amur water after transboundary pollution in November 2005 caused by the incident in the Jilin chemical plant (Songhua river basin). Emphasis is placed on the large role played by environmental measures in China (construction of pollution control facilities and hydraulic structures, shutdown of separate enterprises, etc.) in an improvement of the Songhua water quality. The influence of the regulation of the Zeya and Bureya rivers on the hydrochemical regime of the Middle Amur is shown. A characteristic is provided for the concentration distribution of dissolved matter along the length and width of the Amur in the section from Amurzet and Khabarovsk (400 km). The study revealed a smoothing of the differences in contents of the chemical composition components in the Amur waters along the width downstream of the inflow of Songhua. It is established that the Middle Amur water quality has improved in recent years: an increase in content of dissolved oxygen in the water, no pollution by nitrite nitrogen, and an abrupt decrease in ammonium nitrogen concentration. A predominance of the oxygenated form over the reduced form in the discharge was observed in the Middle Amur waters after 2012. A characteristic is given to the chemical composition of the Middle Amur waters during the freeze-up period after the historical flood of 2013.

A high-resolution bathymetric survey of the entire underwater slope in South Baikal was carried out for the first time by means of the multibeam echosounder. New elements were revealed in the underwater relief of the southern slope of the basin from the Kultuchnaya river to the Mysovka river, and a relevant regionalization was carried out into three areas according to the presence of ancient landforms and the intensity of the processes of their reworking, with the boundaries along the delta-front and the river fan of the Utulik and Pereemnaya. We reconstructed the formation process of the modern relief of this area of the underwater slope and determined a dominant role of the underwater-erosion processes in the formation of the modern relief, with the tectonic movements served as the “trigger” for them. The study revealed a direct correlation between the reworking of the ancient geomorphological surfaces and the occurrence of separate large underwater elevations or group ridges (remnants), canyons and linear depressions. It is determined that the pivotal role in the appearance of the modern relief of the underwater slope in the second area of extensive plano-convex (in section) and fan-shaped (in plan) delta-fronts of large rivers and debris fans enveloping the remnants. The existence of a steep underwater slope from the mouth of the Pereemnaya to the mouth of the Bol’shaya Tel’naya and of two large benches, and also the proximity of the maximum depths of the southern basin at the foot of this slope are explained by a more intense step-like lowering of this part of the lake when compared with the western part of the basin. This also accounts for the absence of large remnants in this part of the slope. The area of occurrence of lacustrine-fluvial and lacustrine-delta deposits of the Tankhoi paleobasin within the southern basin of Baikal is reconstructed. Four new hydrate-bearing structures associated with these deposits and morphologically pronounced in the vertex parts of the remnants were discovered. The morphological exploration indicators of the presence of new accumulations of gas hydrates on the under water slopes of Baikal have been expanded.

We explore the possibility of using space images in the study of the distribution of suspended sediments transported by the sediment runoff of the Selenga river, in the southern part of Lake Baikal. The relative concentration of suspended particles was identified on Landsat images without using ground-based turbidity measurements. The effect of different depths of solar radiation penetration was used to separate suspended matter in the surface layer and in deeper layers. On the basis of satellite image interpretation and using data on the constant currents in the lake, the bottom topography, runoff and prevailing winds for the day before the images were taken, we constructed the maps of suspended sediment distribution in the lake. The maps were used to indirectly estimate the sediment runoff distribution in the by-channels of the Selenga river delta depending on the time and phase of the water regime. A number of factors influencing the sediment runoff distribution were identified: the volume of transported material, longshore and deep-water currents, surface currents caused by short-lasting wind effects, and bottom topography. The effect of each factor on the sediment runoff distribution was analyzed. Analysis of the maps confirmed that the main factor in calm weather conditions is represented by constant currents in the lake. However, in the case of significant unidirectional wind effects, the sediment runoff distribution changes drastically. It is established that the pattern of sediment runoff distribution has remained unchanged for at least the last forty years.

Presented are the results of the winter 2014 radiophysical expedition, within the framework of which the Baikal ice cover was investigated by electromagnetic methods. The primary objectives the expedition were to detect irregularities in the ice cover, such as cracks and thawing steamed holes in the ice, and to determine the ice thickness and structure in the area of the thawing holes by the GPR sounding method. We used in the experiments the “OKO-2” GPR of the decimeter band and the nanosecond radar with the wavelength of 3 cm. The measurements were made carried out from the Khivus hovercraft and from the UAZ automobile. The ice thickness of Lake Baikal was determined by non-contact electromagnetic measurement methods. Radargrams of reflected signals from the ice cover are presented. Radar patterns of reflected signals from artificial irregularities of the ice cover were obtained by the short-pulse radar method. The concept of radiophysical monitoring is suggested, which provides a means of determining the ice cover parameters of a water body with high spatial resolution. We present an integral approach to investigating the state of ice cover in order to integrate different physicochemical methods for diagnosing the objects studied. A further development of the concept of integrated ice cover research, and the creation of the monitoring network involves solving a number of scientific and engineering tasks that include developing physical models and information and measurement systems as well as the rationale for an integrated monitoring network.

For the first time, a detailed analysis is made of the occurrence and different morphodynamical type-channel formation conditions on the Middle Ob within Tomsk oblast, from the mouth of the Tom river to the boundary with Khanty-Mansi Au tonomous Okrug-Yugra. We emphasize the role of a broad floodplain and of its inundation conditions during snowmelt floods, the occurrence conditions for channel-forming water discharges and channel stability in the predominant development of river meandering, including of the branches of floodplain-channel forks. Braided and straight unbraided channels occupy a subordi nate position separating sinuous reaches. It is shown that floodplain-channel forks with meandering branches occur largely at long transitions of the river from one valley side to the other, diagonally across the floodplain flow direction. The parameters of the bends in the forks of this type correspond to their hydraulicity, but no clear-cut hydrological-morphological relationships are determined because of intermittent runoff redistributions between branches. Modal (for the sections of the river between the main tributaries) values of the parameters of the bends depend inversely on the river hydraulicity (order). By introducing a correction coefficient for floodplain dissection by a floodplain fork as the indicator of the degree of diversion of water flow from the channel to the floodplain, it was possible to determine a “normal” relationship between parameters of the bends and hydraulicity of the channel flow during floods. Furthermore, we ascertained the relationships between the degree of development and the coefficient of the form of bends and determined their manifestations. For all the bends, we determined changes in parameters for the time interval 1986-2011 and the transition of some of them from one category to another, and ascertained the causes for runoff re distribution and the development of branches of the floodplain-channel forks.

An assessment is made of the uniqueness of modern vegetation in Prebaikalia as a biogeographical entity. It is shown that its complex structural-cenotic diversity is represented on the new universal geobotanical map of vegetation at a scale of 1:500 000. The map legend, constructed on the principles of V. B. Sochava’s multidimensional and multistage structural-dynamical clas sification of plant communities, displayed more than 160 cenotic subdivisions of vegetation of Prebaikalia representing its differ ent types. An analysis is made of the development paths of vegetation for assessing its evolutionary potential. The study revealed the main stages of philocenogenesis in the Late Cenozoic. Its main directions have been revealed, which are important for un derstanding the characteristics of the region’s modern vegetation cover. The heterogeneity and heterochronicity of modern ceno tic diversity of vegetation is shown. Emphasis is placed on the evolutionary processes of vegetation of Prebaikalia in the Holocene which can last for at least 40 thousand years. In this connection, it is proposed to change interpretation of the Holocene Optimum as an optimum for the evolution of the dark-coniferous taiga of Siberia. It is shown that the genetic linkages of the cenotic struc ture of modern vegetation cover in Prebaikalia are clearly pronounced via regional-typological categories of vegetation reflecting profound links of modern vegetation with natural-geographical regions where its philogenetic processes were taking place in in teraction with the general evolution of the natural environment. An analysis is made of the significance of the floristic and cenotic boundaries having an important biogeographical significance. Such boundaries, on the one hand, are the footprint of the past evolutionary processes in vegetation, and in the natural environment as a whole, and, on the other, indicate the dynamical potential of possible changes in vegetation under global climate change.

To identify current trends in the functioning of the geosystems of the Tunkinskaya depression and the mountains surrounding it, this paper considers the natural course of their development and anthropogenic transformation. The main landscape-forming factor is represented by the characteristics of the morphological structure of the surface of the mountain-basin territories experienc ing the effects of intense current dynamical trends: aeolian processes, debris flow activity and eutrophication which enhance the polychronicity of the landscape structure. Landscape discontinuity is complicated by the ongoing economic activities. Significant areas of the gentle slopes of the depression are occupied by agricultural lands; periodically recurring human-caused fires that are responsible for a widespread occurrence of secondary small-leaved forests. For forecasting the trends in the natural-economic situation, an assessment is made of the rehabilitation dynamics of the biotic component of geosystems. In the absence of the an thropogenic factor, the rehabilitation of natural piedmont pine (Pínus sylvestris) forests will require about 40-50 years, and several centuries in the case of natural mountain taiga larch (Larix sibirica) forests. The characteristics thus identified were used in compiling the landscape map for the Tunkinskaya depression and the mountains surrounding it which gives a complete picture of the current state of the geosystems. Evidence obtained in this study can provide a scientific basis for forecasting the evolution of geosystems, carrying out measures for nature management optimization and in dealing with nature conservation issues.

Presented are the results from investigating glacial terminal basins of Eastern Transbaikalia. The formation conditions are examined for lake basins. This paper provides examples of the parameters of the glacier snout-caused overdeepening crystalline rocks and unconsolidated deposits of intermontane basins. The Late Pleistocene age of the lake basins is determined by the paleogeographical restoration of the ancient glaciations of Transbaikalia. The terminal lakes are direct indicators of the maximum distance of mountain-valley glaciers from the centers of the last glaciation. They Bol’shoe and Maloe Leprindo, Zarod, Nichat ka, Oron, Chitkanda and other lakes. Paleoglaciological restoration of glaciation, and analysis of the neotectonic block structure of the relief determine the genesis of lake depressions occurring in glacial areas. Morphogenetic analysis of terminal formations substantiates the priority of exogenous processes over endogenous processes in the formation of lake basins. The influence of endogenous forces is limited by selective exaration of rocks that are weakened by intense tectonic fissuring. The lake preservation conditions and the dynamics of the filling of glacial lakes with terrigenous material in the Late Pleistocene-Holocene are assessed.

A city is considered as a complex object for study that combines the natural basis and the man-made environment. The landscape-functional differentiation became a fundamental stage of relevant investigations. The modern landscape and functional structures of the territory of Birobidzhan have been studied on the basis of research results and material of previous work. The basic characteristics of the natural and anthropogenic components of Birobidzhan are provided for the period starting from its foundation. Extensive areas of natural landscapes areas little affected by anthropogenic activities have been identified as well as a relatively large number of open spaces and green spaces which refer to potential reserve areas in ecological planning, are identified in the city limits. Furthermore, it was found that the planning structure of Birobidzhan has been an environmentally unreasonable project, which is evidenced by the chaotic location of industrial, residential and recreational areas, and the absence of sanitary protection zones within the urban development. The soil-vegetable cover and planning structure has been used as the main criteria for the selection of landscape-functional complexes. As a result, four landscape-functional complexes were identified in the city: man-made, anthropogenic-man-made, anthropogenic-natural, natural and anthropogenic, with different proportions in the urban system of Birobidzhan. Systematization within these complexes is used as a basis for the legend to the 1:25 000 map “Landscape functional complexes in Birobidzhan”, scale 1:25 000. The results obtained can serve as a basis for a preliminary assessment of the ecological situation and for the development of recommendations for the optimization of the quality of the urban environment. In the structure of the landscape-functional complexes, 35.5 % correspond to the heavily modified technogenic and anthropogenic technogenic landscapes. Some improvements can be achieved by increasing the proportion of anthropogenic-natural complexes and through conservation of those natural and man-made landscape-functional complexes with different levels of disturbance.

We examine the current state of the geosystems on Popov Island. It is found that as a result of the anthropogenic influence there are taking place the transformation of primary forests and an increase in the proportion of adventives vegetation near settlements; depletion of the species composition of lichen cover has been recorded. The soils of the islands are characterized by a small thickness and are highly skeletal of the stony-rubble composition; therefore, most of the island’s territory refers to the erosion-hazardous group of lands. Active sheet erosion is observed on roads and roadsides composed of granites and granitoids, occasional basalts and diorite-basalts dominated by polydominant broad-leaved forests on dark burozems. The anthropogeni cally transformed territories count for 12.57 % of the area. In spite of a relatively strong anthropogenic impact, the geosystems have retained their natural state. The indicator of landscape diversity, and also species diversity of vascular plants and lichens, and the coefficient of natural protection of the territory reflect the persistence of the functioning mechanisms of the system within the island, and ensure its geosystem integrity and the presence of stable internal linkages between natural-territorial com plexes. A reconstruction of the natural environment from data of pollen and radiocarbon analysis revealed natural spatiotempo ral changes of landscapes for the last six thousand years. The structural transformations of geosystems were caused by changes in the climatic regime and occurred in several stages. The latter half of the Atlantic period was characterized by a prevalence of polydominant broad-leaved forests; small-leaved forests dominated during the warming period of the Little Ice Age; the propor tion of broad-leaved species increased during the Little Holocene Optimum and under current global warming.