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We studied the distribution of gold, silver, and platinum group elements (Pd, Pt, Rh, Ir, and Ru) in two bottom sediment cores of the southern Chukchi Sea. It is shown that the Holocene pelite-silty sediments with an age of up to 4.0 ka BP are significantly enriched in these elements, except for Ru and Rh, relative to their clarkes. Native silver minerals were found in all samples by probe microanalysis, whereas gold minerals were revealed only in the surface layer of the sediment core closest to the Chukchi Sea coast. Multicomponent statistical analysis of the chemical composition and grain size of the sediments and the content of organic matter in them has led to the conclusion about the accumulation of clastogenic and chemogenic forms of precious metals. The abnormally high content of gold (0.3 ppm) in the recent sediments near the Chukchi Peninsula coast might be due to its additional removal from the continent as a result of the placer mining there.

Based on integrated structural and geophysical studies and generalization of geophysical, hydrogeological, mineralogical, geochemical and other data, it is shown that the southern cluster of thermal fields of the Kambalny volcanic ridge (South Kamchatka) is included in the modern hydrothermal system. New data on the structure of the steam hydrotherm discharge area investigated to a depth of about 300 m have been obtained. The structural and hydrodynamic connection between two thermal fields from this group has been established. The Kambalny ridge geothermal system embracing all major clusters of thermal fields is assumed to have a single deep-seated source of heat supply.

Surface waves are the main source of coherent noise in land seismic survey, and their suppression is one of the main stages of common depth point data processing designed to improve the quality of tracking primary reflections on time sections. In practice, noise reduction is carried out using procedures from modern software based on numerical modeling of waveforms. However, they are too resource-intensive and have a large number of subjectively customizable parameters. The known algorithms have a common drawback: either the energy of reflected waves is distorted in an interference zone with a noise wave or the noise suppression quality is unsatisfactory. The current research is aimed at improving the filtering algorithm in a time-frequency domain using the slant Karhunen-Loeve transform in order to overcome these limitations, to increase the accuracy and rate of its software implementation, and also to test it when processing profile field data from land-based 2D seismic surveys. The algorithm is modified by developing a new method for determining static corrections for surface wave hodograph rectification in a time-frequency domain and by the application of preprocessing in which the reflected wave signal is removed preliminarily. These and other modifications ensure faster calculations and improve the quality of surface wave interference suppression. In addition, the slant Karhunen-Loeve transform is accelerated by parallelizing calculations across logical processor cores. In this paper, the algorithm is described in detail, its significant advantage over the standard methods of bandpass filtering and f-k filtering is shown, and the results of processing the field data obtained by the SWANA procedure (Geovation 2.0) and by the slant Karhunen-Loeve transform. The result obtained by the slant Karhunen-Loeve transform is superior to the SWANA procedure in terms of the surface wave filtering quality and has only four adjustable parameters (SWANA has 20 parameters).

In the northern spurs of the Manchurian-Korean Mountains (Primorsky Territory), an assembly of dung beetles, inhabitants of cow dung, was studied. Data on species composition, population dynamics, number and biomass of dung beetles are presented. A comparison of the assemblies of sheep and cow dung beetles in the conditions of the northern spurs of the Manchurian-Korean mountains showed that, despite the fact that these assemblies are geographically located in identical areas, formed on the basis of a common pool of species and have a similar species composition of beetles, the structural features of these assemblies, and also the dynamic processes taking place in them have significant differences. This is expressed in a richer species composition in cow dung, in the number of species in individual functional groups, in differences in dominant species, in features of the seasonal distribution of abundance and biomass (including the peak values of these indicators for individual functional groups of dung beetles), and in aggregate indicators of overlapping temporal aspects, ecological niches of coprophilous scarab beetles. It is suggested that the above differences are due to both the historical processes of the formation of assemblies and abiotic factors, first at all, by size and consistency of substrate.

The results of year-round bird counts conducted in Ufa every two weeks for three years (2012-2014), on routes with a length of 5 km in each of the five sites (multi-storey buildings, in areas of old and new individual buildings, on streets and in parks) are analyzed. The methods of cluster analysis revealed the main trends of seasonal and territorial heterogeneity of the bird population. The informativeness of the obtained representations is determined using linear qualitative approximation of community similarity matrices (one of the methods of regression analysis). The selected seasonal aspects are compared with the phenological division according to the seasonal development of nature. The orientation of the constructed graphs in the factor space is compared with the results of non-metric scaling. A map of seasonal and territorial heterogeneity of the surveyed ornithocomplexes has been compiled.

Semi-fossorial Sorex unguiculatus is a common shrew species in the central part of Northeast Asia, and the paper is devoted to elucidating its status in shrew taxocenes within the entire specified range. The configuration of the modern range of the long-clawed shrew differs from the generally accepted one and its formation occurred through distribution from two Late Pleistocene refugiums - mainland and island. According to the status of the long-clawed shrew in the taxocenes, three areas were distinguished: this species is a dominant in low-species insular taxocenes, a subdominant in multispecies taxocenes of coniferous-broad-leaved forests of the Ussuri Territory, and a minor one in the zone of interpenetration of nemoral and taiga vegetation of the left-bank part of the Lower Amur Region. Further northwest expansion of the long-clawed shrew is unlikely due to the specific requirements of this species for the type and structure of soils, which change significantly under the conditions of the appearance of permafrost, and coexistence with an ecologically close species, the flat-skulled shrew.

Small mammal communities in different sections of the Middle Ob valley (floodplain and terrace) are considered in the article based on the analysis of our own data and literature sources. Small mammals were captured using similar methods everywhere: metal cones were used that were dug into ditch with pitfalls or placed along polyethylene film fences. During the period 2004-2022, we counted 16517 individuals of 21 species in the Middle Ob valley within the Khanty-Mansi Autonomous Okrug - Ugra. A total of 28-29 species of insectivores and rodents were recorded in the southern taiga and middle taiga areas of the Middle Ob valley. The lack of specificity in the number of animal species is determined by the fact that at present there is no complete clarity for the studied area with respect to voles of the “arvalis” group. Essays are given for all species encountered, describing the occurrence, abundance, and other aspects of small mammal ecology. The specifics of the southern taiga and middle taiga sections of the Middle Ob valley, as well as the floodplain and terrace as a whole, were revealed. Only in the southern taiga section of the Middle Ob valley, the common hamster, narrow-headed vole (southern subspecies), Korean field mouse, and herb wood mouse, which are not common in the middle taiga sections of the studied area, are found. These same species also avoid floodplain biotopes. The list of dominant species was determined for the floodplain - the common shrew and the root vole, for the terrace - the common shrew and the Northern red-backed vole. The co-dominant species are the Eurasian pygmy shrew and Laxmann’s shrew, as well as the harvest mouse. The valley of the Middle Ob is dominated by western Palearctic species. They tend to dominate both the floodplain and the terrace.

Sakhalin meadow communities are an important component of the vegetation cover of the Far East. The use of phytoindication scales is a possible way to understand the ecology of meadow vegetation. The material of the study was 113 geobotanical descriptions of meadow communities in the southern part of Sakhalin. A similarity matrix of descriptions was calculated by using the quantitative Bray - Curtis index for cluster analysis with the subsequent classification of meadow communities. For the first time, an ecological assessment of meadow vegetation in the southern part of Sakhalin Island was carried out using the scales of I. A. Tsatsenkin and D. N. Tsyganov. As a result of the work, the following meadow communities were identified: Phalaroides arundinacea meadows, seeded forb-grass meadows, coastal forb-grass meadows, floodplain-coastal tall grass meadows, Leymus mollis meadows, Aquilinum pteridium meadows, an Artemisia meadow. It was determined that the meadow communities of the southern Sakhalin are classified as moderately humid with the dominance of eumesophytes and xeromesophytes. Soils, even on the sea coasts, are non-saline, quite rich in nutrients and, at the same time, poor or sufficiently supplied with nitrogen. According to the calculations, the soils under the meadows are acidic and slightly acidic. The climate was defined as subboreal, with a surplus of precipitation. As for the agricultural use of meadows as pastures and hayfields, it has almost no effect on the composition of phytocenoses, however, low indicators on the scale of pasture digression may be a sign of violation of haymaking terms. The discovered feature of the Sakhalin meadow communities is that groups of meadows different in location and species composition, display very similar habitat conditions.

An increase in technogenic impact and the need to conserve biodiversity has set us the task of assessing the baseline biodiversity in mining areas. The aim of this work is to investigate the state of mesofauna of invertebrate animals in the litter and topsoil of typical biotopes of the Middle and Southern taiga. This study is the first in the Perm Krai. The vegetation characteristics of the survey sites are based on field geobotanical descriptions, soil sampling method was used to collect invertebrates, and soil properties were studied using conventional methods. Taxonomic diversity and population structure of soil invertebrates was evaluated, vegetation was described, morphological and physical-chemical analysis of soils as well as correlation analysis of quantitative indicators of soil mesofauna with chemical properties of soils of surveyed sites was performed for the first time on 10 survey sites. All surveyed biotopes have typical for the Ural taiga zone floristic composition and fauna of litter and soil invertebrates. At the same time, vegetation synanthropization is pronounced in all studied forest and meadow phytocenoses. The composition, structure and abundance of invertebrate mesofauna in all studied biotopes depend on the phytocenosis type, litter composition and thickness, the degree of soil and litter moisture. Correlation analysis revealed a relationship between soil acidity level and quantitative indicators of Lumbricidae and Oniscidea. The natural communities studied are affected by anthropogenic factors such as land reclamation, changes in soil composition and structure caused by mechanical disturbances during road construction, etc.

Based on long-term research (1993-2022), the content of chemical elements (Na, K, Ca, Cu, Zn, Fe, Pb, Sr, Zr, Cd, Ni, Co, Cr, Ba, Cd, and Mn) has been determined in 17 plant species of the northern West Siberia region. The regional geochemical background of dominant plant species has been established, and an assessment of changes in the chemical composition of plants in the area of oil and gas condensate field development in the northern West Siberia region has been provided. Indicator species reflecting early trends in ecosystem transformation under the influence of anthropogenic load and associations of chemical elements linked to various sources of pollution have been recommended. The role of phytoindication methods has been demonstrated in detecting subtle changes in the environmental state in the conditions of gas condensate field sites.