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Comparative analysis of the size-mass and biochemical parameters (total lipid content and their fractional and fatty acid composition) of eggs of wild and cultured producers of the Ob muksun showed significant differences between them. Wild eggs is characterized by smaller size (by 7 %) and weight (by 15 %), higher fat content (by 13 %) and the level of diacylglycerols (by 33 %), and lower phospholipid content (by 30 %) in comparison with factory eggs. At the same time, factory eggs differs from wild eggs by a higher level of physiologically significant docosahexaenoic 22:6n-3 (1.8 times) and linoleic 18:2n-6 (7.1 times) acids, but a relatively lower level of eicosapentaenoic 20:5n-3 (in 1.5 times) and arachidonic 20:4n-6 (4.2 times), respectively. Such changes in the fatty acid status led to a decrease in the commercial eggs of n-3/n-6 ratio (by 52 %), palmitic 16:0/ oleic 18:1n-9 (32 %) and α-linolenic 18:3n-3/18:2n-6 (by 45 %), and to an increase of 22:6n-3/20:5n-3 (by 63 %). In addition, in the eggs of factory muksun, 68 % of the total lipids are 4 acids - 16:0, 18:1n-9, 22:6n-3 and 18:2n-6, in wild eggs the share of these acids was 47 %. The established differences in the size-mass parameters, the total lipid content and their fractional and fatty acid composition of wild and hatchery eggs of the Ob muksun are most likely associated with a different diet and habitat conditions of the sexually mature fish in captivity and nature.

Trophic position of fish is one of the most important factors controlling the accumulation of potentially toxic elements and compounds in fish tissues, primarily via the spectrum of fish nutrition. In this study, the content of potentially toxic transition metals (Cu, Zn, Mn, Pb, Cd) and radiocesium (¹³⁷Cs) in the edible tissues (muscles and liver) of two representatives of the fish-eating ichthyofauna of the Yenisei River, northern pike ( Esox lucius ) and burbot ( Lota lota ), have been comparatively studied relatively to the size of the fish. A significant decrease in the content of radiocesium and zinc in the muscles of pike, and zinc in the liver of pike with an increase in body size was recorded in juvenile pikes with a body weight ( W ) of less than 0.35 kg. For larger sexually mature pikes, no significant size dependences of the accumulation of metals in tissues were found. A positive correlation was found between the content of ¹³⁷Cs, Cu, Zn and Mn in muscles and the size of burbot in the W range from 0.42 to 1.62 kg. The tissues of one-sized burbots and pikes significantly ( p < 0.05) differed in the concentration of metals in their tissues: concentrations of Zn and Mn were 1.6-2.2 times higher in muscle of burbot; concentration of Pb was 1.8 times higher in muscle of pike; Cu was twice higher in liver of burbot; Zn and Mn were 4.7 and 1.6 times higher in liver of pike, respectively. The revealed differences may be due to the differing food spectra of pike and burbot. Concentrations of Cu, Zn, and Mn in liver of pike were 3-7 times higher than in muscle; concentration of Cu in liver of burbot was 5 times higher than in muscle. Pb and Cd tended to be higher in liver than muscle for both fish species. Despite the revealed size-dependences, the concentrations of potentially toxic metals and radiocesium in the muscles and liver of fish were below the permissible concentrations for food. The results obtained can be used to assess environmental risks for the population consuming fish, as well as to plan long-term environmental monitoring of rivers using representatives of fish-eating fish fauna.

To identify the causes of activation of cryogenic landslide processes in the territory of South-Eastern Altai, a detailed analysis of temporal changes in the hydrothermal regime of natural seasons from 1936 to 2016 was carried out. Analysis of climatic conditions of the years of peak landslide activity established during processing of ultra-high resolution satellite imagery data and their comparison with indicators calculated for the period before the beginning of steady global climate change (1936-1970) indicates pronounced climate warming and its active influence on high-mountain cryogenic systems. Periods of landslide intensification caused by extreme thawing of the active layer of cryolithozone in 1998, 2012 and 2016 are reliably correlated with anomalies of indicators of hydrothermal regime of natural seasons and their structural units.

The dynamics of forest biomass in boreal forests have a significant impact on global carbon cycles. Biomass assessments contribute to understanding the carbon balance of forest vegetation in Siberia. This paper discusses methods for estimating above-ground forest biomass based on radar remote sensing data used in modern research (2010-2021). Methodologies used for biomass assessments are described, including stages of field research, data pre-processing, and modelling of the relationship of remote sensing (RS) data with biomass. Radar sensing has limited capabilities for assessing forest biomass related to characteristics of the survey equipment and parameters of stands. In modern research, a combination of optical and radar data of RS is carried out, which allows to obtain more accurate assessment of biomass using regression models, machine learning, and special techniques (BIOMASAR, SWCM, MaxEnt). The use of data on the optical depth of vegetation cover, estimated from microwave survey data, makes it possible to solve the saturation problem when estimating large amounts of biomass. Comparison of the accuracy of biomass estimation methods is difficult due to the lack of uniform approaches to conducting experiments and calculating errors. Biomass assessment errors based on optical and radar data vary considerably, averaging ~25 %. The assessment of the biomass of boreal forests of Siberia is difficult due to the small amount of supporting field materials. Nowadays, to assess the biomass of boreal forests with a high spatial resolution, it is promising to develop methods based on machine learning algorithms for radar remote sensing data from the Sentinel-1 and ALOS-PALSAR satellites.

Based on the landscape differentiation of the territory, an assessment of the hydrological role of the forest communities dominating in the Podkamennaya Tunguska basin in terms of their contribution to the total evaporation in the watershed was made. Evapotranspiration indicators, obtained from the Earth remote sensing data from the MODIS Global Evapotranspiration Project (MOD16 ET), which take into account the climatic characteristics of the study area, the types of terrestrial surface, and the diversity of vegetation cover were used. Studies have shown that the evapotranspiration of the identified classes of forest vegetation is characterized by significant variability both in space and in time. The variability of evapotranspiration over the years is primarily related to the variability of meteorological elements and the value of the leaf area index. In the spatial aspect, the variability of evaporation is determined by the general climatic characteristics of the study area and the forest species composition. As a result of data analysis, a reduction trend in annual evapotranspiration in the Podkamennaya Tunguska basin from 2000 to 2014 was revealed. A comparative analysis of evapotranspiration trends with temperature and precipitation trends confirms that the reduction trend in evapotranspiration is due to Climate change in region. It was found that the landscape structure of watersheds can be used to indicate the processes that form evapotranspiration as an important component of the water balance, and to determine the hydrologically significative boundaries of landscapes. An estimation of land surface evaporation from Earth remote sensing data (MOD16 ET product) can be used in water balance calculations in watersheds of various scales, especially in the absence of a runoff database.

A comparative study of the haptoral morphology of three species of diplozoon (Monogenea: Diplozoidae) from the gills of fish from polluted water bodies (the Obʼ River, Rybinsk Reservoir, Russia) and unpolluted Lake Tana (Africa) has been made. An examination of the haptors of Paradiplozoon megan (Bychowsky et Nagibina, 1959) from ide and Diplozoon paradoxum von Nordmann, 1832 from bream caught in the Obʼ River and Rybinsk reservoir has revealed a large number of abnormalities of the attachment clamps. Various abnormalities of the attachment clamps were also found in Paradiplozoon spp. from the barbel from the Lake Tana, which does not experience industrial pollution. According to the literature data, abnormalities in the structure of the attachment haptor in diplosoids were also found in relatively clean water bodies. Only in unpolluted water bodies such type of abnormalities as the formation of rudiments of the fifth and sixth clamps was recorded. It is hypothesized that pollution of water is not the main reason for the formation of anomalies in the structure of clamps, there is a native (“genetic background”) frequency of occurrence of abnormalities in Diplozoidae.

In the course of adaptation of birds to living in urban areas, separate urban populations are formed, which are distinct by many biological and ecological characteristics from birds of the same species that inhabit natural environments. The Woodpigeon is one of the most common representatives of synurbic bird species that successfully managed to spread to cities in most of Europe. This article explores the history of formation of synurbic Woodpigeon groups in Belarus and looks at the differences in the breeding biology of forest and urban birds based on research in 2000-2021. During this period, we collected information about 109 Woodpigeon nests in forest areas and 368 nests in urban areas. In the course of our research, we found out that the synurbic Woodpigeon continues spreading to the north and east parts of Belarus. By now, urban birds live in around 70 % of the entire territory of the country. Our analysis of the Woodpigeon breeding biology showed that there are differences between forest and urban birds that stem from the fact that the latter live in urban areas. Despite the absence of clear differences in the phenology of the arrival of the Woodpigeon in cities and natural landscapes, the nesting period of urban birds starts earlier and lasts much longer. In addition, the share of birds that breeding more than one time a season is larger than in forest birds. The peculiarities of nesting sites observed in urban birds as opposed to wild birds result from the peculiarities of urban green spaces and the effect of predation. We discovered that in spring (April - May) the share of nest failures peaks. The breeding success of the Woodpigeon in urban areas amounts to 52 % of all nesting cases.

For the first time, the differentiation by microsites of the population of dung beetles of the inhabitants of horse droppings in South Sikhote-Alin, Primorsky Territory was studied. The heterogeneity of the substrate has a significant effect on the distribution of beetles among microstations. The key factor affecting the seasonal dynamics of the species composition, abundance and biomass of beetles in different parts of the droppings are the temperature and humidity regime. It is shown that the confinement of certain species of dung beetles to areas of horse manure can serve as a way of dividing their ecological niches and a way of avoiding competition within one functional group.

According to the results of soil collections of earthworms in the Omsk Region for 9 years, in the period from 2009 to 2018, their population was analyzed in order to identify the main environmental factors associated with the territorial heterogeneity of species richness and group density. Five types of Lumbricidae populations have been identified, two of which are divided into two subtypes each, where of 10 species and 2 subspecies of earthworms were found. It has been established that the greatest influence on the distribution of worms is exerted by such environmental factors as zonality and subzonality, the depth of the soil layer, and, to a lesser extent, the topography characteristics: 9, 7 and 0.7 % of the considered variance of the density similarity matrix, respectively. In general, all environmental factors and their combinations (modes) explain 38 % of the considered variance, the multiple correlation coefficient is 0.62. Invading species of European origin Dendrobaena octaedra (7-52 %) and Aporrectodea caliginosa (15-74 %) and native Eisenia n. nordenskioldi (6-28 %), as well as of Asian origin: Eisenia ventripapillata (42 %) and E. nana (16 %), for the territories of the southern forest-steppe and steppe, became the leaders in terms of the share of the population density in most taxa of the classification. Such changes in earthworm populations, namely the replacement of native species of the Eisenia nordenskioldi complex with invasive species, can significantly affect soil characteristics and ecosystem services determined by earthworms.

The composition and content of phenolic compounds in leaves of Dasiphora fruticosa plants growing in the Far East, Southern and Eastern Siberia in the range of geographical coordinates 43°13′-62°52ʹ N was studied. The composition of the phenolic complex of D. fruticosa is represented by 16-22 components and remains constant, its variation occurs mainly due to minor components. Seven flavonolglycosides - hyperoside, isoquercitrin, rutin, avicularin, quercitrin, astragalin, kaempferol rutinoside, two aglycones - quercetin and kaempferol, and ellagic acid and its glycoside were determined using HPLC and UV spectrometry. The total content of phenolic compounds in plant leaves ranged from 13.5 to 28.3 mg/g, that of quercetin glycosides from 4.8 mg/g to 17.3 mg/g, and that of kaempferol glycosides from 0.1 to 1.3 mg/g. The total content of ellagic tannins in leaves varied from 6.9 mg/g to 12.9. mg/g. It was found that as D. fruticosa moved from south to north, increased insolation on the background of low-temperature stress, drought, content of all individual components increased, except for avicularin, the content of which, on the contrary, decreased. It was shown that the content of phenolic compounds (in total and in groups) is 53-75 % determined by temperature, of flavonols by 50-91 % by drought and by 50-54 % by solar radiation. Accumulation of ellagic compounds in leaves of D. fruticosa is 60 % determined by temperature, the other factors are of low importance. The factors making a significant contribution to the accumulation of phenolic compounds in D. fruticosa are air temperature, drought and UV radiation