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A comprehensive study of the biological activity of soils, supra- and periglacial bodies, and their microbiome has been conducted to assess the contribution of microorganisms to the ecological functions of soils in the western part of the Arctic zone of the Russian Federation and the Spitsbergen Archipelago. The methods of gas chromatography, luminescent microscopy, extraction of total soil DNA, and its quantitative real-time PCR were applied. The biological activity of soils was high only in the surface organic horizons and sharply decreased with depth and proximity to large glaciers. Intense anthropogenic impact reduced all parameters of biological activity. Judging by the large number of microorganism cells and a significant level of functional nitrogen cycle genes, the Arctic soil microbiome has a high adaptive potential to extreme environmental conditions, which allows soil microorganisms to perform their functions even under anthropogenic intervention.

In view of the high responsiveness of polar ecosystems to the global climate change, the research of Antarctic microorganisms has become a topical issue. The unique ecosystems that have developed under the severe climate conditions of the continent lack flowering plants but are dominated by soil mycobiota. In addition to performing their classical ecological functions, Antarctic fungi form the basis of local communities, e.g., endoliths and microbial mats. Furthermore, Antarctic fungi are a major force that mediates transformation of rock minerals in situ and makes biologically significant elements available for other organisms. For these reasons, mycobiota plays a central role in the maintenance of ecological equilibrium in Antarctica. The dominant fungal division on the continent is Ascomycota (77.1%), and not Basidiomycota (9.1%), as it is the case on other continents. For a number of reasons, yeasts and yeast-like micromycetes (mainly basidiomycetes) are more tolerant to extreme conditions in various Antarctic biotopes than filamentous fungi. Substantial evidence suggests that filamentous fungi and yeasts are better adapted to existence in ecosystems with extremely low temperatures than other microorganisms. Due to the long-term isolation of Antarctica from other continents, local biota has been evolving largely independently, which led to emergence of multiple endemic fungal taxa. The presence of eurytopes on the continent is presumably related to the global warming and growing anthropogenic pressure. This review discusses the current state of research on the structure of fungal communities of Antarctic subaerial and subaquatic biotopes, the ecological role of yeast–mycelial dimorphism in Antarctic fungi, the problem of endemism of Antarctic mycobiota, as well as the ecological and physiological adaptations of fungi to low temperatures; it also justifies the relevance of research into secondary metabolites of psychrophilic micromycetes.

We study the spatio-temporal dynamics of a multiplex network of delay-coupled FitzHugh–Nagumo oscillators with non-local and fractal connectivities. Apart from chimera states, a new regime of coexistence of slow and fast oscillations is found. An analytical explanation for the emergence of such coexisting partial synchronization patterns is given. Furthermore, we propose a control scheme for the number of fast and slow neurons in each layer. This article is part of the theme issue ‘Nonlinear dynamics of delay systems’.

The soil microbiome plays a crucial role in maintaining healthy ecosystems and supporting sustainable agriculture. Studying its biogeographical structure and distribution is essential for understanding the rates and mechanisms of microbially mediated soil ecosystem services. This study aimed to investigate the spatial distribution patterns of Acidobacteriota and Planctomycetota across soils in Russia, summarizing data from 16S rRNA gene metabarcoding of topsoils. A machine learning approach (Random Forest) was employed to generate digital distribution maps using climatic, topographic, vegetation, geological, and soil variables. Model interpration was performed using variable importance assessment and Shapley values. According to the error metrics, the Acidobacteriota model achieved a root mean squared error (RMSE) of 6.67% and an R 2 of 0.41, while the Planctomycetota model achieved an RMSE of 2.04% and an R 2 of 0.46. Both phyla exhibited similar spatial distribution patterns, with relative abundance decreasing from North to South. For Acidobacteriota, vegetation cover, surface temperature, and soil pH were significant predictors, whereas the relative abundance of Planctomycetota was mainly influenced by climatic variables. Specifically, Acidobacteriota were more abundant in areas with dense vegetation, stable surface temperatures, and acidic soils. In contrast, Planctomycetota showed reduced abundance in regions with higher levels of precipitable water vapor. These results highlight the potential of machine learning techniques to visualize predictive biogeographic patterns in soil microbial taxa abundance at the phylum level. Despite limitations related to the heterogeneous nature of source data, focusing on higher taxonomic ranks less sensitive to methodological variation enabled to identify preliminary large-scale distribution trends of microbial phyla in soils.

The field observation data on soil respiration (SR), or the CO2 emission from soil, over five years (2020–2024) in four regions of the European Russia (Chuvash Republic, Ryazan oblast, Tula oblast, and Kursk oblast) within the biome of broad-leaved forests and forest-steppes were analyzed. In each region, SR was measured in the same set of natural (forests and steppes) and agricultural (arable lands, hayfields, and pastures) ecosystems. SR was estimated with portable infrared gas analyzers and chamber technique in 10 spatial replicates at the height of growing season. In the Kursk oblast, gas measurements were more intensive (once–twice per month) as part of year-round monitoring. The goal was to quantify the relative contributions of SR spatial and temporal variations at different scales of observations, which increases the reliability of SR field estimates for subsequent extrapolation to larger regions or for forecast. Nonparametric statistical method PERMANOVA was used. On the scale of a year or a biotope, the contribution of temporal variation (49.0–59.8%) to the total variance of SR significantly exceeds the contribution of spatial variation (5.4–9.0%). A decrease in the spatiotemporal scale of observations to long-term series and regional ecosystems reduces the contribution of temporal variation to 27% and increases the contribution of spatial variation to 23.2%. In general, temporal variation on the considered scales appears to be more important for the overall variation in SR, suggesting the methodological recommendation to increase the frequency in assessing the SR intra-annual dynamics rather than to increase the number of measurement points in local ecosystems.

The parameters of the microbiome in Albic Podzols are analyzed along the gradient of pollution (3, 16, 30, and 50 km) by Pechenganikel plant emissions (Murmansk oblast, Russia). The amount and structure of the prokaryotic and fungal biomass are assessed by luminescence microscopy; copy number of microbial ribosomal genes is determined by real-time PCR; and taxonomic diversity and abundance of culturable soil micromycetes are estimated. The copy number of the ribosomal genes of bacteria, archaea, and fungi increases close to the source of emissions as compared with remote sites. In all sites, bacteria display the highest copy number of ribosomal genes amounting to (3.21–12) × 10 10 gene copies/g soil). As for fungi and archaea, the copy number varies in the range of (0.53–1.59) × 10 10 and (0.55–11.41) × 10 10 gene copies/g soil, respectively. The minimum copy number for all groups of microorganisms is observed at a distance of 50 km from the Pechenganikel plant and the maximum, in the range of 3–16 km from the source of emission. The abundance of prokaryotes varies in the range of (1.04–8.6) × 10 8 cells/g soil and their biomass, from 0.2 to 18.3 µg/g soil. The fungal biomass changes from 122 to 572 µg/g soil. A significant decrease in the biomass of all groups of microorganisms is recorded near the plant. The fungal mycelium and spores in all sites are mainly represented by small forms with a diameter of 2–3 µm. The length of the fungal mycelium varies from 51.2 m/g near the plant to 397 m/g at remote sites; however, any regular patterns along the pollution gradient are unobservable. The diversity of culturable soil micromycetes at the level of genera and higher taxa decreases along the pollution gradient of Pechenganikel emissions. The structure of fungal communities changes from a polydominant type (background site) to a monodominant type (near the plant). Penicillium raistrickii is dominant in all sites. The fungi Aureobasidium pullulans and Trichoderma viride are dominant at a distance of 16 km from the pollution source and the dark-colored yeast Torula lucifuga, at a distance of 3 km. As for the background site, representatives of the orders Mucorales and Umbelopsidales are prevalent there.

The microbiome of soils and supraglacial formations in background and oil-polluted ecosystems of Hayes Island (Franz Josef Land) was studied using the methods of luminescent microscopyreal-time and polymerase chain reaction. The biomass of microorganisms ranged from 81 to 666 μg C/g substrate; its larger part (up to 88%) was represented by fungi. The length of the fungal mycelium reached more than 360 m/g substrate. The number of prokaryotes varied from 4.0 × 10 7 to 3.75 × 10 9 cells/g substrate; the length of actinomycete hyphae reached 40 m/g substrate. Up to 78% of detected prokaryotic cells were represented by small nanoforms, which is typical for extreme ecosystems. The proportion of viable microbial cells gained maximum (74–86%) in surface organic horizons and minimum (29–54%) in mineral supra-permafrost layers. Bacteria dominated in the prokaryotic complex (from 5.14 × 10 5 to 5.05 × 10 10 16S rRNA copies/g soil); the content of archaea was lower: from 8.46 × 10 5 to 2.28 × 10 9 16S rRNA copies/g substrate. The amount of fungal ITS rRNA in the soil samples ranged from 6.47 × 10 4 to 8.67 × 10 10 copies. The number of copies of the alkB gene (synthesis of alkane monooxygenase for the destruction of n- alkanes of hydrocarbons) varied from 1.2 × 10 1 to 1.8 × 10 5 copies/g substrate and sharply decreased from surface to deep horizons. Oil-contaminated soils and supraglacial objects contained a smaller biomass, but a larger number of ribosomal genes of microorganisms as compared with background ecosystems. An exponential decrease in the analyzed quantitative parameters of microorganisms from surface to deep soil horizons was observed.

— In the 21st century, glaciers are perceived as a distinct biome that has taken on special significance in today’s world of retreating ice. In this paper, we review the results of recent studies of organomineral formations on glaciers, their diversity, genesis, functioning, and the role in the biosphere. The question is raised about the possibility of involving supraglacial organomineral formations in the range of objects of soil science. We review the supraglacial zone as an area of soils and soil-like bodies, the biogeochemical processes in which affect the glacial biome and the surrounding landscapes. Interpretation of supraglacial organomineral formations from a pedological point of view allows us to identify several typical soil processes: accumulation and stabilization of organic matter (OM), its heterotrophic transformation, formation of dark-colored humified OM, accumulation of residual solid-phase products of functioning in situ, fine earth aggregation, and biochemical weathering. Among supraglacial formations, we distinguish pre-soils and soil-like bodies in ice and snow, metastable soil-like bodies on cryoconite, and soils with microprofiles under moss communities on ice, as well as relatively stable soils with macroprofiles on silicate gravelly to fine-earth deposits underlain by moving glacier and dead glacier ice. Labile dissolved OM accumulated and transformed in supraglacial soils and soil-like bodies has a significant impact on the periglacial zone, leading to the reservoir and priming effects. The studies of supraglacial organomineral systems are of fundamental importance for understanding the evolution of ecosystems on Earth, as well as for modeling supraglacial formations of extraterrestrial bodies with a vast cryosphere. Supraglacial soil formation is also a model object for studying common soils under conditions of a continuous external input of organic and mineral components, the contribution of which beyond the glaciers is no less significant, but is masked by the polymineral substrate of soils and parent rocks themselves.

Urban and technogenic landscapes in subarctic zones are not considered comfortable habitats for soil microbiota. However, green infrastructures in polar cities can provide a new niche for the development of a microbial soil community. Soil microbial biomass and the diversity of cultivable microfungi have been studied in relation to the chemical and morphological properties of urban soils in the polar city of Apatity. The quantitative indicators based on fluorescence microscopy and PCR real-time methods as well as the qualitative composition of the cultivable microfungal community were used to characterize the microbial community. Changes in the morphological and chemical composition of urban soils included a shift in pH and increased C and N content compared with forest soil. Studies have shown that the biomass of microfungi and actinomycetes in urban soils was lower than in forest soils and equals 0.12–0.19 mg/g and 0.06–0.44 × 10 −3  mg/g, respectively. Bacterial biomass, on the contrary, increased in urban soils up to 2.6 × 10 –3 – 5.6 × 10 –3  mg/g. The number of ITS gene copies of fungi in urban soils varied from 5.0 × 10 9 to 1.45 × 10 10 copies/g of soil, reaching the highest values in the courtyard. The number of rRNA gene copies of bacteria and archaea in urban soils increased compared with forest soil and amounted to 2.37 × 10 10 – 9.99 × 10 10 and 0.4 × 10 10 – 0.8 × 10 10 copies/g of soil, respectively. In urban soils, morphological changes in microfungi, including the predominance of small spores, were revealed in comparison with forest soils, where mycelium prevailed. An increase in the diversity of microfungi in urban soil and changes in the structure of their communities compared with forest soil was noted. Microfungi found in urban soils are not typical of the background soils of the region and would be expected in more southern conditions. Among them, opportunistic fungi species have been identified in humans, which increases the risk of diseases in residents of the northern region.

The aim of this analytical review is to systematize information on the quantitative characteristics of variation in the content and stock of organic carbon (C org ) in soils. The review considers the estimates for validity and reproducibility of determined C org values, as well as the spatial variation and heterogeneity of C org at different hierarchical levels of the soil cover composition and their changes in time. The most powerful factor of C org changeability in soils is spatial variation. The absolute standard deviation and coefficient of variation for C org content and stock in soil shows the trend of an increase with the logarithm of the examined plot area. This trend is observed on the background of a wide range of the values of the indicators of spatial C org variation in each narrow range of the plot area, which leads to a high uncertainty of the estimates with an increase in the area coverage. Direct dry combustion is considered the preferable method among the methods used to determine C org content. This method gives valid (i.e., with the least biases) and well reproducible data. The indirect Tyurin and Walkley–Black methods systematically underestimate the C org content and their reproducibility is comparable to the amplitude of seasonal dynamics and minimum spatial variation indices within an elementary soil area. The estimates for the long-term trend of C org content require strict adherence to stringent monitoring conditions over the time intervals longer than 15 years. The spatial variation in C org stock is more pronounced as compared with C org content, which further increases the requirements to monitoring.