Forest-steppes are among the most complex temperate ecosystems in the Northern Hemisphere, yet remain among the least investigated from a palaeogeographic perspective. Here we propose a novel approach for reconstructing Holocene vegetation dynamics and climate changes in the forest–steppe ecotone using fossil burrows of fossorial mammals (krotovinas) preserved in chernozems. We analysed 27 krotovinas from six meadow-steppe sites in the East European forest-steppe. Pollen, non-pollen palynomorphs, and soil organic carbon content were obtained for all samples. 14 krotovinas were dated using the humic acids fraction. Palaeoclimate was reconstructed based on the Modern Analogue Technique trained on a regional modern soil pollen dataset. Vegetation changes were additionally derived using a biome-based approach. Studied burrows span 8.4–2.2 ka, and the onset of preserved krotovina formation coincides with regional humidification. Pollen spectra indicate xeric Artemisia-dominated steppe at 8.4–6.5 ka and a transition to forest-steppe vegetation after ∼6.5 ka. Relatively wetter phases (6.5–5.8, 5.4–4.9, and 3.5–3.3 ka) align with forest expansion, whereas drier phases coincide with steppe dominance. The boundaries between the hydrological phases coincide with peaks in Pseudoschizaea, which indicate enhanced surface runoff and erosion and may have contributed to the expansion of the gully system. Evidence of human impact first appears at 5.0–4.9 ka (Copper Age) and peaks at ∼2.2 ka (Iron Age). Overall, the framework is transferable to other semi-arid regions, where fossil burrows can provide a spatially distributed Holocene archive.

The development of rare metal ore deposits in Murmansk oblast over the past 70 years has been accompanied by the storage of fine-grained concentration wastes, which caused the formation of two tailing fields. The field, which was decommissioned 35 years ago, undergoes natural overgrowth processes. Studies of the mineral and chemical composition, quantitative and qualitative characteristics of microbial communities of technogenic surface formations (TSF) and soils formed on wastes being accumulated from the enrichment of loparite ores have been performed. With increasing age of TSF and the destruction of weakly stable alkaline minerals, there was a simultaneous increase in carbon content from 0 to 4.5

Climate mitigation strategies and targeted carbon neutrality highlight the potential of soils as important terrestrial stocks of organic carbon (C). Although global soil models and datasets (e.g., HWSD, SoilGrids, or S-world) provide information on soil C stocks’ distribution around the world, they remain biased both geographically and regarding different land-use types. Geographically, soils of high latitudes are usually underrepresented in global datasets compared to temperate or tropical climates. As for land use, the major part of soil data comes from natural and agricultural areas, whereas soils of urban areas remain overlooked or completely ignored. The research aimed to fill this gap by exploring soil C stocks and factors driving their spatial variability in the Russian Arctic zone. Soil survey was carried out in four cities of the Russian Arctic zone: Apatity (67 N; 33 E), Murmansk (68 N; 33 E), Vorkuta (67 N; 64 E), and Norilsk (69 N; 88 E). Soils in all the cities are exposed to severe climatic conditions combined with strong anthropogenic pressure from the coal and ore mining industries. Vorkuta and Norilsk are located in the permafrost zone, whereas the soils of Apatity and Murmansk do not have the permafrost layer. In each city, 30 to 100 locations were sampled, including topsoil (0-10) and subsoil (till 100 cm) layers. In the collected samples, total and organic carbon (SOC) was measured at the CN analyzer. Bulk density and rock fraction were measured to estimate C stocks. Soil microbial (basal) respiration was measured in standardized lab conditions, and the ratio between basal respiration and SOC contents was used to analyze biodegradation coefficients and half-life time. Spatial patterns of SOC distribution, including inter- and intra-city variability were analyzed by factorial ANOVA. SOC stocks in Arctic cities were quite heterogeneous with a coefficient of variance of up to 100%. Topsoil SOC stocks were similar or even higher compared to the data reported for Russian cities in temperate climates (e.g., Moscow, Saint-Peterburg, or Ekaterinburg). Subsoil stocks were significantly lower compared to topsoil due to a gradual decrease of SOC contents with depth and a high amount of gravel and rock fragments. Elevation, vegetation, and proximity to the sources of anthropogenic disturbance were the main factors driving the intra-city variability. The difference between the cities depended on bioclimatic conditions including permafrost. On average SOC stocks in cities with permafrost were significantly higher compared to those in cities without the permafrost layers. One of the possible reasons can be the conservation of organic matter in subsoil horizons when the mineralization of organic matter is hampered by low temperatures and low microbial activity. Indirectly this statement is confirmed by higher half-life time values, although the difference was not always statistically significant. Under climate changes the role of Arctic soils in carbon balance will further increase, therefore the research outcomes are highly relevant to develop the strategies of sustainable urban development in the region. Acknowledgements This research was supported by RSF # 19-77-30012 and RUDN University Strategic Academic Leadership Program

The soils of boreal landscapes are continuously shaped by fire and keep the memory of this essential ecosystem process. A part of the pyrogenic record is stored in the sequestered charred biomass, including wood charcoal, which is a long-living carrier of information about past vegetation and fire regimes. Raman spectroscopy of charcoal is still a developing tool used to decipher the chemical signature of the original heat impact and further diagenesis of charred wood in a depositional setting. Here, we examine the molecular structure of charcoal sequestered in Podzols and Arenosols of the European north during fires of the recent past and the Holocene paleofires. We combine Raman spectroscopy of charcoal with the extraction of a time factor estimate from the historical records of fire and radiocarbon dating of burned biomass. With these data, we further explore if changes in the molecular structure of charcoal are time-referenced. Over 950 Raman spectra were collected from macrocharcoal particles produced during 10 historically documented fires (2-160 years since fire) and those sequestered in 31 pyrogenic horizons and morphones of paleosols during the last similar to 9700 cal BP. Calculated Raman spectral metrics included D and G bands positions, their separation, and the four ratios: H-D/H-G, H-V/H-G, H-1710/H-G, photoluminescence slope/H-G. Obtained multivariate dataset suggests a continuum of diverse molecular signatures in charcoal associated with production conditions and ageing in soil. With the use of principal component analysis and hierarchical clustering, we assess the blocks of charcoal memory mostly associated with charring conditions and those attributed to such diagenetic processes as oxidative weathering and saturation by C-H-dominated organic matter. Pronounced changes in the molecular structure of charcoal happened rapidly and depended on soil conditions. While many charcoals became significantly altered within years and decades, some fragments may have better preserved the chemical signature of original charring conditions, even if produced in paleofires of the Early- and Mid-Holocene.

Hyperspectral imaging of lake sediment cores offers a promising analytical method being both high-resolution and non-destructive. In this study, we investigate the potential of an industry-standard hyperspectral (VNIR) camera combined with a custom developed software package to provide indirect data on past changes in sediment accumulation conditions of a mid-elevation lake in the Caucasus Mountains. The software allows for automated core fragment stitching, crack removal and spectral analysis. We introduce the technique of wavelength correlation mapping as a tool to trace within-core variations of spectral properties (i.e. absorption features). The absorption feature around 670 nm wavelength marks a characteristic distinction between organic-rich and organic-poor sections of the studied sediment core. This part of the spectrum corresponds to absorption of electromagnetic radiation by chlorophyll a , a pigment ubiquitous in photosynthetic organisms. In this study, we use the techniques of relative absorption band depth (RABD) and area (RABA) with various spectral spans to calculate and compare the 670 nm derived spectral indices. The selected RABD 660;670 index serves as a high-resolution (229 μm/px) proxy for downcore variations of autochthonous organic matter and provides the reconstruction of lake productivity for the period 3000–1000 BP with subannual resolution. The results are supported with independent biogenic proxies – total organic carbon, loss-on-ignition and concentration of bromine in the sediment.

Arctic cities attract researchers’ interest by a unique combination of extreme climatic conditions and anthropogenic pressure. Urban soils are different from natural references in terms of the formation and functioning conditions. Urban soils are very heterogeneous ranging from semi-natural soils altered by: on the urbanization to artificial soil constructions composed from different materials and mixtures. These soil constructions are mainly created to support green infrastructure and can be considered a new ecological niche for microorganisms. This research aimed to identify the microbial features of urban soils and soil constructions in Arctic cities compared to the background soils. The studies were carried out in the recreational zones of Kola region cities: Murmansk (68.58°N, 33.03°E), Monchegorsk (67.56°N, 32.52°E), and Apatity (67.33°N, 33.24°E), different in population, operating industry, and climate. Samples were taken from different soil horizons. Soil morphological (WRB classification), physicochemical properties (density; pH; C, N content (CN analyzer) etc., including heavy metals (ICP) were assessed. Microbiological indicators included the number of archaea, bacteria, fungi genes copies (PCR real time), functional diversity (MicroResp), microbial respiration (SIR). Four main types of urban soil disturbance of the Kola Arctic have been revealed: slightly disturbed natural podzols and podburs; disturbed urban-stratified podzols and podburs; artificially created soil constructions with evidences of soil formation; artificially created soil constructions. Disturbed urban soil profiles contain a gray-humus urban stratified horizon with a low C content, but high N content and pH values. Urban soils in Murmansk and Monchegorsk had higher contents of C and N compared to those in Apatity. Whereas in terms of the content of heavy metals (Cu, Ni) in soils of Monchegorsk was higher compared to the other cities. Microbial communities of soils and soil constructions in the Kola Аrctic cities responded differently to the influence of urban anthropogenic factors. The microbiological parameters were significantly influenced by age, land use history, the productivity and structure of vegetation, the degree of soil cover transformation, and the level of pollution. However, general patterns identified for the microbial communities were similar for all urban soils. There was a tendency towards an increase in the functional activity and diversity of microbial communities in artificially created soil constructions compared to natural urban soils and background references. In contrast, microbial respiration was higher in natural urban soils compared to soil constructions, but no general pattern was found across cities when compared to background soils. For example, in Murmansk and Monchegorsk the values were lower compared to background soils, whereas the opposite was shown for Apatity. The number of archaea genes copy was also higher in urban soils of Apatity compared to background soils. For most chemical and microbiological parameters of urban soils, the highest values were identified in the subsoil horizons, which may be due to the presence of buried horizons, various substrates, and artifacts. Urban soils and soil constructions can provide a niche for microorganisms, but a complex of external factors affecting them in specific conditions plays a fundamental role. Acknowledgements This research was supported by RSF #23-17-00118 and RUDN University Strategic Academic Leadership Program.

The increasing popularity and recognition of citizen science approaches to monitor soil health have promoted the idea to assess soil microbial decomposition based on a standard litter sample - tea bags. Although tea bag initiatives are expanding across the world, the global datasets remain biased in regard to investigating regions and biomes. This study aimed to expand the tea bag initiative to European Russia, which remains a "white spot" on the tea bag index map. We also added urban soils into the analysis, which were underestimated previously. We compared the standard and local tea brands to explore possible adaptations of the standard approach to regions with limited access to standard tea brands. The established monitoring network included natural and urban sites in six vegetation zones along a 3000 km latitudinal gradient. There was a very close linear relationship (R 2 = 0.94-0.98) in the mass loss of alternative and standard tea litter. The mass loss of green tea in soil along the latitudinal gradient showed an increasing trend from north to south. Variations in the microbial decomposition of green tea were mainly explained by the latitudinal gradient, with low soil temperature identified as key factors hampering decomposition. Mass loss of the more recalcitrant rooibos tea was mainly determined via land use, with decomposition rates on average 1.3 times higher in urban soils. This pattern was in line with higher soil temperatures and pH in urban sites compared to natural counterparts. The findings of our study could prove valuable in extending the tea bag network of soil decomposition assessment into broader territories, including urban areas. Additionally, they could facilitate the involvement of citizen science and complete the database for C cycle modeling depending on climatic conditions.

The Russian Arctic presents a unique environment for studying the effects of anthropogenic pressure on soil microbial communities under severe climatic conditions. This study investigated the impact of chemical pollution on soil microbial properties by comparing urban and industrially polluted soils in Murmansk region with natural Podzols. Urban soils exhibited significant alterations, including shifts in pH and increased carbon and nutrient contents compared to natural soils. Industrially polluted soils near the copper-nickel smelter were characterized by elevated heavy metal concentration, while those near the aluminum smelter showed high fluorine and aluminum content. In both cases, carbon content and pH remained similar to natural soils. Industrial emissions significantly changed the soil microbiome, with effects varying depending on the pollution source and chemical composition of the emissions. Soils near the copper-nickel smelter showed a decline in bacterial gene copies and actinomycete mycelium length, with a predominance of Chloroflexii and Ascomycota. Conversely, soils near the aluminum smelter exhibited less pronounced changes, with Proteobacteria and Basidiomycota being prevalent. Despite these differences, both industrially impacted sites displayed reduced microbial diversity, regardless of the composition of the emissions. In contrast, urban soils demonstrated increased microbial diversity, likely attributed to the emergence of new, favorable ecological niches. Microbial communities in both cities were similar, dominated by Proteobacteria and Ascomycota, and displayed an increase in bacterial gene copies compared to natural soils. These findings highlight the contrasting influences of urban and industrial development on soil microbial communities. While industrial activities suppress microbial life, urbanization fosters the creation of new niches, promoting microbial diversity. This underscores the potential of urban soils to support diverse microbial communities, which is crucial for sustainable development and ecological strategies in Arctic cities.

Ecosystem services are a modern tool of environmental assessment, planning, and design, especially in large cities. The top layer (0–10 cm) of soddy-podzolic soils (Albic Retisols) was sampled in urban forest parks of Moscow (Aleshkino, Bitsa, Lesnaya experimental dacha, Troparevo, Lianozovo, and Yugo-Zapadny) and suburban (background) forests. In total, 30 samples (6 × 5 plots) were taken in forest parks and 20 samples (4 × 5 plots) in background areas, altogether 50 samples. The contents of carbon (C); nitrogen (N); phosphorus (P); heavy metals (Pb, Cu, Ni, and Zn); nitrate nitrogen (N– NO_3^ - ); and C, N, and P in microbial biomass (Cmic, Nmic, and Pmic), basal (microbial) respiration were determined. The portion of Cmic, Nmic, and Pmic in the total contents of these elements in soil (Cmic/C, Nmic/N, and Pmic/P) were calculated. We suggest that the values of basal respiration, Cmic/C, Nmic/N, and Pmic/P characterizing the cycles of biophilic elements in the soil may be associated with supporting ecosystem services whereas soil pollution (heavy metals and N– NO_3^ - ), with ecosystem disservice. The basal respiration, Cmic/C, Nmic/N, and Pmic/P in the soils of each studied forest park were, on average, by 4–72 NO_3^ - were by 14–194

For the first time, a comprehensive assessment of the biological activity of the supraglacial systems of the IGAN Glacier—the largest glacier of the Polar Urals—was carried out. The stocks and structure of microbial biomass were estimated using luminescent microscopy and substrate-induced respiration methods; basal respiration, the intensity of methanogenesis and nitrogen fixation, the number of copies of ribosomal genes of microorganisms (bacteria, archaea, and fungi), and the numbers (CFU/g soil) of cultivated micromycetes, saprotrophic bacteria, and actinomycetes were also studied. The highest biological activity was found in the supraglacial zone, and the lowest—along its periphery and in the near periglacial zone. In all zones of the glacier, Geomyces pannorum, G. vinaceus, and Teberdinia hygrophila dominated among micromycetes, and representatives of the Arthrobacter and Bacillus genera dominated among bacteria. The microbiome structure of supraglacial bodies depended on their location on the glacier and differed significantly at the periphery and in the center of the supraglacial zone, as well as in comparison with soils and sediments in the adjacent periglacial landscape. The material released from the glacier body with a high content of organic matter affects the biological activity of supraglacial microbial communities.

An experimental study of the suppression of noise in the image of a dental visiograph, caused by scattered radiation in the X-ray range of the spectrum, is carried out. To suppress noise, a nickel raster fabricated using deep X-ray lithography is used. Placing the raster directly in front of the detector makes it possible to suppress the background caused by scattered radiation and increase the signal-to-noise ratio both in areas with low optical density and in areas with high optical density.

Dynamics in soil CO2 emission, temperature and moisture was observed during the vegetation season (from May to October) in 2021 and 2022 in the residential areas of Murmansk and Apatity cities (Murmansk region) in comparison with natural references. The average emissions from urban soils were 5–7 gC/(m2 day) in summer and 1–2 gC/(m2 day) in spring and autumn. Temperature was the main abiogenic factor that determined the seasonal dynamics of soil respiration (R2 from 0.4 to 0.7, p 0.05; temperature coefficient Q10 up to 2.5), while excess moisture had a limiting effect, especially in the natural areas. The heterogeneity of hydrothermal conditions and the content of biophilic elements determined the differences in the average CO2 emission between natural and urban soils. For the natural soils, the average temperature was lower and the humidity was higher than for urban areas, which determined the lowest emission values. Among urban sites, higher CO2 emissions have been shown for tree and shrub vegetation sites.

Soils formed in treatment facilities of sugar beet factories in the forest-steppe zone of Kursk oblast were studied. Technogenic factors of soil formation associated with the industrial sugar beet activity and post-technogenic processes during the abandonment of treatment facilities are considered. The alternation of settling ponds and the earth walls separating them are the main factors determining “cellular” pattern of the soil cover. The mode of inflow and discharge and the composition of wastewater, as well as the duration of the abandonment of settling ponds determine the specifics of soils forming in the bottoms of the ponds. Mucky–humus quasi-gley stratified soils (Calcaric Gleysol) are formed in operating settling ponds under the periodic impact of sewage mixed with other wastes. When calcareous sewage sludge (press mud) is previously removed from abandoned ponds, dark-humus quasi-gley soils (Gleyic Cambisol) are formed in 30 years in the presence of perched water table, and quasi-gley zooturbated Chernozems are developed in 40 years under the conditions of periodic moistening. Soil formation in settling ponds with preserved sewage sludge and abandoned 20 years ago is noticeably intensive only in the upper 10–15 cm, and properties of the stratified sediment are preserved below. Dark-humus technogenic artistratified soils (Spolic Technosols) are identified there. Typical dark-humus soils (Eutric Cambisols (Organotransportic) are formed on earth walls in about 50–60 years, and incompletely developed strongly alkaline technogenic pelozems (Spolic Technosols (Transportic)) are formed on earth walls covered with calcareous sewage sludge; these soils consist of the virtually unchanged mixed material of technogenic sediments. All soils are alkaline and strongly alkaline and rich in organic matter, carbonates, phosphates, nutrients and some heavy metals from wastewater. According to the combination of properties, the soils of the sugar industry treatment facilities have no direct natural analogues in the central chernozemic region and are a vivid example of soils forming under extreme conditions of resource excess.

In six forest parks of Moscow and four rural forests (5 plots each, n = 50), soil physical, chemical and microbial properties of the upper 10 cm layer were assessed in combination to vegetation properties. The content of carbon (C), nitrogen (N), and phosphorus (P) in soil and microbial biomass was determined. It was revealed that soil density, pH value, content of N–\({\text{NO}}_{3}^{ - },\) Ca and heavy metals (Pb, Cu, Ni, Zn) increase in forest parks compared to rural forests. In the soil of the forest parks, a decrease in the content of microbial biomass C (Cmic), its basal respiration (BR), and microbial C- and N-availability (Cmic/C, Nmic/N, BR/C) was noted. The changes of soil microbial properties are mainly driven by the abundance of leaf litter and the content of available soil C (13–35% of the explained variance). The microbial response to the soil enrichment by low molecular weight organic substrates (carbohydrates, carboxylic and phenolic acids, amino acids, amino sugars) in forest parks and rural forests did not differ significantly. In the soils of forest parks, no changes in microbial mineralization and immobilization of P (Pmic, Pmic/P) were found as well. The impact of urbanization on the forest ecosystems has led mainly to a decrease in the intensity of processes associated with soil C and N cycles. Apparently, such changes are caused by the recreational activity and the management practice of green spaces in the city, which leads, in particular, to a decrease in the amount of forest litter in parks compared to rural forests.

The soils mycobiota of Apatity was first characterized. Significant differences in quantitative and qualitative parameters of urban soils fungal complexes of the Subarctic zone in comparison with zonal soils were revealed. It was shown that the biomass of fungi in the soil of the residential area of Umbric Leptic Entic Podzol (Arenic, Neocambic) is 0.18 – 0.20 mg/g, in the background forest soil Folic Leptic Albic Podzol (Arenic) – 0.31 mg/g. The smallest values (0.04 – 0.08 mg / g) are typical for areas with no vegetation and a densely compacted surface (playground - Leptic Entic Podzol (Arenic, Neocambic, Technic), unpaved pedestrian walkway – Umbric Leptic Entic Podzol (Arenic, Neocambic). In the soils of recreational and forest areas, fungi were mainly in the form of mycelium (66-70% of the total biomass), while in the soils of residential and agricultural areas in the form of spores. Spores are mainly represented by small forms up to 3 microns. The amount of large spores is insignificant, but they were mainly detected in the soil of the residential area. The number of copies of ITS rRNA genes of fungi in soils of different functional zones varies from 4.0×109 to 1.14×1010 copies/g of soil, with the highest values in the natural Podzol of the forest zone and Podzol of the unpaved pedestrian walkway. The number of micromycetes CFU in the upper soil horizon ranges from 1×103 to 9×104 CFU/g of soil, reaching maximum values in the soil of the Umbric Leptic Entic Podzol recreation zone (Arenic, Neocambic, Technic). The features of cultivated forms of micromycetes distribution on the soil profile in different functional zones were revealed: in the Podzol of the residential area, the maximum accumulation of fungi was noted in the lower horizons, while in the soil of the recreational, agricultural and forest areas, their maximum number was noted in the top horizon. However, the first two differed from the background one in the absence of a second maximum accumulation of micromycetes in the illuvial Bs horizon. In general, urban soils were characterized by a low species diversity of micromycetes complexes and a specific structure significantly different from the background soils. The genus Penicillium is characterized by maximum species diversity. Trichocladium griseum and Penicillium dierckxii dominate in the communities of microscopic fungi in the soil of the residential zone, P. melinii in the soil of the recreational areas and in the playground, in the soil of agricultural area Plaggic Entic Podzol (Arenic) - micromycetes of the genus Fusarium, and in the background forest soil - P. decumbens.

Fire relentlessly modifies the belowground pool of pyrogenic carbon (PyC) in boreal ecosystems. However, only a few soils offer a consistent record of PyC accumulation. Here, we report on the Holocene-scale record of biomass burning and PyC sequestration in the paleosoils of dry topographic hollows at the Keiva ice-marginal landform. We combine soil stratigraphy, radiocarbon dating, and chemical analyses to explore the chronology and properties of macrocharcoal that accumulated in soils for millennia. The most ancient pyrogenic horizons refer to 10,700-10,200 cal BP. They contain charred remnants of well-pronounced root systems as a part of the paleosoil, suggesting enough biomass for intensive burning and significant PyC sink into soils soon after deglaciation. The major phase of woody biomass burning occurred during 7000-5000 cal BP and resulted in the abundant deposition of charcoal in topographic hollows. Soil macrocharcoal maintained a remarkably consistent concentration of total organic carbon (70.70 +/- 2.96 %) over the millennial timescale. Its conservation was strengthened by burial in dry sandy soils soon after the fire. Raman spectra of the least weathered charcoal fragments of various ages indicate that intensive biomass burning occurred regularly in the Holocene. Capacity to form pyrogenic archives of Keiva II was predetermined by glacial-associated features like kettle topography and their postglacial modification. Rich PyC record of Keiva II highlights the significance of this landform for soilbased paleofire studies in eastern Fennoscandia.

Dynamics of soil CO 2 emission, temperature, and moisture were studied during the vegetation season (from May to October) in 2021 and 2022 in the residential areas of Murmansk and Apatity cities (Murmansk oblast) in comparison with natural areas. The mean emissions from urban soils were 5–7 g C/(m 2 day) in summer and 1–2 g C/(m 2 day) in spring and fall. Temperature was the main abiogenic factor that determined the seasonal dynamics of soil respiration ( R 2 from 0.4 to 0.7, p < 0.05; Q 10 temperature coefficient up to 2.5), while excess moisture had a limiting effect, especially in the natural areas. The heterogeneity of hydrothermal conditions and the content of biophilic elements determined the differences in the mean CO 2 emission between natural and urban soils. For the natural soils, the mean temperature was lower and the moisture content was higher than for urban areas, which determined the lowest emission values. Among urban sites, higher CO 2 emissions were found for tree and shrub vegetation sites.

Against the backdrop of global warming, urban ecosystems are becoming increasingly vulnerable to climate stresses. Strategies for climate adaptation developed for almost every major city in the world pay considerable attention to urban green infrastructure as a nature-oriented solution for carbon sequestration. However, the influence of urban climate conditions on the spatial and temporal heterogeneity of CO2 emissions from urban soils remains poorly understood, which can lead to inaccurate estimates and probably inflated expectations of urban green infrastructure in the context of carbon neutrality. Studies of CO2 emission dynamics with parallel observation of soil temperature and moisture were conducted at three green infrastructure sites in the Moscow metropolis, which differ in contrasting mesoclimatic conditions, in 2019–2022. Plots with different vegetation types were compared for each site, which allowed us to assess the internal heterogeneity of soil and microclimatic conditions. Soil temperature and moisture were determined to 70% of the total variance of CO2 emissions. At the same time, mean annual soil temperature in the center was almost 3–6°C higher and moisture was 10–15% lower compared to the periphery. Soils under lawns and bushes were, on average, 1–2°C warmer and 10–15% wetter than under trees. Soil CO2 emission under lawns was, on average, 20–30% higher than that under woody plantings in the same plot. At the same time, the differences between the plots with the same vegetation in the center and on the periphery reached 50%, which confirms the high vulnerability of urban soil carbon stocks to mesoclimatic anomalies and the high risks of increased CO2 emission by urban soils against the background of climate change.

The research is devoted to the analysis of biodiversity of Antarctic cyanobacteria in hypolithic organic-accumulative horizons of soils in the Larsemann Hills oasis. Studies of fouling glasses by the methods of light and confocal microscopy, as well as by fluorescent in situ hybridization, indicate that filamentous forms predominate among cyanobacteria in the upper layers of Antarctic hypolithic microbial communities. Strains of the genera Nostoc , Halotia , Leptolyngbya , Plectolyngbya , and Phormidesmis , as well as some new and previously undescribed cyanobacteria, were isolated from corresponding soil samples to clarify their taxonomic status. As a result, a unique collection of Antarctic cyanobacteria isolated from soils was obtained for the first time. The strains were described according to the modern polyphasic taxonomy methods based on an integrated assessment of morphological and molecular-genetic features. Phylogenetic analysis of primary 16S rRNA sequences and peculiarities of secondary structures of internal transcribed spacers enabled us to identify new taxa of potentially endemic cyanobacteria among the strains studied. The high level of similarity between the 16S rRNA gene sequences of soil strains and those previously found in benthic mats of water bodies in the Larsemann Hills confirmed the ability of cyanobacteria to expand beyond different ecological niches and to adapt to contrasting environmental conditions.

Dynamics in soil CO2 emission, temperature and moisture was observed during the vegetation season (from May to October) in 2021 and 2022 in the residential areas of Murmansk and Apatity cities (Murmansk region) in comparison with natural references. The average emissions from urban soils were 5–7 gC/(m2 day) in summer and 1–2 gC/(m2 day) in spring and autumn. Temperature was the main abiogenic factor that determined the seasonal dynamics of soil respiration (R2 from 0.4 to 0.7, p 0.05; temperature coefficient Q10 up to 2.5), while excess moisture had a limiting effect, especially in the natural areas. The heterogeneity of hydrothermal conditions and the content of biophilic elements determined the differences in the average CO2 emission between natural and urban soils. For the natural soils, the average temperature was lower and the humidity was higher than for urban areas, which determined the lowest emission values. Among urban sites, higher CO2 emissions have been shown for tree and shrub vegetation sites.