The article summarized the results of long-term observations (2014–2018) of soil emissions and net CO2 fluxes (2017–2018) in natural and anthropogenically modified (AI) ecosystems of Arctic tundra on the territory of the archipelago of Svalbard (Barentsburg, 78°04′N, 14°13′E). Anthropogenic controls associated with local land use, during the period of their active impact may redouble the emissions of carbon dioxide from soil (0.111 ± 0.021 > 0.064 ± 0.011 gС m–2h–1). During the same period, the net C-balance at the sites with active land use is estimated as a source to the atmosphere. Self-recovering after human influence plots (II) demonstrate intermediate values of soil emissions of СО2 between unaffected tundra (I) and plots with active land use (III). With that they demonstrate the greatest net C-sink within the observed range of Photosynthetically Active Radiation as compared to (I) and (III). At the height of the vegetation period unaffected tundra ecosystems demonstrate a neutral net C-balance. The greatest contribution to soil emissions variance make spatial controls (they explain 56–66% of variance), whereas temporal factors are responsible for 3.8–5.5% only. Amongst spatial controls, the thickness of organogenic layer makes the greatest contribution. Inter-annual fluctuations of key factors, among which the most important are the soil moisture and temperature of the upper soil layer, both affect AI and natural ecosystems hence the spatial differences between them remain constant from year to year. According to preliminary estimates, unlike the carbon dioxide, the contribution of methane and nitrous oxide net fluxes in local ecosystems is insignificant and does not depend on human land use.
Urbanization in the Arctic results in considerable and still poorly known environmental consequences. The effect of urbanization on soil microbiome—an ecosystem component highly sensitive to anthropogenic disturbance—remains overlooked for the Arctic region. The research compared chemical and microbial properties of the natural Podzol soils and urban soils of Murmansk—the largest Arctic city. Particular attention was given to the profile distribution, which is almost completely ignored by most microbial studies. Soil microbiome was investigated by the quantitative indicators based on fluorescence microscopy (microbial biomass) and PCR real-time methods (amount of rRNA genes copies of archaea, bacteria, and fungi). The principal changes in urban soils’ properties compared to the natural references included a shift in pH and an increase in C and nutrients’ contents, especially remarkable for the subsoil. The numbers of rRNA genes copies of archaea, bacteria, and fungi in urban topsoils (106–1010, 109–1010, and 107–109, respectively) were lower than in Podzol; however, the opposite pattern was shown for the subsoil. Similarly, the total microbial biomass in urban topsoils (0.55–0.75 mg g−1) was lower compared to the 1.02 mg g−1 in Podzols, while urban subsoil microbial biomass was 2–2.5 times higher than in the natural conditions. Both for urban and natural soils and throughout the profiles, fungi were dominated by mycelium forms; however, the ratios of mycelium–spores were lower, and the amount of thin mycelium was higher in urban soils than in natural Podzols. Urbanization in the Arctic altered soil morphological and chemical properties and created a new niche for microbial development in urban subsoils; its contribution to biodiversity and nutrient cycling promises to become increasingly important under projected climate change.
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.
In connection with the 1150th anniversary of the Russian State (2012), recent results on soil and archaeological research in Velikii Novgorod, Staraya Ladoga, Rostov Velikii, Moscow are discussed. According to the study of soils, located under the cultural layer, proto-city stage of development of landscape in the ancient Russian cities is identifi ed. This stage is characterized by the spread of arable and grassland, replacing landscape of pre-anthropogenic period.
Tatarstan, Bugulminsky district, Linden-oak forest stands on typical, thin leached and carbonate chernozems. The dendrochronological site was established on the slope of the southern exposure, not far from the village of Petrovka. The hilly territory is dissected by a dense river and gully (the depth of the erosional incision is up to 120 m). Due to the microclimatic features, forest stands may be affected by frosts in June and August.
<p>Soils and sediments serve as complementary sources of detailed information on paleofires in various ecosystems. Despite the abundance of charcoal material entrapped in soils they remain relatively less studied pyrogenic archives in comparison to the sedimentary paleofire records (e.g. lacustrine and peat deposits), and that is especially the case for the most territory of Russia. We report here on the numerous soil archives of the Holocene forest fires at the Kola Peninsula (66.347&#176;N, 37.948&#176;E) and the north of Arkhangelsk region (64.747&#176;N, 43.387&#176;E) in Russia. Series of buried Podzols (up to ten successive profiles) separated by the distinct charcoal layers were revealed in specific geomorphological traps like the thermokarst depressions inherited from the early stages of moraine sediments formation (Kola Peninsula), as well as in active and paleokarst sinkholes in carbonate and sulfate rocks (Arkhangelsk region). The maximum temporal depth of archives was estimated as 10261&#177;40 cal yr BP for the key site in Arkhangelsk region, with up to 12 major pyrogenic events recorded at the local scale. Soil formation at the inter-pyrogenic stages maintained a uniform direction for at least 10 thousand years and profiles of Podzols were regularly replicated at all the key sites. We employ here a combination of soil morphological hierarchical analysis, study of geomorphological processes leading to the burial of pyrogenic carbon, 14C dating of charcoal and TOC derived from the soil organic matter, carbon and nitrogen isotope ratio mass spectrometry and anthracomass concentrations analysis to extract a set of paleoenvironmental information from these soil archives. The study of complementary pyrogenic archives in the three-component system of the karst landscape (including bottom and slopes of the funnels, as well as the flat elevated areas between them) helped to mitigate overestimation or underestimation of the anthracomass concentration and allowed to acquire a detailed dataset on paleopyrogenic events at the local scale. This study is supported by the Russian Foundation for Basic Research, Project No. 19-29-05238.</p>
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