Ice-free areas occupy 5 m in bedrock sites in the Antarctic Peninsula. The deepest and most variable ALTs (ca. 40 to >500 cm) were found in the Antarctic Peninsula, whereas the maximum ALT generally did not exceed 90 cm in Victoria Land and East Antarctica. Notably, found that the mean annual near-surface temperature follows the latitudinal gradient of-0.9 degrees C/deg. (R2 = 0.9) and the active layer thickness 3.7 cm/deg. (R2 = 0.64). The continuous permafrost occurs in the vast majority of the ice-free areas in Antarctica. The modelling of temperature on the top of the permafrost indicates also the permafrost presence in South Orkneys and South Georgia. The only areas where deep boreholes and geophysical surveys indicates discontinuous or sporadic permafrost are South Shet-lands and Western Antarctic Peninsula.

The landscapes in the discontinuous permafrost area of Western Siberia are unique objects for assessing the direct and indirect impact of permafrost on greenhouse gas fluxes. The aim of this study was to identify the influence of permafrost on the CO2 emission at the landscape and local levels. The CO2 emission from the soil surface with the removed vegetation cover was measured by the closed chamber method, with simultaneous measurements of topsoil temperature and moisture and thawing depth in forest, palsa, and bog ecosystems in August 2022. The CO2 emissions from the soils of the forest ecosystems averaged 485 mg CO2 m(-2) h(-1) and was 3-3.5 times higher than those from the peat soils of the palsa mound and adjacent bog (on average, 150 mg CO2 m(-2) h(-1)). The high CO2 emission in the forest was due to the mild soil temperature regime, high root biomass, and good water-air permeability of soils in the absence of permafrost. A considerable warming of bog soils, and the redistribution of CO2 between the elevated palsa and the bog depression with water flows above the permafrost table, equalized the values of CO2 emissions from the palsa and bog soils. Soil moisture was a significant factor of the spatial variability in the CO2 emission at all levels. The temperature affected the CO2 emission only at the sites with a shallow thawing depth.

The influence of the moisture content on the CO2 emission from peat soils of palsa mires in the discontinuous permafrost area was studied in the north of Western Siberia (Nadym region). The CO2 flux was measured in Histic Cryosols of permafrost peatlands (palsas) and Fibric Histosols of surrounding bog using the closed chamber method for four years at the peak of the growing season (August). Despite a significant difference in the soil moisture (34.8 +/- 13.2 and 56.2 +/- 2.1% on average), no significant difference in the CO2 emission from these ecosystems was found in any of the observation years; the rates of emission averaged 199.1 +/- 90.1 and 182.1 +/- 85.1 mg CO2 m(-2) x h(-1), respectively. Experimental wetting or drying (with a twofold difference in the moisture content) of peat soils at the two sites via their transplantation to a different position showed no significant effect on the CO2 emission even three years after the beginning of the experiment. The absence of significant differences in the CO2 flux between the two different ecosystems was explained by the presence of permafrost and the influence of many multidirectional factors mitigating changes in the CO2 production by soils. An increased CO2 emission from the peat soils of bogs was possible due to the additional contribution of the methanotrophic barrier and the lateral runoff of dissolved CO2 over the permafrost table from the palsa toward the surrounding bog. The absence of response of the CO2 emission to a significant change in the soil moisture content may be indicative of a wide optimum of this characteristic for the microbiological activity of peat soils in the studied region. The obtained data suggest that, while studying CO2 fluxes in cryogenic soils of hydromorphic landscapes, it is necessary to take into account not only biogenic sources, but also other factors, often of a physical nature, affecting the balance of CO2 fluxes and CO2 emission from soils.

The soils of Arctic regions are of great interest due to their high sensitivity to climate change. Kvartsittsletta coast in the vicinity of the Baranowski Research Station of the University of Wroclaw constitutes a sequence of differently aged sea terraces covered with different fractions of beach material. It is a parent material for several developing soil types. Despite the low intensity of the modern soil-forming processes, the soil cover is characterized by high diversity. Soil properties are formed mainly by geological and geomorphological factors, which are superimposed by the influence of climate and living organisms. The degree of development of soil is usually an indicator of its relative age. This article highlights the dominant influence of lithology and microrelief over other soilforming factors, including the duration for which the parent material was exposed to external factors. The soils on the highest (oldest) terrace steps of the Kvartsittsletta rarely showed deep signs of soil-forming processes other than cryoturbations. On the youngest terraces, deep-reaching effects of soil processes associated with a relatively warm climate, including the occurrence of cambic horizons, were observed. Their presence in Arctic regions carries important environmental information and may be relevant to studies of climate change.

Understanding the influence of soil-forming factors and processes in ornithogenic soils is important to predict impacts of climate change on Antarctic ecosystems. Herein, we analyzed the soil-landscape interplays and development of ornithogenic soils at Harmony Point (HP), Nelson Island. We collected, described, and classified 24 soil profiles, combined with vegetation and landforms descriptions. Geoprocessing techniques were employed for mapping. Soil physical, chemical, geochemical, and mineralogical analyses were applied. Patterned ground, Ornithogenic/ Typic Gelorthent, and moss carpets were the dominant landform, soil and vegetation classes, respectively. Soils from rocky outcrops were more structured, acidic, with higher organic carbon, organometallic complexes, and secondary phosphate minerals, due to former bird influence. Soils from cryoplanated platforms presented higher water pH, base saturation, clay content, and secondary silicate minerals. Soils from marine terraces presented high exchangeable bases, phosphorous, and amorphous phosphate minerals. Soil chemical weathering is enhanced by ornithogenesis and widespread in HP. Besides ornithogenesis, organic matter accumulation, cryoturbation, and cryoclastic processes are also important to pedogenesis of ornithogenic soils. The soils of the cryoplanated platforms exhibited a gradient of pedogenetic development corresponding to increasing biota influence and distance from glacier. In contrast, soils of rocky outcrops were more developed even close to the glacier, due to ornithogenesis.

Current climatic models and projections forecast further increases in air temperature in the Arctic in the future. Therefore, new knowledge concerning the variability of air and soil temperature as well as its dependence on environmental factors is urgently needed to better understand and forecast the consequences of climate warming in the Arctic region. The main aims of this study were: 1) to determine the variability of the topsoil temperature for the one-year time scale under different types of tundra vegetation in the Adventdalen Valley in the central part of Spitsbergen (Svalbard, High Arctic), and 2) to determine the impact of different types of tundra vegetation on the topsoil temperature on a microscale in this area. The obtained results indicate that wet sites covered with marsh and moss tundra vegetation exhibited a significantly higher mean annual topsoil temperature (-0.7 degrees C and -1.2 degrees C, respectively) than sites featuring bare ground (-1.5 degrees C), Arctic meadow (-2.1 degrees C), and heath tundra vegetation (-2.4 degrees C). The mean topsoil temperature during the summer season was the lowest at sites covered with Arctic meadow and heath tundra vegetation (4.9 degrees C and 5.7 degrees C, respectively), and highest at the site with bare ground (6.9 degrees C). The topsoil temperature was highly and significantly correlated with the air temperature (correlation coefficient between 0.86 and 0.92); however, the correlation was clearly higher during the autumn and summer seasons (correlation coefficient between 0.76 and 0.89; p < 0.001) in comparison with the winter season (correlation coefficient between 0.67 and 0.89; p < 0.001) and especially the spring season (correlation coefficient between 0.62 and 0.71; p < 0.001). Freeze-thaw events were substantially less frequent in the topsoil (up to 16 events) compared to the atmosphere (at least 80 events), and their number was clearly different even at the microscale (from 4 to 16 events). Local microtopography, snow cover, tundra vegetation type, soil properties, and soil moisture were responsible for variances in topsoil temperature and number of freeze-thaw events. The obtained results indicated that the topsoil temperature is significantly different, even at the microscale, and further research is needed in other Arctic terrestrial environments to better understand and forecast the consequences of climate warming in this region of the world.

The annual balance of biogenic greenhouse gases (GHGs; carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)) in the atmosphere is well studied. However, the contributions of specific natural land sources and sinks remain unclear, and the effect of different human land use activities is understudied. A simple way to do this is to evaluate GHG soil emissions. For CO2, it usually comprises 60-75% of gross respiration in natural terrestrial ecosystems, while local human impact can increase this share to almost 100%. Permafrost-affected soils occupying 15% of the land surface mostly in the Eurasia and North America contain approximately 25% of the total terrestrial carbon. The biogenic GHG soil emissions from permafrost are 5% of the global total, which makes these soils extremely important in the warming world. Measurements of CO2, methane, and nitrous oxide, from eighteen locations in the Arctic and Siberian permafrost, across tundra, steppe, and north taiga domains of Russia and Svalbard, were conducted from August to September during 2014-2017 in 37 biotopes representing natural conditions and different types of human impact. We demonstrate that land use caused significant alteration in soil emission and net fluxes of GHGs compared to natural rates, regardless of the type and duration of human impact and the ecosystem type. The cumulative effect of land use factors very likely supported an additional net-source of CO2 into the atmosphere because of residual microbial respiration in soil after the destruction of vegetation and primary production under anthropogenic influence. Local drainage effects were more significant for methane emission. In general, land use factors enforced soil emission and net-sources of CO2 and N2O and weakened methane sources. Despite the extended heat supply, high aridity caused significantly lower emissions of methane and nitrous oxide in ultra-continental Siberian permafrost soils. However, these climatic features support higher soil CO2 emission rates, in spite of dryness, owing to the larger phytomass storage, presence of tree canopies, thicker active layer, and greater expressed soil fissuring. Furthermore, the Birch effect was much less expressed in ultra-continental permafrost soils than in permafrost-free European soils. Models and field observations demonstrated that the areal human footprint on soil CO2 fluxes could be comparable to the effect of climate change within a similar timeframe. Settlements and industrial areas in the tundra function as year-round net CO2 sources, mostly owing to the lack of vegetation cover. As a result, they could compensate for the natural C-balance on significantly larger areas of surrounding tundra. (C) 2020 Elsevier B.V. All rights reserved.

Under the influence of perennial dynamics of soil thawing depth, the upper layer of permafrost periodically thaws and becomes a part of the soil profile in the permafrost zone. In this case, the horizon, which is either frozen or thawed and has a thickness of several tens of centimeters, displays an elevated ice content (moisture). This horizon between the lower boundary of the active layer and the permafrost is named a protective layer or a transient permafrost layer and functions as a buffer that hinders thawing of the ice complex with its high ice content. The study of moisture using soil-regime methods and budget calculations showed that the protective layer of permafrost in sandy and loamy soils (at the depth of 1.5-5 m) contains from 25 to 60 mm (on average, 30 mm) of water in each 10-cm-thick layer of frozen soils under different types of forests in Central Yakutia. An increase in the seasonal thawing depth of permafrost-affected soils under conditions of global climate warming and anthropogenic impacts (forest fires, destruction of forest cover, etc.) causes degradation of the protective layer. The purpose of this article is to show the effect of increasing seasonal thawing depth of permafrost-affected soils on changes in the water content and water budget in permafrost areas because of the release of moisture stored in the protective layer in the context of global climate change. It was found that with an increase in the seasonal thawing depth, the protective layer should release a significant amount of water preserved in permafrost, which may change the water budget of permafrost territories. As calculations show, with an increase in the soil seasonal thawing depth by 20-30 cm on the interfluve areas, the volume of water entering the basins of nearby thermokarst depressions (alases) and rivers from frozen soils may reach 60000-90000 m(3)/km(2). The obtained results can be used in modeling and predicting the dynamics of permafrost environments under the global climate change.