D. A. Kaverin

High‐resolution mapping of ecosystem carbon storage and potential effects of permafrost thaw in periglacial terrain, European Russian Arctic

This study describes detailed partitioning of phytomass carbon (C) and soil organic carbon (SOC) for four study areas in discontinuous permafrost terrain, Northeast European Russia. The mean aboveg ...

Properties of soils and soil-like bodies in the Vorkuta area

The specific features of the formation of soils and soil-like bodies on technogenic substrates in Vorkuta—a polar city specializing in coal mining—are characterized. According to the new Russian soil classification system, these soils are classified as urbanozems (urban soils) and constructozems (soil-like bodies constructed by humans); the latter are subdivided into recreazems (soil-like bodies of recreation zones) and replantozems (soil-like bodies of reclaimed urban areas with planted vegetation). They are characterized by the increased content of heavy metals and by some alkalization of the upper soil horizons in comparison with the natural background soils. The benz(a)pyrene content in most of the soil samples exceeds the maximum permissible concentration (MPC). The maximum levels of the soil contamination with benz(a)pyrene reach 80 MPCs. According to the total contamination index calculated relative to the background concentrations of the major contaminants, the upper horizons of the investigated soils and soil-like bodies are qualified as ecologically hazardous and extremely hazardous bodies.

Water-soluble organic acids in cryomorphic peat soils of the southeastern Bol’shezemel’skaya tundra

The composition of the water extracts, the pH, and the weight concentrations of the total organic carbon and low-molecular-weight organic acids in seasonally thawed and perennially frozen horizons of cryomorphic peat soils have been determined. The quantitative analysis of the acids converted to trimethylsilyl derivatives has been performed by gas chromatography and chromato-mass spectroscopy. Hydroxypropanoic, propanoic, and hydroxyethanoic acids are the prevailing acids (30–50, 10–20, and 10% of the total acids, respectively). Malic, glyceric, hexadionic, trihydroxybutanoic, ribonic, and other acids have also been detected. It has been shown that the differences in the genesis of the peat deposits significantly affect the composition and content of water-soluble organic compounds in soils on the soil-profile and landscape levels.

Morphology and properties of the soils of permafrost peatlands in the southeast of the Bol’shezemel’skaya tundra

The morphology and properties of the soils of permafrost peatlands in the southeast of the Bol’shezemel’skaya tundra are characterized. The soils developing in the areas of barren peat circles differ from oligotrophic permafrost-affected peat soils (Cryic Histosols) of vegetated peat mounds in a number of morphological and physicochemical parameters. The soils of barren circles are characterized by the wellstructured surface horizons, relatively low exchangeable acidity, and higher rates of decomposition and humification of organic matter. It is shown that the development of barren peat circles on tops of peat mounds is favored by the activation of erosional and cryogenic processes in the topsoil. The role of winter wind erosion in the destruction of the upper peat and litter horizons is demonstrated. A comparative analysis of the temperature regime of soils of vegetated peat mounds and barren peat circles is presented. The soil–geocryological complex of peat mounds is a system consisting of three major layers: seasonally thawing layer–upper permafrost–underlying permafrost. The upper permafrost horizons of peat mounds at the depth of 50–90 cm are morphologically similar to the underlying permafrost. However, these layers differ in their physicochemical properties, especially in the composition and properties of their organic matter.

Soil carbon pools in tundra and taiga ecosystems of northeastern Europe

The mean pools of soil carbon were determined for the first time for twelve soil groups (according to the World Reference Base for Soil Resources, 2006) on four test plots with the use of the high-resolution (Landsat and QuickBird) satellite imagery, original field data on more than 200 soil profiles, and literature data included in the soil database. Three test plots belonged to the ecotone between tundra and forest-tundra zones, and the fourth plot characterized the middle taiga zone. Spatial distribution patterns of soil carbon in different soil subgroups and genetic horizons were characterized for the areas with the mosaic soil and vegetation covers. The mean soil carbon content for the first three test plots in permafrost area was estimated at 39.5 kg C/m2, including 28.7 kg C/m2 in the upper soil meter. The mean soil carbon pool of the taiga plot reached 16.7 kg C/m2 (0–100 cm).

Tundra landscape heterogeneity, not interannual variability, controls the decadal regional carbon balance in the Western Russian Arctic

Across the Arctic, the net ecosystem carbon (C) balance of tundra ecosystems is highly uncertain due to substantial temporal variability of C fluxes and to landscape heterogeneity. We modeled both carbon dioxide (CO2 ) and methane (CH4 ) fluxes for the dominant land cover types in a ~100-km2 sub-Arctic tundra region in northeast European Russia for the period of 2006-2015 using process-based biogeochemical models. Modeled net annual CO2 fluxes ranged from -300xa0gxa0Cxa0m-2 xa0year-1 [net uptake] in a willow fen to 3xa0gxa0Cxa0m-2 xa0year-1 [net source] in dry lichen tundra. Modeled annual CH4 emissions ranged from -0.2 to 22.3xa0gxa0Cxa0m-2 xa0year-1 at a peat plateau site and a willow fen site, respectively. Interannual variability over the decade was relatively small (20%-25%) in comparison with variability among the land cover types (150%). Using high-resolution land cover classification, the region was a net sink of atmospheric CO2 across most land cover types but a net source of CH4 to the atmosphere due to high emissions from permafrost-free fens. Using a lower resolution for land cover classification resulted in a 20%-65% underestimation of regional CH4 flux relative to high-resolution classification and smaller (10%) overestimation of regional CO2 uptake due to the underestimation of wetland area by 60%. The relative fraction of uplands versus wetlands was key to determining the net regional C balance at this and other Arctic tundra sites because wetlands were hot spots for C cycling in Arctic tundra ecosystems.

Dynamics of peat plateau near the southern boundary of the East European permafrost zone

Detailed study of a peat plateau near the southern boundary of the East European permafrost zone has been performed. The botanical and palynological compositions of the peat to the depth of 10 m, its radiocarbon dates (the AMS method), and its physical and chemical characteristics have been determined. The accumulation of peat in this area began about 8300 years ago at the end of the Boreal period. In the middle of the Atlantic period, the rate of peat accumulation reached 1.44 mm/yr. During the warming phase in the Middle Subboreal period, the peat plateau was subjected to active thermal erosion; part of the peat was eroded. The processes of thermal erosion are also active at present and destroy the edges of peat mounds. At the same time, the gradual accumulation of peat on the plateau continues. An increase in the degree of peat mineralization is expected upon the establishment of aerobic conditions against the background degradation of the permafrost. Peat plateaus and large peat mounds have been the sinks of atmospheric carbon for a larger part of their history. In this context, we do not expect their significant negative influence on the climate in the future.

Markers of Soil Organic Matter Transformation in Permafrost Peat Mounds of Northeastern Europe

For the paleoreconstruction of permafrost peat mounds and the identification of plant communities participating in the formation of peat, the contents of n-alkanes (C20–C33) have been determined, and relative changes in the stable isotope compositions of carbon and nitrogen and the C/N ratio have been analysed. Several indices (CPIalkanes, Paq, Pwax) have been calculated to assess the degree of decomposition of the peats studied and the contributions of different plant species to their formation. It has been found that shortand long-chain n-alkanes are concentrated in high-moor peat, while medium-chain alkanes are typical for transitional peat. Integrated analysis of the studied markers has shown that the botanical and material composition of peat, anaerobic conditions of bog formation, and permafrost play an important role in the preservation of organic carbon in permafrost peat mounds. Alternation of plant associations is the main reason for changes in n-alkane concentrations, C/N ratios, and δ13C values.

Polycyclic aromatic hydrocarbons in cryogenic peat plateaus of northeastern Europe

The qualitative and quantitative composition of 14 polycyclic aromatic hydrocarbons (PAHs) in peat plateaus at the southern boundary of the permafrost zone in northeastern Europe, where degradation of permafrost occurs because of climate warming, has been studied by high-performance liquid chromatography in gradient mode. PAH concentrations vary from 150 to 3700 ng/g with their average content of about 1500 ± 1000 ng/g. The variation of data is primarily due to the large contribution of heavy PAHs.