Aleksei Vladimirovich Lupachev

The Svalbard Archipelago is a territory with unique landscape, geological, and biological diversity facing the risk of degradation resulting from air tempe

A significant part of the soil cover in the permafrost zone develops under the influence of cryogenic slope processes. Thermal denudation and thermal erosion leading to irreversible destruction of background soil profiles and the underlying frozen layers of soil–cryogenic complex and the development of specific synlithogenic soils (stratozems) are the processes that most crucially influence the soil morphology on relatively steep slopes and in the areas of thermocirques and thermoterraces in permafrost ecosystems. Structures, properties, and formation of these soils, as well as the areas occupied by them, are poorly studied. The soil-forming rock here is the mixed organomineral substrate recently processed by soil formation and currently entering the floor of thermocirques or thermoterraces via slumping and further lateral redistribution. The basic scheme of the formation and development of thermodenudation–accumulative stratozems is suggested on the basis of the field data in northeastern Yakutia and central Yamal Peninsula and comprises four main stages. Characteristic of each stage is a certain combination of the properties of soil-forming substrate and the composition of plant communities. The stages can either sequentially follow one another or cyclically repeat with the reactivation of thermodenudation processes. The specific features in the formation, accumulation, and transformation of soil-forming material suggest a new subtype of thermodenudation–accumulative stratozem to be distinguished in the further version of the Russian soil classification. The studied ecosystems of thermocirques and thermoterraces are of considerable interest for further research as biodiversity foci, areas of potential new formation of permafrost, paleoarchives, and possible carbon sequesters.

The degradation of modern and ancient permafrost-affected soils and organic-rich sediments and the release of relict soil organic matter from the frozen state are critical for understanding the global carbon cycle in a changing climate. The molecular structure of humic acids isolated from modern Cryosols and paleosoils from the Ice Complex deposits in the Batagay megaslump area was investigated. The elemental composition analysis was performed using a CHN analyzer, and molecular composition analysis was determined by CP/MAS ¹³C-NMR spectroscopy. Analysis of the molecular structure of humic acids showed that MIS 5e paleosoils are characterized by a relatively high content of aliphatic structural fragments (C,H-AL—29–36%) and a low content of aromatic structural fragments (AR/AL—0.49–0.43), which reveals low humification rates in this time period. The composition of humic acids from MIS 7 paleosoils shows a relatively high content of aromatic structural fragments compared to modern soils (AR/AL—0.47) and MIS 5e deposits (AR/AL—0.67–0.54), indicating a longer humification process in heterogenic conditions (warm and cold periods). The results indicate that the molecular structure of humic acids is a dynamic parameter of the environment that reflects the local conditions of pedogenesis and organic matter formation. Permafrost thawing leads to the release of organic matter (including matter that is relatively weakly resistant to biodegradation where aliphatic structural fragments dominate the composition of humic acids) that may strengthen the emission of climate-active gases into the atmosphere and boost climate change.

The paleopedology of the world’s largest retrogressive thaw slump, Batagay, is understudied. Micromorphological and geochemical analysis reveal the properties of th host sediments and major pedogenic features. Epigenetic soil profiles of Marine Oxygen Isotope Stage (MIS) 7 (or older) and 5e are clearly distinguished and well developed due to favorable bioclimatic conditions for pedogenesis, probably similar to modern ones. The oldest unit contains a paleosol similar to a Histic Reductaquic Cryosol, indicating a peat-covered, boggy environment. The MIS 5e unit contains organic-rich Histic Spodic Cryosol with well-developed structure, formed during the interglacial optimum, which was relatively warm and presumably resembled modern bioclimatic conditions. MIS 4–3 deposits contains soil-like bodies enriched in coarse organogenic material resembling incipient Histic Reductaquic Cryosols. Interglacial/interstadial units contain micromorphological evidence of aggregate and pore formation, Fe-oxide and organic matter redistribution and clay accumulation. Stadial deposits show weakly expressed soil structure with uneven aggregates, cryogenic disintegration of plant detritus and rare evidence of accumulation of humic substances. Major elemental ratios indicate intensification of biochemical weathering in paleosols and soil-like bodies. Pedogenically reworked material of stadial sedimentary units with sporadic and incipient soil-like bodies provide a significant source for paleoenvironmental reconstruction of harsh Late Pleistocene environments.

Spitsbergen is the territory with unique landscape, geological and biological diversity under threat of degradation as a consequence of air temperature dynamics and permafrost area and thickness decrease. Additionally, nowadays in Spitsbergen the mining activity continues (coal, metal ores, hydrocarbons) and the quantity of tourists rises yearly. These reasons unavoidably lead to ecosystem transformation processes. In 2024 field studies of soils and natural waters at Western Spitsbergen cryogenic landscapes took places around Green-Fjord (Barentsburg) and Colesbay (Polar station). 19 soil profiles were described and classified as 8 types. Soil were described according to classification and diagnostics of Russian soils. Soil peats studies were carried out by the landscape-geochemical (catenar) principle. In soil cover structure of the elevated geomorphological levels – I and II marine terraces (including those covered by deluvial shields), – gleyic cryozems and humified petrozems dominate. Soil surfaces on these levels are complicated by nano-polygonal cryogenic microrelief. Soil diversity of lower geomorphological levels – river floodplains and low (periodically flooding) accumulative sea coasts, – is presented by pelozems, petrozems, and sulfide solonchaks, developing in conditions of shallow dense rocky layer depth. Major part of studied natural waters is characterized by moderate oxidation-reduction potential around 100-250 mV, acidity rate vary within 6.5-9.5. Mineral-peaty gleezems developing in the lowlands with the periodical flooding by sea waters are characterized by the highest acidity rates and compose negative oxidation-reduction potential (down to -3 mV) and high mineralization (between 3-5 g L-1). Soils of these landscapes are most perspective from the point of lateral matter migration in catenas of the Spitsbergen maritime cryogenic landscapes for the reason that contrast lateral geochemical barriers are able to form here.

One of the most important problems of cryopedology is the interaction of pedogenic processes with the processes that form the structure of the uppermost layers of the near‐surface permafrost. The thickness, structure, spatial variability, and other features are responsible for the reaction of the soil‐permafrost system to the bioclimatic fluctuations as well as the contemporary anthropogenic pressure. Together the soil profile and the upper layers of permafrost form the natural body of the “soil–cryogenic complex,” which is the result of simultaneous late Pleistocene–Holocene soil and permafrost coevolution. Pedogenic and cryogenic processes together form organic‐accumulative horizons above the permafrost table that have often been described in the profiles of Cryosols in different regions of Arctic. The multiannual dynamics of summer thawing depth determine the involvement of the material of these shielding horizons into the zone of active modern pedogenesis or its exclusion from it in case of their frozen state. Soil surface microrelief, complexity of the vegetation, and spatial differences of thermal properties of the suprapermafrost soil horizons and the transient layer of permafrost are responsible for the complicated pattern of permafrost table microrelief. Thus, the long‐term study of cryogenic soils that are developed on the close underlying permafrost provides improved understanding of the natural‐historical body—soil‐cryogenic complex.

Soils of the Arctic sea coasts are one of the least studied due to the complex logistical accessibility of the region, as well as the severe climatic conditions. The genesis of these soils is determined by several factors of soil formation simultaneously—cryogenesis, the influence of river alluvial processes, as well as the tidal influence of the sea. The paper presents data on the morphological structure of soils formed on the seacoast of the East-Siberian Sea (Kolyma Lowland, North Yakutia). Under the influence of cryogenesis and sea water tidal input, marsh soils are formed, with a relatively high level of salinity and the development of gleyization. Autochthonous and allochthonous soil organic matter play a leading role in marsh soil formation here, including the possible accumulation and biochemical transformation of incoming pollutants (e.g., hydrocarbons). The main objective of the study was to evaluate the soil organic matter genesis and alteration under the influence of tidal processes in coastal permafrost-affected soils as well as to obtain the previously unknown characteristics of the structural and elemental composition of different fractions of organic matter. The elemental composition and ¹³C NMR spectroscopy of humic acids were analyzed. It was revealed that humic acids extracted from the studied marsh soils accumulate up to 50% C and 4% N. Active processes of dehydrogenation are noted in HAs molecules, which indicates a relatively low degree of aliphatic structure development. According to ¹³C NMR spectroscopy, it was revealed that up to 45% of aromatic structural fragments accumulate in marsh soils, indicating a relatively high degree of organic matter stabilization and resistance to biodegradation.

The analysis of about 200 samples taken from 42 permafrost-affected soil profiles was carried out on four key sites in different regions of cryolithozone (West Siberia, Central, North, and North-East Yakutia) characterized by different active layer depths and soil lithology. The aim of the study was to determine the influence of different processes of cryogenic mass-exchange on the redistribution and accumulation of major pollutants such as petroleum products, acid-soluble forms of trace elements, polycyclic hydrocarbons, and technogenic radionuclides transferred via atmospheric transport or after the local anthropogenic impact in different soil horizons of Cryosols and in the upper layers of permafrost. Samples were analyzed using modern precise techniques (direct γ-spectrometric measurements with Ge(Li) and NaI(Tl) detectors; fluorometric method; reversed-phase high-performance liquid chromatography; spectrofluorimetric detection; atomic absorption spectrometry with flame atomization). The study has shown that processes (cryoturbations, frost heaving, gelifluction along with fluvial processes) that strongly affect Cryosols’ profile structure can also lead to the active migration and accumulation of local and global pollutants in the middle and lowermost suprapermafrost soil horizons. The accumulation of some pollutants in suprapermafrost horizons of cryogenic soils and in the upper layers of permafrost (in particular, petroleum products and mobile forms of trace elements) can be associated with a combination of factors, such as the relatively light particle size distribution, relatively weak manifestation of cryoturbation processes, and low thickness of the active layer (about 40–60 cm). The integral calculation of the geoaccumulation index values has shown that all of the groups of human-affected soil horizons are moderately to extremely polluted by petroleum hydrocarbons (and at a relatively lower level by trace elements) and the maximum pollution stands for the suprapermafrost horizons as well as in cryoturbated or buried fragments of organogenic matter in some cases. The maxima of the heavy PAH content in permafrost-affected soils can be confined to horizons enriched with anthropogenic inclusions and artifacts (for example, construction slag, coal) and to individual horizons of soils buried as a result of both cryogenic and alluvial processes. The specific activity of the technogenic radionuclide cesium in cryogenic soils revealed its association mainly with the surface organogenic and organomineral horizons of the studied profiles and rarely observed in the cryoturbated fragments of these horizons in the middle and suprapermafrost layers of soil profiles. The necessity of the complex analytical assessment of the permafrost-affected soils has been revealed especially in case of studying of the ecological state of the anthropogenically affected Cryosols.