Kolyma Lowland Research Articles

Polychemical pollution of surface waters and permafrost-affected soils in Central and North Yakutia and in North-West Siberia

The concentration of main organic and inorganic pollutants (heavy metals, polyaromatic hydrocarbons, radionuclides) in surface waters and in water-soil solutions was analysed on three keysites within the permafrost zone: Tazovsky Peninsula (North-West Siberia), Kolyma Lowland (North Yakutia) and adjacent to Yakutsk (Central Yakutia). In the majority of sampling points that are not directly impacted by human activity, the pollutants accumulate in the uppermost organogenic and organo-mineral horizons of natural soils. At the human-affected keysites the major pollutants may accumulate not only in the superficial horizons of the disturbed soils due to the surface runoff but also in the central parts of the profile, in the material buried by cryogenic, solifluction or fluvial processes and in some cases – in the suprapermafrost horizons and in the upper layer of permafrost transported via suprapermafrost water runoff.

Essential mineral nutrients of the high-latitude steppe vegetation and the herbivores of mammoth fauna

The geographical distribution of mammoth fauna was based not only on the optimal climatic range and suitable grass-rich ecosystems, but also on stable and sufficient pool of mineral nutrition in the seasonal cycle. Widespread high-latitude steppes or tundra-steppes were the landscape basis for the Beringia herbivores. Now patches of the relict steppes persist only on steep slopes with southern aspects. Numerous palynological, carpological, isotopic, and DNA data from the Pleistocene plant remains show that relict steppes are similar to mammoth steppe in many ways. A six-year study of ash and plant mineral contents of two types of steppes and grass-herb ecosystems at the Kolyma Lowland, Arctic Siberia has been carried out. The comparative content of essential mineral nutrients (Ca, P, K, Mg, Mn, Na, Fe, S) and the important element ratios in different vegetation types were analyzed. Results indicated that the ash and Ca, Mg contents are higher for the steppe vegetation. High Ca : P ratio and optimal K : (Ca+Mg) or tetanic ratio in steppe plants are within the recommended range for large herbivores. Mineral nutrient contents are higher for herbs vs grasses for steppe taxa. Generally accumulation of essential mineral elements of the Siberian Arctic steppes is comparable to those in the Asian temperate steppes. The research results can be used for better understanding of such an important issues of paleoecology of large grazers as availability, sufficiency and equilibration of mineral nutrient elements of grass-rich ecosystems – one of the significant factors of megafauna existence.

Occurrence of two Krsticiella species in Beringia suggests this genus is a Cenozoic relict

The genus Krsticiella Levkov was previously known only from the basins of Lakes Ohrid and Prespa, and from Lake Baikal. Examination of type materials of diatoms originally described by Niels Foged from the North Slope of Alaska revealed that Navicula lenis Foged and N. meadeensis Foged belong to Krsticiella, to which they are formally transferred here. One of these species, K. lenis, is also found in thermokarst tundra lakes of the Kolyma Lowland in Northeastern Siberia. Several illustrations in previously published floras of Pliocene and Pleistocene diatoms of Eurasia indicate wider past distributions of Krsticiella species. The current restriction of this genus to non-glaciated regions of the Arctic and large ancient lakes in temperate zone indicates that it is a Cenozoic relict.

New and Rare Psammothidium Species (Bacillariophyta, Achnanthidiaceae) from Northeastern Siberia

Three rare Psammothidium species were found in recently surveyed lakes of Northeastern Siberia, Russia. One of these species found in lakes of the Kolyma Lowland, is new for science and is formally described here as Psammothidium onufrii sp. nov. It is morphologically similar to the brackish–water species Achnanthes punctulata, but it lacks a central area on rapheless valve and possesses a large central area on the raphe valve. Psammothidium onufrii is characteristic for tundra thermokarst lakes with moderate mineral content. Psammothidium sacculum previously reported from a few subarctic and arctic locations was found in several lakes of the Kolyma Lowland and of the Magadan District. The frustule ultrastructure of this species is documented for the first time here. The third species, known as Achnanthes obliqua (W. Gregory) Hustedt and transferred here to Psammothidium, is a morphologically distinct and relatively rare diatom occasionally reported from northern regions of Eurasia and Western North America. In Northeastern Siberia it was found in sediments of relatively large shallow lakes with low to moderate mineral content. Detailed morphological characterization of the three Psammothidium species will facilitate their detection in environmental surveys and their use in paleoenvironmental reconstructions.

Cohnella kolymensis sp. nov., a novel bacillus isolated from Siberian permafrost.

A facultative anaerobic, rod-shaped, endospore-forming and non-motile bacterium was isolated from permafrost sediment cores in the Kolyma lowland, Siberia, Russia. The permafrost isolate clustered with members of the genus Cohnella on the basis of 16S rRNA gene sequence analysis and showed the highest sequence similarity to Cohnella saccharovorans CJ22T (96.3 %), followed by Cohnella cellulosilytica FCN3-3T (96.0 %) and Cohnella panacarvi KCTC 13060T (96.0 %). The chemotaxonomic characteristics (quinone system, cellular fatty acids and polar lipid profile) of strain 20.16T were consistent with members of the genus Cohnella. The peptidoglycan diaminoacids included meso-diaminopimelic acid and a small amount of ll-diaminopimelic acid. The molar ratio and composition of major amino acids (meso-diaminopimelic acid, alanine, and glutamic acid) correspond to the peptydoglycan type A1γ. The estimated genome size of strain 20.16T is 4.34 Mb (lower than those in other Cohnella species). The genome has a G+C content of 50.5 mol% and encodes 4843 predicted genes, of these 4740 are protein-coding ones. The results of chemotaxonomic, physiological and biochemical characterization allowed clear differentiation of strain 20.16T from the closest Cohnella species. Based on data provided, a new species Cohnella kolymensis sp. nov. is proposed, with 20.16T (=VKM B-2846T=DSM 104983T) as the type strain.

Holocene thermokarst and pingo development in the Kolyma Lowland (NE Siberia)

AbstractGround ice and sedimentary records of a pingo exposure reveal insights into Holocene permafrost, landscape and climate dynamics. Early to mid‐Holocene thermokarst lake deposits contain rich floral and faunal paleoassemblages, which indicate lake shrinkage and decreasing summer temperatures (chironomid‐based TJuly) from 10.5 to 3.5 cal kyr BP with the warmest period between 10.5 and 8 cal kyr BP. Talik refreezing and pingo growth started about 3.5 cal kyr BP after disappearance of the lake. The isotopic composition of the pingo ice (δ18O − 17.1 ± 0.6‰, δD −144.5 ± 3.4‰, slope 5.85, deuterium excess −7.7± 1.5‰) point to the initial stage of closed‐system freezing captured in the record. A differing isotopic composition within the massive ice body was found (δ18O − 21.3 ± 1.4‰, δD −165 ± 11.5‰, slope 8.13, deuterium excess 4.9± 3.2‰), probably related to the infill of dilation cracks by surface water with quasi‐meteoric signature. Currently inactive syngenetic ice wedges formed in the thermokarst basin after lake drainage. The pingo preserves traces of permafrost response to climate variations in terms of ground‐ice degradation (thermokarst) during the early and mid‐Holocene, and aggradation (wedge‐ice and pingo‐ice growth) during the late Holocene.

Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions

Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here, we present a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM, ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (−0.69%), Western Alaska (−2.82%), and Kolyma Lowland (−0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e., upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.

Consistent patterns of the size distribution of thermokarst lakes

The purpose of this work is to study empirically the patterns of size distribution of thermokarst lakes within lacustrine thermokarst plains. Investigations were performed at 16 sites with various geomorphological, geocryological, and physical geographical conditions (Kolyma Lowland, Western Siberia, Lena River valley, Alaska). The accordance of the distribution area with the lognormal and exponential laws, and the accordance of the average diameter distribution with the normal law have been tested; the tested laws of distribution resulted from previous investigations. The results have shown that the lognormal law of distribution of thermokarst lake areas is valid for the vast majority of cases, and the other types of distribution are inconsistent with empirical data. This evidence favors the development pattern for lacustrine thermokarst plains, when thermokarst processes started simultaneously and the rate of lake growth was proportional to the density of heat loss through the side surface.

The Influence of Cryogenic Mass Exchange on the Composition and Stabilization Rate of Soil Organic Matter in Cryosols of the Kolyma Lowland (North Yakutia, Russia)

Soil organic matter (SOM) was studied in different types of organo-mineral material (from surface horizons and partially isolated materials—cryoturbated or buried horizons) sampled from the surface horizons, the central parts of the Cryosol profiles, and the lower active layer. We found that the humic acids (HAs) of the cryoturbated and buried horizons showed an increased degree of oxidation and an increment of alkylaromatic and protonized aromatic fraction content. In contrast, the HAs of the surface horizons showed increased values of alkylic carbon components. The content of free radicals was essentially higher in the surface layers than in the cryoturbated and buried layers. While the bulk soil organic matter composition (total organic carbon, total nitrogen, and aromatic/aliphatic values) was not essentially different between surface, cryoturbated, and buried horizons, there were essential differences in elemental composition, carbon species, and free radical content. This indicates that the degree of humification in cryoturbated and buried organo-mineral material is higher than in surface horizons and that partial isolation results in relative stabilization of such material in soil profiles.

Post-pirogenic Transformation of Soils and Soil Carbon Stocks in Sub-Tundra Woodlands of Kolyma Lowland: a Cascading Effect and Feedbacks

It is found that the high diversity of the upland ecosystems in sub-tundra woodlands of the Lower Kolyma River is caused by frequent fi res. The type of successions, the power of the active layer, the degree of gleization of the soil profi le, the intensity of cryogenic processes of mass transfer, the size of carbon stocks, the classificatory status of soils depends on the strength and duration of the fi re. Post-pirogenic transformation of vegetation, soils and tree species evolve according to the cascade principle, when every previous change generates and enhances subsequent change, i.e. feedback mechanisms are working actively. In the first years after the fire the expected reduction in carbon stocks of organic horizons (–3.4 kilogram of carbon per square meter) is observed, however, in the later stages the post-pirogenic effect of surplus (relative to initial) accumulation of organic matter at mineral surfaces (+1.7 kilogram of carbon per square meter) occurs. Such consequences of fi res as the lowering-lifting of roof permafrost and the intensification of cryogenic mass transfer in conditions of active organic matter accumulation of upper horizons can lead to post-pirogenic increase of the carbon pool of mineral depth (+2.5 kilogram of carbon per square meter). The time required to recover after a severe fire the initial stocks of soil carbon is 60–200 years.

Palaeoenvironmental Interpretation of Yedoma Silt (Ice Complex) Deposition as Cold‐Climate Loess, Duvanny Yar, Northeast Siberia

Uncertainty about the geological processes that deposited syngenetically frozen ice-rich silt (yedoma) across hundreds of thousands of square kilometres in central and northern Siberia fundamentally limits our understanding of the Pleistocene geology and palaeoecology of western Beringia, the sedimentary processes that led to sequestration of hundreds of Pg of carbon within permafrost and whether yedoma provides a globally significant record of ice-age atmospheric conditions or just regional floodplain activity. Here, we test the hypotheses of aeolian versus waterlain deposition of yedoma silt, elucidate the palaeoenvironmental conditions during deposition and develop a conceptual model of silt deposition to clarify understanding of yedoma formation in northern circumpolar regions during the Late Pleistocene. This is based on a field study in 2009 of the Russian stratotype of the ‘Yedoma Suite’, at Duvanny Yar, in the lower Kolyma River, northern Yakutia, supplemented by observations that we have collected there and at other sites in the Kolyma Lowland since the 1970s. We reconstruct a cold-climate loess region in northern Siberia that forms part of a vast Late Pleistocene permafrost zone extending from northwest Europe across northern Asia to northwest North America, and that was characterised by intense aeolian activity.

The amoeboid protists of cryogenic soils in the Kolyma Lowland

The taxonomic diversity of amoeboid protists was examined in three types of tundra soils in the Kolyma Lowland, namely, a podzolized podbur, a cryozem, and a gleyzem. In total, 27 naked amoeba genera were identified in the analyzed samples. It was shown that the individual soil types house different communities of naked amoebas. The distribution of naked amoebas in the cryozem had two peaks: one in the upper organic horizon and the other at the boundary with the permafrost.

Cryogenesis as a factor of methane distribution in layers of permafrost

The gas seeps in Kolyma lowland are associated with methane inclusions in permafrost. These inclusions are formed by methane squeezed by epigenetic freezing of methane saturated deposits. This is proved by the biological genesis of the methane, by the isotopic data and the lower radiocarbon age of the methane from the gas seep in comparison with the radiocarbon age of the host deposits. The experimental data and observations of methane distribution in permafrost indicate that the methane distribution in the stratum of frozen deposits is a result of methane migration during cryolithogenesis. The regularities of methane distribution in the deposits and formation of methane inclusions may change the idea of the character and volumes of emission of greenhouse gases into the atmosphere upon degradation of permafrost.

Reply to Oxelman et al.: On the taxonomic status of the plants regenerated from 30,000-y-old fruit tissue buried in Siberian permafrost

We are grateful to Oxelman et al. (1) for their interest in the problem of taxonomic identification of plants regenerated from the fruit tissues of Late Pleistocene age and plants grown from the seeds of extant species growing in the Kolyma Lowland (2). The authors’ arguments regarding the determination of plant species are rather convincing. Indeed, our regenerated plants, as well as extant examples, show a high degree of similarity with plants of the Silene linnaeana Czerepanov (Lychnis sibirica L.) group, especially concerning the shape of inflorescences and calyces. At the same time, contemporary examples of the Silene genus found in Kolyma Lowland in the area of excavated burrows were identified as Silene stenophylla according to Tolmachev et al. (3). Moreover, the number of styles in our regenerated plants, as well as in extant ones, was found to be preferentially three (rarely 4 to 5), and the number of teeth in the dehiscing capsule was twice as many as the number of styles, which was typical for S. stenophylla, whereas the S. linnaeana group was indicated to have five styles (4). The areas of distribution S. stenophylla and some species of the S. linnaeana group overlap in Kolyma Lowland (3), which is in accordance with the fact of simultaneous discovery of their seeds in fossil burrows (5).

Structure of an acidic polysaccharide isolated from Psychrobacter maritimus 3pS containing a bacillosamine derivative

An acidic polysaccharide was obtained from Psychrobacter maritimus 3pS isolated from a Siberian cryopeg sample (Kolyma lowland). The following structure of the tetrasaccharide repeating unit of the polysaccharide was established by sugar analysis along with 1H and 13C NMR spectroscopy:→2)-α-l-Rhap-(1→4)-α-d-GalpNAcA-(1→3)-α-d-QuipNAc4NHb-(1→3)-β-d-QuipNAc4NHb-(1→where d-GalNAcA indicates 2-acetamido-2-deoxy-d-galacturonic acid and d-QuiNAc4NHb indicates 2-acetamido-2,4,6-trideoxy-4-[(S)-3-hydroxybutanoyl]amino-d-glucose.

Grain‐size properties and organic‐carbon stock of Yedoma Ice Complex permafrost from the Kolyma lowland, northeastern Siberia

The organic carbon stock in permafrost is of increasing interest in environmental research, because during the late Quaternary a large pool of organic carbon accumulated in the sedimentary deposits of arctic permafrost. Because of its potential to degrade and release organic carbon, the organic‐matter inventory of Yedoma Ice Complex deposits is relevant to current concerns about the effects of global warming. In this context, it is essential to improve the understanding of preserved carbon quantities and characteristics. The paper aims to clarify the Yedoma Ice Complex origin, and to develop an approach for volumetric organic‐matter quantification. Therefore, we analyzed the grain size and the organic‐matter characteristics of the deposits exposed at the stratigraphic key site Duvanny Yar (lower Kolyma River, northeast Siberia). A distinct bimodal grain‐size distribution confirms a polygenetic origin of the frozen sediments from a floodplain environment. The total organic‐carbon content averages 1.5 ± 1.4 wt% while the volumetric organic‐carbon content averages 14 ± 8 kg/m3. However, large‐scale extrapolations for Yedoma Ice Complex deposits in general are not reasonable yet because of their rather unclear spatial distribution. We conclude that Yedoma Ice Complex formation at Duvanny Yar was dominated by water‐related (alluvial/fluvial/lacustrine) as well as aeolian processes. The total organic‐carbon content of the studied deposits is low if compared to other profiles, but it is still a significant pool.

Suprapermafrost organic-accumulative horizons in the tundra cryozems of northern Yakutia

Organic-accumulative horizons above the permafrost table have been described in the profiles of cryozems developing on interfluve surfaces in the tundra zone of northern Yakutia. The organic matter content in these suprapermafrost horizons is comparable with or even exceeds the organic matter content in the surface horizons. The dynamics of seasonal thawing specify the annual involvement of the material of these horizons into the zone of active pedogenesis or its exclusion from it in the case of their frozen state. The analysis of the morphology of cryozems of the Kolyma Lowland along a 1000-km-long sublatitudinal transect shows that the accumulation and migration of raw organic materials (predominantly, differently decomposed peat) above the permafrost table take place upon the particular combinations of local factors (the soil moistening, ice content, freezing-thawing conditions, nanotopography of the permafrost table, etc.) at the lower boundary of the active layer. The well-pronounced accumulation of the raw organic material in the suprapermafrost horizons can be reflected in the substantive characteristics of these horizons and should be taken into account in classification decisions.

Late-Pleistocene (MIS 3-2) palaeoenvironments as recorded by sediments, palaeosols, and ground-squirrel nests at Duvanny Yar, Kolyma lowland, northeast Siberia

A detailed study of the Duvanny Yar section in the Kolyma Lowland (Yakutia) provides the most extensive knowledge to date about late-Pleistocene soil formation processes and environments in the North–East Siberian Arctic. Late-Quaternary palaeoenvironmental changes were reconstructed using paleopedological data and a range of palaeoecological bio-indicators (palynomorphs, plant macrofossils and insects). The frozen sediments representing marine isotope stage 3 (MIS-3), which encompasses the Karginsky interstadial, include profiles of four palaeosols of different ages. The oldest palaeosol is early Karginskian, and three overlying soil horizons represent a late-Karginskian pedocomplex. Palaeopedological data indicate a change of from synlithogenic soil formation processes to epigenic ones during these intervals. The intervening periods of synlithogenic pedogenesis were accompanied by active accumulation of eolian deposits. The Earlier Karginskian period of pedogenesis occurred in the absence of eolian sedimentation and when summer conditions were warm. The wide spectrum of peaty and peaty-gley soils observed in the late-Karginskian deposits developed under conditions of progressive cooling. The structure and content of fossil rodent burrows dated to approximately 30 000 yr BP from frozen late-Pleistocene deposits at Duvanny Yar indicate an arid and severe climate, a depth of active layer of 60–80 cm, and a wide distribution of disturbed habitats with pioneer and steppe vegetation.

Growth of the fungus Geomyces pannorum under anaerobiosis

Fungi of the genus Geomyces are eurytopic organ� isms with a broad species distribution area. It is rea� sonable to study the adaptive capabilities of fungal cul� tures in members of the same microbial species exist� ing under drastically different environmental conditions. In our case, these are cryopegs of the Kolyma lowland and the soil of Central Russia. Cry� opegs are supercooled saturated salt solutions charac� terized by a constant temperature (from –10 to ⎯15°C) and total mineralization of 60–300 g/l [1, 2]. Thus, water remains unfrozen and is under anaerobic conditions (Eh from –56 to –240 mV) [3]. The meta� bolic status of mycelial fungi under deep anaerobiosis combined with the low temperature and high salinity of the environment remains unknown; it is, however, highly important to determine the mechanism respon� sible for the preservation of the viability of fungal organisms under such extreme conditions. The goal of the present work was investigation of the metabolic capabilities of two Geomyces pannorum strains, specifically, of their ability to grow and form the fermentation products in the absence of oxygen in the media with different redox potentials (Eh). The objects of research were the strain VKM FW�2241 iso� lated from cryopeg water in permafrost deposits of the Arctic [4] and the strain VKM F�3808 isolated from the hair of bank vole Cletrionomys glareolus (Tver oblast, Russia). The partial 18S rRNA gene sequences of both strains are deposited in GenBank under acces� sion numbers AY873966 and AY873968, respectively. The strains under study were grown on a modified Czapek medium [5]. In the experiments with different reducing agents, ammonium sulfate was added to the

Methanobacterium arcticum sp. nov., a methanogenic archaeon from Holocene Arctic permafrost

A mesophilic, non-motile, hydrogenotrophic, rod-shaped methanogen, designated M2(T), was isolated from Holocene permafrost sediments of the Kolyma lowland in the Russian Arctic. Cells were 3-6 μm long and 0.45-0.5 μm wide. Strain M2(T) grew on H(2)/CO(2) and formate. Optimum conditions for growth were 37°C, pH 6.8-7.2 and 0.1 M NaCl. The DNA G+C content was 38.1 mol%. On the basis of 16S rRNA gene sequence comparison with known methanogens, strain M2(T) was affiliated with the genus Methanobacterium and was most closely related to Methanobacterium veterum MK4(T) and Methanobacterium bryantii DSM 863(T) (both 99 % 16S rRNA gene sequence similarity). However, no significant DNA-DNA relatedness was observed between strain M2(T) and these type strains. We propose that strain M2(T) represents a novel species, with the name Methanobacterium arcticum sp. nov., with type strain M2(T) (=DSM 19844(T) =VKM B-2371(T)).