Cryogenic soils in the Vilyuy River Valley (Yakutia)

The object of this research is the cryogenic soils of the territory located in Central Yakutia, in the middle reach of Vilyuy River nearby Makhatta Tukulan with middle-taiga larch woods landscapes. In July 2021, on the right and left banks of the Vilyuy River, twelve soil sections have been formed, which relate to turf-podzols and turf-sub-units of the illovial-ferruginous, sod and alluvial sod, psammozems and stratozems according to to classification and diagnostics of Russian soils (2004). On the slope of the river valley was also formed the soil catena that included elementary geochemical landscapes of river terraces tops and slopes surfaces, as well as middle and high floodplains on the slopes of thermofusional funnels. Soil sections were also formed in flooded beam bottom and well-drained ravine bottom, on sub-horizontal Makhatta Tukulan surface, bottoms and  slopes of thermo-suffosional funnels. The study involves 46 soil samples for measuring the acidity level (pH), electric conductivity (EC), and concentration of total disolved solids (TDS). The explored soils are characterized with pH ranging from 2.81 to 7.78, with most common fluctuations of 5.5–5.6. TDS rates were often within the limit of 10 mg L-1 and rarely exceeded that threshold, however, there were single valyes higher than 50 mg L-1. Thus, the highest EC values (over 100 μS/cm) were measured in surface and subsurface horizons with high organic matter content, whereas mostly mineral horizons had typical EС values within the limit of 20 μS/cm.

Cryogenic soils near the Yeletsky settlement, northeast of the Komi Republic

The subject of this research is the soils and soil-geochemical catenae in the area of Yeletsky settlement, located in the northeast of the Komi Republic. Catena were deposited on the mound covered with moss-shrub tundra transect from the interfluve of Usa and Yelets Rivers to a lacustrine depression, complicated by arching permafrost mounds. Within the district of research, the authors laid five soil incisions (EL20-P1, EL20-P2, EL20-P3, EL20-P4 and EL20-P5) that formed a soil-geochemical catena along the slope. Complex land cover found at the periphery. The explored soils were formed on silty loams with permafrost horizon at a depth of 0.5-0.7 m and belong to Cryosols, Turbic Cryosols and Histic Gleysols. Cryosols in the upper part of catena show specific cryogenic granular structure due to lack of soil moisture content. The soils on the slope and in the depression are more saturated with water; therefore, structureless Turbic Cryosols and Histic Gleysols are formed. In the soil horizons, the values of pH and electrical conductivity were measured, the content of organic carbon and soil texture were studied. An increase in soil acidity on organogenic zones by 4.3 - 5.7 was noticed; in underlying horizons the pH values reach 6.9.

Cryogenic soils in the area of Batagaika crater in Northern Yakutia

The subject of this research is the soil and catena soils in the area of Batagaika crater located in Verkhoyansk District of Northern Yakutia. Soils are usually represented by Cryosols Gleyic and Podzols Entic, which are formed on eluvial and eluvial-deluvial deposits under larch forests. Exploration of soils was carried out in 2017, 2018 and 2019. On the slope to the Batagaika crater is the soil-geochemical catena, which included the ridge-top surface of the slope of Kirgilyah Mountain, the middle part of the slope, as well as levelled surfaces of Batagaika crater. Soil types are described in accordance with the classification of soils of Russia (2004) and the World Reference Base of Soil Resources (2014 WRB). The following conclusions were made: 1) The soil cover in the area Batagaika crater features various types of soils formed on the permafrost rocks, mainly Cryosols Gleyic, found in various landscape conditions, and Podzols Entic are also sporadically distributed in the area. On alluvial deposits in the valley of the Batagaika River may develop Podzols Haplic. Leptosols Lithic are confined to the elevation of the relief with bedrock located close to the surface; 2). The main processes typical for soils in the area of Batagaika crater are: cryogenic structuring, organic matter accumulation, coarse--humus accumulative processes, gleyification; 3) Nearby the horizon of permafrost rocks in the area of Batagaika crater is marked a local minimum of PH level in Podzols and Cryosols.

Monitoring of soil temperatur on permafrost in natural and anthropogenic disturbed conditions in the Tunkinskaya Depression

The territory of the study is the Tunkinsky intermountain basin (South-Western Baikal region, Republic of Buryatia) which belongs to the area of sporadic (island) distribution of permafrost. Soil temperature controls many biotic and abiotic processes in it, so it is important to monitor the freezing and thawing regimes in peat and mineral soils. The object of the study is coarse-humic cryogenic soils on sandy lacustrine-alluvial sediments. The first site was represented by natural coarse-humic cryogenic soils under spruce forest, while the second site was organized on the area where in 1960s the forest had been destroyed and the soils were ploughed. At the end of XX century, the arable lands were abandoned, and now they are covered with steppe grasses (the long fallow). Both sites are located on the permafrost. The atmospheric-soil measuring complex was used to study the state of both the perennial and seasonal permafrost at these two sites. The soil temperatures were measured in automatic mode with a time interval of 1 hour from July 1, 2013 to June 30, 2017 along the soil profile from the surface down to a depth of 320 cm. Anthropogenic interference on one of the sites resulted in changes in vegetation cover, the soil moisture as well as the morphological structure and granulometric composition of the upper part of the soil layer. This caused changes in the temperature regime of the permafrost and its degradation with lowering of its upper limit. The soil on the long fallow is better warmed up and cools down faster than it takes place under the spruce forest. As a result of this, the maximum annual temperature on the surface here is higher by 10 °C, while at a depth of 320 cm – by 5 °C, and the minimum annual temperature on the surface is lower by 7 °C, while at a depth of 320 cm – by 1 °C. On the anthropogenically disturbed area, the warm period (at the soil temperature above 0 °C) on the surface is, on the average, by 22 days longer than on the natural lot. These differences are observed at all depths. As a result, the perennial permafrost is retained under the spruce forest below 130 cm throughout the year (soil temperature −0.2 ÷ −0.9 °C), while on the fallow the zero isotherm during seasonal thawing falls much deeper 320 cm, and the soil in the layer of 240–320 cm warms up to 2–5 °C.

Content of water-soluble carbohydrates as a quality indicator of cryogenic soils

The content of water-soluble organic matter in the soil is an important indicator of its quality and affects physical, chemical and biological properties of soil. This indicator is widely used for assessment of most zonal soils. However, in some cases, accumulation rates of water-soluble organic compounds in soil may significantly exceed the rate of their destruction. If so, it is more important to quantify not only the fraction of water-soluble organic matter as a whole but also to determine its composition. In this context, it is important to determine the content of the most labile and available for microorganisms compound – water-soluble carbohydrates. In this paper, the content of water-soluble carbohydrates and water-soluble organic matter in soils of Coastal Antarctica was estimated. Soils under three different plant communities were studied. We found that water-soluble organic matter of studied soils may contain up to 50% of carbohydrates. Hence, further research is needed to study other soils of Coastal Antarctica to determine their vulnerability to global climate change

Algae, cyanobacteria, and microscopic fungi complexes in the Rybachy Peninsula soils, Russia

The investigation of algal-mycological complexes in the Rybachy Peninsula soils was carried out. The different types of tundra soils (Al-Fe-humus podzols, podburs, dry-peaty, peats low moor, cryogenic, undeveloped soils) were researched. The soil samples were collected along the route from Bolshaya Volokovaya Bay, which is in the Barents Sea, to the west of the Cape Nemetskiy. The organic horizons of the tundra podzols and podburs on the Rybachy Peninsula are less acid in comparison with the continental tundra soils of the region. Number of microfungi in the Peninsula soils varied from 9 to 70 thousand colony-forming units per 1 g of soil (CFU/g). It was the least in the cryogenic soils. The fungal mycelium length was significant in all the soils with the exception of the undeveloped one – more than 1 thousand m in 1 g of soil. The biomass amounted to 1.7 mg/g of soil. The species diversity of the soil micromycetes complexes is represented by 12 species. The species Penicillium decumbens dominated by the abundance and frequency of occurrence in the podburs, dry-peaty soils, podzols and peats low moor soils. P. raistrickii and P. glabrum predominated in the undeveloped soils, while Mortierella stylospora prevailed in the cryogenic soils. 62 eukaryotic algae as well as 18 species of cyanobacteria were found in the soil samples from Peninsula. The cryogenic and undeveloped soils, as well as Al-Fe-humus podzols and podburs were characterized by low species diversity, predominantly of green algae of classes Chlorophyceae and Trebouxiophyceae. Cyanobacteria and diatoms were noted by their considerable diversity in the dry-peaty soils and peats low moor soils.