In connection with the progressing climate change in the Arctic, it is extremely important to conduct systematic long-term monitoring in the high-latitude Arctic. An important place in the network of monitoring stations is occupied by the research Station «Cape Baranov» Ice base», located on Severnaya Zemlya (in the area of the Shokalsky Strait). The article presents the results of hydrochemical observations at the Ice base from December 02, 2018 to July 15, 2019. 35 hydrochemical stations were operated from the ice of the strait in the seawater layer of 0–110 m. A significant temporal variability of the characteristics in the upper layer (0–10 m) has been recorded. Four phases of variability of the hydrochemical parameters (HP) have been identified. In December (phase 1) the HP values indicate the presence of surface waters, the origin of which we associate with the transformed river waters (TRW) of the Ob and Yenisei, coming from the Kara Sea. From January to mid-April (phase 2) the highest salinity levels and homogeneous HP are observed due to intensive vertical mixing of waters in the autumn-winter period. At the end of April — May (phase 3) there is a slight desalination of the surface layer in the Shokalsky Strait, with HP pointing to the presence of TRW. From June to July, 15 (4th phase), there is a sharp decrease in the salinity, an increase in oxygen and pH, as well as a drop in the concentration of all the biogenic elements. Such HPs indicate both additional desalination from ice and snow melting and the beginning of phytoplankton bloom. An estimation has been carried out of the proportion of TRW and waters formed during sea ice melting. The average integral proportion of TRW in the water column is ~ 4 %, and for melt water this indicator is close to zero. The influence of ice formation on the hydrochemical characteristics of the surface layers is most noticeable in the 1st and 3rd phases. During the period of strong desalination of the surface waters (May —July), the TRW proportion can reach 10 % or more. From July, the contribution of the melting of sea ice is comparable to that of TRW.

Despite the great interest in the study of the chemical composition of the surface snow cover in Antarctica, the knowledge of the Enderby Land area remains extremely limited. In the Vecherny Oasis, where the construction of the Belarusian Antarctic Research Station has been carried out since 2015, the study of the chemical composition of the surface snow began in 2012 in preparation for the Comprehensive Environmental Evaluation. Its continuation is due to the need to assess the consequences of the construction and operation of the station in accordance with the requirements of the Antarctic Treaty Protocol on Environmental Protection.

Snow samples were taken from 2012 to 2019 during the seasonal Belarusian Antarctic expeditions. Sampling was carried out from the surface horizons, which characterize the annual snow fallout. Chemical analytical studies were performed using standard methods. A total of 144 samples of snow water were analyzed.

The aim of the study is to characterize the chemical composition of the surface snow of the Vecherny Oasis (and of the Thala Hills as a whole) to identify the areas of anthropogenic impact and trends in its change.

The data on the main ions content in the surface snow, the value of pH and electrical conductivity, as well as the variabilities of the main indicators are presented. It is shown that the snow water of the Vecherny Oasis is very low-mineralized, with the sum of ions in the range of 1,04–57,3 mg/l (average — 7,4 mg/l), the values of electrical conductivity — 2,7–85,1 µS/cm (10,7 µS/cm). The snow water in most cases is characterized as slightly acidic. The chemical composition of the snow water and its mineralization is determined mainly by the content of chlorides and sodium ions. The high variability of the indicators of snow water hydrochemical composition within the areas of former and current human activities, as well as the increased content of sulfate ions, is considered to be indicative of anthropogenic impact.

An ice ridge is a special case of granular medium with a wide range of fractions. It represents a chaotic piling-up of blocks occurring under the action of gravity in the sail and due to the Archimedes force in the keel. An important characteristic of the internal structure of ice ridges is their porosity. Scientists from different countries have been dealing with this problem. First-year ice ridges are taken into consideration in Arctic and subarctic marine structural design, and the calculation of ice loads includes ridge porosity and strength, as well as other parameters. The aim of the present work is to discern the regularities of porosity distribution in the unconsolidated part of the keel with depth. Ice ridge porosity is identified by means of processing thermodrilling records. In this paper, porosity is interpreted as a step function equal to zero if there is ice at the point (x, y, z), and to one if there is no ice at the point (x, y, z). The author applies the model of compaction of the bulk medium under the influence of gravity, and, particularly for the keel, due to the Archimedes force. A zero depth corresponds to the lower surface of the keel, so each individual porosity distribution of the unconsolidated part of the keel at the drilling point must be shifted down until the maximum keel draft depth is reached in the region under consideration. After alignment, the step curves are averaged. The distance is measured up, starting from the depth of the maximum keel draft. The curve of the averaged porosity can be divided into segments reflecting the characteristic features of the distribution. According to the graphs, average porosity decreases exponentially. Ice ridges of several geographical regions are considered, and in each region is divided into groups by years of research. On the whole, 17 depth-wise distributions of the average porosity are obtained for seven regions. Each distribution was approximated according to the model, taking into account the average density of water and ice in the region. For each distribution, the values of compactibility and porosity at the zero depth, i. e. at the lower edge of the keel, were obtained; the second value only has mathematical sense. It is more convenient to consider the maximum value of the average porosity, which is taken as the initial porosity. With a probability of 90 %, the initial porosity is within the range of 0.450 ± 0.125. As the distance from the keel edge increases, the porosity curves converge to a fairly narrow range of values. At a distance of 12–14 m, this range is 0.07…0.12. The second parameter characterizing the porosity distribution in the unconsolidated part of the keel is compactibility. The steepness of the exponent approximating the average porosity curve depends on it, too. Compactibility is most affected by the strength of the ridged ice as well as the ice thickness. From the literature on the physical properties of ice it is known that as the temperature of ice increases, its strength decreases, and its plasticity increases. Thus, it can be concluded that compactibility is determined by the ice crystal structure as well the ice average temperature at the time of ridging — the warmer the ice, the higher the compactibility of the ice blocks in the keel.

The article discusses whether the model of loose granular medium is applicable to the analysis of physical processes in the ridge keel. It is argued that the model is not valid for dealing with a number of problems such as the evolution of the ridge keel. It is also suggested that the decrease in keel porosity in time is primarily caused by thermodynamic factors.

The polythermal Aldegondabreen is one of the most widely studied glaciers of the Nordenskjöld Land (Svalbard). However, the structure of its internal drainage network remains poorly understood. In order to determine the position and hydro-chemical characteristics of the surface and internal drainage channels of the glacier complex studies were carried out including ground penetrating radar (GPR) measurements and hydrological surveys. The GPR profiling performed in 2018–2020 identified four channels of internal drainage network, two of which are found along the northern side of the glacier in the area of cold ice and are subglacial. The other two are located in the area of temperate ice along the southern side of the glacier and are englacial, stretching at the cold-temperate surface. At the outlet grotto, the subglacial waters have a bicarbonate-calcium composition and low salinity (electrical conductivity 30–40 μS/cm), inherited from the surface meltwater streams that enter the moulins in the upper part of the glacier. No noticeable increase in mineralization occurs during the movement of the flow along the glacier bed. The englacial channels’ waters at the outlet grotto have the same bicarbonate-calcium composition but a higher salinity (electrical conductivity 100 μS/cm), which we attribute to the filtration through the rocks of the riegel near the Aldegonda terminus, or, alternatively, to the influx of the groundwater at the same spot. Measuring the hydrochemistry of the Aldegonda river tributaries both on the glacier’s surface, at the grottos and on the moraine in the valley made it possible to identify the zone of enrichment of the main volume of the low-mineralization glacial meltwater of bicarbonate-calcium composition by the high-mineralization (electrical conductivity up to 760 μS/cm) groundwater of sulphate-calcium composition coming from the springs on the riegel in front of the glacier’s terminus in the central part of the Aldegonda Valley. Presumably, the springs are fed by the deep filtration of melted glacial waters along the Aldegonda subglacial talik.

To assess the magnetic activity, various indices (numerical characteristics of the planetary and local disturbance of the Earth’s magnetic field) are used. Most widely used for various purposes are the planetary Kp-index and the local K-index, proposed by Bartels. The K-index characterizes the Earth’s magnetic field disturbance in a 3-hour interval (0–3, 3–6, etc. UTC) and is defined in a range from 0 to 9 by the amplitude of the horizontal component deviation from the quiet level. K = 0 indicates the absence of geomagnetic activity, and K = 9 corresponds to a strong geomagnetic storm. The lower limit of K = 9 is the amplitude of magnetic field horizontal component variation above which the K-index is assigned the maximum value of 9. This limit is selected individually for each station, depending on its geomagnetic latitude. The latest scales of the K-indices boundaries for the Russian Arctic stations were determined in the middle of the last century and have not been corrected since then. The significant discrepancy between the K-indices calculated using these scales and the planetary Kp-index shows that they had to be refined, and in some cases, they must be re-selected. The local indices lower boundaries (K = 9) for stations in the Arctic Russian sector were determined. K-indices lower boundaries were received for the strong magnetic storm according to the IAGA procedure. It is shown that for different magnetic field horizontal component variation values K-indices for different observation points practically coincide with the Kp-index. The lower value K = 9 dependence on the observation point geomagnetic latitude is presented. This relation can be used to obtain the lower boundary of K = 9 for any magnetic station. A table with local K-index scales for Russian Arctic magnetic stations has been compiled.

The water ecosystems of the Arctic region are most vulnerable to modern climatic changes since the global biogeochemical processes mostly occur on the territories of the permafrost zone. Aquatic ecosystems show a high degree of sensitivity to climatic changes; both in these and in other ecosystems, the biogeochemical processes are intense. These water bodies are located in the permafrost zone, which is vulnerable to temperature increases. The paper gives new insights into the fundamental research question of how fast the organic matter of thawing permafrost can be converted to greenhouse gases emitted into the atmosphere (CO₂, CH₄). We aimed to assess the microbial response and the associated release of CO₂ and CH₄ from the Arctic lakes in response to temperature increase. We investigated lakes located in the Lena River delta in the Samoylov Island, Russia, at 72° 22′ N, 126° 28′ E. Bottom sediments from three thermokarst and three oxbow lakes were anaerobically incubated in the laboratory at two temperature regimes (at 4 °C and at 25 °C). All the oxbow lakes have shown similar dynamics of methane emission both at low temperatures (4 °C) and at high temperatures (25 °C). The shift of carbon isotopic composition in methane has indicated that methane is emitted in all the oxbow lakes with a similar composition of microbial communities. In the thermokarst lakes, the emission of methane in the sediments proceeded differently at low and at high temperatures. These results have indicated a dissimilar composition of methanogenic / methanotrophic populations in the thermokarst and oxbow lakes. In both cases, the temperature increase caused a growth in methane emission from the sediments of the Arctic lakes. The thermokarst lakes will make a greater contribution to methane emission than the oxbow lakes. Thus, it is believed that the emission of methane from the thermokarst lakes will rise from 6 to 46 times due to ambient temperature increase. Methane emission from the oxbow lakes will grow from 1.8 to 7.6 times. Our results suggest that with the global warming both thermokarst and oxbow lakes could become a great source of methane emission into the atmosphere.