Recent years of increasing air temperature in the Arctic have led to a significant increase in the rate of retreat of permafrost coast, which has threatened livelihoods and infrastructure in these areas. The Kara Sea hosts more than 25% of the total Arctic coastline. However, little is known about how coastal erosion in the Kara Sea may have changed through time, and the climatic and environmental drivers remain unclear. Here we study coastal dynamics along a 4‐km stretch of permafrost and sea‐ice‐affected coastline in south‐west Baydaratskaya Bay of the Kara Sea, western Siberia, between 2005 and 2016, by using handheld differential GPS mapping and satellite imagery. We identified temporal and spatial variations in the retreat rates, ranging between 1.0 (+0.1/−0.6) and 1.9 (+0.7/−1.3) m/yr over the studied coastline during 2005–2016. We also made ground temperature measurements, subsurface resistivity measurements and estimates of wave energy flux of wind‐driven ocean waves, to investigate the dominant climatic factors influencing the observed retreat rates through time. We found that wind‐driven wave activity during sea‐ice‐free days influences the magnitude of coastal retreat in the study area, while recent temperature rise has contributed less to enhancing coastal retreat during the study period. This suggests that the amount of eroded sediment and the associated release of nutrient to the nearshore zone are controlled by the magnitude of wave activity, which may influence infrastructure along the permafrost coast and marine ecosystems in the proximal ocean.

Hydrochemical and geophysical data collected during a hydrological survey in September 2017, reveal patterns of small-scale hydrological connectivity in a small water track catchment in the north-European Arctic. The stable isotopic composition of water in different compartments was used as a tracer of hydrological processes and connectivity at the water track catchment scale. Elevated tundra patches underlain by sandy loams were disconnected from the stream and stored precipitation water from previous months in saturated soil horizons with low hydraulic conductivity. At the catchment surface and in the water track thalweg, some circular hollows, from 0.2 to 0.4 m in diameter, acted as evaporative basins with low deuterium excess (d-excess) values, from 2‰ to 4‰. Observed evaporative loss suggests that these hollows were disconnected from the surface and shallow subsurface runoff. Other hollows were connected to shallow subsurface runoff, yielding d-excess values between 12‰ and 14‰, close to summer precipitation. ‘Connected’ hollows yielded a 50% higher dissolved organic carbon (DOC) content, 17.5 ± 5.3 mg/L, than the ‘disconnected’ hollows, 11.8 ± 1.7 mg/L. Permafrost distribution across the landscape is continuous but highly variable. Open taliks exist under fens and hummocky depressions, as revealed by electric resistivity tomography surveys. Isotopic evidence supports upward subpermafrost groundwater migration through open taliks under water tracks and fens/bogs/depressions and its supply to streams via shallow subsurface compartment. Temporal variability of isotopic composition and DOC in water track and a major river system, the Vorkuta River, evidence the widespread occurrence of the described processes in the large river basin. Water tracks effectively drain the tundra terrain and maintain xeric vegetation over the elevated intertrack tundra patches.

Permian plant remains from the Vorkuta 1 location collected at the Earth Science Museum of the Moscow State University were characterized (at outcrop 38 at the left bank of the Vorkuta River within...

An increase in air temperature leads to a significant transformation of the relief and landscapes of the Arctic. The rate of permafrost degradation, posing a profound change in the Arctic landscape, depends on air temperature, vegetation cover, type of soils, surface and ground waters. The existing international circumpolar programs dedicated to monitoring the temperature state of permafrost TSP (Thermal State Permafrost) and active layer thickness CALM (Circumpolar Active Layer Monitoring) are not sufficient for a comprehensive characterization of geocryological conditions. Yet, no standardized protocol exists for permafrost monitoring and related processes. Here, we propose a novel multi-parameter monitoring protocol and implement it for two sites in the European part of the Russian Arctic: the Yary site along the coast of the Baydaratskaya Bay in the Kara Sea (68.9° N) within the continuous permafrost area and the Hanovey site in the Komi Republic (67.3° N) within the discontinuous permafrost area. The protocol includes drilling boreholes, determining the composition and properties (vegetation cover and soils), snow cover measurement, geophysical imaging, active layer estimation and continuous ground temperature measurements. Ground temperature measured in 2014–2020 revealed that amplitudes of surface temperature fluctuations had no significant differences between the Yary and Hanovey sites, while that the mean annual temperatures between the areas had a considerable difference of greater than 3.0 °C. The period of the presence of the active layer changed with the year (e.g., ranging between 135 and 174 days in the Yary site), showing longer when the air temperatures in summer and the preceding winter were higher. Electrical resistivity tomography (ERT) allowed determining the permafrost distribution and active layer thicknesses. Thermometry results were consistent with our geophysical data. Analyzing the composition and properties of frozen soils helped better interpret the data of geophysical and temperature measurements. By integrating the study of the soil properties, ground temperatures, and ERT, our work allowed us to fully characterize these sites, suggesting that it helps better understand the thermal state at any other research sites in the European north of Russia. Our suggested monitoring protocol enables calibrating and verifying the numerical and analytical models of the heat transfer through the earth’s surface.

Hillslope water tracks are landmark features of permafrost landscapes, yet their origin and future evolution are debated. Water track networks are believed to be fully developed fluvial networks constrained by permafrost. Hence one potential evolution scenario under future climate is rapid thermo-erosional development of water tracks. Permafrost tundra environment near Vorkuta, European Russian Arctic, N67°17’, E63°39’, is a model ecosystem for this scenario, developing under changing climate and permafrost degradation.Figure 1 Hydrographical network of the study region, 30 km south of Vorkuta, European Arctic RussiaField works at the study site were carried out in September 2017 and repeated in 2021. Local streams and groundwater, from both boreholes and soil pits, were sampled for dissolved organic carbon (DOC) and nitrogen (DON), major ions, stable water isotopes and trace elements. Electrical resistivity tomography (ERT) was used to study permafrost distribution.First-order water tracks are minor linear depressions, occupied by Betula nana and rarely expressed in local topography, hosting fast subsurface runoff. Initial stages of permafrost perturbation, these forms are major pathways of DOC export from permafrost slopes, with mean DOC content is 29 ± 2 mg/L. Channelized runoff appears farther downslope, at the slope bend. Increased input from supra-permafrost groundwater is traced by Ca2+ increase, and rapid decline in DON content, from 0.1-0.3 mg/L to zero. At toeslopes adjacent to the Vorkuta R., larger streams coexist with polygonal depressions dissecting otherwise flat riverine terrace. In streams, the DOC content decreases to 12 ± 1.5 mg/L, while in depressions, it raises to 38-39 mg/L. Terrain perturbation by water tracks provides initial slope drainage and promotes fast DOC export from slope soils and its potential microbial consumption.Permafrost is discontinuous, and open taliks are present under water tracks and polygonal depressions, as shown by ERT survey. Taliks allow upward groundwater movement and drainage to the fluvial network. Sub-permafrost groundwaters were sampled from two boreholes, draining two major regional aquifers, and their traces were found in both large streams and minor water bodies of the region.