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Research in Antarctica is of great importance for understanding the Earth's climate system and the processes that drive it. This study evaluated the spatial distribution of glacial sediment properties on the Bellingshausen Dome or Collins Ice Cap (King George Island, Antarctica). The particle-size distribution, pH H2O, total organic carbon (TOC), mobile forms of ammonium nitrogen (N–NH4), potassium (K2O), and phosphorus (P2O5) were measured and then spatially modelled using regression kriging (RK) and ordinary kriging (OK) approaches. The terrain attributes (elevation, aspect, slope) derived from a digital elevation model with 10-m spatial resolution and distance from a coast were used as explanatory variables. Multiple linear regression models were fitted to describe the relationships between the covariates and properties. The performance of the models was evaluated by the mean absolute error (MAE), root mean square error (RMSE), coefficient of determination (R2), and Nash–Sutcliffe efficiency coefficient (NSE) indices. Overall, model performance statistics showed that RK models performed better than OK and the spatial patterns of some properties were closely related to the character of the glacier topography. Thus, the application of the RK method in combination with auxiliary environmental covariates improved the accuracy of spatial prediction. [ABSTRACT FROM AUTHOR]

In the extraordinary weather conditions of the austral summer of 2023, fossil mosses thawed out from under the Bellingshausen Ice Dome, King George Island, Southern Shetland Archipelago of maritime Antarctica. At the end of the austral summer, we directly measured greenhouse gas fluxes (CH 4 and CO 2) from the surface of fossil mosses. We showed that fossil mosses were strong emitters of CH 4 and weak emitters of CO 2. The real-time measured CH 4 emissions reached 0.173 μmol m−2 s−1, which is comparable to CH 4 efflux in water bodies or wet tundra in the Arctic. [Display omitted] • Fossil mosses appear from the retreated Antarctic glacier. • Glacier ice in the upper parts of the Bellingshausen Ice Dome emits CH 4 and CO 2. • Fossil mosses thawed out from the retreated Antarctic glacier are the source of CH 4 and CO 2. [ABSTRACT FROM AUTHOR]

Enormous deglaciation in the polar and mountainous regions of the Earth is associated not only with large-scale climatic changes but also with the global transfer of black carbon (BC) microparticles, which accumulate on the surface of glaciers and lead to changes in albedo and the rate of degradation of ice. BC is the product of an incomplete combustion of fossil fuels, volcanic eruptions, and wildfires. The accumulation of organogenic microparticles leads to the formation of cryoconites, which are dust made of a combination of small rock particles and the result of anthropogenic activities (fossil fuel combustion) that play a special role in deglaciation. Here, we describe the content of trace metals and nutrients in accumulation of the BC from glaciers of Fildes Peninsula, King George Island, Western Antarctica. The analysis of trace metals concentrations showed that most of the studied elements (Cr, Pb, Zn, Ni) have a volcanic origin; at the same time, Cd and Cu have been accumulated as a result of anthropogenic activity. The content of nutrients in BC are most similar with Technosols, which forms near the scientific station at King George Island. The particles of BC can be translocated into organisms, which could pose a significant risk for living organisms and humans. [ABSTRACT FROM AUTHOR]

Research into sediment provenance identification in Antarctica is emerging as a relevant field of study, providing a unique insight into understanding geomorphological processes in extreme climatic environments. This study focusses on the mechanisms of sediment redistribution in the catchment of the Korabelny Stream, located at the western end of the Bellingshausen Ice Dome on King George Island (Shetland Islands). The catchment area of the stream covers 2.83 km2, with 1.17 km2 under the glacier. Two main sediment sources have been identified: a) the glacierized part, extending along the glacier edge and represented by a complex of moraine deposits lacking protective vegetation cover, along with part of the catchment under the glacier; b) the periglacial part, occupying territory with permafrost and a thin loose cover unevenly protected by early successional vegetation. We combine a tracer-based fingerprinting technique, sediment delivery estimates based on sediment flow connectivity index and geomorphological mapping to quantify the sources contribution to sediment yield. The proportional contribution of the glacierized part was 60–66 % of the total sediment yield based on two independent methods, suggesting the reliability of the results. It is noteworthy that sediment transport from the glacierized part exceeds that from the periglacial part. However, a significant portion of the sediment is redeposited in temporary reservoirs formed along the glacier edge and Lake Mesyats, located in the central part of the Korabelny Stream catchment. The main factor determining sediment yield in the catchment is the water reserves in snow at the beginning of the ablation season. In years when water reserves in snow significantly exceed long-term average values, such as observed in the austral summer of 2014–2015 when study was conducted, sediment yield was low. This is attributed to the faster melting of ice on the glacier compared to snow, due to differences in albedo. • First time, assessed sediment sources in small Maritime Antarctica catchment. • Two independent methods used to determine proglacial and periglacial contributions. • Proglacial part contributes significantly more to sediment runoff. • The higher snow water reserves at ablation start the lower proglacial sediment runoff. [ABSTRACT FROM AUTHOR]

In ice-free surfaces of King George Island (South Shetland Islands, Maritime Antarctica) themain formations along topographic chronosequences consist of weathered volcanic rockoutcrops, marine platforms, deposits of glacial materials such as moraines, andpresent day beaches. In relation with recent glacier retreat processes of sedimentredistribution in unstable paraglacial environments are highly active in the area. Togetherwith soil particles the mobilization of associated soil organic carbon (SOC) can befurther enhanced under conditions of climate change by melting snow and ice. InFebruary 2015 we conducted a selective sampling of reference sites on marineplatforms and moraines to be compared with surface sediments recently deposited inlakes on the platforms and in the proglacial environment of the Bellingshausen IceDome. During a 15 days field campaign funded by IAEA INT5153 project wecollected soil and sediment profiles and lake surface sediments to assess if there weredifferences between old marine platforms and contemporary moraines in their FRNs andSOC signatures, as both proxies have been found to be effective tracers of recentglacier retreat in other polar environments. The reference samples on the platformswere characterized by relatively slightly higher contents of sand (> 50%) thansilt fraction and low clay contents (< 5%) accompanied by SOC contents rangingbetween 1 and 3.5 % and FRNs values of 3.5 Bq kg−1for 137Cs and of 8 Bq kg−1for210Pbex. In contrast, on moraines the dominant grain size was silt (> 70 %), theSOC contents were below 0.5% and FRNs were much lower than in platforms soilswith activities of 137Cs below the detection limit and of 210Pbex less than 5 Bqkg−1. The surface sediments accumulated in the proglacial lakes were enrichedin sand (> 80 %) while in the platform lake they were mainly silt (> 70 %) andclay fractions reached up to 12 %. The sediments of the platform lake had highSOC contents (6.3 %) but the proglacial lakes had negligible values (< 0.1%).FRNs were not detected at the proglacial Upper Lake where the source materials aremoraine and fresh glacier materials. However, the low FRNs activities found at theLower Lake are because its headwaters also comprise soils developed on marineplatforms. Our results regarding contents of FRNs and SOC in the source areas and thesediments accumulated in the lakes, reflect a clear link on the provenance of sediments.The differences of grain size in lake sediments might suggest a relatively moreenergetic runoff in the proglacial lakes related to melting snow and ice directlyfrom glacier in comparison with that on platforms. These results are consistentwith a highly dynamic environment and in which soil and sediment particles areredistributed along the sediment cascade system in ice-free areas of Maritime Antarctica. [ABSTRACT FROM AUTHOR]