Based on the methodics we developed, an analysis of a new GLE event registered on November 11, 2025, has been carried out. This event is the first major event of Solar Cycle 25, which began in 2019. The four previous GLEs in 25th solar cycle were low amplitude, with increases not exceeding 10%. In GLE77, the increase exceeded 100% at several neutron monitors, for example, Mawson, Nain, and the South Pole NM stations. A number of stations exhibited temporal profiles with two peaks: Apatity, Oulu, and Mirny. Based on data from the global neutron monitor network, the inverse problem was solved, and a set of parameters of the solar cosmic ray spectrum was obtained over several hours from the onset of the event. The characteristic energy of the exponential spectrum corresponding to the first peak (10:30 UT) takes the value E0 = 0.74 GeV, which indicates a high spectral hardness at the beginning of the event. This is confirmed by recorded increases of 2-4% at low-latitude stations such as Mexico and Beijing. During the second peak (11:00 UT), the spectrum takes a power-law form with an index γ = -4.2. Later (by 12:00 UT), the spectrum becomes exponential again and remains so until the end of the considered period. Such strong differences in spectral shapes indicate different mechanisms of solar cosmic ray acceleration. The obtained pitch-angle distribution shows that initially the flux was strongly anisotropic, but after 2-3 hours it becomes significantly isotropic.
The growing anthropogenic emissions of Hg in the Southern Hemisphere necessitate studies on the spatiotemporal distributions of environmental Hg levels in Antarctica. According to current opinion, snow and ice intended for Hg analysis must be stored in acid-cleaned glass containers. However, the brittleness of such containers and hazards associated with their cleaning hinder their use in polar research expeditions. Herein, we examined the feasibility of replacing glass containers with lightweight sterilized polyethylene (PE) bags for accurate Hg quantification in Antarctic snow. Low Hg concentrations of 0.05 ± 0.01 ng L-1 were observed in acidic blank solutions stored in PE bags. The total Hg concentrations (determined without sample filtration) of the Antarctic snow stored in glass containers for 50 days did not significantly differ (p > 0.05) from those of snow stored in PE bags for the same time when the meltwater formed in these bags was treated with BrCl. In combination with dissolved Hg concentrations in snow samples stored in PE bags and subsequently thawed and filtered through glass filtration funnels, for which stability was confirmed for up to 115 days, atmospheric particulate-bound Hg concentrations can be evaluated. These results indicate that PE bags are viable alternatives to glass containers for storing snow.
Discovery of nursery habitats of the sea cucumber Cucumaria frondosa in Qikiqtait (Canadian Arctic) allows the first study of ontogenetic development in wild individuals. Here, podia count, dermal ossicle density, and body wall melanization were examined along with sexual changes across size classes. Age corresponding to major steps of the life cycle was estimated. Individuals developed a gonad at ∼5 mm in length (∼8–12 months old) and reached sexual maturity at ∼80 mm (∼4–5 y old), followed by a period of allometric gonad development until functional maturity was attained at ∼116 mm (∼6–7 y old). Juveniles were uniformly orange while subadults acquired the brown pigmentation after developing their first gonad tissues. The number of podia increased by ∼68-fold before first sexual maturity and thereafter doubled. The smallest juveniles displayed a dense layer of ossicles on the body wall; subsequently, the ossicles thinned out. This study provides the most detailed outline of sexual maturation in wild sea cucumbers, including a clearer picture of age-related phenotypic development, supporting local sustainable harvesting and management practices.
The Arctic region is undergoing environmental changes due to global warming, with an increasing discharge from glacial meltwater that is significantly affecting fjord ecosystems. This study investigates the hydrography, nutrient dynamics, and sedimentary characteristics of the Kongsfjorden–Krossfjorden system in Svalbard, based on water and surface sediment samples collected in June 2023. The fjords exhibited stratification near glacier fronts, contributed by meltwater runoff and solar insolation. The minimum salinity was recorded in eastern arm of Krossfjorden and at the glacier front of Kongsfjorden. Elevated turbidity in the water column was related to suspended particles, probably affecting light penetration and primary productivity. Surface waters showed nitrogen and silicate depletion, especially in Krossfjorden, possibly due to nutrient utilization after the spring bloom and the influence of nutrient-deficient meltwater runoff. Anomalously high nutrient concentrations in mid-Kongsfjorden bottom waters (nitrate: 40.01 μmol/L; silicate: 53.53 μmol/L; phosphate: 6.43 μmol/L; ammonia: 8.29 μmol/L) was observed during the present study. Sediment geochemistry revealed spatial variability in carbon and nutrient concentrations, with mid-fjord sites showing higher inorganic carbon, likely influenced by meltwater runoff. TOC/TN ratios indicated terrestrial organic matter input near the glacial end of fjords. Fine-grained sediments were dominant, suggesting deposition from suspended matter under low-energy conditions. Sedimentary phosphorus was mainly present in inorganic forms, with higher retention in deeper stations. These results indicate that ongoing meltwater input and temperature changes are altering nutrient cycling and the sedimentary environment and may also contribute to changes in ecosystem productivity and the resilience of polar marine environments.
Accurate prediction of borehole closure is critical for Antarctic drilling, but is highly sensitive to the stress exponent, n, in Glen's flow law. While n = 3 is widely assumed, the optimal value for modeling ice sheet deformation remains poorly constrained. This study employs a 2D axisymmetric model of ice creep flow, heat conduction, and elastic deformation to quantitatively examine the influence of Glen's stress exponent n on predicting borehole diameter change rates in Antarctic ice. Results demonstrate that a slight 0.05 increase in the stress exponent can nearly double the predicted borehole closure, highlighting its critical influence. By validating our model against Vostok 3G borehole data, we find that an exponent of n ≈ 2.60 provides a significantly better fit than the conventional n = 3. Specifically, parametric analysis of the dry-hole drilling limit reveals that the engineered stress exponent required to maintain a fixed safety closure threshold is not constant, decreasing from 2.93 to 2.77 as drilling depth increases from ∼300 m to ∼500 m under coupled thermal boundary conditions. This trajectory highlights the necessity of accounting for multidimensional thermal-viscoplastic coupling, explaining why conventional lower-dimensional models assuming a constant overestimate closure risks when environmental boundaries shift. These insights provide both a refined physical understanding of deep ice sheet rheology () and a robust predictive framework for optimizing safety boundaries in polar drilling operations.
We present results from simultaneous ground-based observations of very low frequency (VLF) auroral hiss and Global Navigation Satellite System (GNSS) phase scintillations at high latitudes. Eight events exhibiting concurrent occurrences of both phenomena during 2021-2023 were selected for a detailed spatio-temporal analysis. For each event, the illumination area of the auroral hiss was inferred from the wave arrival direction (backazimuth) and circular polarization index, and compared with the ionospheric projections of GNSS satellite pierce points at an altitude of 300 km for satellites exhibiting phase scintillations. In all events, the dominant hiss arrival direction pointed toward the same sector in which phase scintillations were observed. In events for which all-sky camera data were available, this spatial coincidence was further supported by the simultaneous presence of auroral arcs. Although the temporal relationship between hiss bursts and scintillations varied from case to case, the spatial correspondence suggests that both phenomena are influenced by a common high-latitude ionospheric environment. We propose that small-scale plasma density irregularities generated by auroral particle precipitation may simultaneously scatter magnetospherically generated VLF hiss into the ground transmission cone and diffract trans-ionospheric GNSS signals, producing phase scintillations. These results demonstrate a consistent spatial association between auroral hiss and GNSS phase scintillations, highlighting the role of ionospheric irregularities in linking wave propagation and radio signal disturbances in the polar ionosphere.
Sea ice impacts the energy budget of the ocean both by regulating heat exchange with the atmosphere and through modifying the ocean's freshwater budget by freezing, melting, and transporting freshwater in solid form. As such, sea ice acts as an important component of the climate system and plays a major role for dense-water formation at high latitudes. In the Greenland Sea, significant ice-edge retreat over the past century has been reported, impacting marine ecosystems as well as local dense-water formation and thus potentially the global overturning circulation. In this study, we provide an updated and robust analysis of the recent development of sea-ice extent in the Greenland Sea by using high-resolution Sentinel-1 SAR remote sensing data covering the period 2017 to 2024. After several years of small sea-ice extent, we observe particularly large sea-ice extent at the end of the study period in 2023 and 2024, with the largest extent found in January 2024, covering 20308 km2. Characteristic for the sea-ice extent in the Greenland Sea was its shape, the so-called Odden ice tongue which formed regularly near West Jan Mayen Ridge but had disappeared with the retreating ice edge. The remarkably large sea-ice extent in 2023 and 2024 strongly reminds of a re-occurrence of Odden. Further analysis of atmospheric conditions and sea-surface temperature in the study area suggests that the large sea-ice extent in 2023 and 2024 cannot be explained by a single driver but is the result of several interacting factors.
Superimposed ice formation is a key component of the surface mass balance and meltwater runoff of polar glaciers, yet direct in situ measurements remain limited. To investigate meltwater percolation and refreezing in the wet-snow zone, we measured snow and ice temperatures and snow permittivity on Qaanaaq Ice Cap in northwestern Greenland from 2022 to 2023. Time-series data show that (1) meltwater percolates downward until reaching an impermeable boundary such as the snow-ice interface, where temperatures remain at the melting point; (2) saturation develops above this boundary during the melt season; and (3) latent heat released during refreezing warms the underlying ice throughout summer. Temperature-profile analysis indicates that 16.8 cm of superimposed ice formed between July 2022 and August 2023, representing 28% of seasonal snowmelt. The annual mean temperature at 9.3 m depth was 6.9 degrees C higher than the annual mean air temperature and 2.6 degrees C higher than measurements collected at a similar elevation in 2014. One-dimensional heat-conduction modelling suggests that increased latent-heat input from enhanced superimposed-ice formation-likely driven by a lengthening melt season-is responsible for the observed subsurface warming. These findings show that meltwater refreezing at the snow-ice boundary transfers substantial heat into the glacier, reducing future superimposed-ice formation potential and contributing to increased runoff.
Ice-marginal lakes in Antarctica are found between the coastal ice-free areas and the Antarctic Ice Sheet, its outlet glaciers, and the ice shelves. Since ice-marginal lakes may play a role in the surrounding environment (e.g., glacier variation and freshwater storage), recent observations of glacial lake outburst floods (GLOFs) from Antarctic ice-marginal lakes suggest that meltwater systems in Antarctica may be more dynamic than previously recognized. However, available lake inventories in Antarctica lack coverage and accuracy, resulting in a limited understanding of the role ice-marginal lakes play in the Antarctic environment. In this study, we developed a comprehensive inventory of ice-marginal lakes in Antarctica by using Sentinel-2 composite imagery obtained during the austral summer months from 2017 to 2022 for each lake, including information on geographical coordinates, lake area, surface elevation, and lake type. This new inventory includes 417 ice-marginal lakes from 17 regions across Antarctica. Eighty-seven percent of the ice-marginal lakes were in East Antarctica, and their total area was 493.3 ± 1.0 km2. This work presents the first comprehensive overview of ice-marginal lakes across Antarctica, emphasizes the need for further understanding of lake formation and evolution in this region, and builds a foundation for future studies of Antarctic hydrology, including ice-marginal GLOFs.
Geomagnetically Induced Currents (GIC) are ground-level electric currents driven by rapid changes in the Earth’s magnetic field during geomagnetic disturbances. The impact of GIC is often estimated using the direct current in high voltage AC transformers. Alternatively, the time derivative of the magnetic field (|dB/dt| ) can provide an approximation to the GIC signatures. While most GIC investigations focus on the northern hemisphere, observations in the southern hemisphere, particularly over Antarctica, remain limited. This study examines large amplitude |dB/dt| signatures during the super-intense geomagnetic storm of 10–12 May 2024 using magnetometer data from the Indian stations, complemented by AAL-PIP and the SuperMag network. Applying a threshold of |dB/dt| ≥ 300 nT/min, three |dB/dt| events are identified: one during the storm sudden commencement and two during the recovery phase. The events identified in the recovery phase are associated with large substorms. Further analysis of geomagnetic pulsations indicates that Pi3-Pc5 wave activity contributed to amplified |dB/dt| variations. The contribution of Region 1 Field-Aligned Currents (R1-FAC) is analyzed using AMPERE observations, which show the intensified FAC along with Ps6 pulsations. This study highlights the different sources of large-amplitude |dB/dt| over the less-explored Antarctic region under extreme geomagnetic conditions.
Fish have evolved numerous adaptations to cope with the unique biological stresses of living in the deep ocean. In September 2012 and 2013, deep-sea Arctic skates (Amlyraja hyperborea) were collected from the Canadian Beaufort Sea along a depth gradient ranging from 500 to 1515 m. Total lipids, lipid classes, and fatty acid profiles of both liver and muscle tissue were compared at various depths. The goal was to expand on previous biochemical depth-related patterns. Both liver and muscle samples exhibited no significant differences at any depth for total lipids nor any lipid class proportion. Liver samples showed significant differences among depths for numerous fatty acid proportions. The saturated fatty acid myristic acid (14:0), and polyunsaturated fatty acids eicosapentaenoic (EPA; 20:5ω3) and docosapentaenoic (ω3DPA; 22:5ω3) all decreased from shallow to deeper depths along a gradient. In turn, monounsaturated fatty acids oleic (18:1ω9), octadecenoic (18:1ω5), and erucic (22:1ω9), increased from shallow to deeper depths. Muscle samples exhibited significant differences among depths for two fatty acids, stearic (18:0) and 22:5ω3 which drove the difference between the most shallow and deepest depths. Our data show that intraspecific changes exist for a deep-sea Arctic elasmobranch, adding to previous research showing adaptations associated with pressure and energy metabolism.
Attenuated total reflection Fourier transform infrared (ATR-FTIR) is a useful tool for the study of plant litter decomposition, but its applicability for documenting the chemical changes in decomposing plant litter in high-arctic tundra has rarely been explored. In the present study, we investigated the chemical changes in decomposing leaves and stems of Salix arctica collected on Ellesmere Island, high Arctic Canada using ATR-FTIR. In the ATR-FTIR spectra in the fingerprint region of leaves and stems, at least 11 major peaks were detectable that were attributed to chemical features of lignin, cellulose, and/or hemicellulose. The overall spectra were significantly different between the decay classes of leaves and stems, indicating that ATR-FTIR spectroscopy is applicable for discriminating plant litter in different degrees of decomposition. Principal component analyses showed that the patterns of chemical change were characterized by the loss of cellulose and the decrease of cellulose crystallinity. These results illustrated that ATR-FTIR spectroscopy is applicable to documenting the chemical changes during decomposition of arctic shrub under dry moraine conditions and suggest its potential usefulness in the study of decomposition of tundra plants.
This study examines impact of geomagnetic storm occurred on 22-27 March, 22-27 April, and 03-08 November, 2023 on the variability of the ionospheric storm. Global Navigation Satellite System (GNSS) data in the North-South American, Europe-African, and Asia-Australian longitudinal sectors were utilized across various latitudes. We assessed the ionospheric storm by analyzing Total Electron Content (TEC) deviation (Delta TEC). In this study, the ionospheric response to a geomagnetic storm is deemed significant when TEC deviation is beyond +/- >= 45%. The main phase of the geomagnetic storm occurred at 02:00 UT, 05:00 UT, and 19:00 UT on March 24, April 24, and November 05, 2023. There was a notable positive ionospheric storm during these events. The ionospheric storm's behavior during different geomagnetic storms varies across latitudes in various longitudinal sectors. Positive ionospheric storms were observed in the North-South America, Europe-Africa, and Asia longitudinal sectors during the March storm. In April, positive storms were observed at stations MGO3, TNIF, YKRO, MBAR, however, during November, significant positive storms were observed with maximum Delta TEC values at stations MGO3 (169.6%), TNIF (157.7%), SANT (87.81%), SVTL (160.8%), OPTM (110.3%), RABT (274.1%), and YKRO (106.2%). The recovery phase of the geomagnetic storm revealed a series of positive and negative storms in different longitudinal sectors at various latitudes. The observed positive and negative ionospheric storms were found to be due to (PPEFs and enhanced of [O]/[N2] ratio) and (DDEFs and reduced [O]/[N2] ratio).
Climate change is reshaping contaminant pathways in Antarctica by mobilizing rare earth elements (REEs) and heavy metals from the cryosphere into marine ecosystems. Thaw-driven changes in salinity, pH, stratification, and primary productivity modify contaminant behaviour and bioavailability. The ice-algae interface is hypothesized to concentrate these elements; for heavy metals this pathway is empirically supported, while for REEs it remains to be directly measured in krill Krill are the fundamental species of the food web in the Southern Ocean. Krill are well established as biovectors for metals and may represent an important pathway for future transfer of emerging contaminants, including REEs, although direct empirical evidence in Antarctic krill remains absent. Krill are established biovectors for metals and may represent a plausible exposure pathway for emerging contaminants, including REEs, although direct field measurements of REEs in Antarctic krill remain unavailable. Current evidence reveals substantial knowledge gaps in Antarctic contaminant research, particularly because mercury remains the only contaminant with comparatively coherent Southern Ocean datasets, whereas REEspecific field measurements in Antarctic krill remain entirely absent. This evidence gap continues to limit quantitative assessment of climate-driven contaminant mobilisation, ecological exposure pathways, and foodweb transfer in Antarctic marine ecosystems. The lack of baseline data and long-term datasets necessitates advanced ultra-trace analytical approaches and sustained monitoring frameworks to enable comprehensive quantitative risk assessment and the detection of climate-driven trends in contaminant dynamics. Antarctica's protected status under the Antarctic Treaty System highlights the critical need for enhanced international cooperation and integrated governance frameworks to address REE and metal concerns in a rapidly warming Southern Ocean.
This study presents the first comprehensive bibliometric assessment of research on shipping emissions and energy efficiency in polar regions, aiming to overcome the fragmentation between environmental, technological, and policy perspectives. A dataset of 546 publications (1983-2025) indexed in the Web of Science within engineering and environmental sciences was systematically analyzed through citation, co-authorship, co-citation, and keyword co-occurrence mapping to examine temporal trends, leading contributors, intellectual influence, and evolving thematic clusters. Findings indicate a clear shift in scholarly focus, from early studies on black carbon and sea-ice interactions to more recent solution-oriented research emphasizing decarbonization, alternative fuels, and advanced emission modeling. Europe, led by Finland and Germany, has historically shaped the intellectual foundations, while China and the United States have become major contributors in recent years. Collaboration patterns reveal the global and interdisciplinary nature of the field, highlighting the role of joint research in driving both technological innovation and regulatory development. The results demonstrate that sustainable polar shipping requires not only technical improvements but also region-specific policies, coordinated international governance, and context-adapted efficiency strategies. By consolidating four decades of dispersed scholarship, this study clarifies the intellectual structure of polar shipping research and provides actionable insights for policymakers, engineers, and environmental scientists seeking to address the disproportionate climate risks of high-latitude maritime transport.
The Antarctic environment imposes extreme physiological challenges that can alter oral health. This prospective, single-group, pre-post quasi-experimental design (census type, n = 25) evaluated changes in oral clinical markers among Peruvian military personnel after 2 months at the Machu Picchu Scientific Station during the ANTAR XXXI campaign. Pre- and post-expedition variables including Oral Hygiene Index (OHI-S), bleeding on probing (BOP), tooth sensitivity (Schiff Scale), non-stimulated salivary flow, and salivary pH were measured by calibrated dentists (kappa = .85). Statistical analysis involved McNemar's, Student's t, and Wilcoxon signed-rank tests. Participants were predominantly male (88%), aged 31-40 (44%). Results showed a statistically significant increase in bleeding on probing, from 28% to 40% (p = .046), and a significant decrease in normal salivary flow (68% to 52%), as well as an increase in mild (24% vs. 36%) and severe (8% vs. 12%) cases (Z = 2.885; p = .008). Although poor oral hygiene rose from 28% to 40%, trend was not statistically significant (p > .05). No significant changes occurred in salivary pH or sensitivity. In conclusion, a two-month Antarctic stay is associated with a significant worsening of periodontal health and salivary flow, likely due to environmental factors and diet. These findings underscore the necessity for rigorous dental screening and specific preventive strategies for personnel in extreme isolation.
Eastern Antarctica plays a crucial role in Southern Ocean (SO) circulation and deep-water formation. Using Argo profiles, the present study reported the anomalous upper-layer warming in eastern Antarctica during the austral summer of 2019-20, with sea surface temperature (SST) exceeding 1 degrees C in some regions. The reanalysis data indicated enhanced intrusion of relatively warm Circumpolar Deep Water (CDW) onto the continental shelf, resulting in active ocean-shelf exchange processes during this time. This intrusion was associated with pronounced westerly wind, negative wind stress curl and strong southward surface current favoring on-shelf transport of warmer subsurface waters and enhanced vertical mixing. The atmospheric forcing was further linked to elevated mean sea level pressure over the region, consistent with a negative phase of the Southern Annular Mode (SAM), which likely modulated regional wind patterns and ocean circulation. The coupled oceanatmosphere anomalies coincided with reduction in sea-ice extent and notable variations in chlorophyll concentration, highlighting the sensitivity of the coastal Antarctica region to short-term climatic variability.
