Using nine ice-tethered buoys deployed across the marginal ice zone (MIZ) and pack ice zone (PIZ) north of the Laptev Sea during the expedition of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) in 2019–2020, we characterized the spatiotemporal variations in sea ice kinematics and deformation between October 2019 and  July 2020 in the Transpolar Drift (TPD). From October to November, the buoys were in the upstream area of the TPD; spatial variations of deformation rates were significantly correlated with initial ice thickness (R=−0.84, P<0.05). From December 2019 to March 2020, the buoys were in the high Arctic and the ice cover was consolidated; heterogeneity in ice kinematics as measured across the buoys reduced by 65%. From April to May 2020, the buoys were in the downstream TPD; amplified spatial variations in ice kinematics were observed. This is because two buoys had drifted over the shallow waters north of Svalbard earlier; trajectory-stretching exponents derived from the data from these two buoys indicate deformation rates (10.6 d⁻¹) that were about twice those in the deep basin (4.2 d⁻¹). By June 2020, a less consolidated ice pack and enhanced tidal forcing in the Fram Strait MIZ resulted in ice deformation with a semi-diurnal power spectral density of >0.25 d⁻¹, which is about 1.5 times that in PIZ. Therefore, in both the upstream and downstream regions of the TPD, the transition between the MIZ and the PIZ contribute to the spatial and seasonal variations of sea ice motion and deformation. The results from this study can be used to support the characterization of the momentum balance and influencing factors during the ice advection along the TPD, which is a crucial corridor for Arctic sea ice outflow to the north Atlantic Ocean.

The 5th International Polar Year (IPY-5) 2032–2033 is the next step with the “oldest continuous climate research program created by humanity”, which started in 1882–1883 with IPY-1 intentionally during a Solar Maximum after the “Little Ice Age” had impacted Europe across the previous four centuries. IPY-5 is a rare research opportunity to stimulate transdisciplinary initiatives with efficiencies and synergies that are relevant to all people and life on Earth pole-to-pole, across the cryosphere that includes high mountains on lands in between, connected by the atmosphere and ocean with Solar forcing across periods relevant to human survival. This editorial explores current and accelerating momentum to implement science with society across the International Decade of Sciences for Sustainable Development (IDSSD) 2024–2033 with IPY-5 as a guiding light.

Geomorphometric modeling and mapping of Antarctic oases are promising for obtaining new quantitative knowledge about the topography of these unique landscapes and for the further use of morphometric information in Antarctic research. Within the framework of a project to create a thematic physical-geographical scientific reference geomorphometric atlas of ice-free areas of Antarctica, we performed geomorphometric modeling and mapping of the Bunger Hills (Knox Coast, Wilkes Land, East Antarctica), one of the largest Antarctic oases. By processing a fragment of the Reference Elevation Model of Antarctica (REMA) covering the Bunger Hills and adjacent glaciers, we created, for the first time, a series of 37 medium- to large-scale maps of nine of the most scientifically important morphometric variables (i.e., slope gradient, slope aspect, vertical curvature, horizontal curvature, maximal curvature, minimal curvature, catchment area, topographic wetness index, and stream power index). The morphometric maps describe the topography of the Bunger Hills in a quantitative, rigorous, and reproducible manner. New morphometric data can be useful for further geological, geomorphological, glaciological, ecological, and hydrological studies of this Antarctic oasis.

This paper was based on data collected during the 38th and 39th Chinese National Antarctic Research Expeditions in the Amundsen Sea. The spatiotemporal distribution patterns of length (total length, AT) and sexual maturity stages of Antarctic krill (Euphausia superba) were examined. The age structure and geographic distribution of cluster groups also were studied. The results reveal significant diurnal variations in the length and maturity stages of Antarctic krill during the morning (MRN) to morning twilight (MTW) period, with mean lengths ranging from 28.92 to 45.87 mm. Two cyclical patterns were observed. Regarding maturity stages, the krill were composed of juveniles, adult males, and adult females in increasing order of proportion, with a notably higher proportion of non-gravid females compared to gravid females, and mainly distributed in evening twilight (ETW) to dawn (DWN), MTW to day (DAY), MRN to MTW, MRN to MTW and night (NIT) to DAY periods, respectively. Significant spatial variations in krill length and maturity stages occur, with a marked regional boundary around 130°W. K-means clustering analysis of krill length identified Group I, Group II, and Group III, with dominant age classes of 3+, 0 and 3+, and 3+ to 4+, respectively. Group II was widely distributed in the surveyed waters, whereas Group I and Group III were distributed only in waters west of 130°W. The study area features a significant continental slope, where adults and gravid females were primarily distributed on its slopes and to the south. This spatial pattern also profoundly influenced the distribution of different cluster groups.

The accelerated decline of Arctic sea ice since the 1980s has paradoxically amplified greenhouse gas (GHG) emissions through increased shipping activities in this ecologically vulnerable region. This study investigates how to reconcile the decarbonization of Arctic shipping with conflicting environmental, economic, and geopolitical interests. Through systematic literature review and interest-balancing analysis, our findings identify three systemic barriers: (1) inadequate adaptation of International Maritime Organization (IMO) regulations to Arctic-specific environmental risks, (2) fragmented enforcement mechanisms among Arctic and non-Arctic States, and (3) technological limitations in clean fuel adoption for ice-class vessels. To address these challenges, a tripartite governance framework is proposed. First, legally binding amendments to International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI introducing Arctic-specific Energy Efficiency eXisting ship Index (EEXI) standards and extending energy efficiency regulations to fishing vessels. Second, a phased fuel transition prioritizing liquefied natural gas (LNG) and methanol, followed by hydrogen-ammonia synthetics. Third, enhanced multilateral cooperation through an Arctic Climate Shipping Alliance to coordinate joint research and development in cold-adapted technologies and ice-route optimization. By integrating United Nations Convention on the Law of the Sea (UNCLOS) obligations with IMO Polar Code implementation, this study advances a dynamic interest-balancing framework for policymakers, offering actionable pathways to achieve Paris Agreement targets while safeguarding Arctic ecosystems.

A seismic swarm occurred southeast of King George Island, South Shetland Islands, Antarctica, between August 2020 and February 2021. This work intends to parameterize seismic events recorded by seismic station AM.R4DE2 from 15 September to 31 October 2020. Using the localization methodology with a single station, the record of the entire period was analyzed manually to determine the local magnitude, hypocentral distance, epicentral distance, backazimuth, and location of the epicenter for each event. We could parameterize 6362 events, although we estimate the occurrence to be around 20000 for the period. The results suggest a magmatic origin for the swarm, supporting previous studies. Seismicity exhibited a southeastward migration away from King George Island, as indicated by a progressive increase in epicentral distance over time. Most events were classified as volcanic and volcano-tectonic, supporting a magmatogenesis hypothesis linked to the opening of Bransfield Ridge.

Opinion Editorial

5th International Polar Year (IPY-5) 2032—2033 with global inclusion

Articles

Geomorphometry of the Bunger Hills, East Antarctica

Comprehensive analysis of seismic activity on King George Island, Antarctica: insights from the September— October 2020 seismic swarm

Spatiotemporal characteristics of population structure for Antarctic krill (Euphausia superba) during austral summer in Amundsen Sea

Spatiotemporal variations of sea ice kinematics in the Transpolar Drift of the Arctic Ocean in 2019/2020 derived from buoy measurements during MOSAiC

Shipping decarbonization governance in Arctic waters: theoretic logic and implementation pathways

Announcements

Call for paper: 2025 Special Issue “New Horizons in the Exploration of Polar Biodiversity, Ecosystem and Genetic Resources”

Call for paper: 2026 Special Issue “Changes of the Arctic Climate System and Its Global Connections”

Special Issue “New Horizons in the Exploration of Polar Biodiversity, Ecosystem and Genetic Resources” will be published in December 2025, as the general issue (Vol. 36, No.4), and Special Issue “Changes of the Arctic Climate System and Its Global Connections" will be published in June 2026, as the general issue (Vol. 37, No.2).

Under ongoing global warming, reliable projections of Arctic sea-ice conditions and future navigability are of strategic significance. Using a combination of observational and physical constraints, we systematically evaluated the performance of 48 Coupled Model Intercomparison Project 6 (CMIP6) models in simulating Arctic sea ice and selected 12 skillful models for detailed analysis. Navigability of the Northeast Passage (NEP), Northwest Passage (NWP), and Transpolar Sea Route (TSR) during 2015–2100 was assessed under Shared Socioeconomic Pathways (SSP) 2-4.5 and SSP5-8.5 scenarios. Results indicate that for open water vessels under the SSP2-4.5, TSR is not projected to become navigable until 2029. In contrast, under the SSP5-8.5 scenario, both NWP and NEP are expected to support year-round navigation by the late 21st century, while TSR is not anticipated to become fully operational until after 2090. Polar Class 6 vessels achieve near year-round navigation by 2100 under SSP2-4.5, and full-year operation as early as 2048 under SSP5-8.5.

Understanding the sediment record during the Little Ice Age (LIA) can help elucidate natural sea ice fluctuation and carbon cycle variability. This study analyzed the grain size composition (including ice-rafted debris), total organic carbon (TOC), total nitrogen (TN) content, and stable isotopic composition (δ¹³C and δ¹⁵N) of the sediment record (approximately 490 a) of core ARC7-R11 in the northern part of the Chukchi Shelf. The sediment grains comprise mostly (>90%) silt and clay components. The grain size composition suggests generally low-energy hydrodynamic conditions across the region, yet reveals a trend of enhancement in hydrodynamics from the bottom to top layers of the sediment core, particularly after the 1940s. It also shows occurrences of seasonal sea ice and retreat of the perennial sea ice margin during warmer periods of the LIA and the post-LIA period. The organic matter content is high throughout the core, with heavier δ¹³C values and moderate TOC/TN ratios indicating primarily marine origin; the terrestrial input is <37.5% according to the endmember model. The variation trend of marine-derived organic carbon (OC) content is similar to that of summer temperature anomalies; while variation trend of terrestrially derived OC shows significant correlation with that of the number of ice-free days in the southern shelf region, except for the period from approximately 1700s to the 1870s. During the LIA, the TOC content fluctuated and decreased, and the relative contribution of terrestrial OC was higher than during the modern warm period. The amount of OC buried in the sediment has increased with climate warming, especially after the 1940s, reflecting the enhanced ability of sediment to sequester carbon during warmer periods.

The North Water Polynya (NOW) is one of the largest and most productive polynyas in the Arctic. Compared to the surrounding sea ice, the combination of high winds and cold air, together with the thin ice or open water surface of the NOW, produces large turbulent heat fluxes (THFs). The accurate estimation of these parameters requires high-resolution atmospheric data, which can be provided by the reanalysis products from different sources. In this study, we calculated the winter latent heat flux (LHF) and sensible heat flux (SHF) over the NOW and its surrounding sea ice area from 2005/2006 to 2015/2016 using high-resolution (15 km) Arctic System Reanalysis version 2 (ASRv2) data and low-resolution (30 km) European Centre for Medium-Range Weather Forecasts ERA5 data. Results show that the LHF/SHF over the surrounding sea ice is about 82%/88% lower than over the NOW, as estimated using either dataset. Furthermore, within each area, the difference in the THFs estimated from the two datasets is small. The spatial distribution of the LHF/SHF estimated from both data sources is similar to that of sea ice concentration. The average LHF/SHF in the polynya obtained using ASRv2 data is only 5%/7% higher than that from the values obtained using ERA5 data. This is because the wind speed and air temperature from the ASRv2 data are higher than those of ERA5, and their effects on the THFs can cancel each other out. Furthermore, the estimated THFs do not necessarily improve with the refined resolution of ASRv2.

On 19 June 2023, the Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction (BBNJ Agreement) was adopted. The BBNJ Agreement aims to regulate the conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction, including the high seas and the international seabed area. The BBNJ Agreement enters into an already crowded institutional landscape as a global authority with broad objectives, inevitably interacting with existing institutions, frameworks, and bodies (IFBs). Existing research has primarily focused on two areas: the first examines the impact of the institutions established by the BBNJ Agreement on existing marine governance IFBs; the second explores its influence on issues currently lacking institutional arrangements. However, comparatively little attention has been given to the Agreement’s potential impact on governance gaps within established systems. This paper takes the case of marine genetic resource (MGRs) management in the Antarctic Treaty Area to explore how the BBNJ Agreement may address regulatory gaps in a competent governance framework. Due to shortcomings in addressing core issues, concerning the legal status of MGRs access regulations, benefit-sharing mechanisms, and disclosure of origin, the Agreement is unlikely to have a significant impact on the governance of MGRs in the Antarctic Treaty System (ATS) in the short term. On the other hand, the ATS, as an effective governance framework for the Antarctic Treaty Area, has mature regulations and practical experience in Antarctic governance. Over the years, the ATS has focused on regulating bioprospecting activities as scientific research ones and strict environmental impact assessment procedures. However, there has not been an effective consensus on the regulation of commercial biological prospecting. This paper further explores the coordination issue between the BBNJ Agreement and the ATS, suggesting that in the future, MGRs governance in the Antarctic Treaty Area may evolve into a polycentric governance system.

Global warming has made the regular operation of Arctic routes possible. This study selects hub ports based on infrastructure conditions and sea ice status, and then designs two pendulum route solutions for the Northeast Passage according to the distance between hub ports and ice-covered areas. We employ an evaluation framework combining annual profit metrics with discounted net present value (NPV) analysis, conducting probabilistic economic assessments through Monte Carlo simulations (20,000 iterations). Key findings indicate that (1) both solutions demonstrate >90% probability of economic viability and (2) Solution I′, with hub ports closer to ice-covered areas than those in Solution II, yields 5.02% higher mean annual profit and 4.69% greater NPV. The results indicate that pendulum routes in the Northeast Passage can achieve economic benefits by enabling year-round regular operations. Moreover, shorter shipping distances between hub ports and ice-covered areas enhance economic viability.

Global warming has led to a gradual extension of the navigable window for the Arctic Route, providing a realistic possibility for the normalized commercial operation of the Northeast Passage (NEP). Based on the changes in the navigable window of the NEP, Russia’s proposed nuclear-powered icebreaker construction scheme, and China’s potential development of a moderately sized ice-class fleet, this study establishes three scenarios for the commercial operation of the NEP. These scenarios include: (a) normalized summer operational scenario (from July to October each year), (b) normalized summer- autumn operational scenario (from June to January of the following year), and (c) normalized year-round operational scenario (12 months per year). The cargo transportation potential of the NEP under three normalized operational scenarios was predicted based on the grey prediction model. On this basis, construction scale plans for China’s ice-class fleet to meet cargo transportation demands under the three normalized operational scenarios were designed. The economic benefits of different plans were evaluated using a profit-maximization linear programming model. The research results show the following: (1) The cargo transportation potential of the NEP demonstrates a rapid growth trend in the future, with annual throughput under year-round normalized operations expected to exceed 100 million tonnes and reach 297 million tonnes. (2) Under different normalized operational scenarios, the fleet scale and vessel type composition vary. Under the normalized summer operational scenario, the optimal scale for China’s ice-class fleet is 20 vessels, consisting solely of ships classed as PC7 by the International Association of Classification Societies (IACS). Under the normalized summer-autumn operational scenario, the optimal fleet scale is 31 vessels, including 30 IACS PC7 ships and 1 IACS PC3 ship. Under the normalized year-round operational scenario, the optimal fleet scale is 45 vessels, composed of 30 IACS PC7 ships, 8 IACS PC3 ships, and 7 IACS PC2 ships. (3) Among the three normalized operational scenarios, the normalized year-round operational scenario yields the best economic benefits for the fleet scale, while the normalized summer operational scenario yields the lowest economic benefits.

Antarctic ice-free areas (<0.4% of the continent) represent Antarctic biodiversity oases, where microbial communities sustain terrestrial ecosystem functions. These habitats—encompassing mineral, ornithogenic soils, biological soil crusts, and hypolithic/endolithic niches—are shaped by environmental factors such as pH, organic C/N ratios, moisture, elevation, and trace element availability. The diversity of prokaryotes, eukaryotes, and viruses is lower than in other regions, yet the communities exhibit strong endemism, with site-specific uncultivated lineages. Microorganisms persist through cold and stress adaptations, performing organic carbon decomposition, phototrophy, and oxidation of trace gases to drive carbon and nitrogen cycling in various Antarctic soil habitats. Climate change and anthropogenic disturbances are shifting communities toward copiotrophic generalists, altering elementary cycling and feeding back to climate change. Culturation and genomic-based techniques reveal novel microbial taxa with broad biotechnological potentials on bioactive compounds and cryotolerant enzymes. In summary, this review offers a foundation for exploring Antarctic microbial biodiversity, ecosystem resilience, and the development of novel biotechnologies, while also highlighting the urgent need for effective monitoring and preservation strategies to mitigate the impacts of ongoing environmental changes on Antarctic soil ecosystems.

The extreme environment of the polar regions has driven the evolution of unique metabolic mechanisms in microorganisms, resulting in structurally diverse and highly active secondary metabolites. These metabolites are not only crucial for microbial adaptation to extreme conditions, but also exhibit significant potential for applications in medicine, agriculture (e.g., biocontrol), and industry. This review provides a comprehensive overview of 111 secondary metabolites derived from polar microorganisms reported between 2013 and 2025, with a focus on advances in their classification, biological activities, and biosynthetic gene cluster mining techniques. Additionally, it highlights key strategies for advancing future investigations, providing a valuable reference for continued exploration in this promising field. Notably, polar microbial secondary metabolites also hold promising applications in agriculture, particularly in biocontrol, soil health enhancement, and stress-resistant crop development.

This paper explores the archaeology of whaling in Arctic prehistory, focusing on the emergence and development of whaling as a central component of cultural ecology among prehistoric Inuit and related societies. Drawing on archaeological evidence from key sites across Alaska, the Chukchi Peninsula, and the Bering Strait region, the study examines how whaling technologies and practices evolved alongside climatic fluctuations, ecological shifts, and social transformations. Integrating ethnographic insights and paleoclimatic data, the study argues that Inuit engagement with whales was not only a subsistence strategy but a long-term, historically contingent relationship that shaped and was shaped by broader cultural systems.

The Fildes Peninsula is among the Antarctic regions most affected by human activity. As the interface between terrestrial and marine ecosystems, the intertidal is a gateway for ecological and public health risks. Antibiotic resistance genes (ARGs) and virulence factor genes (VFGs) intensify these risks by transferring pathogenic traits via horizontal gene transfer. However, a comprehensive assessment of ARGs and VFGs in Fildes Peninsula intertidal sediments is lacking. We addressed this gap by performing shotgun metagenomic sequencing on 14 intertidal sediments. We detected 20 ARG types comprising 397 subtypes. Multidrug, bacitracin, and polymyxin resistance dominated the resistome, although their overall abundance was relatively low. A total of 4,204 VFGs were identified and were primarily associated with adherence, motility, immune modulation, and effector delivery. The abundance of VFGs was also relatively low and significantly correlated with the abundance of ARGs. Additionally, we also identified 787 mobile genetic elements (MGEs) that carried 138 VFGs but found no ARGs associated with MGEs at the contig level. Host assignment implicated taxa such as Ilumatobacter as major ARG carriers and detected opportunistic pathogen Pseudomonas aeruginosa carrying CAM-1, a metallo-β-lactamase gene. In summary, our results reveal a highly diverse but generally low-abundance resistome and virulome in Fildes Peninsula intertidal sediments, with limited evidence for MGE-mediated ARG dissemination. However, they emphasize the necessity of monitoring to protect Antarctic microbial integrity.

Phytoplankton play a pivotal role in the Southern Ocean ecosystem. This study examines the phytoplankton community structure and the environmental factors driving it in the Cosmonaut Sea, based on samples collected using a net during the summer of 2020/2021. We identified 99 phytoplankton species, predominantly comprising diatoms and dinoflagellates. Among these, diatoms—notably Pseudo-nitzschia, Chaetoceros, and Fragilariopsis, dominated the community in terms of species richness, abundance, and biomass. Endemic species of the Southern Ocean, such as Corethron pennatum, Proboscia alata, and Cylindrotheca closterium, also made significant contributions. Phytoplankton abundance and biomass showed similar spatial distribution patterns, with hotspots in the northern section of the survey area that gradually diminished towards the coastal regions. The oceanic area exhibited low phytoplankton diversity but pronounced regional variations in community distribution, with the northern region emerging as a key zone for abundance, biomass, and diversity. Nutrient distribution was identified as the primary environmental driver shaping the phytoplankton community, with silicate levels having a significant negative impact on overall phytoplankton abundance and the dominant species.

 A polyketide synthase–nonribosomal peptide synthetase gene cluster twn in Talaromyces sp. HDN1820200 was activated by overexpression of the pathway-specific transcriptional factor TwnD. Large-scale fermentation and chemical investigation of the mutant strain HDN1820200/TwnD led to the discovery of one new polyketide–amino acid conjugate, bipolamide C and one new polyketide compound, variotin A. The structures of the new compounds were determined by nuclear magnetic resonance (NMR) analysis, high-resolution electrospray ionization mass spectrometry, feeding experiments, NMR calculation and DP4⁺ analysis. This study revealed that the overexpression of the pathway-specific transcriptional factor represents a promising approach for the discovery of new natural products in fungi within specialized habitat.

Understanding microbial responses to polycyclic aromatic hydrocarbon (PAH) pollution is crucial for assessing the current status of PAH contamination in polar regions. In this study, intertidal and marine sediments were enriched with a mixture of PAHs (naphthalene, phenanthrene, fluorene, pyrene, and fluoranthene). Isolation of culturable bacteria, high-throughput sequencing, and functional prediction were combined to systematically analyze bacterial structural and predicted functional responses to PAH exposure. High-throughput sequencing results showed that the relative abundance of Proteobacteria was significantly increased after enrichment, and Pseudomonas and Acinetobacter were identified as dominant genera under PAH exposure. These findings were consistent with the 19 potential PAH-degrading strains (mainly Pseudomonas) that were successfully isolated from enrichment cultures. Distinct bacterial taxa between enriched marine and intertidal sediments indicated the existence of distinct PAHdegrading groups. PICRUSt2-based functional predictions suggested higher predicted abundances of PAH-degradation pathways in polar sediments, likely through the preferential degradation of parent PAH compounds in response to elevated concentrations. This study provides valuable data on microbial responses to PAH pollution in polar regions and offers new insights for evaluating ecological hazards induced by PAHs.

Samples for this study were collected from Geologists Island and Prydz Bay in different seasons. Otolith sections were analyzed for elemental composition in the nucleus, juvenile, and edge areas. Elements including Mg, Sr, P, K, Fe, and Zn, normalized to calcium (C_Me/C_Ca), were selected for analysis. To explore population structure, factors influencing during life stage, and regional distribution characteristics. For identified individual origins and explored the distribution and migration between regions and migration from hatching to adulthood provide a basis. So as to understand the distribution and migration pattern of Pagothenia borchgrevinki across various life history stages. Results indicated a consistent P. borchgrevinki population spawning across various regions of Southern Ocean, with eggs distributed at the bottom. Coastal slope topography changes and water compensation facilitated egg transportation from the bottom to under sea ice during hatching to juvenile stages. Long-distance migration was facilitated by the Antarctic Circumpolar Current and regional currents during development to adulthood. Multiple spawning grounds and ocean currents contributed to diverse distribution environments during the hatching period. Differences in individual development were important factors during the juvenile period, while ocean currents and autonomous behaviors influenced regional transportation patterns in the post development stages. Therefore, the research holds that differences in distribution environment and behavior during each period led to distinct factors influencing C_Me/C_Ca variations.

Antarctic krill (Euphausia superba), widely distributes around Antarctica, is a key species supporting the biodiversity of the Southern Ocean ecosystem. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has thus managed the krill fishery according to a precautionary way. Currently, CCAMLR is making effort to develop a refined krill fishery management approach based on more solid science, which requires accurate predictions of krill distribution. To address this need, this study investigated the effects of algorithm and spatial resolution on the performance of Antarctic krill distribution modelling. We integrated acoustic data from 4 surveys conducted in the waters adjacent to the Antarctic Peninsula with 11 environmental variables characterizing krill prey conditions, water mass properties, and seafloor topography. These data were processed at 4 spatial resolutions (5, 10, 15, and 20 km) to fit distribution models using 4 algorithms: Random Forests (RF), Generalized Additive Models (GAM), Extreme Gradient Boosting (XGBoost), and Artificial Neural Networks (ANN). Model performance was assessed and compared in terms of goodness-of-fit and predictive accuracy. The results showed that RF achieved the highest predictive performance at most resolutions, whereas GAM performed best at the coarsest resolution (20 km). XGBoost closely following RF in accuracy and demonstrated robustness as evidenced by the highly consistent partial dependence curves across resolutions. In contrast, ANN exhibited limitations with smaller sample sizes, resulting in comparatively poorer predictive performance. The analysis revealed a trade-off whereby reducing spatial resolution improved model fit and mitigated zero-inflation at the expense of fine-scale information and overall predictive accuracy. Ensemble models, integrating RF, GAM, and XGBoost, are proposed as potential balanced solutions to improve predictive stability, offering a more robust scientific basis for the refinement of krill management.

Research on Antarctic microbial diversity has primarily focused on 3 areas: freshwater lake sediments, penguin colonies, and seawater in ice-free regions. There is a scarcity of research on the impact of slopes on microbial community structure, and this study effectively fills this gap. This study focused on the soil in the sparse vegetated tundra on a hillside near the southern coastline of the Antarctic Great Wall Station. The influence of slope position, soil physicochemical properties, and vegetated area on soil bacterial community structure was analyzed. High-throughput sequencing technology was employed to characterize a 16S rRNA gene fragment in soil samples from 5 slope areas and estimate bacterial abundance. Calculation of α-diversity and β-diversity indices, and community structure analysis were used to compare the species richness among sampling points, analyze similarities in soil bacterial community structure and composition, and identify the core bacterial population. In the non-vegetated area, the soil on the mountaintop, hillside, and at the foot of the slope showed similar physicochemical properties. In the vegetated area, the soil physicochemical properties were highly similar on the mountaintop, hillside, the foot of the slope, and the foot of the mountain. Weighted Gene Co-expression Network Analysis showed that total organic carbon, pH, and PO₄^3–-P might affect the structure of bacterial communities at the sampling point by changing the relative abundance of Chthoniobacterales, Sediminibacterium, and Actinobacteria. We hypothesize that slope-driven nutrient transport, amplified by vegetated areas (in the tundra), is a primary driver of bacterial community structure in the Antarctic tundra soil. These results provide insights into the impact of slope on microbial community structure in Antarctica.