Arctic Sites Research Articles (Page 1)

Introduction. Scientific research convincingly proves the presence of a complex of harmful and dangerous natural, climatic and professional risk factors at Arctic production sites. The study aim is to scientifically substantiate the criteria for assessing the individual susceptibility of a shift worker to the hazardous effects of polar stress. Materials and methods. The object of the study was risk factors associated with the adverse effects of polar stress, as well as workers engaged in shift work in the Arctic. At the 1st stage of the study, 87 workers were examined using the case-control method. At the 2nd stage of the study, a systematic analysis of the results of 12 epidemiological studies was carried out. Results. The population relative risk of developing arterial hypertension in shift workers was R=1.2 (1.1–1.5), (p<0.05) with an average Arctic work experience of 6.18+3.0 years. The results of research made it possible to determine the criteria for assessing the phenogenetic determinants that modify the risk of health disorders associated with stress-induced changes. Based on the principles of comorbidity, a methodology has been developed for quantitatively assessing the risk of individual susceptibility to the hazardous effects of polar stress. A list of health disorders has been determined, the occurrence, severity of the clinical course and outcomes of which are etiologically and pathogenetically associated with stress. This list includes 12 classes of diseases. Limitations. The small sample size and participation of only men of working age in the study are limitations of this study. The proposed methodology for predictive assessment of the individual susceptibility is limited to exposure conditions related to the category of hazardous, which can lead to a sudden sharp deterioration in health or death in the first 10 days of a 30-day shift or on the 40 or 55 days of an extended shift. Conclusions. The results of the studies prove the validity of the widespread use of diagnostic criteria of personalized medicine in a set of preventive measures aimed at increasing the effectiveness of pre-shift medical examinations of workers engaged in work in the Arctic. Ethics. The study was conducted in compliance with the norms of biomedical ethics in accordance with the Declaration of Helsinki and the relevant GPT (Good Clinical Practice) standards. The protocol was approved by the Ethics Committee of the Tyumen Cardiology Research Center (No. 183 06.02.2023).

Variability of Methane Plumes at an Arctic Analogue Site with Implications for Martian Exploration

Chemical Composition and Mixing State of Wintertime Aerosol from the European Arctic Site of Ny-Ålesund, Svalbard

This volume, Sedimentary Successions of the Arctic Region and their Hydrocarbon Prospectivity , developed around maps of the sedimentary successions of the Arctic Region, and contains a brief, but comprehensive compilation of geological and geophysical data characterizing all significant sedimentary successions in the Arctic, which cover 57% of the polar area north of 64° N. Its two main goals are to provide, based on present-day knowledge and data, a characterization of all Arctic sedimentary successions (or sedimentary accumulations) and to supply a snapshot of hydrocarbon-related exploration in the Arctic at the end of the first quarter of this century. To achieve these goals, we represent sedimentary successions as consisting of one or several ‘tectono-sedimentary elements’ (TSEs) based on the main tectonic regimes that formed accommodation space for accumulation of sediments. A TSE characterization template has been developed as an efficient method of organizing and presenting the most important information about the stratigraphy, structure and petroleum geology of a TSE, including the most significant exploration facts. This organizational architecture is the backbone of the volume and is a key feature that distinguishes it from other studies of Arctic sedimentary basins. The online volume includes six large-size foldout maps portraying the mapped TSEs in the Circum-Arctic context, including tectonic grain of the consolidated basement, anomalous gravity and magnetic fields, location of the Arctic sampling sites and seismic profiles.

Abstract. Snow sublimation plays a fundamental role in the winter water balance. To date, few studies have quantified sublimation in tundra and boreal forest snow by direct measurements. Continuous latent heat data collected with eddy covariance (EC) measurements from 2010–2021 were used to calculate snow sublimation at six locations in northern Alaska: three Arctic tundra sites at distinct topographical and vegetation communities in the Imnavait Creek watershed on the North Slope underlain by continuous permafrost, and three lowland boreal forest/taiga sites in discontinuous permafrost in interior Alaska near Fairbanks. Mean surface sublimation rates range from 0.08–0.15 mm d−1 and 15–27 mm yr−1 at the six sites, representing, on average, 21 % of the measured solid precipitation and 8 %–16 % of the cumulative annual water vapor flux to the atmosphere (evaporation plus sublimation). The mean daily sublimation rates of the lowland boreal forest sites are higher than those of the tundra sites, but the longer snow cover period of the tundra sites leads to greater mean annual sublimation rates. We examined the potential controls, drivers, and trends of the sublimation rates by using meteorological data collected in conjunction with EC measurements. This research improves our understanding of how site conditions affect sublimation rates and highlights the fact that sublimation is a substantial component of the winter hydrologic cycle. In addition, the study contributes to the sparse literature on tundra and boreal sublimation measurements, and the measured rates are comparable to sublimation estimates in other northern climates.

Abstract. Tracking the extent of seasonal snow on glaciers over time is critical for assessing glacier vulnerability and the response of glacierized watersheds to climate change. Existing snow cover products do not reliably distinguish seasonal snow from glacier ice and firn, preventing their use for glacier snow cover detection. Despite previous efforts to classify glacier surface facies using machine learning on local scales, currently there is no published comparison of machine learning models for classifying glacier snow cover across different satellite image products. We present an automated snow detection workflow for mountain glaciers using supervised machine-learning-based image classifiers and Landsat 8 and 9, Sentinel-2, and PlanetScope satellite imagery. We develop the image classifiers by testing numerous machine learning algorithms with training and validation data from the U.S. Geological Survey Benchmark Glacier Project glaciers. The workflow produces daily to twice monthly time series of several glacier mass balance and snowmelt indicators (snow-covered area, accumulation area ratio, and seasonal snow line) from 2013 to present. Workflow performance is assessed by comparing automatically classified images and snow lines to manual interpretations at each glacier site. The image classifiers exhibit overall accuracies of 92 %–98 %, κ scores of 84 %–96 %, and F scores of 93 %–98 % for all image products. The median difference between automatically and manually delineated median snow line altitudes is −31 m (IQR of −73 to 0 m) across all image products. The Sentinel-2 classifier (support vector machine) produces the most accurate glacier mass balance and snowmelt indicators and distinguishes snow from ice and firn the most reliably. Although they are less accurate, the Landsat- and PlanetScope-derived estimates greatly enhance the temporal coverage of observations. The transient accumulation area ratio produces the least noisy time series, making it the most reliable indicator for characterizing seasonal snow trends. The temporally detailed accumulation area ratio time series reveal that the timing of minimum snow cover conditions varies by up to a month between Arctic (63° N) and midlatitude (48° N) sites, underscoring the potential for bias when estimating glacier minimum snow cover conditions from a single late-summer image. Widespread application of our automated snow detection workflow has the potential to improve regional assessments of glacier mass balance, land ice representations within Earth system models, water resources, and the impacts of climate change on snow cover across broad spatial scales.

Abstract. The processes contributing to Arctic cold-season (November–April) sea salt aerosols (SSAs) remain uncertain. Observations from coastal Alaska suggest that emissions from open leads in sea ice, which are not included in climate models, may play a dominant role. Their Arctic-wide significance has not yet been quantified. Here, we create an emission parameterization of SSAs from leads by combining satellite data of lead area (the Advanced Microwave Scanning Radiometer–Earth Observation System (AMSR-E) product) and a chemical transport model (GEOS-Chem) to quantify pan-Arctic SSA emissions from leads during the cold season from 2002 to 2008 and to predict their impacts on atmospheric chemistry, evaluating the results of our simulated SSAs against in situ observations. The AMSR-E product detects large leads with certainty (> 3 km in size), and, hence, our study is limited to quantifying emissions from large leads. Lead emissions vary seasonally and interannually. Simulated total monthly SSA emissions increase by 1.1 %–1.8 % (≥60° N latitude) and 5.6 %–7.5 % (≥75° N) for the 2002–2008 cold seasons. SSA concentrations primarily increase at the location of leads, where standard model concentrations are low. GEOS-Chem overestimates SSA concentrations at Arctic sites compared to ground observations, even when lead emissions are not included, suggesting underestimation of SSA sinks and/or uncertainties in SSA emissions from blowing snow and the open ocean. Multi-year monthly mean surface bromine atom (Br) concentrations increase by 2.8 %–8.8 % due to SSAs from leads for the 2002–2008 cold seasons. Changes in ozone concentrations are negligible. While leads contribute < 10 % to Arctic-wide SSA emissions in the years 2002–2008, these emissions occur in regions of low background aerosol concentrations. Leads may increase in frequency under future climate change, which could increase SSA emissions from leads.

In the current warming climate, many organisms in seasonal environments advance their timing of reproduction to benefit from resource peaks earlier in spring. For migrants, the potential to advance reproduction may be constrained by their migration strategies, notably their ability to advance arrival at the breeding grounds. Recent studies show various changes in migration strategies, including wintering closer to the breeding grounds, earlier departure from the wintering grounds or faster travels by spending less time at stopover sites. However, whether such changes lead to earlier arrival or earlier breeding remains an open question. We studied changes in migration and reproduction timing in 12 populations of nine migratory birds, including seabirds, shorebirds, birds of prey and waterfowl breeding at Arctic sites bordering the Greenland and Barents Sea, a region undergoing rapid climate warming. The timing of migration and reproduction was derived from tracking and field data and analysed to study (1) how timing has changed in response to the changing moment of snowmelt at the breeding grounds and (2) what adjustments in migration strategies this involved. We found that in years with early snowmelt, egg-laying in multiple populations advanced, but only two waterfowl populations also advanced arrival in the Arctic. In contrast, arrival in the Arctic generally advanced with time, even when snowmelt or egg-laying dates did not advance. Earlier arrival with time was mostly explained by populations traveling to the Arctic faster, likely spending less time at stopover sites. Inability to forecast conditions in the Arctic may limit birds to adjust migration timing to annually varying snowmelt, but we show that several species, particularly waterfowl, are able to travel faster and advance the timing of migration over the years. The question remains whether this reflects adaptations to Arctic climate change or other factors, for example, environmental changes along the migratory route.

Abstract Climate change in the Arctic is occurring more rapidly than anywhere on the globe and changes in the marine environment can impact the distribution and abundance of Arctic and subarctic marine species. Understanding how a species responds to climate change can aid conservation planning and recovery. Somateria fischeri (Spectacled Eider) winter in the Bering Sea and breed along coastal areas of Alaska and Arctic Russia. The severity of winter conditions in the Bering Sea has been associated with both reduced annual survival and reduced breeding abundance and may have sublethal effects during the breeding season. In this study, we used long-term nest monitoring data from 2 sites in Alaska; Kigigak Island, a subarctic site on the coast of the Bering Sea, and Utqiaġvik, on the Arctic coast, to examine the hypothesis that winter conditions in the Bering Sea influence the reproductive performance of eiders in the following breeding season. For both sites, we examined the effects of winter ice conditions, spring temperature, and spring wind in the Bering Sea wintering area on nest initiation date, clutch size, and nest survival. Nest initiation date was not strongly associated with conditions in the wintering area experienced prior to the breeding season and mean initiation date was 20 days later at the Arctic site, Utqiaġvik, than at the subarctic site, Kigigak Island. We found no evidence that winter and spring conditions on the wintering area preceding the breeding season explained variation in clutch size. Nest survival varied by year and site and increased asymptotically with increasing sea ice cover at both sites. We speculate that low sea ice winters reduce nest survival through negative effects on body condition. Negative effects of changing ice conditions on multiple demographic rates may lead to future population declines for S. fischeri at rates higher than previously predicted.

Arrival timing in spring may be mediated by conditions experienced during migratory stopovers or staging areas, but our knowledge about their impact on migration timing and reproduction is limited. We explored the role of stopover duration on spring migration timing and successful incubation in cackling geese (Branta hutchinsii), which breed at high arctic latitudes where climate change effects are more pronounced. To track migration phenology and incubation duration, 236 light-level geolocators were deployed on cackling geese during the breeding period at Baffin Island, Nunavut, Canada between 2016 and 2018. Using data available for spring migration in the year following tag deployment (25 tags retrieved), we found that most geese had long, coastal stopovers (8–39 days) before crossing Hudson Bay on the last leg of their spring migration to their Baffin Island breeding area. We show that longer stopover durations at these Hudson Bay Lowland sites were associated with successful completion of incubation (a proxy for breeding success). Although spending more time at the stopover led to a later arrival date at the breeding ground, longer stopovers may increase the energy stores necessary for reproduction in these capital breeders. Stopover duration did not influence the incubation interval (number of days between arrival date at the breeding ground and start of incubation). Lastly, we found that the temperature at stopovers influenced migration timing, with higher temperatures resulting in earlier arrival at the breeding ground. Overall, our results demonstrate that conditions and behaviour at distant stopovers (1700–3000 km away) have important influence on timing and breeding success once birds arrive at their Arctic breeding sites. Therefore, our understanding of climate change impacts on these Arctic-breeding geese must also include the influence of en route conditions

BackgroundSince the 1980s, Pacific Black Brant (Branta bernicla nigricans, hereafter brant) have shifted their winter distribution northward from Mexico to Alaska (approximately 4500 km) with changes in climate. Alongside this shift, the primary breeding population of brant has declined. To understand the population-level implications of the changing migration strategy of brant, it is important to connect movement and demographic data. Our objectives were to calculate migratory connectivity, a measure of spatial and temporal overlap during the non-breeding period, for Arctic and subarctic breeding populations of brant, and to determine if variation in migration strategies affected nesting phenology and nest survival.MethodsWe derived a migratory network using light-level geolocator migration tracks from an Arctic site (Colville River Delta) and a subarctic site (Tutakoke River) in Alaska. Using this network, we quantified the migratory connectivity of the two populations during the winter. We also compared nest success rates among brant that used different combinations of winter sites and breeding sites.ResultsThe two breeding populations were well mixed during the winter, as indicated by a migratory connectivity score close to 0 (− 0.06) at the primary wintering sites of Izembek Lagoon, Alaska (n = 11 brant) and Baja California, Mexico (n = 48). However, Arctic birds were more likely to migrate the shorter distance to Izembek (transition probability = 0.24) compared to subarctic birds (transition probability = 0.09). Nest survival for both breeding populations was relatively high (0.88–0.92), and we did not detect an effect of wintering site on nest success the following year.ConclusionsNest survival of brant did not differ among brant that used wintering sites despite a 4500 km difference in migration distances. Our results also suggested that the growing Arctic breeding population is unlikely to compensate for declines in the larger breeding population of brant in the subarctic. However, this study took place in 2011–2014 and wintering at Izembek Lagoon may have greater implications for reproductive success under future climate conditions.

IntroductionEnvironmental DNA (eDNA) metabarcoding of water is increasingly being used to monitor coastal biodiversity shifts. However, we have limited knowledge of whether samples collected during discreet temporal periods depict holistic ecosystem changes over longer time spans.MethodsHere, we show how eDNA community structure varies across repeated sampling events at different temporal scales ranging from years to months to days at an Arctic coastal site, Churchill (Canada), using metabarcoding analyses of water eDNA samples with four universal primer pairs (two primers in COI and two in the 18S rRNA).ResultsDaily variations were highly dynamic and less structured, likely due to the stochastic nature of estuarine ecosystems, but there was a clear annual consistency in eDNA communities with a high proportion of shared taxa between years. However, monthly sampling was the most efficient for capturing holistic biodiversity.DiscussionWe provide recommendations for optimal eDNA metabarcoding sampling design based on our observations. The study underscores the importance of understanding biological and physical factors altering eDNA detection to improve the efficiency of detecting and interpreting long-term eDNA changes.

Abstract. Temporally continuous snow depth estimates are vital for understanding changing snow patterns and impacts on permafrost in the Arctic. We trained a random forest machine learning model to predict snow depth from variability in snow–ground interface temperature. The model performed well on Alaska's Seward Peninsula where it was trained and at Arctic evaluation sites (RMSE ≤ 0.15 m). It performed poorly at temperate sites with deeper snowpacks, partially due to training data limitations. Small temperature sensors are cheap and easy to deploy, so this technique enables spatially distributed and temporally continuous snowpack monitoring at high latitudes to an extent previously infeasible.

In Arctic Canada, the development of long-term research sites to study vertebrates (principally marine birds and marine mammals) has supported the safe delivery of collaborative science that is unique in its ability to assess the impacts of rapid environmental change and increasing human-generated pressures (e.g., fisheries bycatch, harvest, tourism, resource development) to wildlife and their habitats. The longevity of these research programs has enabled them to be impactful in their ability to inform environmental and wildlife conservation and management actions in Canada and internationally. In this Special Issue, we have collected a series of papers describing key long-term (>10 years) Arctic wildlife research and monitoring sites (mainly in Nunavut), including why they were developed, their scientific accomplishments, their impact on domestic or international policy, the relevance of the research to local Inuit communities, and how they might evolve to address future conservation issues. In this overview paper, we describe the social, political, and scientific context underlying the development and delivery of science at these sites over the past 40 years, and comment on the role of these programs in supporting the evolution of wildlife research in Arctic Canada.

Near-surface tropospheric ozone depletion events (ODEs) occur in the polar regions during springtime when ozone reacts with bromine radicals, driving tropospheric ozone mole ratios below 15 ppb (part-per-billion; nmol mol-1). ODEs alter atmospheric oxidative capacity by influencing halogen radical recycling mechanisms and the photochemical production of hydroxyl radicals (˙OH). Herein, we examined five years of continuous ozone measurements at two coastal Arctic sites: Utqiaġvik, Alaska and ∼260 km southeast at Oliktok Point, within the North Slope of Alaska oil fields. These data informed seasonal ozone trends, springtime ozone depletion, and the influence of oil field combustion emissions. Ozone depletion occurred frequently during spring: 35% of the time at Utqiaġvik and 40% at Oliktok Point. ODEs often occurred concurrently at both sites (40-92% of observed ODEs per year), supporting spatially widespread ozone depletion. Observed ozone depletion timescales are consistent with transport of ozone-depleted air masses, suggesting regional active bromine chemistry. Local-scale ozone depletion affecting individual sites occurred less frequently. Ozone depletion typically coincided with calm winds and had no clear dependence on temperature. Consistently lower ozone mole ratios year-round at Oliktok Point, compared to Utqiaġvik, indicate local-scale ozone titration within the stable boundary layer by nitric oxide (NO˙) combustion emissions in the Arctic oil fields. Oxidation of combustion-derived volatile organic compounds in the presence of NOx also likely contributes to ozone formation downwind, for example at Utqiaġvik, pointing to complex local and regional impacts of combustion emissions as Arctic anthropogenic activity increases.

Abstract This study examines how human activities influenced soil development at two contrasting Arctic sites: Maiva, a 19th-century farmstead, and Snuvrejohka, a seasonal Sámi reindeer herding settlement in the Lake Torneträsk region, northern Sweden. Using geochemical and geophysical soil analyses, we explore the spatial distribution and vertical development of anthropogenic signals in the soil. At Maiva, prolonged agricultural use and earthworm bioturbation have led to extensive soil mixing and altered soil horizons, resulting in elevated phosphate, lead, and organic matter concentrations in Ap and Ah horizons. In contrast, Snuvrejohka displays more stratified profiles with localized chemical enrichment around hearths, primarily within E horizons. These results highlight how different land-use practices leave distinct geochemical fingerprints in Arctic soils and emphasize the need for sampling strategies adapted to site-specific soil formation processes. Our findings demonstrate that even short-term or seasonal human activities can leave distinct and detectable signatures in Arctic soils. Through an integrated approach combining soil science, geoarchaeological methods, and historical data, this study provides new insights into the reconstruction of past land-use practices and highlights the vulnerability of archaeological soil records in Arctic environments facing rapid climate-driven change.

Abstract. Ozone depletion events (ODEs) occur every spring in the Arctic and have implications for the region's atmospheric oxidizing capacity, radiative balance, and mercury oxidation. Here, we comprehensively analyze ozone, ODEs, and their connection to meteorological and air mass history variables through statistical analyses, back trajectories, and machine learning (ML) at Villum Research Station, Station Nord, Greenland, from 1996 to 2019. We show that the ODE frequency and duration peak in May, followed by April and March, which is likely related to air masses spending more time over sea ice and increases in radiation from March to May. Back trajectories indicate that, as spring progresses, ODE air masses spend more time within the mixed layer, and the geographic origins move closer to Villum. Positive trends in ODE frequency and duration are observed during May (low confidence) and April (high confidence), respectively. Our analysis revealed that ODEs are favorable under sunny, calm conditions, with air masses arriving from northerly wind directions with sea ice contact. The ML model was able to reproduce the ODE occurrence and illuminated that radiation, time over sea ice, and temperature were important variables for modeling ODEs during March, April, and May, respectively. Several variables displayed threshold ranges for contributing to the positive prediction of ODEs vs. non-ODEs, notably temperature, radiation, wind direction, time spent over sea ice, and snow on land. Our ML methodology provides a framework for investigating and comparing the environmental drivers of ODEs between different Arctic sites and can be applied to other atmospheric phenomena (e.g., atmospheric-mercury depletion events).

ABSTRACT Motivated by the need for more paleodata for Pliocene paleoclimate data-model comparison, we revisited unpublished investigations of a fossiliferous site on the Niguanak River in Arctic North America. Analyses of the samples indicates forested conditions during an early phase of sedimentation in which environments were perhaps similar to those near tree line in the modern Anchorage area or farther south along the Pacific coast, whereas during a later phase of sedimentation, environments were characterized by shrub tundra vegetation and were possibly similar to the present-day conditions in the interior of southern Seward Peninsula. We describe the site stratigraphy and discuss the macrofossils and pollen recovered from the sediments, their paleoecological implications, and their significance for paleoclimate and sea ice. Mean annual temperatures were found to be 12.7°C warmer than current, with a pattern of much warmer winters, and less difference in summer warming as observed at other Pliocene Arctic sites. Finally, we discuss possible age assignments for the sediments, based on regional stratigraphy and geomorphology, and the probable sequence of evolution of arctic borderland climate and ecosystems.

Arctic tundra soil depth, more than seasonality, determines active layer bacterial community variation down to the permafrost transition

ABSTRACTConstraining the variability of soil organic carbon (SOC) and total nitrogen (TN) stocks across hillslopes in Low Arctic permafrost‐affected landscapes remains a significant challenge for improving global estimates of permafrost SOC stocks. We investigated SOC and TN stocks across hillslopes at two sites in the Arctic Foothills of Alaska, United States (Happy Valley and Sagwon Hills). Average SOC and TN stocks for the 0–1‐m depth interval were high (52.0 ± 15.1 kg C m−2 and 2.74 ± 0.82 kg N m−2) and linearly related (R2 = 0.74, p < 0.0001). Unlike soils of other permafrost and nonpermafrost landscapes, variability was greatest within rather than between hillslope positions. Furthermore, SOC and TN stocks in the surface 1 m did not exhibit strong patterns by hillslope position and were only weakly associated with major geomorphic parameters that typically predict SOC and TN stocks well in other landscapes. Although sampling at upper hillslope positions was largely limited to depths of less than 1.5 m due to the presence of coarse fragments in reworked glacial till, deeper observations at lower hillslope positions (footslopes, toeslopes, and basins) revealed significantly larger SOC stocks (92.0 ± 18.0 kg C m−2 at 2 m; 117.1 ± 10.4 kg C m−2 at 3 m). The unique small‐scale variability in ice content, cryoturbation, patterned ground, and organic layer thickness on these broad, Low Arctic sites contributes to the relatively homogeneous distribution of SOC and TN stocks across hillslope positions in the top 1 m, but a future focus on deeper sampling may reveal greater differences in SOC and TN stocks.