North Water Polynya Research Articles

Marine Aerosol Records of Arctic Sea‐Ice and Polynya Variability From New Ellesmere and Devon Island Firn Cores, Nunavut, Canada

AbstractSea ice plays a critical role in the Earth’s climate system, including influencing ocean heat uptake, reflecting solar radiation, and contributing to dense water formation. Instrumental records of polar sea ice extent are only available since 1979, however. The short length of such records also limits our knowledge of polynya variability, which can reflect large‐scale atmospheric and climate changes. Ice core proxy records can extend these observations, but require further development and regional validation. We compare chloride and methanesulfonic acid concentrations from two new firn cores from the Canadian Arctic with satellite‐derived observations of regional sea‐ice concentration and polynya variability from 2002 to 2014. The sub‐annual resolution of these cores allows for detailed investigation of how regional sea‐ice concentration is recorded in the ice at Prince of Wales Icefield (POW), Ellesmere Island and Devon Ice Cap (DIC), Devon Island, Nunavut. Over the period 2002–2014 we find that the primary sources of marine aerosols to POW are polynyas within Arctic Canada and the Canada basin of the Arctic Ocean, whereas the primary sources of marine aerosols to DIC are a broader region of the Queen Elizabeth Islands, Baffin Bay, and the Arctic Ocean. Marine aerosol sources to the two core sites are distinct, reflecting different moisture source regions and, likely, differing transport pathways. Air mass back trajectory results support the satellite‐derived results. Glaciochemical records from this dynamic, warming region may provide a proxy for reconstructing North Water polynya and other regional polynya and shore‐lead variability prior to the satellite era.

Arctic Cloud Response to a Perturbation in Sea Ice Concentration: The North Water Polynya

AbstractSurface and atmosphere energy exchanges play an important role in the Arctic climate system by influencing the lower atmospheric stability and humidity, sea ice melt and growth, and surface temperature. Sea ice significantly alters the character of these energy exchanges relative to ice‐free ocean. The observed decline in Arctic sea ice since 1979 motivates questions related to the evolving role of surface‐atmosphere coupling and potential feedbacks on the Arctic system. Due to the strong wintertime cloud warming effect, a critical question concerns the potential response of low clouds to Arctic sea ice decline. Previous approaches relied on interannual variability to investigate the cloud response to sea ice decline. However, the covariation between atmospheric conditions and sea ice makes it difficult to define an observational control when using interannual variability. To circumvent this difficulty, we exploit the recurring North Water polynya, an episodic opening in the northern Baffin Bay sea ice, as a natural laboratory to isolate the cloud response to a rapid, near‐step perturbation in sea ice. Our results show that during the event, (a) low‐cloud cover is 10%–33% larger over the polynya than nearby sea ice, (b) cloud liquid water content is up to 400% larger over the polynya than nearby sea ice, and (c) the surface cloud radiative effect is 18 W m−2 larger over the polynya than nearby sea ice. Our results provide evidence that the low‐cloud response during a polynya is a positive feedback lengthening the event.

On the Physical Settings of Ice Bridge Formation in Nares Strait

AbstractThe ice bridge that forms seasonally across Nares Strait impedes the southward transport of sea ice from the Lincoln Sea to Baffin Bay and contributes to the maintenance of the North Water Polynya. Previous studies have quantified how the bridge affects ice export and highlighted a long term decline in the duration of the bridge; however, the specific mechanism by which the bridge forms has remained unstudied. In this study we first used a mix of satellite imagery to refine the timing of formation for the 16 bridges that formed between 2000 and 2021, and subsequently examine the atmospheric and oceanic forcing around these events. It was found that, on average, the ice bridges formed 3 days earlier than reported in previous studies. In general, the bridges formed during periods of cold air temperatures (less than −15°C), around neap tide, and during a cessation or even reversal in the prevailing north‐northeasterly winds. Specific quantitative criteria of the environmental conditions favorable for bridge formation are presented and discussed. It was shown, however, that the alignment of these conditions does not always lead to the formation of a bridge, indicating that other factors such as ice thickness and landfast ice stability may limit the formation. A comparison of ice freeboard in Kane Basin between winter 2020 (bridge) and 2019 (no bridge) revealed that the ice pack was thinner in 2019, which may have precluded the formation of the bridge. This is critical as the Arctic ice pack continues to thin.

Vulnerability of the North Water ecosystem to climate change

High Arctic ecosystems and Indigenous livelihoods are tightly linked and exposed to climate change, yet assessing their sensitivity requires a long-term perspective. Here, we assess the vulnerability of the North Water polynya, a unique seaice ecosystem that sustains the world’s northernmost Inuit communities and several keystone Arctic species. We reconstruct mid-to-late Holocene changes in sea ice, marine primary production, and little auk colony dynamics through multi-proxy analysis of marine and lake sediment cores. Our results suggest a productive ecosystem by 4400–4200 cal yrs b2k coincident with the arrival of the first humans in Greenland. Climate forcing during the late Holocene, leading to periods of polynya instability and marine productivity decline, is strikingly coeval with the human abandonment of Greenland from c. 2200–1200 cal yrs b2k. Our long-term perspective highlights the future decline of the North Water ecosystem, due to climate warming and changing sea-ice conditions, as an important climate change risk.

A climatology of wintertime low-level jets in Nares Strait

Intense, southward low-level winds are common in Nares Strait, between Ellesmere Island and northern Greenland. The steep topography along Nares Strait leads to channelling effects, resulting in an along-strait flow. This research study presents a 30-year climatology of the flow regime from simulations of the COSMO-CLM climate model. The simulations are available for the winter periods (November–April) 1987/88 to 2016/17, and thus, cover a period long enough to give robust long-term characteristics of Nares Strait. The horizontal resolution of 15 km is high enough to represent the complex terrain and the meteorological conditions realistically. The 30-year climatology shows that LLJs associated with gap flows are a climatological feature of Nares Strait. The maximum of the mean 10-m wind speed is around 12 m s-1 and is located at the southern exit of Smith Sound. The wind speed is strongly related to the pressure gradient. Single events reach wind speeds of 40 m s-1 in the daily mean. The LLJs are associated with gap flows within the narrowest parts of the strait under stably stratified conditions, with the main LLJ occurring at 100–250 m height. With increasing mountain Froude number, the LLJ wind speed and height increase. The frequency of strong wind events (>20 m s-1 in the daily mean) for the 10 m wind shows a strong interannual variability with an average of 15 events per winter. Channelled winds have a strong impact on the formation of the North Water polynya.

Interspecific differences in feeding selectivity shape isotopic niche structure of three ophiuroids in the Arctic Ocean

Understanding the mechanisms that support feeding interactions and species co-occurrence in regions subject to rapid environmental changes is becoming increasingly important to predict future trends in population dynamics. However, there is still little information available on the trophic ecology for many benthic species to help us better understand trophic interactions and individual trophic roles. Here, we used stable isotopes (δ13C, δ15N) in conjunction with the Bayesian ellipses approach to explore spatial trends in isotopic niche width and overlap of 3 syntopic arctic brittle stars (Echinodermata: Ophiuroidea; Ophiacantha bidentata, Ophiocten sericeum, and Ophiopleura borealis) in Baffin Bay (BB), the Canadian Arctic Archipelago (CAA), and the North Water Polynya (NOW). These 3 coexisting ophiuroids displayed great interspecific plasticity in foraging behaviors and showed a high degree of inter-individual dietary flexibility. However, differences in surface carbon composition drove the variability of resource utilization at the individual level across stations, which in turn affected trophic interactions, niche overlaps, and isotopic niche breadth of ophiuroids. Greater niche overlap was found in the highly productive region of the NOW, where consumers exhibited similar food selectivity, whereas an increase in niche segregation occurred in regions with greater sea-ice concentration. These results suggest that isotopic niche size reflects individual responses to fluctuations in food availability and possibly past competition, both induced by local oceanographic features. Our study indicates that niche parameters of ophiuroids can respond quickly to ecological and environmental gradients, which suggests an important adaptability of these species facing multiple stressors.

Shells of the bivalve Astarte moerchi give new evidence of a strong pelagic-benthic coupling shift occurring since the late 1970s in the North Water polynya.

Climate changes in the Arctic may weaken the currently tight pelagic-benthic coupling. In response to decreasing sea ice cover, arctic marine systems are expected to shift from a 'sea-ice algae-benthos' to a 'phytoplankton-zooplankton' dominance. We used mollusc shells as bioarchives and fatty acid trophic markers to estimate the effects of the reduction of sea ice cover on the food exported to the seafloor. Bathyal bivalve Astarte moerchi living at 600 m depth in northern Baffin Bay reveals a clear shift in growth variations and Ba/Ca ratios since the late 1970s, which we relate to a change in food availability. Tissue fatty acid compositions show that this species feeds mainly on microalgae exported from the euphotic zone to the seabed. We, therefore, suggest that changes in pelagic-benthic coupling are likely due either to local changes in sea ice dynamics, mediated through bottom-up regulation exerted by sea ice on phytoplankton production, or to a mismatch between phytoplankton bloom and zooplankton grazing due to phenological change. Both possibilities allow a more regular and increased transfer of food to the seabed. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.

An Examination of the Non-Formation of the North Water Polynya Ice Arch

The North Water (NOW), situated between Ellesmere Island and Greenland in northern Baffin Bay, is the largest recurring polynya in the Canadian Arctic. Historically, the northern border of the NOW is defined by an ice arch that forms annually in Kane Basin, which is part of the Nares Strait system. In 2007 the NOW ice arch failed to consolidate for the first time since observations began in the 1950s. The non-formation of the NOW ice arch occurred again in 2009, 2010, 2017 and 2019. Satellite Advanced Very High Resolution Radiometry data shows that large floes broke off from the normally stable landfast ice in Kane Basin for each of these years, impeding ice arch formation. A closer analysis of a 2019 event, in which 2500 km2 of ice sheared away from Kane Basin, indicates that significant tidal forces played a role. The evidence suggests that thinning ice from a warming climate combined with large amplitude tides is a key factor in the changing ice dynamics of the NOW region. The non-formation of the NOW ice arch results in an increased loss of multiyear ice through Nares Strait.

Local and regional controls on Holocene sea ice dynamics and oceanography in Nares Strait, Northwest Greenland

Nares Strait is one of three channels that connect the Arctic Ocean to Baffin Bay. Unique sea-ice conditions in the strait lead to the formation of landfast ice arches at its northern and southern ends. These ice arches regulate Arctic sea-ice and freshwater export through the strait and promote the opening of the North Water polynya. The present study addresses the paucity of pre-satellite records of environmental conditions in the Nares Strait area, and aims at reconstructing Holocene sea-ice conditions and ocean circulation in the strait. The investigation is based on a marine sediment core strategically retrieved from under the current ice arch in Kane Basin to the south of Nares Strait, and provides a continuous record spanning the past ca 9 kyrs. We use benthic foraminiferal assemblages and sea-ice biomarkers to infer changes in Holocene ocean circulation and sea-ice conditions in Kane Basin. The establishment of the modern ocean circulation in Kane Basin is related to ice sheet retreat and postglacial rebound, while changes in sea-ice cover concur with major shifts in the Arctic Oscillation (AO). Our results suggest that sea-ice cover in Kane Basin was highly variable between ca 9.0 and 8.3 cal. ka BP, before increasing, probably in link with the 8.2 cold event and the opening of Nares Strait. A short period of minimum sea-ice cover and maximum Atlantic bottom water influence occurred between ca 8.1 and 7.5 cal. ka BP, when Kane Basin was deeper than for the remaining of the Holocene. As atmospheric temperatures dropped, sea-ice cover intensified in Kane Basin between ca 7.5 and 5.5 cal. ka BP, but strong winds under prevailing positive-like AO conditions likely prevented the formation of ice arches in Nares Strait. During this time, our micropaleontological data show that Atlantic water was progressively excluded from Kane Basin by the postglacial isostatic rebound. Increasingly cooler atmospheric temperatures and a shift towards more negative phases of the AO may have promoted the establishment of ice arches in Nares Strait between ca 5.5 and 3.0 cal. ka BP. Instabilities in the Kane Basin ice arch ca 3.0 cal. ka BP coincide with a shift towards prevailing positive phases of the AO, while a brief recovery of the ice arch occurred during more negative-like AO conditions between ca 1.2 and 0.2 cal. ka BP.

A Study of the North Water Polynya Ice Arch using Four Decades of Satellite Data

Polynyas are sections of the polar ocean that remain relatively ice-free during winter, imparting significant physical and biological impact on the region. The North Water polynya (NOW) situated between Ellesmere Island and Greenland is the largest recurring Arctic polynya. Historically, the NOW forms every season when Arctic Ocean floes moving southward through Nares Strait become congested and form an ice arch that defines the northern border of the polynya. This blockage usually forms during winter and breaks down in spring. It is conjectured that the polynya is maintained by latent heat of fusion from the continuous formation of new ice as floes are swept southward from the ice arch by wind and ocean currents. Analysis of four decades of satellite imagery indicates a growing instability in the location of the ice arch, challenging previous models of polynya maintenance. A linear trend of the data indicates the number of days of Nares Strait blockage has decreased 2.1 days/year between 1979 and 2019 with wide interannual variations. Prior to 2007, ice arches blocked Nares Strait an average of 177 days/year compared to 128 days/year since that time. The overall trend of reduced ice arch duration is a contributing factor to the dramatic loss of multiyear ice in the Arctic basin.

Stable isotope signatures of Holocene syngenetic permafrost trace seabird presence in the Thule District (NW Greenland)

Abstract. Holocene permafrost from ice wedge polygons in the vicinity of large seabird breeding colonies in the Thule District, NW Greenland, was drilled to explore the relation between permafrost aggradation and seabird presence. The latter is reliant on the presence of the North Water Polynya (NOW) in the northern Baffin Bay. The onset of peat accumulation associated with the arrival of little auks (Alle alle) in a breeding colony at Annikitisoq, north of Cape York, is radiocarbon-dated to 4400 cal BP. A thick-billed murre (Uria lomvia) colony on Appat (Saunders Island) in the mouth of the Wolstenholme Fjord started 5650 cal BP. Both species provide marine-derived nutrients (MDNs) that fertilize vegetation and promote peat growth. The geochemical signature of organic matter left by the birds is traceable in the frozen Holocene peat. The peat accumulation rates at both sites are highest after the onset, decrease over time, and were about 2-times faster at the little auk site than at the thick-billed murre site. High accumulation rates induce shorter periods of organic matter (OM) decomposition before it enters the perennially frozen state. This is seen in comparably high C∕N ratios and less depleted δ13C, pointing to a lower degree of OM decomposition at the little auk site, while the opposite pattern can be discerned at the thick-billed murre site. Peat accumulation rates correspond to δ15N trends, where decreasing accumulation led to increasing depletion in δ15N as seen in the little-auk-related data. In contrast, the more decomposed OM of the thick-billed murre site shows almost stable δ15N. Late Holocene wedge ice fed by cold season precipitation was studied at the little auk site and provides the first stable-water isotopic record from Greenland with mean δ18O of -18.0±0.8 ‰, mean δD of -136.2±5.7 ‰, mean d excess of 7.7±0.7 ‰, and a δ18O-δD slope of 7.27, which is close to those of the modern Thule meteoric water line. The syngenetic ice wedge polygon development is mirrored in testacean records of the little auk site and delineates polygon low-center, dry-out, and polygon-high-center stages. The syngenetic permafrost formation directly depending on peat growth (controlled by bird activity) falls within the period of neoglacial cooling and the establishment of the NOW, thus indirectly following the Holocene climate trends.

Biodiversity and Species Change in the Arctic Ocean: A View Through the Lens of Nares Strait

Nares Strait is the Northern most outflow gateway of the Arctic Ocean, with a direct connection to the remaining multi-year ice covered central Arctic Ocean. Nares Strait itself flows into the historically highly productive North Water Polynya (Pikialasorsuaq). Satellite data shows that Nares Strait ice is retreating earlier in the season. The early season surface chlorophyll signal, which was a characteristic of the North Water, has also moved north into Nares Strait. However, given the vast differences in the hydrography and physical oceanographic structure of the North Water and Nares Strait there is no a priori reason to assume that the species assemblages and overall productivity this region between Greenland and Canada will be maintained in the face of ongoing sea ice decline. The North Water’s high marine mammal and bird populations are dependent on seasonally persistent diatom dominated phytoplankton productivity, and although there have been several studies on North Water phytoplankton, virtually nothing is known about the communities in Nares Strait. Here we investigated the microbial eukaryotes, including phytoplankton in Nares Strait using high throughput amplicon sequencing. Samples were collected from Kennedy Channel below the northern ice edge of Nares Strait through the Kane Basin and into the northern limit of the North Water. The physical oceanographic structure and initial community rapidly changed between the faster flowing Kennedy Channel and the comparatively wider shallower Kane Basin. The community changes were evident in both the upper euphotic zone and the deeper aphotic zone. Heterotrophic taxa were found in the deeper waters along with ice algae that would have originated further to the north following release from the ice. Although there was a high proportion of pan-arctic species throughout, the Nares Strait system showed little in common with the Northern North Water station, suggesting a lack of connectivity. We surmise that a direct displacement of the rich North Water ecosystem is not likely to occur. Overall our study supported the notion that the microbial eukaryotic community, which supports ecosystem function and secondary productivity is shaped by a balance of historic and current processes, which differed by seascape.

POTENTIALS FOR THE PROTECTION OF PIKIALASORSUAQ IN THE SHADOW OF CONTEMPORARY MARITIME INDUSTRIES

The Pikialasorsuaq or North Water Polynya is a polynya that lies between Greenland and Canada in northern Baffin Bay. For centuries small scale family-based markets had been developed between the Inuit of two sides based on cross-border transportation. However, the emerged modern maritime industries have posed serious challenges for the polynya where the free cross-border transportation is nowadays banned, and the environmental threat has become a reality deteriorated further by climate change. Indigenous participation and Free Prior and Informed Consent are crucial for the conservation of the polynya. Accordingly, this article was designed as a descriptive study of the current situation in Pikialasorsuaq, providing the legal framework for the protection of the region and highlighting the existing system’s shortcomings.

Baffin Bay sea ice inflow and outflow: 1978–1979 to 2016–2017

Abstract. Baffin Bay serves as a huge reservoir of sea ice which would provide the solid freshwater sources to the seas downstream. By employing satellite-derived sea ice motion and concentration fields, we obtain a nearly 40-year-long record (1978–1979 to 2016–2017) of the sea ice area flux through key fluxgates of Baffin Bay. Based on the estimates, the Baffin Bay sea ice area budget in terms of inflow and outflow are quantified and possible causes for its interannual variations and trends are analyzed. On average, the annual (September–August) inflows through the northern gate and Lancaster Sound are on the order of 205.8(±74.7)×103 km2 and 55.2(±17.8)×103 km2. In particular, a comparison with published results seems to suggest that about 75 %–85 % of the inflow through the northern gates is newly formed ice produced in the recurring North Water Polynya (NOW), in addition to the inflow via Nares Strait and Jones Sound. Meanwhile, the mean outflow via the southern gate approaches 394.3(±110.2)×103 km2. The distinct interannual variability for ice area flux through the northern gate and southern gate is partly explained by wind forcing associated with cross-gate sea level pressure difference, with correlations of 0.62 and 0.68, respectively. Also, significant increasing trends are found for the annual sea ice area flux through the three gates, amounting to 38.9×103, 82.2×103, and 7.5×103 km2 decade−1 for the northern gate, southern gate, and Lancaster Sound. These trends are chiefly related to the increasing ice motion, which is associated with thinner ice owing to the warmer climate (i.e., higher surface air temperature and shortened freezing period) and increased air and water drag coefficients over the past decades.

Zooplankton phenology may explain the North Water polynya’s importance as a breeding area for little auks

Zooplankton phenology may explain the North Water polynya’s importance as a breeding area for little auks

An Aircraft-Based Study of Strong Gap Flows in Nares Strait, Greenland

AbstractGap flows and the stable boundary layer were studied in northwest Greenland during the aircraft-based Investigation of Katabatic Winds and Polynyas during Summer (IKAPOS) experiment in June 2010. The measurements were performed using the research aircraft POLAR 5 of Alfred Wegener Institute (AWI; Bremerhaven). Besides navigational and basic meteorological instrumentation, the aircraft was equipped with radiation and surface temperature sensors and a turbulence measurement system. In the area of Smith Sound at the southern end of the Nares Strait, a stable, but fully turbulent, boundary layer with strong winds of up to 22 m s−1 was found during conditions of synoptically induced northerly winds through the Nares Strait. Strong surface inversions were present in the lowest 100–200 m. As a consequence of channeling effects, a well-pronounced low-level jet system was documented for each of four flights. The wind maximum is located at 20–50-km distance from the exit of Smith Sound. The 3D boundary layer structure past this gap is studied in detail. The channeling process is consistent with gap flow theory. The flow through the gap and over the surrounding mountains leads to the lowering of isotropic surfaces and the acceleration of the flow. The orographically channeled flow through Smith Sound plays a key role for the formation of the North Water polynya being the largest ice-producing polynya in the Arctic.

Impact of model resolution on the representation of the air–sea interaction associated with the North Water Polynya

The North Water Polynya (NOW), one of the largest and most productive of the Arctic polynyas, is situated just downwind of Smith Sound, the southern terminus of Nares Strait. The high topography along the narrow strait results in common occurrences of high‐speed northerly flow that is accelerated through Smith Sound. The resulting divergence of the surface wind field contributes to the formation of the polynya. Within the NOW, the combination of high winds, cold and dry Arctic air, and reduced ice cover can result in the transfer of heat, moisture and momentum from the ocean to the atmosphere. Much of our knowledge of the air–sea interaction over the NOW comes from atmospheric models, many of which have horizontal resolutions greater than 75 km. As such, there is concern that they may under‐represent the characteristics of the flow in the region, impacting the representation of the resulting air–sea interaction. In this study we use a set of atmospheric analyses with a common lineage but with horizontal resolutions that range from ∼75 to ∼9 km to characterize this interaction. We show that increasing the model resolution leads to an improved representation of the kinematics of the flow along the strait. However, details of the thermodynamics are more nuanced and, as a result, the intensity of the air–sea interaction over the NOW does not simply increase with increasing resolution. The results suggest that a horizontal atmospheric model resolution lower than ∼30 km is needed to represent the air–sea interaction over the NOW and that a re‐evaluation of previous modelling efforts in the region is needed.

The history of seabird colonies and the North Water ecosystem: Contributions from palaeoecological and archaeological evidence

The North Water (NOW) polynya is one of the most productive marine areas of the Arctic and an important breeding area for millions of seabirds. There is, however, little information on the dynamics of the polynya or the bird populations over the long term. Here, we used sediment archives from a lake and peat deposits along the Greenland coast of the NOW polynya to track long-term patterns in the dynamics of the seabird populations. Radiocarbon dates show that the thick-billed murre (Uria lomvia) and the common eider (Somateria mollissima) have been present for at least 5500 cal. years. The first recorded arrival of the little auk (Alle alle) was around 4400 cal. years bp at Annikitsoq, with arrival at Qeqertaq (Salve Ø) colony dated to 3600 cal. years bp. Concentrations of cadmium and phosphorus (both abundant in little auk guano) in the lake and peat cores suggest that there was a period of large variation in bird numbers between 2500 and 1500 cal. years bp. The little auk arrival times show a strong accord with past periods of colder climate and with some aspects of human settlement in the area.

Walrus history around the North Water: Human\u2013animal relations in a long-term perspective

This article highlights the relationship between walruses and humans in and around the North Water polynya in a long-term perspective. The present study draws on a combination of biological, archaeological, archaeo-zoological, historical, and ethnographic sources covering the period from the 8th century ad to the late 20th century. The study demonstrates that the walrus was an important resource of meat, blubber, and other products throughout all the studied periods, if always supplemented by other kinds of game. It is suggested that walrus distribution and behaviour, as well as hunting strategies and technologies historically constituted a powerful component not only in forming human action and social life in the region but also in serving as an imaginative resource. It is further argued that the walrus and the walrus hunt still play a significant role in the present community living on the edge of the North Water, even if the hunt is increasingly circumscribed due to changing ice conditions.

On the crucial importance of a small bird: The ecosystem services of the little auk (Alle alle) population in Northwest Greenland in a long-term perspective

The little auk is the most numerous seabird in the North Atlantic and its most important breeding area is the eastern shores of the North Water polynya. Here, a population of an estimated 33 million pairs breeds in huge colonies and significantly shapes the ecosystem. Archaeological remains in the colonies document that the little auk has been harvested over millennia. Anthropological research discloses how the little auk has a role both as social engineer and as a significant resource for the Inughuit today. The hunting can be practiced without costly equipment, and has no gender and age discrimination in contrast to the dominant hunt for marine mammals. Little auks are ecological engineers in the sense that they transport vast amounts of nutrients from sea to land, where the nutrients are deposited as guano. Here, the fertilized vegetation provides important foraging opportunities for hares, geese, fox, reindeer, and the introduced muskox. We estimate that the relative muskox density is ten times higher within 1 km of little auk fertilized vegetation hotspots.