Baffin Island Research Articles

Experimental investigation of hydrogen isotope fractionation during hydration of olivine-hosted melt inclusions: Implications for D/H in Baffin Island picrites

Olivine-hosted melt inclusions are used to investigate the hydrogen isotope compositions (D/H) of Earth's mantle reservoirs. Studies have shown, however, that hydrogen in melt inclusion can equilibrate rapidly in response to changes to the external environment via the diffusion of protons (H+) and deuterons (D+) through the host olivine. Given that protons diffuse faster than deuterons, a kinetic fractionation of hydrogen isotopes is expected to accompany both the hydration and dehydration of melt inclusions. Other volatile species in the melt inclusion may also be affected by changes to the internal pressure and/or oxygen fugacity (fO2). Here we report results from experiments designed to investigate the behaviors of volatiles and hydrogen isotopes during the hydration of olivine-hosted melt inclusions. We show that the concentration of H2O in initially H2O-poor inclusions increases rapidly (up to ∼4 wt.% within 24 h) when the host olivine is in contact with aqueous fluid at 1200 °C and 300 MPa. The extent of hydration is controlled by time, temperature, melt inclusion volume, and H+ diffusion distance. Hydrogen isotopes initially become lighter (i.e., D/H decreases) as hydration proceeds, defining a negative correlation with H2O concentration. This trend reverses with increasing hydration as the inclusions must eventually equilibrate with the external fluid. These experimental results agree well with diffusion calculations carried out using a spherical geometry and a lattice diffusivity of 10–11.2±0.2 m2/s for H+ at 1200 °C. Therefore, anomalously light hydrogen isotopes in olivine-hosted melt inclusions from Baffin Island may not be taken as representative of the composition of the mantle source unless post-entrapment hydration can be excluded as a possibility. An increase in CO2 concentration and a significant drop in sulfur concentration accompany hydration of the melt inclusions in our experiments. The former is consistent with an observed decrease in vapor bubble size and results from a hydration-induced internal pressure increase. The latter is ascribed to the exsolution of molten sulfide from the silicate melt, which might be related to a lower fO2 in the experiments as compared to the starting materials. We find no evidence for exchange of F or Cl between the melt inclusion and external fluid.

Seasonal Variability in Baffin Bay

AbstractThree dominant characteristics and underlying dynamics of the seasonal cycle in Baffin Bay are discussed. The study is based on a regional, high‐resolution coupled sea ice‐ocean numerical model that complements our understanding drawn from observations. Subject to forcing from the atmosphere, sea ice, Greenland, and other ocean basins, the ocean circulation exhibits complex seasonal variations that influence Arctic freshwater storage and export. The basin‐scale barotropic circulation is generally stronger (weaker) in summer (winter). The interior recirculation (∼2 Sv) is primarily driven by oscillating along‐topography surface stress. The volume transport along the Baffin Island coast is also influenced by Arctic inflows (∼0.6 Sv) via Smith Sound and Lancaster Sound with maximum (minimum) in June‐August (October‐December). In addition to the barotropic variation, the Baffin Island Current also has changing vertical structure with the upper‐ocean baroclinicity weakened in winter‐spring. It is due to a cross‐shelf circulation associated with spatially variable ice‐ocean stresses that flattens isopycnals. Greenland runoff and sea ice processes dominate buoyancy forcing to Baffin Bay. Opposite to the runoff that freshens the west Greenland shelf, stronger salinification by ice formation compared to freshening by ice melt enables a net densification in the interior of Baffin Bay. Net sea ice formation in the past 30 years contributes to ∼25% of sea ice export via Davis Strait. The seasonal variability in baroclinicity and water mass transformation changes in recent decades based on the simulation.

Morphological variation in first-formed shells of the Ordovician Paucicrura–Diceromyonia brachiopod lineage of North America

Abstract First-formed shells of several species of Dalmanellidae (Brachiopoda) from the Ordovician (Katian) of North America were measured and compared: Cincinnetina multisecta, Diceromyonia tersa, Diceromyonia storeya, Paucicrura corpulenta, Paucicrura rogata, and Paucicrura sillimani. Sizes and structures of the first-formed shells suggest that members of this family had planktotrophic subadults, with some species showing indications of only an unshelled larval stage and others showing both a larval stage and a shelled juvenile stage. This differs from modern rhynchonelliformean brachiopods, which all possess only a lecithotrophic larval stage. The range of sizes of first-formed shells of most studied species are similar, but P. sillimani of Baffin Island, Canada (middle Katian), has a significantly larger first-formed shell that formed during an extended juvenile stage. This may have enabled the species to colonize newly exploitable habitats during an interval of rapid sea level rise in Laurentia during the Katian. This plasticity of developmental modes in the Dalmanellidae shows not only that using distantly related modern brachiopods as an analog for extinct Paleozoic lineages may be misleading, but also that development can vary within a single lineage and that timing of developmental stages should not be considered a reliable character for use in phylogenetic studies of brachiopods.

Ice Darkening on Turner Glacier in Auyuittuq National Park, Nunavut

The glaciers of the Canadian Arctic are currently the third largest contributor to global sea level rise due to enhanced Arctic warming driving increased glacier melt and runoff (Zemp et al., 2019). Recent modelling suggests that the glaciers of the southern Qikiqtaaluk region, specifically Baffin and Bylot Islands, are 70% more sensitive to 1°C of warming (Brice et al., 2018). However, these studies lack field-based data to contextualize the drivers of glacier change in this region. Light absorbing particles (LAPs) such as dust, ash, and algae lower the albedo of snow and ice, which is the fraction of light a surface reflects, leading to an increase in the absorption of incoming radiation (Aubry-Wake et al., 2022). On glaciers in western Canada (Engstrom et al., 2022), the European Alps (Di Mauro et al., 2020) and south-western Greenland (Cook et al., 2020), positive feedback mechanisms have been discovered where summer snow and ice melt, augmented by LAPs, leads to the localized release of nutrients in ice and the subsequent enhanced growth of algae. Preliminary remote sensing analysis revealing a dark purple hue on glaciers in the Akshayuk Pass region of Auyuittuq National Park in Baffin Island, NU indicate these processes are likely occurring. The question of how this phenomenon is impacting glacier albedo, and therefore glacier melt which has implications for mass balance and regional sea level rise in the Canadian High Arctic has yet to be answered. Field-based sampling of LAPs on Turner Glacier, characterized through light microscopy and scanning electron microscopy, combined with in-situ hyperspectral spectroradiometer measurements (320nm-1100nm) of the sampled LAPs, and fine resolution (1cm) UAV surveys of sampling sites, are integral to develop a field-calibrated remote sensing approach to monitor LAP accumulation on the glacier surface and to assess the associated melt potential.

Arctic raptor occupancy and reproductive success near a remote open-cut mine: North Baffin Island, Nunavut

Arctic raptor occupancy and reproductive success near a remote open-cut mine: North Baffin Island, Nunavut

Strong pCO2 Undersaturation in an Arctic Sea: A Decade of Spatial and Temporal Variability in Baffin Bay

AbstractUtilizing an 11‐year (2011–2021) data set, we report surface‐ocean pCO2 in Baffin Bay during the open‐water season (June–October) to establish a baseline understanding of surface seawater carbon dynamics in this region. We found pCO2 was strongly undersaturated (70–130 μatm below saturation, depending on year), albeit with substantial regional variability. Though temperature was found to be a generally strong control of pCO2, sea‐ice dynamics and other non‐thermal drivers controlled pCO2 at certain times and in certain regions. The Baffin Island Current region (western Baffin Bay) experienced relatively high pCO2 during instances of high sea‐ice cover, usually in early spring. Average pCO2 was comparatively lower in the West Greenland Current region (eastern Baffin Bay) which is ice‐free substantially longer (by 3–4 months) and where temperature acted as the dominant control to pCO2. With respect to temporal variations, June had the lowest pCO2 of the open‐water season, coinciding with active sea‐ice melt. Surface‐ocean pCO2 then increased month‐to‐month through July and August due to warming and decreased meltwater dilution, increasing again into September before stabilizing into October. Generally, non‐thermal controls acted to decrease pCO2 during mid‐summer (possibly primary production, sea‐ice melt, and circulation), but acted to increase pCO2 during early fall (vertical mixing). Despite spatial and temporal variation over the open‐water season, persistent undersaturation suggests that Baffin Bay is a potentially strong CO2 sink, even in comparison to other uptake regions across the western Arctic.

Rock avalanches in northeastern Baffin Island, Canada: understanding low occurrence amid high hazard potential

Rock avalanches in fjord environments can cause direct catastrophic damage and trigger secondary submarine landslides and tsunamis. These are well-documented in Greenland, Norway, and Alaska but have gone largely unreported in the extensive fjord terrain of the eastern Canadian Arctic. We provide the first inventory of rock avalanche deposits in northeastern Baffin Island—a region characterized by moderate to high seismic hazard, steep and high-walled fjords and glacial valleys, active deglaciation, and observed climate warming. Over a broad study area of ~60,000 km2, one sixth of the terrain had sufficient slope height and gradient to potentially generate rock avalanches. Within that hazard zone, we identified eight rock avalanche deposits at six locations. Only three rock avalanche deposits at two locations are dated, using aerial imagery (1958-present), to the last century while five deposits at four locations are inferred as syn- to post-glacial, likely occurring shortly after local debuttressing. These total numbers fall well below documented inventories from Greenland, Norway, and Alaska. We hypothesize that (1) continuous permafrost persists throughout this region and continues to act as a stabilizing factor and (2) rock mass quality is high in areas of most extreme relief contrast within the study region relative to analogous high-latitude fjord systems such as those in southwestern Greenland. We suggest that Baffin Island is currently in a period of quasi-stability that follows the intense instability during initial deglaciation, yet precedes the higher anticipated slope instability that may occur during permafrost degradation.

Dietary plasticity and broad North Atlantic origins inferred from bulk and amino acid-specific δ15N and δ13C favour killer whale range expansions into Arctic waters.

Killer whales (Orcinus orca) occur seasonally in the eastern Canadian Arctic (ECA), where their range expansion associated with declining sea ice have raised questions about the impacts of increasing killer whale predation pressure on Arctic-endemic prey. We assessed diet and distribution of ECA killer whales using bulk and compound-specific stable isotope analysis (CSIA) of amino acids (AA) of 54 skin biopsies collected from 2009 to 2020 around Baffin Island, Canada. Bulk ECA killer whale skin δ15N and δ13C values did not overlap with potential Arctic prey after adjustment for trophic discrimination, and instead reflected foraging history in the North Atlantic prior to their arrival in the ECA. Adjusted killer whale stable isotope (SI) values primarily overlapped with several species of North Atlantic baleen whales or tuna. Amino acid (AA)-specific δ15N values indicated the ECA killer whales fed primarily on marine mammals, having similar glutamic acid δ15N-phenylalanine δ15N (δ15NGlx-Phe) and threonine δ15N (δ15NThr) as mammal-eating killer whales from the eastern North Pacific (ENP) that served as a comparative framework. However, one ECA whale grouped with the fish-eating ENP ecotype based δ15NThr. Distinctive essential AA δ13C of ECA killer whale groups, along with bulk SI similarity to killer whales from different regions of the North Atlantic, indicates different populations converge in Arctic waters from a broad source area. Generalist diet and long-distance dispersal capacity favour range expansions, and integration of these insights will be critical for assessing ecological impacts of increasing killer whale predation pressure on Arctic-endemic species.

Using Relationships Between Vegetation and Surface Soil Biogeochemical Properties to Assess Regional Soil Carbon Inventories for South Baffin Island, Nunavut, Canada

AbstractAs Arctic regions warm rapidly, it is unclear whether high‐latitude soil carbon (C) will decrease or increase. Predicting future dynamics of Arctic soil C stocks requires a better understanding of the quantities and controls of soil C. We explore the relationship between vegetation and surface soil C in an understudied region of the Arctic: Baffin Island, Nunavut, Canada. We combined soil C data for three vegetation types—polar desert, mesic tundra, and wet meadow—with a vegetation classification to upscale soil C stocks. Surface soil C differed significantly across vegetation types, and interactions existed between vegetation type and soil depth. Polar desert soils were consistently mineral, with relatively thin organic layers, low percent C, and high bulk density. Mesic soils exhibited an organic‐rich epipedon overlying mineral soil. Wet meadows were consistently organic soil with low bulk density and high percent C. For the top 20 cm, polar desert contained the least soil C (2.17 ± 0.48 kg m−2); mesic tundra had intermediate C (8.92 ± 0.74 kg m−2); wet meadow stored the most C (13.07 ± 0.69 kg m−2). Extrapolating to the top 30 cm, our results suggest that approximately 44 Tg C is stored in the study region with a mean landscape soil C stock of 2.75 kg m−2 for non‐water areas. Combining vegetation mapping with local soil C stocks considerably narrows the range of estimates from other upscaling approaches (27–189 Tg) for soil C on South Baffin Island.

Macroalgal eukaryotic microbiome composition indicates novel phylogenetic diversity and broad host spectrum of oomycete pathogens.

Seaweeds are important components of marine ecosystems with emerging potential in aquaculture and as sources of biofuel, food products and pharmacological compounds. However, an increasingly recognised threat to natural and industrial seaweed populations is infection with parasitic single-celled eukaryotes from the relatively understudied oomycete lineage. Here we examine the eukaryomes of diverse brown, red and green marine macroalgae collected from polar (Baffin Island), cold-temperate (Falkland Islands) and tropical (Ascension Island) locations, with a focus on oomycete and closely related diatom taxa. Using 18S rRNA gene amplicon sequencing, we show unexpected genetic and taxonomic diversity of the eukaryomes, a strong broad-brush association between eukaryome composition and geographic location, and some evidence of association between eukaryome structure and macroalgal phylogenetic relationships (phylosymbiosis). However, the oomycete fraction of the eukaryome showed disparate patterns of diversity and structure, highlighting much weaker association with geography and no evidence of phylosymbiosis. We present several novel haplotypes of the most common oomycete Eurychasma dicksonii and report for the first time a cosmopolitan distribution and absence of host specificity of this important pathogen. This indicates rich diversity in macroalgal oomycete pathogens and highlights that these pathogens may be generalist and highly adaptable to diverse environmental conditions.

Sea Ice‐Driven Iceberg Drift in Baffin Bay

AbstractBaffin Bay is the travel destination of most icebergs calving from west Greenland. They commonly follow the bay's cyclonic circulation and might end up far south along the coast of Newfoundland and Labrador, where many shipping routes converge. Given the hazard that icebergs pose to marine transportation, understanding their distribution is fundamental. One of the forces driving iceberg drift arises from the presence of sea ice. Observations in the Southern Ocean indicate that icebergs get locked in thick and concentrated sea ice. We present observations that support the occurrence of this sea ice locking mechanism (SIL) in Baffin Bay as well. Most iceberg models, however, represent the sea ice force over an iceberg as a simple drag force. Here, we implement a new parameterization in the iceberg module of the Nucleus for European Modeling of the Ocean (NEMO‐ICB) to represent SIL. We show that, by using this new parameterization, icebergs are more likely to travel outside of the Baffin Island Current during winter, which is supported by satellite observations. There is a slight improvement in the representation of iceberg severity along the coast of Newfoundland and Labrador and a slight shift of iceberg melt toward this region and Lancaster Sound/Hudson Strait. Although the impacts of icebergs on sea ice are still not represented, and targeted observations are needed for model calibration regarding sea ice concentration thresholds from which icebergs get locked, we are confident that this model improvement takes iceberg modeling one step forward toward reality.

Environmental controls on the generation of submarine landslides in Arctic fjords: Insight from Pangnirtung Fjord, Baffin Island, Nunavut

High-latitude fjords are susceptible to hazardous subaerial and submarine mass movements such as rock avalanches and landslides. Geophysical surveys in the fjords of Baffin Island (Nunavut) have shown widespread evidence of submarine landslides, but their timing and triggers remain relatively unconstrained, limiting our ability to understand the environmental controls on the wide range of landslides occurring in high latitude fjords. Using bathymetric, sub-bottom, and sediment core data, this study seeks to generate a comprehensive understanding of the distribution, morphology, lithology, and timing of submarine landslides in Pangnirtung Fjord (SE Baffin Island, Nunavut). These results are used to evaluate the influence of different environmental controls on the generation of submarine landslides in Arctic fjords. We identified 180 near-surface submarine landslides, most of which are relatively small (∼ 0.13 km2), with elongated depletion zones and wide deposits dispersed along the basin floor of the fjord. Landslide ages, calculated from radiocarbon dating and 210Pb/137Cs activities, indicate that 8 of the 11 dated landslides occurred in the last 200 years. Four types of environmental controls were identified, which are believed to have preconditioned or triggered the observed landslides: 1) 51% of landslides, by area, are associated with subaerial sources and extend offshore of debris flow channels and fans; 2) 23% are initiated in shallow-water (< 40 m), are non-subaerially influenced, and may have been triggered by nearshore processes and sea-ice loading; 3) 13% are located in deeper waters (>40 m) and associated with sills and moraines, suggesting they are older deposits associated with the retreat of the ice sheet in the fjord; and 4) 13% are offshore of river deltas, likely associated with delta progradation; they form the largest landslide deposits in the fjord. This research suggests that the main triggers for submarine landslides in high-latitude fjords are climatically influenced (rainfall, floods, subaerial debris flows, and sea ice loading). Consequently, the predicted increase in the frequency of subaerial debris flows and river floods due to anthropogenic climate change will likely result in an increase in the recurrence of these types of submarine landslides. Additional monitoring efforts will be then needed to fully evaluate how future climate will impact the submarine landslide hazard across the Arctic.

Climate Model Simulations of the Effects of Orbital Parameters on Glacier Equilibrium Line Altitude

AbstractThe effects of obliquity and precession on conditions favorable for Northern Hemisphere glaciation are explored using an energy balance and mass balance model of equilibrium line altitude (ELA), the height on a glacier where accumulation and ablation are in balance annually. Climate forcing for the ELA model is obtained from idealized single‐forcing orbital simulations with two atm‐ocean general circulation models, Geophysical Fluid Dynamics Laboratory (GFDL) CM2.1 and National Center for Atmospheric Research (NCAR) Community Earth System Model version 1.2. Over Scandinavia and Baffin Island, the respective locations in which the Scandinavian and Laurentide ice sheets are thought to have originated, low obliquity and perihelion at the boreal winter solstice are associated with lower ELA values, as would be expected from the orbital theory of the ice ages. Linear reconstructions of ELA variations over the past 800 kyr indicate that precession dominated ELA variations in Scandinavia and Baffin Island in the GFDL model, and in Scandinavia in the NCAR model. Obliquity and precession played equal roles in Baffin Island in the NCAR model. A decomposition of the ELA responses finds that the effects of ablation on ELA are much larger than the effects of precipitation. Overall, the findings of this study point to precession being a more important factor in glacial inception than obliquity, which contrasts with previous findings in which obliquity had a slightly larger effect on positive degree days (PDDs), a simple metric for ablation. This is likely due to differences in seasonality of melt from the ELA model and PDDs.

Vascular plant, bryophyte, and lichen biodiversity of Agguttinni Territorial Park, Baffin Island, Nunavut, Canada: an annotated species checklist of a new Arctic protected area

Agguttinni Territorial Park is a large, newly established park on the east-central coast of Baffin Island in Nunavut, Canada. Previous knowledge of the plant and lichen biodiversity was limited and based mostly on collections made during the 1950 Baffin Island Expedition. We conducted a &amp;#64258;oristic inventory of the park in 2021 and re-examined previous collections. We recorded 141 species of vascular plants belonging to 25 families, 69 species of bryophytes in 27 families, and 93 species of lichens in 23 families. Most of the vascular plant and bryophyte species are new records for the park area, and some vascular plants, bryophytes, and lichens are newly reported for Baffin Island, Nunavut, or the Canadian Arctic or represent signi&amp;#64257;cant range extensions. Vascular plant species diversity varied greatly among localities, with inland valleys at the heads of &amp;#64257;ords showing highest diversity and interior rocky barrens showing the lowest.

Ordovician conodont biostratigraphy of northwestern Baffin Island, Nunavut, Canada, with new insights into the age and diachronism of the Ship Point Formation in the Foxe Basin

Northwestern Baffin Island, Nunavut, Canada, preserves the stratigraphic record in the northern margin of the Foxe Basin. The Ordovician succession exposed on an unnamed peninsula west of Steensby Inlet, northwestern Baffin Island includes the Lower and Middle Ordovician Ship Point Formation and Upper Ordovician Frobisher Bay and Amadjuak formations. Nearly 7000 conodont specimens recovered from six sections on this peninsula allow the establishment of seven conodont zones throughout this succession: Rossodus manitouensis Taxon-range Zone, Acodus deltatus–Oneotodus costatus Assemblage Zone, Oepikodus communis Interval Zone, and Cooperignathus aranda–Jumudontus gananda Assemblage Zone in units 2 and 3 of the Ship Point Formation, correlative to the upper Tremadocian and Floian, Lower Ordovician; Phragmodus polonicus Taxon-range Zone confined to unit 4 of the Ship Point Formation, correlative to the middle Darriwilian, Middle Ordovician; and Appalachignathus delicatuluss– Belodina confluens and Belodina confluens–Periodon grandis Assemblage zones limited to the Frobisher Bay and Amadjuak formations, respectively, correlative to the lower Katian, Upper Ordovician. The establishment of these conodont zones proves that (1) the Ship Point Formation in the Foxe Basin is not a continuous stratigraphic unit but has a stratigraphic interval missing that is assignable to the Dapingian and lower Darriwilian, Middle Ordovician; (2) the base of the Ship Point Formation is diachronous in the Foxe Basin, which is correlated to the upper Tremadocian on northwestern Baffin Island but to the upper Floian on Melville Peninsula; and (3) the strata younger than lower Amadjuak Formation have been eroded in this area.

Cryologger Ice Tracking Beacon: A Low-Cost, Open-Source Platform for Tracking Icebergs and Ice Islands.

Icebergs and ice islands (large, tabular icebergs) present a significant hazard to marine vessels and infrastructure at a time when demand for access to Arctic waters is increasing. There is a growing demand for in situ iceberg tracking data to monitor their drift trajectories and improve models used for operational forecasting of ice hazards, yet the high cost of commercial tracking devices often prevents monitoring at optimal spatial and temporal resolutions. Here, we provide a detailed description of the Cryologger Ice Tracking Beacon (ITB), a low-cost, robust, and user-friendly data logger and telemeter for tracking icebergs and ice islands based on the Arduino open-source electronics platform. Designed for deployments of at least 2 years with an hourly sampling interval that is remotely modifiable by the end user, the Cryologger ITB provides long-term measurements of position, temperature, pressure, pitch, roll, heading, and battery voltage. Data are transmitted via the Iridium satellite network at user-specified intervals. We present the results of field campaigns in 2018 and 2019, which saw the deployment of 16 ITBs along the coasts of Greenland and Ellesmere and Baffin islands. The overall success of these ITB deployments has demonstrated that inexpensive, open-source hardware and software can provide a reliable and cost-effective method of monitoring icebergs and ice islands in the polar regions.

Cold Air Outbreaks in Winter over the Continental United States and Its Possible Linkage with Arctic Sea Ice Loss

The mechanism for the paradox of global warming and successive cold winters in mid-latitudes remains controversial. In this study, the connection between Arctic sea ice (ASI) loss and frequent cold air outbreaks in eastern Continental United States (CONUS) is explored. Two distinct periods of high and low ASI (hereafter high- and low-ice phases) are identified for comparative study. It is demonstrated that cold air outbreaks occur more frequently during the low-ice phase compared to that during the high-ice phase. The polar vortex is weakened and shifted southward during the low-ice phase. Correspondingly, the spatial pattern of 500 hPa geopotential height (GPH), which represents the mid-tropospheric circulation, shows a clear negative Arctic Oscillation-like pattern in the low-ice phase. Specifically, positive GPH anomalies in the Arctic region with two centers, respectively located over Greenland and the Barents Sea, significantly weaken the low-pressure system centered around the Baffin Island, and enhance Ural blocking in the low-ice phase. Meanwhile, the high ridge extending from Alaska to the west coast of North America further intensifies, while the low trough over eastern CONUS deepens. As a result, the atmospheric circulation in North America becomes more conductive to frigid Arctic air outbreaks. It is concluded that the ASI loss contributes to more cold air outbreaks in winter in eastern CONUS through the polar vortex weakening with southward displacement of the polar vortex edge, which lead to the weakening of the meridional potential vorticity gradient between the Arctic and mid-latitude and thus are conducive to the strengthening and long-term maintenance of the blocking high.

Breaking barriers: Indigenous nurse navigator role in oncology care for the Inuit.

Individuals who live in the north of Canada face many challenges when they are diagnosed with cancer. Accessing cancer care usually means having to travel to a cancer centre in southern facilities and stay in a city away from family, local community, language and culture. The Indigenous Cancer Program atThe Ottawa Hospital was established to assist these individuals in navigating a complex and unfamiliar system of care. The First Nations, Inuit, Métis Nurse Navigator role was designed to collaborate with these patients and develop interventions to meet their unique needs. Recently, a satellite oncology clinic was opened in the territory of Baffin Island Nunavut where patients can be assessed, receive cancer immunotherapy therapy treatment, if required, and be followed after their primary treatment is finished. Holding the clinic in the local setting reduces the travel and time away from home for cancer patients. It is hoped this type of care can be expanded in the remote areas of the country.

Moss kill dates and modeled summer temperature track episodic snowline lowering and ice cap expansion in Arctic Canada through the Common Era

Abstract. Most extant ice caps mantling low-relief Arctic Canada landscapes remained cold based throughout the late Holocene, preserving in situ bryophytes killed as ice expanded across vegetated landscapes. After reaching peak late Holocene dimensions ∼1900 CE, ice caps receded as Arctic summers warmed, exposing entombed vegetation. The calibrated radiocarbon ages of entombed moss collected near ice cap margins (kill dates) define when ice advanced across the site, killing the moss, and remained over the site until the year of their collection. In an earlier study, we reported 94 last millennium radiocarbon dates on in situ dead moss collected at ice cap margins across Baffin Island, Arctic Canada. Tight clustering of those ages indicated an abrupt onset of the Little Ice Age at ∼1240 CE and further expansion at ∼1480 CE coincident with episodes of major explosive volcanism. Here we test the confidence in kill dates as reliable predictors of expanding ice caps by resampling two previously densely sampled ice complexes ∼15 years later after ∼250 m of ice recession. The probability density functions (PDFs) of the more recent series of ages match PDFs of the earlier series but with a larger fraction of early Common Era ages. Post 2005 CE ice recession has exposed relict ice caps that grew during earlier Common Era advances and were preserved beneath later ice cap growth. We compare the 106 kill dates from the two ice complexes with 80 kill dates from 62 other ice caps within 250 km of the two densely sampled ice complexes. The PDFs of kill dates from the 62 other ice caps cluster in the same time windows as those from the two ice complexes alone, with the PDF of all 186 kill dates documenting episodes of widespread ice expansion restricted almost exclusively to 250–450 CE, 850–1000 CE, and a dense early Little Ice Age cluster with peaks at ∼1240 and ∼1480 CE. Ice continued to expand after 1480 CE, reaching maximum dimensions at ∼1880 CE that are still visible as zones of sparse vegetation cover in remotely sensed imagery. Intervals of widespread ice cap expansion coincide with persistent decreases in mean summer surface air temperature for the region in a Community Earth System Model (CESM) fully coupled Common Era simulation, suggesting the primary forcings of the observed snowline lowering were both modest declines in summer insolation and cooling resulting from explosive volcanism, most likely intensified by positive feedbacks from increased snow cover and sea ice and reduced northward heat transport by the oceans. The clusters of ice cap expansion defined by moss kill dates are mirrored in an annually resolved Common Era record of ice cap dimensions in Iceland, suggesting this is a circum-North-Atlantic–Arctic climate signal for the Common Era. During the coldest century of the Common Era, 1780–1880 CE, ice caps mantled &gt;11 000 km2 of north-central Baffin Island, whereas &lt;100 km2 is glaciated at present. The peak Little Ice Age state approached conditions expected during the inception phase of an ice age and was only reversed after 1880 CE by anthropogenic alterations of the planetary energy balance.

Modeling the surface mass balance of Penny Ice Cap, Baffin Island, 1959–2099

Abstract Glaciers of Baffin Island and nearby islands of Arctic Canada have experienced rapid mass losses over recent decades. However, projections of loss rates into the 21st century have so far been limited by the availability of model calibration and validation data. In this study, we model the surface mass balance of the largest ice cap on Baffin Island, Penny Ice Cap, since 1959, using an enhanced temperature index model calibrated with in situ data from 2006–2014. Subsequently, we project changes to 2099 based on the RCP4.5 climate scenario. Since the mid-1990s, the surface mass balance over Penny Ice Cap has become increasingly negative, particularly after 2005. Using volume–area scaling to account for glacier retreat, peak net mass loss is projected to occur between ~2040 and 2080, and the ice cap is expected to lose 22% (377.4 Gt or 60 m w.e.) of its 2014 ice mass by 2099, contributing 1.0 mm to sea level rise. Our 2015–2099 projections are approximately nine times more sensitive to changes in temperature than precipitation, with an absolute cumulative difference of 566 Gt (90 m w.e.) between +2 and −2°C scenarios, and 63 Gt (10 m w.e.) between +20% and −20% precipitation scenarios.