High Arctic Greenland Research Articles

Book review] Peter R. Dawes, Expedition Relics from High Arctic Greenland

Review of: Peter R. Dawes, Expedition Relics from High Arctic Greenland. Eight Decades of Exploration History Told through 102 Objects, [Chicago]: Museum Tusculanum Press/University of Chicago Press [2022]

Peter R. Dawes, Expedition Relics from High Arctic Greenland – Eight decades of exploration history told through 102 objects by Ingo Heidbrink

Peter R. Dawes, Expedition Relics from High Arctic Greenland – Eight decades of exploration history told through 102 objects by Ingo Heidbrink

Little directional change in the timing of Arctic spring phenology over the past 25 years

With the global change in climate, the Arctic has been pinpointed as the region experiencing the fastest rates of change. As a result, Arctic biological responses-such as shifts in phenology-are expected to outpace those at lower latitudes. 15 years ago, a decade-long dataset from Zackenberg in High Arctic Greenland revealed rapid rates of phenological change.1 To explore how the timing of spring phenology has developed since, we revisit the Zackenberg time series on flowering plants, arthropods, and birds. Drawing on the full 25-year period of 1996-2020, we find little directional change in the timing of events despite ongoing climatic change. We attribute this finding to a shift in the temporal patterns of climate conditions, from previous directional change to current high inter-annual variability. Additionally, some taxa appear to have reached the limits of their phenological responses, resulting in a leveling off in their phenological responses in warm years. Our findings demonstrate the importance of long-term monitoring of taxa from across trophic levels within the community, allowing for detecting shifts in sensitivities and responses and thus for updated inference in the light of added information.

Sequential analysis of δ15 N in guard hair suggests late gestation is the most critical period for muskox calf recruitment.

Analysis of stable isotopes in tissue and excreta may provide information about animal diets and their nutritional state. As body condition may have a major influence on reproduction, linking stable isotope values to animal demographic rates may help unravel the drivers behind animal population dynamics. We performed sequential analysis of δ15 N values in guard hair from 21 muskoxen (Ovibos moschatus) from Zackenberg in high arctic Greenland. We were able to reconstruct the dietary history for the population over a 5-year period with contrasting environmental conditions. We examined the linkage between guard hair δ15 N values in 12 three-month periods and muskox calf recruitment to detect critical periods for muskox reproduction. Finally, we conducted similar analyses of the correlation between environmental conditions (snow depth and air temperature) and calf recruitment. δ15 N values exhibited a clear seasonal pattern with high levels in summer and low levels in winter. However, large inter-annual variation was found in winter values, suggesting varying levels of catabolism depending on snow conditions. In particular δ15 N values during January-March were linked to muskox recruitment rates, with higher values coinciding with lower calf recruitment. δ15 N values were a better predictor of muskox recruitment rates than environmental conditions. Although environmental conditions may ultimately determine the dietary δ15 N signal in muskox guard hairs, muskox calf recruitment was more strongly correlated with δ15 N values than ambient snow and temperature. The period January-March, corresponding to late gestation, appears particularly critical for muskox reproduction.

Expedition Relics from High Arctic Greenland eight decades of exploration history told through 102 objects. Peter R. Dawes. With artefact photography by Roberto Fortuna. 2023. Museum Tusculanum Press/Copenhagen: Denmark. 500 p, illustrated, hardcover. ISBN 9788763546867. $102 (US).

Expedition Relics from High Arctic Greenland eight decades of exploration history told through 102 objects. Peter R. Dawes. With artefact photography by Roberto Fortuna. 2023. Museum Tusculanum Press/Copenhagen: Denmark. 500 p, illustrated, hardcover. ISBN 9788763546867. $102 (US). - Volume 59

Hair mineral levels as indicator of wildlife demographics?—a pilot study of muskoxen

The tight linkage between mineral status and health and demographics in animals is well documented. Mineral deficiencies have been coupled to population declines in wildlife. Current practices typically rely on liver, kidney and/or serum samples to assess mineral levels. Such destructive sampling strategies are, however, not feasible for remote or endangered populations. Hair may constitute an alternative tissue, sampled through non-invasive means, to investigate mineral levels in wildlife. In the pilot study presented here, we examine whether mineral levels in hair samples from a well-studied muskox (Ovibos moschatus) population in High-Arctic Greenland are associated with a vital rate and may, therefore, serve as indicators of wildlife population demographics. We show that inter-annual variations in levels of three minerals—copper, selenium and molybdenum—are associated with fluctuations in annual calf recruitment, with poor recruitment in years of low mineral levels in hair. Local environmental conditions also varied with calf recruitment but appeared to be less robust predictors of calf recruitment than hair mineral levels. Our results suggest that hair mineral levels may serve as an indicator of vital demographic rates and, ultimately, of wildlife population trends.

Spatio-temporal patterns in arctic fox (Vulpes alopex) diets revealed by molecular analysis of scats from Northeast Greenland

The arctic fox (Vulpes lagopus) is endemic to the Arctic where it holds a central position in the trophic interactions. The diet of the species has previously been described as being highly flexible, but whether this flexibility is a constant trait through time, or merely reflects fast temporal changes in abundance among prey taxa, has so far been poorly resolved. Using molecular analyses of arctic fox scats from Northeast Greenland, we first examined the temporal dynamics of arctic fox diets during the short snow-free season, and then examined whether local food availability at different sites affected arctic fox dependence on lemmings. Arctic fox diets included most terrestrial vertebrate species found in the region, and exhibited substantial temporal changes, generally reflecting the dynamic changes in prey availability from late winter through autumn. This dietary flexibility was also reflected geographically, with arctic foxes consuming a variety of local prey (mainly waterfowl and lemmings) in summer. Moreover, the dietary response of arctic foxes to changes in lemming abundance depended on access to non-lemming prey. Based on these findings, we discuss whether varying degrees of lemming-dependency, combined with geographical differences in winter food availability, may explain previously published differences in arctic fox breeding patterns in high arctic Greenland.

High-Arctic Greenland breeding wader populations remained relatively unchanged for 25 years, but more frequent severe spring events lurk in the future

High-Arctic Greenland breeding wader populations remained relatively unchanged for 25 years, but more frequent severe spring events lurk in the future

An on-ice aerial survey of the Kane Basin polar bear (Ursus maritimus) subpopulation

There is an imminent need to collect information on distribution and abundance of polar bears (Ursus maritimus) to understand how they are affected by the ongoing decrease in Arctic sea ice. The Kane Basin (KB) subpopulation is a group of high-latitude polar bears that ranges between High Arctic Canada and NW Greenland around and north of the North Water polynya (NOW). We conducted a line transect distance sampling aerial survey of KB polar bears during 28 April–12 May 2014. A total of 4160 linear kilometers were flown in a helicopter over fast ice in the fjords and over offshore pack ice between 76° 50′ and 80° N′. Using a mark-recapture distance sampling protocol, the estimated abundance was 190 bears (95% lognormal CI: 87–411; CV 39%). This estimate is likely negatively biased to an unknown degree because the offshore sectors of the NOW with much open water were not surveyed because of logistical and safety reasons. Our study demonstrated that aerial surveys may be a feasible method for obtaining abundance estimates for small subpopulations of polar bears.

Trends in breeding performance in wader populations at Zackenberg, high Arctic Greenland, in relation to environmental drivers 1996–2018

Trends in breeding performance in wader populations at Zackenberg, high Arctic Greenland, in relation to environmental drivers 1996–2018

Mercury contamination of seabird and sea duck eggs from high Arctic Greenland

Mercury (Hg) levels in the environment have substantially increased over the past century leading to increased concentrations in many high trophic level predators, including Arctic seabirds. From the Canadian high Arctic, research on seabird eggs has documented some of the greatest concentrations of egg Hg anywhere in the Arctic. Farther east, in high Arctic Greenland, no similar data on Hg concentrations in eggs exist, making spatial comparisons unfeasible. To address this paucity of data, we collected whole eggs from Thick-billed Murre Uria lomvia (n = 11), Black-legged Kittiwake Rissa tridactyla (n = 9), and Common Eider Somateria mollissima (n = 12) in the high Arctic of northwest Greenland in the summer of 2014 and assessed their concentration of total Hg. Thick-billed Murre eggs had the highest mean total Hg concentrations (1.32 ± 0.42 mg g−1 dw) followed by kittiwakes (0.64 ± 0.19) and eiders (0.23 ± 0.10). When compared with murre and kittiwake egg samples collected in high Arctic Canada during the same time period, total Hg concentrations from northwest Greenland were higher, but not significantly. Based on what is known about lethal Hg concentrations in murre eggs, these results indicate that some murre eggs may be at risk for increased embryonic mortality and further monitoring is suggested to determine long-term trends in egg Hg concentrations.

Gemmatimonas groenlandica sp. nov. Is an Aerobic Anoxygenic Phototroph in the Phylum Gemmatimonadetes.

The bacterial phylum Gemmatimonadetes contains members capable of performing bacteriochlorophyll-based phototrophy (chlorophototrophy). However, only one strain of chlorophototrophic Gemmatimonadetes bacteria (CGB) has been isolated to date, hampering our further understanding of their photoheterotrophic lifestyle and the evolution of phototrophy in CGB. By combining a culturomics strategy with a rapid screening technique for chlorophototrophs, we report the isolation of a new member of CGB, Gemmatimonas (G.) groenlandica sp. nov., from the surface water of a stream in the Zackenberg Valley in High Arctic Greenland. Distinct from the microaerophilic G. phototrophica strain AP64T, G. groenlandica strain TET16T is a strictly aerobic anoxygenic phototroph, lacking many oxygen-independent enzymes while possessing an expanded arsenal for coping with oxidative stresses. Its pigment composition and infra-red absorption properties are also different from G. phototrophica, indicating that it possesses a different photosystem apparatus. The complete genome sequence of G. groenlandica reveals unique and conserved features in the photosynthesis gene clusters of CGB. We further analyzed metagenome-assembled genomes of CGB obtained from soil and glacier metagenomes from Northeast Greenland, revealing a wide distribution pattern of CGB beyond the stream water investigated.

Nonlinear trends in abundance and diversity and complex responses to climate change in Arctic arthropods

Time series data on arthropod populations are critical for understanding the magnitude, direction, and drivers of change. However, most arthropod monitoring programs are short-lived and restricted in taxonomic resolution. Monitoring data from the Arctic are especially underrepresented, yet critical to uncovering and understanding some of the earliest biological responses to rapid environmental change. Clear imprints of climate on the behavior and life history of some Arctic arthropods have been demonstrated, but a synthesis of population-level abundance changes across taxa is lacking. We utilized 24 y of abundance data from Zackenberg in High-Arctic Greenland to assess trends in abundance and diversity and identify potential climatic drivers of abundance changes. Unlike findings from temperate systems, we found a nonlinear pattern, with total arthropod abundance gradually declining during 1996 to 2014, followed by a sharp increase. Family-level diversity showed the opposite pattern, suggesting increasing dominance of a small number of taxa. Total abundance masked more complicated trajectories of family-level abundance, which also frequently varied among habitats. Contrary to expectation in this extreme polar environment, winter and fall conditions and positive density-dependent feedbacks were more common determinants of arthropod dynamics than summer temperature. Together, these data highlight the complexity of characterizing climate change responses even in relatively simple Arctic food webs. Our results underscore the need for data reporting beyond overall trends in biomass or abundance and for including basic research on life history and ecology to achieve a more nuanced understanding of the sensitivity of Arctic and other arthropods to global changes.

Morphological measurements of Atlantic puffin (Fratercula arctica naumanni) in High-Arctic Greenland

Morphological measurements of 45 adult Atlantic puffins Fratercula arctica were collected in High-Arctic Greenland between 2010 and 2016. Measurements support that the population belongs to the F. a. naumanni subspecies and were significantly larger than those from populations found at lower latitudes, including F. a. grabae and F. a. arctica populations. Male puffins from High-Arctic Greenland had greater mass, bill length and tarsus length than females, but no difference was found in wing length. In comparison to other naumanii populations, body size was most similar to puffins in Svalbard. Overall, the measured Atlantic puffins from High-Arctic Greenland had some of the largest and most variable morphological measurements reported for any studied Atlantic puffin population. While morphological measurements and the relative geographic isolation of the puffin population in High-Arctic Greenland support the naumanni subspecies designation, additional research should use genetic methods to determine if this population and other populations in the North Atlantic are isolated. This is the only collection of naumanni morphometric measurements from geographical North America and enhances our collective knowledge of the species.

Baffin Bay sea ice extent and synoptic moisture transport drive water vapor isotope (<i>δ</i><sup>18</sup>O, <i>δ</i><sup>2</sup>H, and deuterium excess) variability in coastal northwest Greenland

Abstract. At Thule Air Base on the coast of Baffin Bay (76.51∘ N, 68.74∘ W), we continuously measured water vapor isotopes (δ18O, δ2H) at a high frequency (1 s−1) from August 2017 through August 2019. Our resulting record, including derived deuterium excess (dxs) values, allows an analysis of isotopic–meteorological relationships at an unprecedented level of detail and duration for high Arctic Greenland. We examine isotopic variability across multiple temporal scales from daily to interannual, revealing that isotopic values at Thule are predominantly controlled by the sea ice extent in northern Baffin Bay and the synoptic flow pattern. This relationship can be identified through its expression in the following five interacting factors: (a) local air temperature, (b) local marine moisture availability, (c) the North Atlantic Oscillation (NAO), (d) surface wind regime, and (e) land-based evaporation and sublimation. Each factor's relative importance changes based on the temporal scale and in response to seasonal shifts in Thule's environment. Winter sea ice coverage forces distant sourcing of vapor that is isotopically light from fractionation during transport, while preventing isotopic exchange with local waters. Sea ice breakup in late spring triggers a rapid isotopic change at Thule as the newly open ocean supplies warmth and moisture that has ∼10 ‰ and ∼70 ‰ higher δ18O and δ2H values, respectively, and ∼10 ‰ lower dxs values. Sea ice retreat also leads to other environmental changes, such as sea breeze development, that radically alter the nature of relationships between isotopes and many meteorological variables in summer. On synoptic timescales, enhanced southerly flow promoted by negative NAO conditions produces higher δ18O and δ2H values and lower dxs values. Diel isotopic cycles are generally very small as a result of a moderated coastal climate and the counteracting isotopic effects of the sea breeze, local evaporation, and convection. Future losses in Baffin Bay's sea ice extent will likely shift mean annual isotopic compositions toward more summer-like values, and local glacial ice could potentially preserve isotopic evidence of past reductions. These findings highlight the influence that the local environment can have on isotope dynamics and the need for dedicated, multiseason monitoring to fully understand the controls on water vapor isotope variability.

First record of horned puffin in the North Atlantic and tufted puffin in High Arctic Greenland

An accelerating decrease in summer sea-ice extent in the Arctic Ocean and Canadian Arctic Archipelago (North-west Passage) is predicted to increase the movement of species between the North Pacific and North Atlantic oceans. Here we report observations of two Subarctic North Pacific puffin species in the North Atlantic near the coast of north-west Greenland. We observed a horned puffin (Fratercula corniculata) repeatedly during the summer months of 2002–06 and 2013–19 and a single tufted puffin (F. cirrhata) in 2019. While single tufted puffins have been observed a few times in the North Atlantic, this is the first record of a horned puffin in the North Atlantic, and the first record for both horned and tufted puffins in north-west Greenland. In 2019, both puffin species were observed simultaneously at an Atlantic puffin (F. arctica) colony.

Uncovering their tracks: Intra-site behaviour at a Paleo-Inuit multiple dwelling site

To reveal prehistoric behaviours and modes of conduct from an archaeological assemblage it is necessary to employ more encompassing methodological approaches that bring people’s acts and thoughts into focus. The following study investigates the lithic assemblage, from a fully excavated multiple dwelling site from High Arctic Greenland, in an attempt to demonstrate that the application of the chaîne opératoire, with an emphasis on problem-oriented refitting, can produce unexpected and often surprising outcomes. Furthermore, this approach offers a unique opportunity to explore the dynamics of activity structure, technological organization, disposal mode, and spatial patterning normally considered beyond the grasp of archaeological investigations.

Density, snow, and seasonality lead to variation in muskox (Ovibos moschatus) habitat selection during summer

Understanding how environmental conditions influence habitat selection and suitability of free-ranging animals is critical, as the outcome may have implications for individual fitness and population dynamics. Density and snow are among the most influential environmental conditions driving habitat-selection patterns of northern ungulates. We used two decades of census data from high Arctic Greenland to quantify inter- and intra-annual variations in muskox (Ovibos moschatus (Zimmermann, 1780)) habitat selection and suitability during the Arctic summer (July through October). Across years, habitat selection varied considerably, and the strength of habitat selection appeared negatively related to both muskox density and spring snow cover. In early summer, habitat suitability was high and spatially rather uniform. Towards the autumn, suitable habitats contracted to just the lower elevations, when muskoxen exhibited increasingly stronger habitat selection towards low elevations and dense vegetation. This selection strategy clearly reflects the need to build up fat reserves for the upcoming winter, highlighting the energetic importance of the Arctic summer. Extreme climatic events such as freezing rain in autumn are increasing in frequency in Greenland and limit muskox access to high-quality forage in fens. Such events may therefore negatively affect the energy acquisition process of muskox with potential cascading consequences on population dynamics.

Muskoxen Modify Plant Abundance, Phenology, and Nitrogen Dynamics in a High Arctic Fen

Herbivores are key drivers of vegetation dynamics in most ecosystems. However, the effect of high arctic herbivores on vegetation dynamics throughout a growing season is not well understood. In this study, we examine the impacts of a large dominant herbivore in the tundra ecosystem, the muskox, Ovibos moschatus, using exclosures established in a fen in high Arctic Greenland. Using weekly sampling throughout the growing season, we quantified the effects of muskox exclusion on aboveground plant biomass and on concentrations and pools of carbon and nitrogen, and explored the timing of peak biomass and nutrient pools. Excluding muskoxen profoundly changed plant abundances and dynamics of the fen, with more than a doubling of aboveground plant biomass and carbon and nitrogen pool sizes. Specifically, large increases in mosses and litter were observed, while graminoid biomass did not change significantly with exclusion of muskoxen. Excluding muskoxen advanced the peak of plant biomass, but also led to a more rapid decline, resulting in an earlier and shorter period of maximal plant biomass inside the exclosures. The largest impact of muskoxen on the arctic fen ecosystem seems to be through their trampling effects on the moss layer, which likely mediated most of the observed changes. This study demonstrates how quickly an ecosystem may respond to changes in the abundance of large herbivores and highlights their pivotal role in modifying vegetation dynamics and nutrient cycling in tundra ecosystems.

High‐resolution proglacial lake records of pre‐Little Ice Age glacier advance, northeast Greenland

Understanding Arctic glacier sensitivity is key to predicting future response to air temperature rise. Previous studies have used proglacial lake sediment records to reconstruct Holocene glacier advance–retreat patterns in South and West Greenland, but high‐resolution glacier records from High Arctic Greenland are scarce, despite the sensitivity of this region to future climate change. Detailed geochemical analysis of proglacial lake sediments close to Zackenberg, northeast Greenland, provides the first high‐resolution record of Late Holocene High Arctic glacier behaviour. Three phases of glacier advance have occurred in the last 2000 years. The first two phases (c. 1320–800 cal. a BP) occurred prior to the Little Ice Age (LIA), and correspond to the Dark Ages Cold Period and the Medieval Climate Anomaly. The third phase (c. 700 cal. a BP), representing a smaller scale glacier oscillation, is associated with the onset of the LIA. Our results are consistent with recent evidence of pre‐LIA glacier advance in other parts of the Arctic, including South and West Greenland, Svalbard, and Canada. The sub‐millennial glacier fluctuations identified in the Madsen Lake succession are not preserved in the moraine record. Importantly, coupled XRF and XRD analysis has effectively identified a phase of ice advance that is not visible by sedimentology alone. This highlights the value of high‐resolution geochemical analysis of lake sediments to establish rapid glacier advance–retreat patterns in regions where chronological and morphostratigraphical control is limited.