Polar Research最新文献

Norwegian killer whales (Orcinus orca) are thought to be generalists that feed primarily on fish, but some individuals have been observed targeting pinnipeds. In the study reported here, field observations of foraging behaviours formed the basis of a priori classification as either seal-eaters or fish-eaters. Concurrent collection of photographic identification and biopsies for stable isotope analysis were used to validate prey choice classification. We found through satellite tracking that whales classified as seal-eaters took different paths south after leaving the northern fjords seemingly optimized for pinniped predation. Specifically, we found that seal-eaters took paths that tightly followed the coastline, remaining on average 6.9 ± 10.7 km (mean ± SD, n = 315) from the coast, whereas fish-eaters moved offshore along the continental shelf, travelling on average 45.1 ± 30.2 km (n = 1534) from the coast. We also found that, compared to fish-eaters, seal-eaters displayed more movements directed towards harbour seal haul-outs (p = 0.001). As expected, our data suggest that the fish-eaters feed primarily on fish, whilst seal-eaters appear to opportunistically use diverse foraging strategies optimized for either fish or seals based on availability and preference. Our findings demonstrate that tracking data can elucidate Norwegian killer whale movements associated with different prey types and selection.

Beluga whales are rare along the coast of east Greenland and the closest recognized stock occurs around Svalbard. Here we report on an ice entrapment of an adult beluga whale (Delphinapterus leucas) in north-east Greenland. The whale was observed entrapped in the fast ice on 21 April 2023 in Loch Fyne (73°54’N, 21°51’W) during a visual aerial survey for polar bears (Ursus maritimus). The whale was located >100 km from open water (i.e., pack ice) and appeared in poor body condition. A literature review back to the early 1900s failed to produce any other records of beluga whale ice entrapments in east Greenland.

The nephropid lobster Hoploparia stokesi (Weller 1903a) is widely distributed among the islands of the Antarctic Peninsula, where it occurs in strata of Cretaceous (Campanian–Maastrichtian) to Palaeogene (Paleocene) age. Specimens of H. stokesi collected during expeditions in the 1980s that were in the collection of the United States Polar Rock Repository at The Ohio State University have been transferred to the Orton Geological Museum, joining other geological collections from Antarctica. Some of the transferred specimens are voucher specimens described or illustrated in earlier published work.

Garbage may cause substantial environmental perturbations, in part because of its consumption by wildlife. Such consumption may have direct health implications for animals and may also influence trophic relationships. Even in pristine Arctic ecosystems, wildlife feeding in marine environments consume garbage in the form of plastic debris transported by ocean currents. We show that Arctic wildlife in pristine terrestrial environments may also ingest garbage or food items derived from abandoned camp sites. We found the remains of a chocolate wrapper and a milk powder bag in two Arctic fox (Vulpes lagopus) scats and a piece of cloth in an Arctic wolf (Canis lupus arctos) scat collected near Nares Strait, northern Greenland, one of the most pristine terrestrial wilderness regions on Earth. Found on Washington Land and associated with long-abandoned camp sites, these three scats were among 657 Arctic fox scats and 92 wolf scats collected as part of a larger study. Our study demonstrates that these two highly opportunistic predators managed to consume garbage despite the almost complete lack of human activity in this High-Arctic region. Our results highlight that abandoned anthropogenic material in the High Arctic may function as a source of garbage for local terrestrial wildlife over extended time periods, and that garbage consumption may become a potential issue if human activity in remote Arctic regions increases.

The Arctic region is warming at over twice the mean rate of the Northern Hemisphere and nearly four times faster than the globe since 1979. The local rate of warming is even higher in the European archipelago of Svalbard. This warming is transforming the terrestrial snow cover, which modulates surface energy exchanges with the atmosphere, accounts for most of the runoff in Arctic catchments and is also a transient reservoir of atmospherically deposited compounds, including pollutants. Improved observations, understanding and modelling of changes in Arctic snow cover are needed to anticipate the effects these changes will have on the Arctic climate, atmosphere, terrestrial ecosystems and socioeconomic factors. Svalbard has been an international hub of polar research for many decades and benefits from a well-developed science infrastructure. Here, we present an agenda for the future of snow research in Svalbard, jointly developed by a multidisciplinary community of experts. We review recent trends in snow research, identify key knowledge gaps, prioritize future research efforts and recommend supportive actions to advance our knowledge of present and future snow conditions pertaining to glacier mass balance, permafrost, surface hydrology, terrestrial ecology, the cycling and fate of atmospheric contaminants, and remote sensing of snow cover. This perspective piece addresses issues relevant to the circumpolar North and could be used as a template for other national or international Arctic research plans.

Rapid Arctic warming and sea ice loss have led to an intensification of the Arctic hydrological cycle, which is characterized by increased local evaporation and precipitation. Stable water isotopes as environmental tracers can provide useful insights into the Arctic hydrological cycle. However, the paucity of isotopic observations in the Arctic has limited our understanding of the hydrological changes. Here, we use an isotope-enabled atmospheric general circulation model (IsoGSM) combined with the Global Network of Isotopes in Precipitation (GNIP) observations to investigate the relationship between sea ice changes and Arctic precipitation d¹⁸O (d¹⁸O_p), and reveal the relative influence of local air temperature and evaporation on Arctic summer and winter d¹⁸O_p. We find that the Arctic d¹⁸O_p is negatively correlated with sea ice concentration, but positively with air temperature. Sea ice loss leads to enriched Arctic d¹⁸O_p through enhanced local evaporation and warming, but the relative importance of these processes varies between seasons. During summer, both local evaporation and warming contribute equally to d¹⁸O_p changes. In contrast, winter δ¹⁸O is predominantly driven by air temperature. This work improves our understanding of how Arctic precipitation isotopes respond to sea ice changes and has implications for the Arctic hydrological cycle and paleotemperature reconstructions.

Climate change portends serious implications for Arctic vegetation. Understanding these effects is likely to be enhanced with long-term observations from permanent plots. I evaluated three decades of change in tundra vegetation from 80 permanent plots on south-eastern Victoria Island, Nunavut, Canada. I compared baseline (1991 and 1992) and contemporary (2019 and 2022) periods in the cover and frequency of graminoids, mosses and common species of forbs, shrubs and lichens. I found substantial shifts in cover of several species and growth forms—an increase in graminoids, decreases in Dryas integrifolia, Polygonum viviparum and Saxifraga oppositifolia, and marginally significant declines in mosses and Cassiope tetragona, but no detectable changes in other groups. The decline in Dryas integrifolia was more pronounced at lower elevations and was noticeable as patches of apparent mortality, inside the plots and elsewhere. The shifts in species abundance were not significantly correlated with each other, nor with changes in soil depth. These changes, manifest as communities with more abundant graminoids, are consistent with expected climate change effects in colder regions of the Arctic. Repeated observations of permanent plots can aid in detecting and understanding long-term ecological change.