Ice-shelf collapse, climate change, and habitat loss in the Canadian high Arctic

AbstractEarly explorers in the Canadian high Arctic described a fringe of thick, landfast ice along the 500-km northern coast of Ellesmere Island. This article shows from analyses of historical records, aerial photographs, and satellite imagery (ERS-1, SPOT, RADARSAT-1) that this ancient ice feature (‘Ellesmere Ice Shelf’) underwent a 90% reduction in area during the course of the twentieth century. In addition, hydrographic profiles in Disraeli Fiord (83°N, 74°W) suggest that the ice-shelf remnant that presently dams the fiord (Ward Hunt Ice Shelf) decreased in thickness by 13 m (27%) from 1967 to 1999. Mean annual air temperatures at nearby Alert station showed a significant warming trend during the last two decades of this period, and a significant decline in the number of freezing degree days per annum. The ice-dammed fiord provides a stratified physical and biological environment (epishelf lake) of a type that is otherwise restricted to Antarctica. Extensive meltwater lakes occur on the surface of the ice shelf and support a unique microbial food web. The major contraction of these ice–water habitats foreshadows a much broader loss of marine cryo-ecosystems that will accompany future wanning in the high Arctic.

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Proxy-based 300-year High Arctic climate warming record from Svalbard

Polar Record ◽

10.1017/s0032247419000275 ◽

2019 ◽

Vol 55 (3) ◽

pp. 132-141 ◽

Cited By ~ 1

Author(s):

Tomi P. Luoto ◽

Antti E. K. Ojala ◽

Marek Zajaczkowski

Keyword(s):

Climate Warming ◽

Break Point ◽

Warming Trend ◽

High Arctic ◽

Ice Age ◽

Arctic Climate ◽

Air Temperatures ◽

Summer Temperatures ◽

Meteorological Observations ◽

Arctic Climate Change

AbstractWe used fossil Chironomidae assemblages and the transfer function approach to reconstruct summer air temperatures over the past 300 years from a High Arctic lake in Hornsund, Svalbard. Our aims were to compare reconstructed summer temperatures with observed (last 100 years) seasonal temperatures, to determine a potential climate warming break point in the temperature series and to assess the significance and rate of the climate warming trend at the study site. The reconstructed temperatures were consistent with a previous proxy record from Svalbard and showed good correlation with the meteorological observations from Bjørnøya and Longyearbyen. From the current palaeoclimate record, we found a significant climate warming threshold in the 1930s, after which the temperatures rapidly increased. We also found that the climate warming trend was strong and statistically significant. Compared with the reconstructed Little Ice Age temperatures in late eighteenth century cooling culmination, the present day summer temperatures are >4°C higher and the temperature increase since the 1930s has been 0.5°C per decade. These results highlight the exceptionally rapid recent warming of southern Svalbard and add invaluable information on the seasonality of High Arctic climate change and Arctic amplification.

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Factors influencing the basal temperatures of a High Arctic polythermal glacier

Annals of Glaciology ◽

10.3189/172756409789624210 ◽

2009 ◽

Vol 50 (52) ◽

pp. 9-16 ◽

Cited By ~ 11

Author(s):

Trudy Wohlleben ◽

Martin Sharp ◽

Andrew Bush

Keyword(s):

Thermal Characteristics ◽

High Arctic ◽

Ice Thickness ◽

Temperature Model ◽

Canadian High Arctic ◽

Basal Ice ◽

Air Temperatures ◽

Modelling Studies ◽

Pressure Melting ◽

Polythermal Glacier

AbstractA number of glaciers in the Canadian High Arctic are composed primarily of cold ice, but the ice at or near their beds reaches the pressure-melting point (PMP) in the ablation zone. Past modelling studies have suggested that the basal temperatures of some of these glaciers reach the PMP where they should not, indicating that they are not in thermal equilibrium with present-day surface air temperatures. To investigate the possible reasons for thermal disequilibria in such glaciers, a two-dimensional ice temperature model was used to simulate the inferred thermal characteristics of John Evans Glacier, Ellesmere Island. Results indicate that while surface refreezing and historical ice-thickness changes have had a warming effect upon basal ice temperatures, supraglacial meltwater reaching the glacier bed provides the single most critical heat source for explaining the apparent thermal disequilibrium between present-day inferred ice–bed temperatures and those modelled under present-day boundary conditions.

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Influence of the Arctic Circumpolar Vortex on the Mass Balance of Canadian High Arctic Glaciers

Journal of Climate ◽

10.1175/jcli4268.1 ◽

2007 ◽

Vol 20 (18) ◽

pp. 4586-4598 ◽

Cited By ~ 34

Author(s):

Alex S. Gardner ◽

Martin Sharp

Keyword(s):

Mass Balance ◽

Regime Shift ◽

High Arctic ◽

Western Hemisphere ◽

The Arctic ◽

Glacier Mass Balance ◽

Canadian High Arctic ◽

Circumpolar Vortex ◽

Eastern Hemisphere ◽

Air Temperatures

Abstract Variability in July mean surface air temperatures from 1963 to 2003 accounted for 62% of the variance in the regional annual glacier mass balance signal for the Canadian High Arctic. A regime shift to more negative regional glacier mass balance occurred between 1986 and 1987, and is linked to a coincident shift from lower to higher mean July air temperatures. Both the interannual changes and the regime shifts in regional glacier mass balance and July air temperatures are related to variations in the position and strength of the July circumpolar vortex. In years when the July vortex is “strong” and its center is located in the Western Hemisphere, positive mass balance anomalies prevail. In contrast, highly negative mass balance anomalies occur when the July circumpolar vortex is either weak or strong without elongation over the Canadian High Arctic, and its center is located in the Eastern Hemisphere. The occurrence of westerly positioned July vortices has decreased by 40% since 1987. The associated shift to a dominantly easterly positioned July vortex was associated with an increased frequency of tropospheric ridging over the Canadian High Arctic, higher surface air temperatures, and more negative regional glacier mass balance.

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Extreme Viral Partitioning in a Marine-Derived High Arctic Lake

mSphere ◽

10.1128/msphere.00334-20 ◽

2020 ◽

Vol 5 (3) ◽

Cited By ~ 2

Author(s):

Myriam Labbé ◽

Catherine Girard ◽

Warwick F. Vincent ◽

Alexander I. Culley

Keyword(s):

Arctic Ocean ◽

Water Column ◽

High Arctic ◽

Meromictic Lake ◽

The Arctic ◽

Northern Coast ◽

Canadian High Arctic ◽

Viral Abundance ◽

Viral Communities ◽

Rapid Transition

ABSTRACT High-latitude, perennially stratified (meromictic) lakes are likely to be especially vulnerable to climate warming because of the importance of ice in maintaining their water column structure and associated distribution of microbial communities. This study aimed to characterize viral abundance, diversity, and distribution in a meromictic lake of marine origin on the far northern coast of Ellesmere Island, in the Canadian High Arctic. We collected triplicate samples for double-stranded DNA (dsDNA) viromics from five depths that encompassed the major features of the lake, as determined by limnological profiling of the water column. Viral abundance and virus-to-prokaryote ratios were highest at greater depths, while bacterial and cyanobacterial counts were greatest in the surface waters. The viral communities from each zone of the lake defined by salinity, temperature, and dissolved oxygen concentrations were markedly distinct, suggesting that there was little exchange of viral types among lake strata. Ten viral assembled genomes were obtained from our libraries, and these also segregated with depth. This well-defined structure of viral communities was consistent with that of potential hosts. Viruses from the monimolimnion, a deep layer of ancient Arctic Ocean seawater, were more diverse and relatively abundant, with few similarities to available viral sequences. The Lake A viral communities also differed from published records from the Arctic Ocean and meromictic Ace Lake in Antarctica. This first characterization of viral diversity from this sentinel environment underscores the microbial richness and complexity of an ecosystem type that is increasingly exposed to major perturbations in the fast-changing Arctic. IMPORTANCE The Arctic is warming at an accelerating pace, and the rise in temperature has increasing impacts on the Arctic biome. Lakes are integrators of their surroundings and thus excellent sentinels of environmental change. Despite their importance in the regulation of key microbial processes, viruses remain largely uncharacterized in Arctic lacustrine environments. We sampled a highly stratified meromictic lake near the northern limit of the Canadian High Arctic, a region in rapid transition due to climate change. We found that the different layers of the lake harbored viral communities that were strikingly dissimilar and highly divergent from known viruses. Viruses were more abundant in the deepest part of the lake containing ancient Arctic Ocean seawater that was trapped during glacial retreat and were genomically unlike any viruses previously described. This research demonstrates the complexity and novelty of viral communities in an environment that is vulnerable to ongoing perturbation.

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Under-ice limnology of coastal valley lakes at the edge of the Arctic Ocean

Arctic Science ◽

10.1139/as-2020-0038 ◽

2021 ◽

Author(s):

Yohanna Klanten ◽

Katherine Triglav ◽

Catherine Marois ◽

Dermot Antoniades

Keyword(s):

Arctic Ocean ◽

Surface Sediments ◽

Major Ions ◽

High Arctic ◽

The Arctic ◽

Rapid Decline ◽

Northern Coast ◽

Canadian High Arctic ◽

Sea Ice Extent ◽

Water Columns

The northern coast of Ellesmere Island in the Canadian High Arctic is undergoing amplified warming that parallels the rapid decline in Arctic Ocean sea ice extent, and many lakes in this region have already shown changes in response to warming. However, biogeochemical data from High Arctic freshwaters are limited, and mostly restricted to the short, ice-free period. We sampled four coastal lakes in Stuckberry Valley (82° 54’ N, 66° 56’ W) before the onset of spring melting in 2017, 2018 and 2019, to assess biogeochemical gradients in their water columns and characteristics of their surface sediments. Despite their proximity, there were large differences in limnological properties. The two shallower lakes closer to the ocean were oxygen deficient while the two deeper, more distant lakes were more oxygenated. There were pronounced vertical gradients in major ions, metals and nutrients that suggested large differences in the extent of anaerobic microbial processes among the lakes. Morphometry and dissolved oxygen were the overriding determinants of biogeochemical differences rather than position along this short ocean-inland gradient. The diversity of limnological conditions, and the sensitivity of these characteristics to changes in ice cover, underlines the need for further study of under-ice processes in extreme northern lakes.

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Evidence of recent climatic warming on the eastern Antarctic Peninsula

Annals of Glaciology ◽

10.3189/s0260305500018164 ◽

1998 ◽

Vol 27 ◽

pp. 628-632 ◽

Cited By ~ 62

Author(s):

Pedro Skvarca ◽

Wolfgang Rack ◽

Helmut Rott ◽

Teresa Ibarzábal Y Donángelo

Keyword(s):

Antarctic Peninsula ◽

Warming Trend ◽

Western Coast ◽

Ice Shelf ◽

Orkney Islands ◽

Air Temperatures ◽

Recent Climate ◽

Summer Temperatures ◽

The Antarctic ◽

Larsen Ice Shelf

Air temperatures at the Marambio (MAR), Esperanza (ESP) and Matienzo (MAT) stations have been analyzed to investigate recent climate change on the eastern part of the Antarctic Peninsula. They are compared with data from the Oreadas station on the South Orkney Islands, the longest record available in Antarctica, and from the Faraday (FAR) station on the western coast of the Peninsula. Though the interannual variability is comparatively high and the stations are located in different climatic regimes, a pronounced warming trend shows up in all records. At MAR a temperature increase of 1.5°C has been observed since the beginning of the record in 1971. This is of similar magnitude to the increase at FAR on the west coast, which was 2.5°C for the longer period since 1945. The steady retreat and collapse of the northern Larsen Ice Shelf (LIS) coincided with this warming trend. of particular importance for the ice-shelf mass balance in this region are the summer temperatures which show a statistically significant warming trend at MAR and ESP. The representativity of the summer temperatures of MAR for northern LIS is confirmed by intercomparison with the parallel measurements at MAT which is located on the ice shelf.

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