scholarly journals Sea-ice crossings by caribou in the south-central Canadian Arctic Archipelago and their ecological importance

Rangifer ◽  
2005 ◽  
Vol 25 (4) ◽  
pp. 77 ◽  
Author(s):  
Frank L. Miller ◽  
Samuel J. Barry ◽  
Wndy A. Calvert
Keyword(s):  
Sea Ice ◽  
Rangifer Tarandus ◽  
Canadian Arctic ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
The South ◽  
South Central ◽  
Straight Line ◽  
Straight Line Distance ◽  
Ecological Importance

The islands of the Canadian Arctic Archipelago lie immediately north of mainland North America in the Arctic Ocean. They are surrounded by ice for most of each year. Caribou (Rangifer tarandus) cross the sea ice in seasonal migrations among the islands and between the mainland and Arctic Islands. We compiled observations of 1272 discrete caribou crossings on the sea ice of northeastern Franklin Strait, Bellot Strait, Peel Sound and Baring Channel in the south-central Canadian Arctic Archipelago during four May—June search periods from 1977 to 1980. We clustered the 850 caribou trails found on the sea ice of northeastern Franklin Strait and on outer Peel Sound as 73 sea-ice crossing sites. We investigated whether caribou at the origin of a sea-ice crossing site could see land on the opposite side at the potential terminus. We measured the straight-line distance from where the caribou first came onto the ice (origin) to the first possible landfall (potential terminus). Potential termini were geodetically visible to caribou from elevated terrain near 96% of the origins of the 73 sea-ice crossing sites and still visible at sea-level at the origins on 68%. Caribou are able to take advantage of seasonal use of all of the islands and the peninsula by making sea-ice crossings, thereby helping to increase the magnitudes and durations of population highs and reduce their lows. Knowledge of these alternative pat¬terns of use made possible by sea-ice crossings is necessary to fully understand the population dynamics of these caribou and the importance of possible future changes in ice cover.

Recent changes in the exchange of sea ice between the Arctic Ocean and the Canadian Arctic Archipelago

2013 ◽  
Vol 118 (7) ◽  
pp. 3595-3607 ◽  
Author(s):  
Stephen E. L. Howell ◽  
Trudy Wohlleben ◽  
Mohammed Dabboor ◽  
Chris Derksen ◽  
Alexander Komarov ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Canadian Arctic ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
The Arctic Ocean

scholarly journals Recent extreme light sea ice years in the Canadian Arctic Archipelago: 2011 and 2012 eclipse 1998 and 2007

2013 ◽  
Vol 7 (2) ◽  
pp. 1313-1358 ◽  
Author(s):  
S. E. L. Howell ◽  
T. Wohlleben ◽  
A. Komarov ◽  
L. Pizzolato ◽  
C. Derksen
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Atmospheric Circulation ◽  
Canadian Arctic ◽  
Surface Air Temperature ◽  
Ice Cover ◽  
The Arctic ◽  
First Year ◽  
Canadian Arctic Archipelago ◽  
Northwest Passage

Abstract. Record low mean September sea ice area in the Canadian Arctic Archipelago (CAA) was observed in 2011 (146 × 103 km2), a level that was nearly exceeded in 2012 (150 × 103 km2). These values eclipsed previous September records set in 1998 (200 × 103 km2) and 2007 (220 × 103 km2) and are ∼60% lower than the 1981–2010 mean September climatology. In this study, the driving processes contributing to the extreme light years of 2011 and 2012 were investigated, compared to previous extreme minima of 1998 and 2007, and contrasted against historic summer seasons with above average September ice area. The 2011 minimum was driven by positive July surface air temperature (SAT) anomalies that facilitated rapid melt, coupled with atmospheric circulation in July and August that restricted multi-year ice (MYI) inflow from the Arctic Ocean into the CAA. The 2012 minimum was also driven by positive July SAT anomalies (with coincident rapid melt) but further ice decline was temporarily mitigated by atmospheric circulation in August and September which drove Arctic Ocean MYI inflow into the CAA. Atmospheric circulation was comparable between 2011 and 1998 (impeding Arctic Ocean MYI inflow) and 2012 and 2007 (inducing Arctic Ocean MYI inflow). However, evidence of both preconditioned thinner Arctic Ocean MYI flowing into CAA and maximum landfast first-year ice (FYI) thickness within the CAA was more apparent leading up to 2011 and 2012 than 1998 and 2007. The rapid melt process in 2011 and 2012 was more intense than observed in 1998 and 2007 because of the thinner ice cover being more susceptible to positive SAT forcing. The thinner sea ice cover within the CAA in recent years has also helped counteract the processes that facilitate extreme heavy ice years. The recent extreme light years within the CAA are associated with a longer navigation season within the Northwest Passage.

scholarly journals Dimethylsulfide dynamics in first-year sea ice melt ponds in the Canadian Arctic Archipelago

2017 ◽  
Author(s):  
Margaux Gourdal ◽  
Martine Lizotte ◽  
Guillaume Massé ◽  
Michel Gosselin ◽  
Michael Scarratt ◽  
...  
Keyword(s):  
Sea Ice ◽  
Canadian Arctic ◽  
The Arctic ◽  
First Year ◽  
Canadian Arctic Archipelago ◽  
Ice Melt ◽  
Melt Pond ◽  
Potential Source ◽  
Melt Ponds ◽  
Cover Up

Abstract. Melt pond formation is a natural seasonal pan-Arctic process. During the thawing season, melt ponds may cover up to 90 % of the Arctic first year sea ice (FYI) and 15 to 25 % of the multi-year sea ice (MYI). These pools of water lying at the surface of the sea-ice cover are habitats for microorganisms and represent a potential source of the biogenic gas dimethylsulfide (DMS) for the atmosphere. Here we report on the concentrations and dynamics of DMS in nine melt ponds sampled in July 2014 in the Eastern Canadian Arctic. DMS concentrations were under the detection limit (

scholarly journals Regional variability of acidification in the Arctic: a sea of contrasts

2013 ◽  
Vol 10 (2) ◽  
pp. 2937-2965 ◽  
Author(s):  
E. E. Popova ◽  
A. Yool ◽  
A. C. Coward ◽  
T. R. Anderson
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Arctic Ocean ◽  
Canadian Arctic ◽  
Atmospheric Co2 ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Climate Feedbacks ◽  
Regional Variability ◽  
The Arctic Ocean

Abstract. The Arctic Ocean is a region that is particularly vulnerable to the impact of ocean acidification driven by rising atmospheric CO2, negatively impacting calcifying organisms such as coccolithophorids and foraminiferans. In this study, we use an ocean general circulation model, with embedded biogeochemistry and a full description of the carbon cycle, to study the response of pH and saturation states of calcite and aragonite to changing climate in the Arctic Ocean. Particular attention is paid to the strong regional variability within the Arctic and, for comparison, simulation results are contrasted with those for the global ocean. Simulations were run to year 2099 using the RCP 8.5 (the highest IPCC AR5 CO2 emission scenario). The separate impacts of the direct increase in atmospheric CO2 and indirect effects via climate feedbacks (changing temperature, stratification, primary production and fresh water fluxes) were examined by undertaking two simulations, one with the full system and the other in which ocean-atmosphera exchange of CO2 was prevented from increasing beyond the flux calculated for year 2000. Results indicate that climate feedbacks, and spatial heterogeneity thereof, play a strong role in the declines in pH and carbonate saturation (Ω) seen in the Arctic. The central Arctic, Canadian Arctic Archipelago and Baffin Bay show greatest rates of acidification and Ω decline as a result of melting sea ice. In contrast, areas affected by Atlantic inflow including the Greenland Sea and outer shelves of the Barents, Kara and Laptev seas, had minimal decreases in pH and Ω because weakening stratification associated with diminishing ice cover led to greater mixing and primary production. As a consequence, the predicted onset of undersaturation is highly variable regionally within the Arctic, occurring during the decade of 2000–2010 in the Siberian shelves and Canadian Arctic Archipelago, but as late as the 2080s in the Barents and Norwegian Seas. We conclude that, in order to make future projections of acidification and carbon saturation state in the Arctic, regional variability needs to be adequately resolved, with particular emphasis on reliable predictions of the rates of retreat of the sea-ice which are a major source of uncertainty.

scholarly journals An enigmatic group of arctic island caribou and the potential implications for conservation of biodiversity

Rangifer ◽  
2014 ◽  
Vol 34 (1) ◽  
pp. 73 ◽  
Author(s):  
Keri McFarlane ◽  
Frank L. Miller ◽  
Samuel J. Barry ◽  
Gregory A. Wilson
Keyword(s):  
Rangifer Tarandus ◽  
Canadian Arctic ◽  
High Arctic ◽  
Canadian Arctic Archipelago ◽  
Scale Level ◽  
Geographic Population ◽  
Dna Analyses ◽  
South Central ◽  
The Status ◽  
Victoria Island

We investigated the status of caribou classified as Rangifer tarandus pearyi by DNA analyses, with an emphasis on those large-bodied caribou identified as ultra pearyi that were collected in summer 1958 on Prince of Wales Island, south-central Canadian Arctic Archipelago. Our comparative assessment reveals that the ultra pearyi from Prince of Wales Island belong to a group of pearyi and are not hybrids of pearyi x groenlandicus, as we found for the caribou occurring on nearby Banks Island and northwest Victoria Island. The ultra pearyi from Prince of Wales Island cluster with high arctic pearyi and are separated genetically from the caribou populations that we sampled on the low Canadian Arctic Islands and the Canadian mainland. Our findings reveal biodiversity below the level of subspecies or regional designations. These results support the position that to retain the biodiversity present among caribou populations on the Canadian Arctic Islands, conservation efforts should be targeted at the smaller scale level of the geographic population, rather than on a wider regional or subspecific range-wide basis.

Increased Arctic Ocean sea ice loss through the Canadian Arctic Archipelago under a warmer climate

2020 ◽  
Author(s):  
Stephen Howell ◽  
Mike Brady
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Canadian Arctic ◽  
Open Water ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Nares Strait ◽  
The Arctic Ocean ◽  
Important Pathway

<p>The ice arches that ring the northern Canadian Arctic Archipelago have historically blocked the inflow of Arctic Ocean sea ice for the majority of the year. However, annual average air temperature in northern Canada has increased by more than 2°C over the past 65+ years and a warmer climate is expected to contribute to the deterioration of these ice arches, which in turn has implications for the overall loss of Arctic Ocean sea ice. We investigated the effect of warming on the Arctic Ocean ice area flux into the Canadian Arctic Archipelago using a 22-year record (1997-2018) of ice exchange derived from RADARSAT-1 and RADARSAT-2 imagery. Results indicated that there has been a significant increase in the amount of Arctic Ocean sea ice (10<sup>3</sup> km<sup>2</sup>/year) entering the northern Canadian Arctic Archipelago over the period of 1997-2018. The increased Arctic Ocean ice area flux was associated with reduced ice arch duration but also with faster (thinner) moving ice and more southern latitude open water leeway as a result of the Canadian Arctic Archipelago’s long-term transition to a younger and thinner ice regime. Remarkably, in 2016, the Arctic Ocean ice area flux into the Canadian Arctic Archipelago (161x10<sup>3</sup> km<sup>2</sup>) was 7 times greater than the 1997-2018 average (23x10<sup>3</sup> km<sup>2</sup>) and almost double the 2007 ice area flux into Nares Strait (87x10<sup>3</sup> km<sup>2</sup>). Indeed, Nares Strait is known to be an important pathway for Arctic Ocean ice loss however, the results of this study suggest that with continued warming, the Canadian Arctic Archipelago may also become a large contributor to Arctic Ocean ice loss.</p>

Llandovery graptolite biostratigraphy and paleobiogeography, Cape Phillips Formation, Canadian Arctic Islands

1989 ◽  
Vol 26 (9) ◽  
pp. 1726-1746 ◽  
Author(s):  
Michael J. Melchin
Keyword(s):  
North America ◽  
Canadian Arctic ◽  
The Arctic ◽  
Canadian Cordillera ◽  
Canadian Arctic Archipelago ◽  
The South ◽  
Cape Phillips Formation ◽  
Shallow Basin

Llandovery graptolites have been collected from 11 sections in the Cape Phillips Formation of the Canadian Arctic Archipelago: Melville, Bathurst, Truro, Cornwallis, Devon, and Ellesmere islands. The Cape Phillips Formation appears to have been deposited in a distinct subbasin, here termed the Cape Phillips Basin, under deep-shelf to shallow-basin conditions intermediate in position between the Arctic Platform to the south and east and the deeper Hazen Trough to the northwest.A total of 170 graptolite species and a further 25 subspecies have been identified. Their stratigraphic distribution allows the recognition of 11 graptolite zones: the acuminatus, atavus, acinaces, cyphus, curtus, convolutus, minor, turriculatus, crispus, griestoniensis, and sakmaricus zones. The curtus Zone can be subdivided into the pectinatus and orbitus subzones. The zones can be correlated with graptolite sequences worldwide.The Canadian Arctic faunas show strong affinities with those of Siberia, China, and the northern Canadian Cordillera. It may be possible to recognize a circum-equatorial faunal province in northern North America, Siberia, and China based on the occurrence of distinctive forms including Agetograptus and "Paramonoclimacis" in the middle Llandovery and certain Cyrtograptus species (especially C. sakmaricus) in the upper Llandovery.

scholarly journals Dimethyl sulfide dynamics in first-year sea ice melt ponds in the Canadian Arctic Archipelago

2018 ◽  
Vol 15 (10) ◽  
pp. 3169-3188 ◽  
Author(s):  
Margaux Gourdal ◽  
Martine Lizotte ◽  
Guillaume Massé ◽  
Michel Gosselin ◽  
Michel Poulin ◽  
...  
Keyword(s):  
Sea Ice ◽  
Dimethyl Sulfide ◽  
De Novo ◽  
Canadian Arctic ◽  
The Arctic ◽  
First Year ◽  
Canadian Arctic Archipelago ◽  
Ice Melt ◽  
Melt Ponds ◽  
Arctic Atmosphere

Abstract. Melt pond formation is a seasonal pan-Arctic process. During the thawing season, melt ponds may cover up to 90 % of the Arctic first-year sea ice (FYI) and 15 to 25 % of the multi-year sea ice (MYI). These pools of water lying at the surface of the sea ice cover are habitats for microorganisms and represent a potential source of the biogenic gas dimethyl sulfide (DMS) for the atmosphere. Here we report on the concentrations and dynamics of DMS in nine melt ponds sampled in July 2014 in the Canadian Arctic Archipelago. DMS concentrations were under the detection limit (< 0.01 nmol L−1) in freshwater melt ponds and increased linearly with salinity (rs = 0.84, p ≤ 0.05) from ∼ 3 up to ∼ 6 nmol L−1 (avg. 3.7 ± 1.6 nmol L−1) in brackish melt ponds. This relationship suggests that the intrusion of seawater in melt ponds is a key physical mechanism responsible for the presence of DMS. Experiments were conducted with water from three melt ponds incubated for 24 h with and without the addition of two stable isotope-labelled precursors of DMS (dimethylsulfoniopropionate), (D6-DMSP) and dimethylsulfoxide (13C-DMSO). Results show that de novo biological production of DMS can take place within brackish melt ponds through bacterial DMSP uptake and cleavage. Our data suggest that FYI melt ponds could represent a reservoir of DMS available for potential flux to the atmosphere. The importance of this ice-related source of DMS for the Arctic atmosphere is expected to increase as a response to the thinning of sea ice and the areal and temporal expansion of melt ponds on Arctic FYI.

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