Arctic Archipelago [NEW]
The Arctic Archipelago, also known as the Canadian Arctic Archipelago, is an archipelago lying to the north of the Canadian continental mainland, excluding Greenland (an autonomous territory of Denmark) and Iceland (an independent country).
Situated in the northern extremity of North America and covering about 1,424,500 km2 (550,000 sq mi), this group of 36,563 islands, surrounded by the Arctic Ocean, comprises much of Northern Canada, predominately Nunavut and the Northwest Territories. The archipelago is showing some effects of climate change, with some computer estimates determining that melting there will contribute 3.5 cm (1.4 in) to the rise in sea levels by 2100.
The archipelago extends some 2,400 km (1,500 mi) longitudinally and 1,900 km (1,200 mi) from the mainland to Cape Columbia, the northernmost point on Ellesmere Island. It is bounded on the west by the Beaufort Sea; on the northwest by the Arctic Ocean; on the east by Greenland, Baffin Bay and Davis Strait; and on the south by Hudson Bay and the Canadian mainland. The various islands are separated from each other and the continental mainland by a series of waterways collectively known as the Northwest Passage. Two large peninsulas, Boothia and Melville, extend northward from the mainland. The northernmost cluster of islands, including Ellesmere Island, is known as the Queen Elizabeth Islands and was formerly the Parry Islands.
The archipelago consists of 36,563 islands, of which 94 are classified as major islands, being larger than 130 km2 (50 sq mi), and cover a total area of 1,400,000 km2 (540,000 sq mi). The islands of the archipelago over 10,000 km2 (3,900 sq mi), in order of descending area, are:
After Greenland, the archipelago is the world's largest high-Arctic land area. The climate of the islands is Arctic, and the terrain consists of tundra except in mountainous regions. Most of the islands are uninhabited; human settlement is extremely thin and scattered, being mainly coastal Inuit settlements on the southern islands.
The major islands in the eastern Arctic (Baffin, Devon, Ellesmere,Axel Heiberg) are mountainous, with peaks over 2,000 m. The higher land on these islands is commonly occupied by ice caps that contain most (75 per cent) of the glacierice and the largest glaciers in Canada, and one-third of the volume of land ice worldwide, not including the ice sheets found on Greenland and Antarctica. These highland areas were the major source area for the Innuitian ice sheet during the last glaciation(see also Innuitian Region).
The sea ice cover, with an average thickness of about 1.5 to 2 m is complete in winter throughout the archipelago, with the exception of several recurring polynyas (areas of open water surrounded by sea ice), the largest of which is in northern BaffinBay and in the southeastern Beaufort Sea. These polynyas, which freeze late and thaw early, are a focus for marine and bird life. There is evidence of early human habitation,by the early Inuit (Thule) and Dorset peoples, on the landmasses adjoining them.
As in the case of plants, the number of animal species decreases north from the mainland. Some 20 species of land mammals live on the archipelago, generally in small numbers restricted to certain areas. The High Arctic islands are home to Peary caribouthat are smaller and lighter in colour than the barren ground caribou. Other mammals in the archipelago include the muskox, Arctic fox, Arctic wolf, lemmingand Arctic hare. More than 60 species of birds spend the summer in the High Arctic islands, while only six species overwinter there. The surrounding seas are home to thepolar bear, the walrus and various types ofseal and whale, including thenarwhal and the beluga.
During the 1950s, Canadian government, university and private sector research and exploration expanded. Aerial photo coverage of the archipelago was completed and the Geological Survey of Canada was very active, mapping the geology and determining, amongother things, the presence of oil in the islands. McGill University expeditions to Axel Heiberg Island and the Arctic Institute of North America (now University ofCalgary) expeditions to Devon Island began regular glacier measurements that continue to this day as a way of monitoring glacier change in the region. Today, Resolute, CambridgeBay and Nanisivik (Northern Baffin Island) are developing centres of research and military activity.
Though much attention has been focused in recent years on the melting of ice from Greenland and Antarctica, nearly half of the ice volume currently being lost to the ocean is actually coming from other mountain glaciers and ice caps. Ice loss from a group of islands in northern Canada accounts for much of that volume.
The Arctic is warming more rapidly than other region on the planet, and the northern Barents Sea, including the Svalbard Archipelago, is experiencing the fastest temperature increases within the circumpolar Arctic, along with the highest rate of sea ice loss. These physical changes are affecting a broad array of resident Arctic organisms as well as some migrants that occupy the region seasonally. Herein, evidence of climate change impacts on terrestrial and marine wildlife in Svalbard is reviewed, with a focus on bird and mammal species. In the terrestrial ecosystem, increased winter air temperatures and concomitant increases in the frequency of 'rain-on-snow' events are one of the most important facets of climate change with respect to impacts on flora and fauna. Winter rain creates ice that blocks access to food for herbivores and synchronizes the population dynamics of the herbivore-predator guild. In the marine ecosystem, increases in sea temperature and reductions in sea ice are influencing the entire food web. These changes are affecting the foraging and breeding ecology of most marine birds and mammals and are associated with an increase in abundance of several temperate fish, seabird and marine mammal species. Our review indicates that even though a few species are benefiting from a warming climate, most Arctic endemic species in Svalbard are experiencing negative consequences induced by the warming environment. Our review emphasizes the tight relationships between the marine and terrestrial ecosystems in this High Arctic archipelago. Detecting changes in trophic relationships within and between these ecosystems requires long-term (multidecadal) demographic, population- and ecosystem-based monitoring, the results of which are necessary to set appropriate conservation priorities in relation to climate warming.
Seabirds are thought to provide ecological services such as the movement of nutrients between marine and terrestrial ecosystems, which may be especially critical to productivity and diversity in nutrient-poor environments. Most Arctic ecosystems are unaffected by local human impacts and are naturally nutrient poor and especially sensitive to warming. Here, we assessed the effects of nesting common eider ducks (Somateria mollissima) on soil, vegetation, and pond sediments on island archipelagoes in Hudson Strait between Nunavut and Québec, Canada. Soil, moss, and pond sediments were significantly higher in nitrogen on islands with large numbers of nesting eiders compared to sites with no nesting birds. The highest concentrations of nitrogen in soils and moss occurred at the margins of ponds on eider islands, which correspond to the areas of highest eider use. δ15N and δ34S values in soils, moss, and sediments indicated substantial marine-derived organic matter inputs at the higher nutrient sites. We propose that by foraging on coastal marine benthic invertebrates and returning to islands to nest, eider ducks bio-transport and concentrate marine-derived nutrients to their colony islands, fertilizing Arctic island ecosystems in the process. As common eiders nest on thousands of low to mid-latitude islands throughout the circumpolar Arctic, these nutrient inputs likely dramatically affect biota and ecosystem functioning throughout the tundra biome.
The islands of the Hudson Strait region present an important study opportunity as these islands are representative of thousands of similar low-lying, nearshore coastal islands across a large area of the eastern Canadian Arctic and West Greenland, many of which are used for nesting by northern common eiders (Somateria mollisima borealis). Whereas other studies have demonstrated seabirds that breed in very large colonies or at very high densities, and that feed at high trophic levels (e.g. are piscivorous), can be effective bio-vectors of nutrients (e.g., Keatley et al. 2011; Caut et al. 2012; Hargan et al. 2017), few studies have investigated whether seabirds that feed at lower trophic levels (e.g., feed on invertebrates) supplement nutrient levels in the terrestrial environment at or near their colonies. However, one study from the Canadian High Arctic did demonstrate that eiders deliver distinct contaminant mixtures to ponds that is distinguishable from a pond predominantly influence by nesting arctic terns (Michelutti et al. 2010). Still fewer studies have investigated whether important nutrient inputs occur across large geographical scales, such as large island archipelagos (but see Maron et al. 2006).
Our results, taken together, strongly suggest that common eider ducks are acting as ecologically important bio-vectors of marine nutrients to the terrestrial environment of the Arctic islands where they nest, both in small numbers and large. As common eider ducks nest throughout Hudson Strait, including Ungava Bay and the surrounding areas (Cooch 1986; Iverson et al. 2014), our study demonstrates that these marine-derived nutrients could have broad regional-scale effects on soil and water chemistry across these island archipelagos.
Abstract. In the Arctic Ocean region, methane concentrations are higher than the global average; high concentrations of dissolved CH4 are detectable especially across many subarctic and Arctic continental shelf margins. Yet the Arctic Ocean appears to emit only minimal methane fluxes to the atmosphere across the air-sea interface, suggesting water column oxidation of methane may be an important process. Here we paired thermohaline, chemical, and biological data collected during the Northwest Passage Project transit through the Canadian Arctic Archipelago (CAA) waters in the Summer of 2019, with in-situ and in-vitro methane data. Our results showed high meltwater (meteoric water + sea ice melt) throughout the Western CAA and Croker Bay in the East, and these surface meltwaters showed methane excess. The meteoric waters showed a strong correlation with chlorophyll-α fluorescence (r=0.63), as well as a correlation between dissolved [CH4] and chlorophyll-α fluorescence (r=0.74). Methane oxidation rate constants were highest in Wellington Channel and Croker Bay surface waters (av. 0.010 d-1), characterized by meltwaters and Pacific-origin waters. The average oxidation rates in meteoric and Pacific waters were respectively 24.4 % and 12.6 % higher than the entire survey average. Moreover, Pacific and meteoric waters hosted microbial taxa of Pacific-origin that are associated with methane oxidation, Oleispira (γ-proteobacteria), and Aurantivirga (Flavobacteria). The deeper layers were characterized by low methane concentrations and low methane oxidation rate constants (av. 0.0040.002 d-1). Sea ice covered much of the Western CAA, in the same region with high sea ice meltwater concentrations. These waters also hosted higher average methane oxidation rates (av. 0.0070.002 d-1). To the east, open coastal water coincided with methane enrichment, but low chlorophyll fluorescence and weak methane oxidation. These results suggest that methane production in ice-associated Arctic blooms may be quickly oxidized by microbes that are also found in these waters, associated with seasonal biology. 041b061a72