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Regional Overview & Fact Sheet
The Central Arctic Archipelago includes thousands of islands with jagged coastlines, making it one of the biggest archipelagos in the world and one of areas containing the longest coastlines. The ecoregion is composed of waters mostly 200–500 m deep, and includes most of the Arctic Islands east of the Arctic Basin Ecoregion, such as Ellesmere Island, the Queen Elizabeth Islands (with glacially scoured fjords 600–920 m deep) and the northeastern part of Victoria Island. During the brief Arctic summer, many of species of migrating birds are dependent on the ecoregion, making use of the unpredictable sections of open water that appear.
Fact Sheet
Ice regimes (faunal assemblages as a result).
Largely permanent ice in the long winter as well as short summer seasons.
Cape Bathurst polynya. A smaller polynya in Lambert Channel appears in the spring.
Predominantly a system of channels, straits, and fjords surrounding the Arctic islands.
shelf (roughly 0–200 m): 60%
slope (roughly 200–2,500/3,000 m): 40%
abyssal plain (roughly 3,000+ m): 0%
Note that the deepest area, reaching 900 m, is around the Queen Elizabeth Islands.
estuaries, rocky shores
Moderately high productivity ecosystem (150-300 gCm-2yr-1).
polar bear, bowhead, beluga whale and narwhal.
Major seabird, waterfowl, and shorebird feeding, staging, and moulting areas.
Pesticides used in agriculture in southern and western latitudes are carried by wind to northern latitudes including the Arctic islands.
Hunting, fishing, adventure tours
Oil and gas exploration and recovery
Climate change
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Physical and Oceanographic Setting
A patchwork of interconnecting bays, fjords, channels, straits, sounds and gulfs comprise the ecoregion, with very little of it composed of shallow waters. This lattice of marine water bodies surrounds the hundreds of islands that form the Queen Elizabeth chain. As with the neighboring Arctic Basin, this ecoregion’s very cold seawater and northern latitude, as well as the little influence warmer southern waters have on the realm, make for its relatively constant cover of ice sheets and ice pack.
The water column is relatively stable, with a permanent layer of relatively low salinity in the upper 100 m. This sets up a strong salinity-based vertical structure that restricts primary productivity during the summer period due to nutrient limitations. This stratification also establishes horizontal density gradients that are responsible for the surface ocean currents. Tides in this ecoregion are minimal, as are the associated tidal currents.
During the winter, sea ice is jammed fast to the land and extends over the seas as a solid sheet. Polynyas, localized breaches in the ice where currents and upwellings create open water, can occur throughout the ecoregion. The ice cover reaches its maximum thickness in May, and in the brief spring and summer periods, the ice will break up. In the northwestern parts of the ecoregion, the sea ice normally shatters into massive sheets that are separated by narrow channels of open water. The sea ice persists throughout the summer. Along the east coast of Ellesmere Island, icebergs occasionally calve (break off) from adjacent coastal glaciers, making their way to the ocean.
As with the neighboring ecoregion, the Arctic Basin Ecoregion, the climate of the Central Arctic Archipelago is extremely cold and dry. Air temperatures remain chilly. Even in July, mean daily temperatures average just 10°C. In winter, temperatures average about 30°C, and often much lower.
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Biological Setting
Biological productivity in the Central Arctic Archipelago is limited primarily by the availability of sunlight as well as by low year-round cold water temperatures and the very brief summer period. Biological hotspots, consisting of blooms of phytoplankton, occur in spring and summer along the edges of the pack ice and algae grows on the underside of sea ice. These blooms are the basis of some of the Arctic food chains.
During the brief Arctic summer, dozens of species of migrating birds make use of the unpredictable sections of open water that appear in the ecoregion. As the pack ice breaks up, ice edges become vital areas for mammals and seabirds. Taking advantage of the conditions there to feed, stage, and moult are small numbers of tundra swan, loons, geese, ducks, and several species of shorebirds, gulls, jaegers, Arctic tern, alcids, and fulmars.
Polar bears and ringed seals roam throughout the region. Bearded and harp seals are found along the east coast of Ellesmere Island, where open waters promise easy breathing. In winter, the unfrozen North Water Polynya serves as a refuge for marine mammals. In the 19th and early 20th centuries, whalers hunted the bowhead whale almost to extinction. While their numbers have rebounded in western waters, the eastern stock is still severely depleted and the species is considered endangered. Large schools of small Arctic cod exist across the ecoregion, supporting populations of seals, beluga whale and narwhal. The greatest numbers of fish species occur in the west and south, with schools of Arctic cod, Greenland cod, Arctic char, sculpins, eelpouts, and snailfish the most common. Other creatures such as anemones, clams, sponges, sea worms, and sea stars are also present.
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Human Activities and Impacts
Human presence is sparse in this northern ecoregion. Although limited, hunting, fishing, and adventure tours exist. Oil and gas exploration is also found and scientific expeditions have concentrated largely on finding reserves along the edges of the ice pack, but the permanent ice poses formidable challenges to petroleum exploration and drilling.
As with its neighboring ecoregions, this relatively isolated northern system is also affected by substances such as PCBs, DDT and mercury from urban and industrial areas and human activities far to the south. PCBs, for example, are a known contaminant in the breast milk of Inuit women (Miller 2000). Additionally, commercial over-harvesting of mammals and birds has endangered wildlife populations, most notably the bowhead whale (Wiken et al. 1996; WHC 2001). Climate change has been altering the ecology of the region and is expected to cause major impacts into the future.
Level II and Level III Descriptions
Level II captures the break between neritic (near shore) and oceanic areas and is determined by large-scale physiography (continental shelf, slope, and abyssal plain, as well as areas of oceanic islands and major trenches, ridges and straits). This level reflects the importance of depth as a major determinant of benthic marine communities as well as the importance of major physiographic features in determining current flows and upwelling. Like Level I, it extends from the coasts to the EEZ.
Level III captures differences within the neritic realm and is based on more locally significant variables (local characteristics of the water mass, regional landforms, as well as biological community type). Level III is limited to the continental shelf, since only this area has sufficient information for finer-scale delineation.
Level II and Level III Ecoregions
Other Marine Ecoregions
Marine ecoregions are areas of general similarity in terms of physiographic, oceanographic and biological characteristics, which fall within the Exclusive Economic Zones of the North American countries. There are 24 marine ecoregions in North America.
