{ "Introduction": { "Background": { "text": "The Arctic Ocean is the smallest of the world's five ocean basins (after the Pacific Ocean, Atlantic Ocean, Indian Ocean, and the Southern Ocean). The Northwest Passage (US and Canada) and Northern Sea Route (Norway and Russia) are two important seasonal waterways. In recent years, the polar ice pack has receded in the summer allowing for increased navigation and raising the possibility of future sovereignty and shipping disputes among the Arctic coastal states affected (Canada, Denmark (Greenland), Iceland, Norway, Russia, US)." } }, "Geography": { "Location": { "text": "body of water between Europe, Asia, and North America, mostly north of the Arctic Circle" }, "Geographic coordinates": { "text": "90 00 N, 0 00 E" }, "Map references": { "text": "Arctic Region" }, "Area": { "total ": { "text": "15.558 million sq km" }, "note": "note: includes Barents Sea, Beaufort Sea, Chukchi Sea, East Siberian Sea, Greenland Sea, Kara Sea, Laptev Sea, Northwest Passage, Norwegian Sea, and other tributary water bodies" }, "Area - comparative": { "text": "slightly less than 1.5 times the size of the US" }, "Coastline": { "text": "45,389 km" }, "Climate": { "text": "polar climate characterized by persistent cold and relatively narrow annual temperature range; winters characterized by continuous darkness, cold and stable weather conditions, and clear skies; summers characterized by continuous daylight, damp and foggy weather, and weak cyclones with rain or snow" }, "Ocean volume": { "ocean volume": { "text": "18.75 million cu km" }, "percent of World Ocean total volume": { "text": "1.4%" } }, "Major ocean currents": { "text": "
two major, slow-moving, wind-driven currents (drift streams) dominate: a clockwise drift pattern in the Beaufort Gyre in the western part of the Arctic Ocean and a nearly straight line Transpolar Drift Stream that moves eastward across the ocean from the New Siberian Islands (Russia) to the Fram Strait (between Greenland and Svalbard); sea ice that lies close to the center of the gyre can complete a 360 degree circle in about 2 years, while ice on the gyre periphery will complete the same circle in about 7-8 years; sea ice in the Transpolar Drift crosses the ocean in about 3 years
" }, "Bathymetry": { "continental shelf": { "text": "The continental shelf (see Figure 1), a rather flat area of the sea floor adjacent to the coast that gradually slopes down from the shore to water depths that are typically less than 200 m (660 ft). Dimensions can vary: they may be narrow or nearly nonexistent in some places or extend for hundreds of miles in others. The waters above the continental shelf are usually productive in both plant and animal life, both from sunlight and nutrients from ocean upwelling and terrestrial runoff. More than one quarter of the Arctic sea floor is continental shelf. The Eurasian shelf is very wide, extending out 1,500 km (930 mi), and is the largest continental shelf in the world. The following are examples of features found on the continental shelf of the Arctic Ocean (see Figure 2).The Abyssal Plain is commonly interrupted by a variety of undersea terrain features including seamounts, guyots, ridges, and plateaus.
Seamounts (see Figure 1) are submarine mountains at least 1,000 m (3,300 ft) high that are formed from individual volcanoes on the ocean floor. They are distinct from the plate-boundary volcanic system of the mid-ocean ridges because seamounts tend to be circular or conical. A circular-collapse caldera is often centered at the summit, evidence of a magma chamber within the volcano. \"Hot spots\" in the deep mantle often feed long chains of seamounts. These hot spots are associated with stationary plumes of molten rock rising from deep within the Earth's mantle. The hot-spot plumes melt through the overlying tectonic plate as it moves and supplies magma to the active volcanic island at the end of the chain of volcanic islands and seamounts.
Flat-topped seamounts are known as guyots.
An undersea ridge is an elongated elevation of varying complexity and size, generally having steep sides.
An undersea plateau is a large, relatively flat elevation that is higher than the surrounding relief, with one or more relatively steep sides. Although submerged, these features can reach close to sea level.
The following are examples of undersea terrain features found on the floor of the Arctic Ocean (see Figure 2):
Lomonosov Ridge
Gakkel Ridge
Alpha Ridge
Mendeleev Rise
Chukchi Plateau