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Arctic Ocean

2007 Schools Wikipedia Selection. Related subjects: General Geography

   Earth's five oceans
     * Atlantic Ocean
     * Arctic Ocean
     * Indian Ocean
     * Pacific Ocean
     * Southern Ocean

   Arctic Ocean

   The Arctic Ocean, located mostly in the Arctic north polar region, is
   the smallest of the world's five oceans and the shallowest. Even though
   the International Hydrographic Organization (IHO) recognizes it as an
   ocean, oceanographers may call it the Arctic Mediterranean Sea or
   simply the Arctic Sea, classifying it as one of the mediterranean seas
   of the Atlantic Ocean.

   Much of the ocean is covered by sea ice, either during the colder
   months or year-round. Little marine life exists where the ocean surface
   is covered with ice throughout the year. The Arctic Ocean's temperature
   and salinity vary seasonally as the ice cover melts and freezes; its
   salinity is the lowest on average of the five major seas, due to low
   evaporation, as well as limited outflow to the world ocean with heavy
   freshwater inflow.

   The greatest inflow of water comes from the Atlantic by way of the
   Norwegian Current, which then flows along the Eurasian coast. Water
   also enters from the Pacific via the Bering Strait. The East Greenland
   Current carries the major outflow. Ice covers most of the ocean surface
   year-round, causing subfreezing temperatures much of the time. The
   Arctic is a major source of very cold air that inevitably moves toward
   the equator, meeting with warmer air in the middle latitudes and
   causing rain and snow. Marine life abounds in open areas, especially
   the more southerly waters. The ocean's major ports are the Russian
   cities of Murmansk and Arkhangelsk. The Arctic Ocean is important as
   the shortest air route between the Pacific coast of North America and
   Europe overflies it.

Geography

   The Arctic Ocean occupies a roughly circular basin and covers an area
   of about 14,056,000 square km (5,440,000 mi²), slightly less than 1.5
   times the size of the United States. The coastline length is 45,389
   kilometers (28,203 mi). Nearly landlocked, it is surrounded by the land
   masses of Eurasia, North America, Greenland, and several islands. It
   includes Baffin Bay, Barents Sea, Beaufort Sea, Chukchi Sea, East
   Siberian Sea, Greenland Sea, Hudson Bay, Hudson Strait, Kara Sea,
   Laptev Sea, White Sea and other tributary bodies of water. It is
   connected to the Pacific Ocean by the Bering Strait and to the Atlantic
   Ocean through the Greenland Sea. Its geographic coordinates are: 90 _
   00 _ N _ 0 _ 00 _ E_ 90 ° 00 ′ N 0 ° 00 ′ E

   An underwater mid-ocean ridge, the Lomonosov Ridge, divides the deep
   sea North Polar Basin into two basins: the Eurasian, or Nansen, Basin,
   (after Fridtjof Nansen) which is between 4,000 and 4,500 meters (13,000
   and 15,000 ft) deep, and the North American, or Hyperborean, Basin,
   which is about 4,000 meters (13,000 ft) deep. The bathymetry of the
   ocean bottom is marked by fault-block ridges, plains of the abyssal
   zone, ocean deeps, and basins. The average depth of the Arctic Ocean is
   1,038 meters (3,407 ft). . The deepest point is in the Eurasian Basin
   deepest point, at 5,450 meters (17,881 ft).

   The Arctic Ocean contains a major chokepoint in the southern Chukchi
   Sea, which provides northern access to the Pacific Ocean via the Bering
   Strait between North America and Russia. The Arctic Ocean also provides
   the shortest marine link between the extremes of eastern and western
   Russia. There are several floating research stations in the Arctic,
   operated by the U.S. and Russia.

History

   For much of Western history, the geography of the North Polar regions
   remained largely unexplored and conjectural. Pytheas of Massalia
   recorded an account of a journey northward in 325 B.C. to a land he
   called "Ultima Thule," where the sun only set for three hours each day
   and the water was replaced by a congealed substance "on which one can
   neither walk nor sail." He was probably describing loose sea ice known
   today as "growlers" and "bergy bits." His "Thule" may have been
   Iceland, though the Faroe Islands have also been suggested.

   Early cartographers were unsure whether to draw the region around the
   Pole as land (as in the map of Johannes Ruysch in 1507, or Gerardus
   Mercator's map of 1595) or water (as with Martin Waldseemüller's world
   map of 1507). The fervent desire of Europeans for a northern passage to
   "Cathay" (China) caused water to win out, and by 1723 mapmakers such as
   Johann Homann featured an extensive "Oceanus Septentrionalis" at the
   northerm edge of their charts. The few expeditions to penetrate much
   beyond the Arctic Circle in this era added only small islands, such as
   Nova Zemlya (11th century) and Spitzbergen (1596), though since these
   were often surrounded by pack-ice their northern limits were not so
   clear. The makers of navigational charts, more conservative than some
   of the more fanciful cartographers, tended to leave the region blank,
   with only the bits of known coastline sketched in.

   This lack of knowledge of what lay north of the shifting barrier of ice
   gave rise to a number of conjectures. In England and other European
   nations, the myth of an "Open Polar Sea" was long-lived and persistent.
   John Barrow, longtime Second Secretary of the British Admiralty, made
   this belief the cornerstone of his campaign of Arctic exploration from
   1818 to 1845. In the United States in the 1850s and '60s, the explorers
   Elisha Kent Kane and Isaac Israel Hayes both claimed to have seen the
   shores of this elusive body of water. Even quite late in the century,
   the eminent authority Matthew Fontaine Maury included a description of
   the Open Polar Sea in his textbook The Physical Geography of the Sea
   (1883). Nevertheless, as all the explorers who trekked closer and
   closer to the pole reported, the Polar Ice Cap was ultimately quite
   thick, and persists year-round.

   Fridtjof Nansen was the first to make a naval crossing of the Arctic
   Ocean in 1896. The first surface crossing of the Arctic Ocean was led
   by Wally Herbert in 1969, in a dogsled expedition from Alaska to
   Svalbard with air support.

Climate

   Extent of the Arctic ice-pack in September, 1978-2002
   Enlarge
   Extent of the Arctic ice-pack in September, 1978-2002
   Extent of the Arctic ice-pack in February, 1978-2002
   Enlarge
   Extent of the Arctic ice-pack in February, 1978-2002

   The ocean is contained in a polar climate characterized by persistent
   cold and relatively narrow annual temperature ranges. Winters are
   characterized by continuous darkness, cold and stable weather
   conditions, and clear skies; summers are characterized by continuous
   daylight, damp and foggy weather, and weak cyclones with rain or snow.

   There is considerable seasonal variation in how much pack ice covers
   the Arctic Ocean. Much of the ocean is also covered in snow for about
   10 months of the year. The maximum snow cover is in March or April —
   about 20 to 50 centimeters (8 to 20 in) over the frozen ocean.

   The average temperature is approximately -2° celsius.

Natural hazards

   Ice islands occasionally break away from northern Ellesmere Island, and
   icebergs are formed from glaciers in western Greenland and extreme
   northeastern Canada. Permafrost is found on most islands. The ocean is
   virtually ice locked from October to June, and ships are subject to
   superstructure icing from October to May.

Plantlife

   The Arctic Ocean has relatively little plantlife except for
   Phytoplankton. Phytoplankton are a crucial part of the ocean and there
   are massive amounts of them in the Arctic. This is because during
   summer, the sun is out day and night, thus enabling the phytoplankton
   to photosynthesize for long periods of time and reproduce quickly.
   Phytoplankton can also reproduce by splitting themselves. Nutrients
   from the gulfstream and currents wash into the ocean too, making it the
   ocean with the most diverse wildlife.
   The Arctic Ocean is used by both marine mammals and nuclear submarines.
   Enlarge
   The Arctic Ocean is used by both marine mammals and nuclear submarines.

Environmental concerns

   Endangered marine species include walruses and whales. The area has a
   fragile ecosystem which is slow to change and slow to recover from
   disruptions or damage. The polar icepack is thinning, and there is a
   seasonal hole in ozone layer over the North Pole.

   Reduction of the area of Arctic sea ice will have an effect on the
   planet's albedo, thus possibly affecting global warming. Many
   scientists are presently concerned that warming temperatures in the
   Arctic may cause large amounts of fresh meltwater to enter the North
   Atlantic, possibly disrupting global ocean current patterns.
   Potentially severe changes in the Earth's climate might then ensue.

Major ports and harbors

   Arctic Ocean Seaports, Churchill, Inuvik, Prudhoe Bay, Barrow, Pevek,
   Tiksi, Dikson, Dudinka, Arkhangelsk, Murmansk
   Enlarge
   Arctic Ocean Seaports, Churchill, Inuvik, Prudhoe Bay, Barrow, Pevek,
   Tiksi, Dikson, Dudinka, Arkhangelsk, Murmansk
     * Churchill, Manitoba, Canada
     * Inuvik, Canada
     * Prudhoe Bay, Alaska, United States
     * Barrow, Alaska, United States
     * Pevek, Russia
     * Tiksi, Russia
     * Dikson, Russia
     * Dudinka, Russia
     * Murmansk, Russia
     * Arkhangelsk, Russia
     * Kirkenes, Norway
     * Vardø, Norway

   Retrieved from " http://en.wikipedia.org/wiki/Arctic_Ocean"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
