Arctic Ocean
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The Arctic Ocean is the smallest and shallowest of the world's five
oceanic divisions Oceanic may refer to: *Of or relating to the ocean *Of or relating to Oceania **Oceanic climate **Oceanic languages **Oceanic person or people, also called "Pacific Islander(s)" Places *Oceanic, British Columbia, a settlement on Smith Island, B ...
. It spans an area of approximately and is known as one of the coldest of oceans. The
International Hydrographic Organization The International Hydrographic Organization (IHO) is an intergovernmental organisation representing hydrography. , the IHO comprised 98 Member States. A principal aim of the IHO is to ensure that the world's seas, oceans and navigable waters a ...
(IHO) recognizes it as an ocean, although some
oceanographers Oceanography (), also known as oceanology and ocean science, is the scientific study of the oceans. It is an Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, Wind wave, waves, and geophysical flu ...
call it the Arctic Mediterranean Sea. It has also been described as an
estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...
of the
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
. It is also seen as the northernmost part of the all-encompassing
world ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the worl ...
. The Arctic Ocean includes the
North Pole The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface. It is called the True North Pole to distinguish from the Mag ...
region in the middle of the
Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...
and extends south to about 60°N. The Arctic Ocean is surrounded by
Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago a ...
and North America, and the borders follow topographic features: the Bering Strait on the
Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
side and the Greenland Scotland Ridge on the Atlantic side. It is mostly covered by
sea ice Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oce ...
throughout the year and almost completely in
winter Winter is the coldest season of the year in polar and temperate climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Different cultures ...
. The Arctic Ocean's surface temperature and
salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
vary seasonally as the
ice cover Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the wo ...
melts and freezes; its salinity is the lowest on average of the five major oceans, due to low
evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
, heavy
fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities. The summer shrinking of the ice has been quoted at 50%. The US
National Snow and Ice Data Center The National Snow and Ice Data Center (NSIDC) is a United States information and referral center in support of polar and cryospheric research. NSIDC archives and distributes digital and analog snow and ice data and also maintains information abo ...
(NSIDC) uses satellite data to provide a daily record of Arctic sea ice cover and the rate of melting compared to an average period and specific past years, showing a continuous decline in sea ice extent. In September 2012, the Arctic ice extent reached a new record minimum. Compared to the average extent (1979–2000), the sea ice had diminished by 49%.


History


North America

Human habitation in the North American polar region goes back at least 17,000–50,000 years, during the
Wisconsin glaciation The Wisconsin Glacial Episode, also called the Wisconsin glaciation, was the most recent glacial period of the North American ice sheet complex. This advance included the Cordilleran Ice Sheet, which nucleated in the northern North American Cor ...
. At this time, falling
sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...
s allowed people to move across the
Bering land bridge Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72 degrees north latitude in the Chukchi Sea; and on the south by the tip of ...
that joined
Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...
to northwestern North America (Alaska), leading to the
Settlement of the Americas The settlement of the Americas began when Paleolithic hunter-gatherers entered North America from the North Asian Mammoth steppe via the Beringia land bridge, which had formed between northeastern Siberia and western Alaska due to the lowering of ...
.
Early Paleo-Eskimo The Early Paleo-Eskimo is the first of three distinct periods of human occupation recognized by archaeologists in the eastern North American Arctic, the others being the Late Paleo-Eskimo and the Thule. Dates for these occupations vary according ...
groups included the
Pre-Dorset The Pre-Dorset is a loosely defined term for a Paleo-Eskimo culture or group of cultures that existed in the Eastern Canadian Arctic from c. 3200 to 850 cal BC, and preceded the Dorset culture. Due to its vast geographical expanse and to history ...
(); the
Saqqaq culture The Saqqaq culture (named after the Saqqaq settlement, the site of many archaeological finds) was a Paleo-Eskimo culture in southern Greenland. Up to this day, no other people seem to have lived in Greenland continually for as long as the Saqqaq. ...
of Greenland (2500–800 BC); the Independence I and
Independence II culture Independence II was a Paleo-Eskimo culture that flourished in northern and northeastern Greenland from around 700 to 80 BC, north and south of the Independence Fjord. The Independence II culture existed in roughly the same areas of Greenland as th ...
s of northeastern Canada and
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
( and ); and the Groswater of
Labrador , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ...
and
Nunavik Nunavik (; ; iu, ᓄᓇᕕᒃ) comprises the northern third of the province of Quebec, part of the Nord-du-Québec region and nearly coterminous with Kativik. Covering a land area of north of the 55th parallel, it is the homeland of the I ...
. The
Dorset culture The Dorset was a Paleo-Eskimo culture, lasting from to between and , that followed the Pre-Dorset and preceded the Thule people (proto-Inuit) in the North American Arctic. The culture and people are named after Cape Dorset (now Kinngait) in N ...
spread across Arctic North America between 500 BC and AD 1500. The Dorset were the last major
Paleo-Eskimo The Paleo-Eskimo (also pre-Thule or pre-Inuit) were the peoples who inhabited the Arctic region from Chukotka Autonomous Okrug, Chukotka (e.g., Chertov Ovrag) in present-day Russia across North America to Greenland prior to the arrival of the mode ...
culture in the Arctic before the migration east from present-day
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
of the
Thule people The Thule (, , ) or proto-Inuit were the ancestors of all modern Inuit. They developed in coastal Alaska by the year 1000 and expanded eastward across northern Canada, reaching Greenland by the 13th century. In the process, they replaced people ...
, ancestors of the modern
Inuit Inuit (; iu, ᐃᓄᐃᑦ 'the people', singular: Inuk, , dual: Inuuk, ) are a group of culturally similar indigenous peoples inhabiting the Arctic and subarctic regions of Greenland, Labrador, Quebec, Nunavut, the Northwest Territories ...
. The Thule Tradition lasted from about 200 BC to AD 1600, arising around the Bering Strait and later encompassing almost the entire Arctic region of North America. The Thule people were the ancestors of the Inuit, who now live in
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
,
Northwest Territories The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...
,
Nunavut Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost Provinces and territories of Canada#Territories, territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the ''Nunavut Act'' ...
,
Nunavik Nunavik (; ; iu, ᓄᓇᕕᒃ) comprises the northern third of the province of Quebec, part of the Nord-du-Québec region and nearly coterminous with Kativik. Covering a land area of north of the 55th parallel, it is the homeland of the I ...
(northern Quebec),
Labrador , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ...
and
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
.


Europe

For much of
European history The history of Europe is traditionally divided into four time periods: prehistoric Europe (prior to about 800 BC), classical antiquity (800 BC to AD 500), the Middle Ages (AD 500 to AD 1500), and the modern era (since AD 1500). The first early ...
, the north
polar region The polar regions, also called the frigid geographical zone, zones or polar zones, of Earth are the regions of the planet that surround its geographical poles (the North Pole, North and South Poles), lying within the polar circles. These high l ...
s remained largely unexplored and their geography conjectural.
Pytheas Pytheas of Massalia (; Ancient Greek: Πυθέας ὁ Μασσαλιώτης ''Pythéas ho Massaliōtēs''; Latin: ''Pytheas Massiliensis''; born 350 BC, 320–306 BC) was a Greeks, Greek List of Graeco-Roman geographers, geographer, explor ...
of
Massilia Massalia (Greek: Μασσαλία; Latin: Massilia; modern Marseille) was an ancient Greek colony founded ca. 600 BC on the Mediterranean coast of present-day France, east of the river Rhône, by Ionian Greek settlers from Phocaea, in Western An ...
recorded an account of a journey northward in 325 BC, to a land he called " Eschate 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" or "bergy bits"; his "Thule" was probably
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
, though the
Faroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark. They are located north-northwest of Scotland, and about halfway bet ...
or
Shetland Shetland, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom. The islands lie about to the no ...
have also been suggested. Early
cartographers Cartography (; from grc, χάρτης , "papyrus, sheet of paper, map"; and , "write") is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an im ...
were unsure whether to draw the region around the North Pole as land (as in
Johannes Ruysch Johannes Ruysch (c. 1460? in Utrecht – 1533 in Cologne), a.k.a. ''Johann Ruijsch'' or ''Giovanni Ruisch'' was an explorer, cartographer, astronomer, manuscript illustrator and painter from the Low Countries who produced a famous map of the world ...
's map of 1507, or
Gerardus Mercator Gerardus Mercator (; 5 March 1512 – 2 December 1594) was a 16th-century geographer, cosmographer and Cartography, cartographer from the County of Flanders. He is most renowned for creating the Mercator 1569 world map, 1569 world map based on ...
's map of 1595) or water (as with
Martin Waldseemüller Martin Waldseemüller (c. 1470 – 16 March 1520) was a German cartographer and humanist scholar. Sometimes known by the Latinisation of names, Latinized form of his name, Hylacomylus, his work was influential among contemporary cartographers. He ...
's world map of 1507). The fervent desire of European merchants for a northern passage, the
Northern Sea Route The Northern Sea Route (NSR) (russian: Се́верный морско́й путь, ''Severnyy morskoy put'', shortened to Севморпуть, ''Sevmorput'') is a shipping route officially defined by Russian legislation as lying east of Nov ...
or the
Northwest Passage The Northwest Passage (NWP) is the sea route between the Atlantic and Pacific oceans through the Arctic Ocean, along the northern coast of North America via waterways through the Canadian Arctic Archipelago. The eastern route along the Arct ...
, to "
Cathay Cathay (; ) is a historical name for China that was used in Europe. During the early modern period, the term ''Cathay'' initially evolved as a term referring to what is now Northern China, completely separate and distinct from China, which ...
" (
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
) caused water to win out, and by 1723 mapmakers such as
Johann Homann Johann Baptist Homann (20 March 1664 – 1 July 1724) was a German geographer and cartographer, who also made maps of the Americas. Life Homann was born in Oberkammlach near Kammlach in the Electorate of Bavaria. Although educated at a Jesui ...
featured an extensive "Oceanus Septentrionalis" at the northern edge of their charts. The few expeditions to penetrate much beyond the
Arctic Circle The Arctic Circle is one of the two polar circles, and the most northerly of the five major circles of latitude as shown on maps of Earth. Its southern equivalent is the Antarctic Circle. The Arctic Circle marks the southernmost latitude at w ...
in that era added only small islands, such as
Novaya Zemlya Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, ...
(11th century) and
Spitzbergen Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
(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 fragments of known coastline sketched in.


19th century

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 Myth is a folklore genre consisting of Narrative, narratives that play a fundamental role in a society, such as foundational tales or Origin myth, origin myths. Since "myth" is widely used to imply that a story is not Objectivity (philosophy), ...
of an "
Open Polar Sea The Open Polar Sea was a hypothesized ice-free ocean surrounding the North Pole. This unproved and eventually-disproved theory was once so widely believed that many exploring expeditions used it as justification for attempts to reach the North P ...
" was persistent. John Barrow, longtime Second Secretary of the
British Admiralty The Admiralty was a department of the Government of the United Kingdom responsible for the command of the Royal Navy until 1964, historically under its titular head, the Lord High Admiral – one of the Great Officers of State. For much of it ...
, promoted exploration of the region from 1818 to 1845 in search of this. In the United States in the 1850s and 1860s, the explorers
Elisha Kane Elisha Kent Kane (February 3, 1820 – February 16, 1857) was a United States Navy medical officer and Arctic explorer. He served as assistant surgeon during Caleb Cushing's journey to China to negotiate the Treaty of Wangxia and in the Af ...
and
Isaac Israel Hayes Isaac Israel Hayes (March 5, 1832 – December 17, 1881) was an American Arctic explorer, physician, and politician, who was appointed as the commanding officer at Satterlee General Hospital during the American Civil War, and was then elected, ...
both claimed to have seen part of this elusive body of water. Even quite late in the century, the eminent authority
Matthew Fontaine Maury Matthew Fontaine Maury (January 14, 1806February 1, 1873) was an American oceanographer and naval officer, serving the United States and then joining the Confederacy during the American Civil War. He was nicknamed "Pathfinder of the Seas" and i ...
included a description of the Open Polar Sea in his textbook ''The Physical Geography of the Sea'' (1883). Nevertheless, as all the explorers who travelled closer and closer to the pole reported, the
polar ice cap A polar ice cap or polar cap is a high-latitude region of a planet, dwarf planet, or natural satellite that is covered in ice. There are no requirements with respect to size or composition for a body of ice to be termed a polar ice cap, nor a ...
is quite thick and persists year-round.
Fridtjof Nansen Fridtjof Wedel-Jarlsberg Nansen (; 10 October 186113 May 1930) was a Norwegian polymath and Nobel Peace Prize laureate. He gained prominence at various points in his life as an explorer, scientist, diplomat, and humanitarian. He led the team t ...
was the first to make a
nautical Seamanship is the art, knowledge and competence of operating a ship, boat or other craft on water. The'' Oxford Dictionary'' states that seamanship is "The skill, techniques, or practice of handling a ship or boat at sea." It involves topics a ...
crossing of the Arctic Ocean, in the Fram Expedition from 1893 to 1896.


20th century

The first surface crossing of the ocean was led by
Wally Herbert Sir Walter William Herbert (24 October 1934 – 12 June 2007) was a British polar explorer, writer and artist. In 1969 he became the first man fully recognized for walking to the North Pole, on the 60th anniversary of Robert Peary's disputed exp ...
in 1969, in a
dog sled A dog sled or dog sleigh is a sled pulled by one or more sled dogs used to travel over ice and through snow. Numerous types of sleds are used, depending on their function. They can be used for dog sled racing. Traditionally in Greenland and the e ...
expedition from
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
to
Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
, with air support. The first nautical transit of the north pole was made in 1958 by the submarine USS ''Nautilus'', and the first surface nautical transit occurred in 1977 by the
icebreaker An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters, and provide safe waterways for other boats and ships. Although the term usually refers to ice-breaking ships, it may also refer to smaller ...
NS ''Arktika''. Since 1937,
Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
and Russian manned
drifting ice station A drifting ice station is a temporary or semi-permanent facility built on an ice floe. During the Cold War the Soviet Union and the United States maintained a number of stations in the Arctic Ocean on floes such as Fletcher's Ice Island for rese ...
s have extensively monitored the Arctic Ocean. Scientific settlements were established on the drift ice and carried thousands of kilometres by
ice floe An ice floe () is a large pack of floating ice often defined as a flat piece at least 20 m across at its widest point, and up to more than 10 km across. Drift ice is a floating field of sea ice composed of several ice floes. They may caus ...
s. In
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, the European region of the Arctic Ocean was heavily contested: the Allied commitment to resupply the Soviet Union via its northern ports was opposed by German naval and air forces. Since 1954 commercial airlines have flown over the Arctic Ocean (see
Polar route A polar route is an aircraft route across the uninhabited polar ice cap regions. The term "polar route" was originally applied to great circle navigation routes between Europe and the west coast of North America in the 1950s. The Arctic Early ye ...
).


Geography


Size

The Arctic Ocean occupies a roughly circular basin and covers an area of about , almost the size of
Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
. The coastline is long. It is the only
ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...
smaller than
Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
, which has a land area of .


Surrounding land and exclusive economic zones

The Arctic Ocean is surrounded by the land masses of Eurasia (
Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
and
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
), North America (
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
and the U.S. state of
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
),
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
, and
Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
. Note: Some parts of the areas listed in the table are located in the
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
. Other consists of
Gulf A gulf is a large inlet from the ocean into the landmass, typically with a narrower opening than a bay, but that is not observable in all geographic areas so named. The term gulf was traditionally used for large highly-indented navigable bodie ...
s,
Strait A strait is an oceanic landform connecting two seas or two other large areas of water. The surface water generally flows at the same elevation on both sides and through the strait in either direction. Most commonly, it is a narrow ocean channe ...
s,
Channel Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austral ...
s and other parts without specific names and excludes Exclusive Economic Zones.


Subareas and connections

The Arctic Ocean is connected to the
Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
by the Bering Strait and to the Atlantic Ocean through the
Greenland Sea The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined as p ...
and
Labrador Sea The Labrador Sea (French: ''mer du Labrador'', Danish: ''Labradorhavet'') is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelf, continental shelves to the southwest, northwest, ...
. (The Iceland Sea is sometimes considered part of the
Greenland Sea The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined as p ...
, and sometimes separate.) The largest seas in the Arctic Ocean: #
Barents Sea The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territo ...
—1.4 million km2 #
Hudson Bay Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...
—1.23 million km2 (sometimes not included) #
Greenland Sea The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined as p ...
—1.205 million km2 #
East Siberian Sea The East Siberian Sea ( rus, Восто́чно-Сиби́рское мо́ре, r=Vostochno-Sibirskoye more) is a marginal sea in the Arctic Ocean. It is located between the Arctic Cape to the north, the coast of Siberia to the south, the New Si ...
—987,000 km2 #
Kara Sea The Kara Sea (russian: Ка́рское мо́ре, ''Karskoye more'') is a marginal sea, separated from the Barents Sea to the west by the Kara Strait and Novaya Zemlya, and from the Laptev Sea to the east by the Severnaya Zemlya archipelago. ...
—926,000 km2 #
Laptev Sea The Laptev Sea ( rus, мо́ре Ла́птевых, r=more Laptevykh; sah, Лаптевтар байҕаллара, translit=Laptevtar baỹğallara) is a marginal sea of the Arctic Ocean. It is located between the northern coast of Siberia, th ...
—662,000 km2 #
Chukchi Sea Chukchi Sea ( rus, Чуко́тское мо́ре, r=Chukotskoye more, p=tɕʊˈkotskəjə ˈmorʲɪ), sometimes referred to as the Chuuk Sea, Chukotsk Sea or the Sea of Chukotsk, is a marginal sea of the Arctic Ocean. It is bounded on the west b ...
—620,000 km2 #
Beaufort Sea The Beaufort Sea (; french: Mer de Beaufort, Iñupiaq: ''Taġiuq'') is a marginal sea of the Arctic Ocean, located north of the Northwest Territories, the Yukon, and Alaska, and west of Canada's Arctic islands. The sea is named after Sir Fr ...
—476,000 km2 #
Amundsen Gulf Amundsen Gulf is a gulf located mainly in the Inuvik Region, Northwest Territories, Canada with a small section in the Kitikmeot Region of Nunavut. It lies between Banks Island and Victoria Island and the mainland. It is approximately in length ...
—93,000 km2 #
White Sea The White Sea (russian: Белое море, ''Béloye móre''; Karelian and fi, Vienanmeri, lit. Dvina Sea; yrk, Сэрако ямʼ, ''Serako yam'') is a southern inlet of the Barents Sea located on the northwest coast of Russia. It is su ...
—90,000 km2 #
Pechora Sea Pechora Sea (russian: link=no, Печо́рское мо́ре, or Pechorskoye More), is a sea at the northwest of Russia, the southeastern part of the Barents Sea The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево ...
—81,263 km2 #
Lincoln Sea Lincoln Sea (french: Mer de Lincoln; da, Lincolnhavet) is a body of water in the Arctic Ocean, stretching from Cape Columbia, Canada, in the west to Cape Morris Jesup, Greenland, in the east. The northern limit is defined as the great circle line ...
—64,000 km2 # Prince Gustaf Adolf Sea #
Queen Victoria Sea The Queen Victoria Sea (russian: Море королевы Виктории, ''Morye Korolevy Viktorii'') is a body of water in the Arctic Ocean, stretching from northeast of Svalbard to northwest Franz Josef Land. It is obstructed by ice most of ...
#
Wandel Sea The Wandel Sea ( da, Wandelhavet; also known as McKinley Sea) is a body of water in the Arctic Ocean, stretching from northeast of Greenland to Svalbard. It is obstructed by ice most of the year. This sea is named after Danish polar explorer an ...
Different authorities put various marginal seas in either the Arctic Ocean or the Atlantic Ocean, including:
Hudson Bay Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...
,
Baffin Bay Baffin Bay ( Inuktitut: ''Saknirutiak Imanga''; kl, Avannaata Imaa; french: Baie de Baffin), located between Baffin Island and the west coast of Greenland, is defined by the International Hydrographic Organization as a marginal sea of the Arct ...
, the
Norwegian Sea The Norwegian Sea ( no, Norskehavet; is, Noregshaf; fo, Norskahavið) is a marginal sea, grouped with either the Atlantic Ocean or the Arctic Ocean, northwest of Norway between the North Sea and the Greenland Sea, adjoining the Barents Sea to ...
, and
Hudson Strait Hudson Strait (french: Détroit d'Hudson) links the Atlantic Ocean and Labrador Sea to Hudson Bay in Canada. This strait lies between Baffin Island and Nunavik, with its eastern entrance marked by Cape Chidley in Newfoundland and Labrador and ...
.


Islands

The main islands and archipelagos in the Arctic Ocean are, from the
prime meridian A prime meridian is an arbitrary meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great c ...
west: *
Jan Mayen Jan Mayen () is a Norwegian volcanic island in the Arctic Ocean with no permanent population. It is long (southwest-northeast) and in area, partly covered by glaciers (an area of around the Beerenberg volcano). It has two parts: larger nort ...
(Norway) *
Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
*
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
*
Arctic Archipelago 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). Situated in the northern extremity of No ...
(Canada, includes the
Queen Elizabeth Islands The Queen Elizabeth Islands (french: Îles de la Reine-Élisabeth; formerly Parry Islands or Parry Archipelago) are the northernmost cluster of islands in Canada's Arctic Archipelago, split between Nunavut and the Northwest Territories in Northe ...
and
Baffin Island Baffin Island (formerly Baffin Land), in the Canadian territory of Nunavut, is the largest island in Canada and the fifth-largest island in the world. Its area is , slightly larger than Spain; its population was 13,039 as of the 2021 Canadia ...
) *
Wrangel Island Wrangel Island ( rus, О́стров Вра́нгеля, r=Ostrov Vrangelya, p=ˈostrəf ˈvrangʲɪlʲə; ckt, Умӄиԓир, translit=Umqiḷir) is an island of the Chukotka Autonomous Okrug, Russia. It is the 91st largest island in the w ...
(Russia) *
New Siberian Islands The New Siberian Islands ( rus, Новосиби́рские Oстрова, r=Novosibirskiye Ostrova; sah, Саҥа Сибиир Aрыылара, translit=Saña Sibiir Arıılara) are an archipelago in the Extreme North of Russia, to the north o ...
(Russia) *
Severnaya Zemlya Severnaya Zemlya (russian: link=no, Сéверная Земля́ (Northern Land), ) is a archipelago in the Russian high Arctic. It lies off Siberia's Taymyr Peninsula, separated from the mainland by the Vilkitsky Strait. This archipelago s ...
(Russia) *
Novaya Zemlya Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, ...
(Russia, includes
Severny Island Severny Island (russian: Се́верный о́стров, Severnyy ostrov, Northern Island) is a Russian Arctic island. It is the northern island of the Novaya Zemlya archipelago. It was historically called Lütke Land after Friedrich Benjamin ...
and
Yuzhny Island Yuzhny (russian: Южный остров, lit. southern island) is the southern island of the Novaya Zemlya archipelago, lying north of Russia. It has an area of , which while smaller than the northern island of Severny, makes it one of the larg ...
) *
Franz Josef Land , native_name = , image_name = Map of Franz Josef Land-en.svg , image_caption = Map of Franz Josef Land , image_size = , map_image = Franz Josef Land location-en.svg , map_caption = Location of Franz Josef ...
(Russia) *
Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
(Norway, including Bear Island)


Ports

There are several ports and
harbour A harbor (American English), harbour (British English; see spelling differences), or haven is a sheltered body of water where ships, boats, and barges can be docked. The term ''harbor'' is often used interchangeably with ''port'', which is a ...
s on the Arctic Ocean.Arctic Ocean
. CIA World Fact Book
* Alaska **
Utqiaġvik Utqiagvik ( ik, Utqiaġvik; , , formerly known as Barrow ()) is the borough seat and largest city of the North Slope Borough in the U.S. state of Alaska. Located north of the Arctic Circle, it is one of the northernmost cities and towns in the ...
(Barrow) **
Prudhoe Bay Prudhoe Bay is a census-designated place (CDP) located in North Slope Borough in the U.S. state of Alaska. As of the 2010 census, the population of the CDP was 2,174 people, up from just five residents in the 2000 census; however, at any give ...
*
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
**
Manitoba Manitoba ( ) is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population o ...
:
Churchill Sir Winston Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 during the Second World War, and again from 1 ...
(
Port of Churchill The Port of Churchill is a privately-owned port on Hudson Bay in Churchill, Manitoba, Canada. Routes from the port connect to the North Atlantic through the Hudson Strait. , the port had four deep-sea berths capable of handling Panamax-size vesse ...
) **
Nunavut Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost Provinces and territories of Canada#Territories, territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the ''Nunavut Act'' ...
:
Nanisivik Nanisivik ( iu, ᓇᓂᓯᕕᒃ, lit=the place where people find things; ) is a now-abandoned company town which was built in 1975 to support the lead-zinc mining and mineral processing operations for the Nanisivik Mine, in production between 19 ...
(
Nanisivik Naval Facility The Nanisivik Naval Facility (french: links=no, installation navale de Nanisivik) is a Canadian Forces naval facility on Baffin Island, Nunavut. The station is built at the former lead-zinc mine site near the former company town of Nanisivik. Th ...
) **
Tuktoyaktuk Tuktoyaktuk , or ''Tuktuyaaqtuuq'' (Inuvialuktun: ''it looks like a caribou''), is an Inuvialuit hamlet located in the Inuvik Region of the Northwest Territories, Canada, at the northern terminus of the Inuvik–Tuktoyaktuk Highway.Montgomery, ...
and
Inuvik Inuvik (''place of man'') is the only town in the Inuvik Region, and the third largest community in Canada's Northwest Territories. Located in what is sometimes called the Beaufort Delta Region, it serves as its administrative and service cen ...
in the
Northwest Territories The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...
* Greenland:
Nuuk Nuuk (; da, Nuuk, formerly ) is the capital and largest city of Greenland, a constituent country of the Kingdom of Denmark. Nuuk is the seat of government and the country's largest cultural and economic centre. The major cities from other co ...
(
Nuuk Port and Harbour Nuuk Port and Harbour is the largest port in Greenland. It is located in the southeastern area of the city of Nuuk known as Old Nuuk. The harbour entrance is restricted due to tides during much of the year, and ice during winter. The inner p ...
) *
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
** Mainland:
Kirkenes Kirkenes (; ; Skolt Sami: ''Ǩeârkknjargg;'' fi, Kirkkoniemi; ; russian: Киркенес) is a List of towns and cities in Norway, town in Sør-Varanger Municipality in Troms og Finnmark county, in the far northeastern part of Norway. The town ...
and
Vardø ( fi, Vuoreija, fkv, Vuorea, se, Várggát) is a municipality in Troms og Finnmark county in the extreme northeastern part of Norway. Vardø is the easternmost town in Norway, more to the east than Saint Petersburg or Istanbul. The administra ...
**
Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
:
Longyearbyen Longyearbyen (, locally lɔ̀ŋjɑrˌbyːən "The Longyear Town") is the world's northernmost settlement with a population greater than 1,000 and the largest inhabited area of Svalbard, Norway. It stretches along the foot of the left bank ...
* Iceland **
Akureyri Akureyri (, locally ) is a town in northern Iceland. It is Iceland's fifth-largest municipality, after Reykjavík, Hafnarfjörður, Reykjanesbær and Kópavogur, and the largest town outside Iceland's more populated southwest corner. Nicknamed ...
* Russia ** Barents Sea:
Murmansk Murmansk (Russian: ''Мурманск'' lit. "Norwegian coast"; Finnish: ''Murmansk'', sometimes ''Muurmanski'', previously ''Muurmanni''; Norwegian: ''Norskekysten;'' Northern Sámi: ''Murmánska;'' Kildin Sámi: ''Мурман ланнҍ'') i ...
** White Sea:
Arkhangelsk Arkhangelsk (, ; rus, Арха́нгельск, p=ɐrˈxanɡʲɪlʲsk), also known in English as Archangel and Archangelsk, is a types of inhabited localities in Russia, city and the administrative center of Arkhangelsk Oblast, Russia. It lies o ...
** Kara Sea:
Labytnangi Labytnangi (russian: Лабытна́нги; from Khanty: ; lit. ''seven larches''; Nenets: Лабытнаӈгы. ''Labytnaŋgy'') is a town in Yamalo-Nenets Autonomous Okrug, Russia, located on the left bank of the Ob River, northwest of Salek ...
,
Salekhard Salekhard (russian: Салеха́рд; Khanty: , ''Pułñawat''; yrk, Саляʼ харад, ''Saljaꜧ harad'') is a town in Yamalo-Nenets Autonomous Okrug, Russia, serving as the okrug's administrative centre. It crosses the Arctic Circle, th ...
,
Dudinka Dudinka (russian: Дуди́нка; Nenets: Тут'ын, ''Tutꜧyn'') is a town on the Yenisei River and the administrative center of Taymyrsky Dolgano-Nenetsky District of Krasnoyarsk Krai, Russia. It used to be the administrative center of Tay ...
,
Igarka Igarka (russian: Ига́рка) is a town in Turukhansky District of Krasnoyarsk Krai, Russia, located north of the Arctic Circle. Igarka is a monotown established around a sawmill which processed timber logged in the basin of the Yenisei River ...
and Dikson ** Laptev Sea:
Tiksi Tiksi ( rus, Ти́кси, , ˈtʲiksʲɪ; sah, Тиксии, ''Tiksii'' – lit. ''a moorage place'') is an urban locality (an urban-type settlement) and the administrative center of Bulunsky District in the Sakha Republic, Russia, located o ...
** East Siberian Sea:
Pevek Pevek (russian: Певе́к; Chukchi: , ''Pèèkin'' / ''Pèèk'') is an Arctic port town and the administrative center of Chaunsky District in Chukotka Autonomous Okrug, Russia, located on Chaunskaya Bay (part of the East Siberian Sea) on a pe ...


Arctic shelves

The ocean's Arctic shelf comprises a number of
continental shelves A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...
, including the Canadian Arctic shelf, underlying the
Canadian Arctic Archipelago 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). Situated in the northern extremity of No ...
, and the
Russian continental shelf The continental shelf of Russia (also called the Russian continental shelf or the Arctic shelf in the Arctic region) is a continental shelf adjacent to the Russian Federation. Geologically, the extent of the shelf is defined as the entirety of the ...
, which is sometimes called the "Arctic Shelf" because it is larger. The Russian continental shelf consists of three separate, smaller shelves: the Barents Shelf,
Chukchi Sea Shelf The Chukchi Sea Shelf or Chukchi Shelf is the westernmost part of the continental shelf of the United States and the easternmost part of the continental shelf of Russia. Within this shelf, the 50-mile Chukchi Corridor acts as a passageway for one ...
and
Siberian Shelf The Siberian Shelf is a coastal shelf in the Arctic Ocean and is the largest continental shelf of the Earth, a part of the continental shelf of Russia. It extends from the continent of Eurasia in the general area of North Siberia (hence the name) ...
. Of these three, the Siberian Shelf is the largest such shelf in the world; it holds large oil and gas reserves. The Chukchi shelf forms the border between Russian and the United States as stated in the
USSR–USA Maritime Boundary Agreement The Russia–United States maritime boundary was established by the June 1, 1990 USA/USSR Maritime Boundary Agreement (since Russia declared itself to be the successor of the Soviet Union). The United States Senate gave its advice and consent to ...
. The whole area is subject to international territorial claims. The
Chukchi Plateau The Chukchi Plateau or Chukchi Cap is a large subsea formation extending north from the Alaskan margin into the Arctic Ocean. The ridge is normally covered by ice year-round, and reaches an approximate bathymetric prominence of 3,400 m with i ...
extends from the Chukchi Sea Shelf.


Underwater features

An
underwater ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a diver ...
, the
Lomonosov Ridge The Lomonosov Ridge (russian: Хребет Ломоносова, da, Lomonosovryggen) is an unusual underwater ridge of continental crust in the Arctic Ocean. It spans between the New Siberian Islands over the central part of the ocean to Elle ...
, divides the deep sea North Polar Basin into two
oceanic basin In hydrology, an oceanic basin (or ocean basin) is anywhere on Earth that is covered by seawater. Geologically, ocean basins are large  geologic basins that are below sea level. Most commonly the ocean is divided into basins foll ...
s: the
Eurasian Basin The Eurasian Basin, or Eurasia Basin, is one of the two major basins into which the Arctic Basin of the Arctic Ocean is split by the Lomonosov Ridge (other being the Amerasia Basin). The Eurasia Basin may be seen as an extension of the North Atla ...
, which is deep, and the
Amerasian Basin The Amerasia Basin, or Amerasian Basin, is one of the two major basins from which the Arctic Ocean can be subdivided (the other one being the Eurasian Basin). The triangular-shaped Amerasia Basin broadly extends from the Canadian Arctic Islands to ...
(sometimes called the North American or Hyperborean Basin), which is about deep. The
bathymetry Bathymetry (; ) is the study of underwater depth of ocean floors (''seabed topography''), lake floors, or river floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The first recorded evidence of water de ...
of the ocean bottom is marked by
fault block Fault blocks are very large blocks of rock, sometimes hundreds of kilometres in extent, created by tectonic and localized stresses in Earth's crust. Large areas of bedrock are broken up into blocks by faults. Blocks are characterized by rela ...
ridges,
abyssal plain An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between and . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface. T ...
s, ocean deeps, and basins. The average depth of the Arctic Ocean is . The deepest point is
Molloy Hole The Molloy Deep (also known as the Molloy Hole) is a bathymetry, bathymetric feature in the Fram Strait, within the Greenland Sea east of Greenland and about 160 km west of Svalbard. It is the location of the deepest point in the Arctic Ocean. The ...
in the
Fram Strait The Fram Strait is the passage between Greenland and Svalbard, located roughly between 77°N and 81°N latitudes and centered on the prime meridian. The Greenland and Norwegian Seas lie south of Fram Strait, while the Nansen Basin of the Arctic ...
, at about . The two major basins are further subdivided by ridges into the
Canada Basin The Canada Basin is a deep oceanic basin within the Arctic Ocean. It is part of the Amerasian Basin and lies off the coast of Alaska and northwest Canada between the Chukchi Plateau north of Alaska and the Alpha Ridge north of Ellesmere Island ...
(between Beaufort Shelf of North America and the
Alpha Ridge The Alpha Ridge is a major volcanic ridge under the Arctic Ocean between the Canada Basin (off Ellesmere Island) and the Lomonosov Ridge. It was active during the formation of the Amerasian Basin. It was discovered in 1963. The highest elevatio ...
),
Makarov Basin The Makarov Basin is a seafloor basin in the Arctic Ocean, part of the Amerasian Basin. It lies between the Alpha Ridge and the Lomonosov Ridge The Lomonosov Ridge (russian: Хребет Ломоносова, da, Lomonosovryggen) is an unusual ...
(between the Alpha and Lomonosov Ridges),
Amundsen Basin The Amundsen Basin, with depths up to , is the deepest abyssal plain in the Arctic Ocean, and contains the geographic North Pole. The Amundsen Basin is embraced by the Lomonosov Ridge (from to ) and the Gakkel Ridge (from to ). It is named after ...
(between Lomonosov and Gakkel ridges), and
Nansen Basin The Nansen Basin (also Central Basin, formerly Fram Basin) is an abyssal plain with water-depths of around 3 km in the Arctic Ocean and (together with the deeper Amundsen Basin) part of the Eurasian Basin. It is named after Fridtjof Nansen. The ...
(between the Gakkel Ridge and the continental shelf that includes the
Franz Josef Land , native_name = , image_name = Map of Franz Josef Land-en.svg , image_caption = Map of Franz Josef Land , image_size = , map_image = Franz Josef Land location-en.svg , map_caption = Location of Franz Josef ...
).


Geology

The crystalline basement rocks of mountains around the Arctic Ocean were recrystallized or formed during the Ellesmerian orogeny, the regional phase of the larger
Caledonian orogeny The Caledonian orogeny was a mountain-building era recorded in the northern parts of the British Isles, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occ ...
in the
Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...
Era. Regional subsidence in the
Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
and
Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
periods led to significant sediment deposition, creating many of the reservoirs for current day oil and gas deposits. During the
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
period, the Canadian Basin opened, and tectonic activity due to the assembly of Alaska caused hydrocarbons to migrate toward what is now Prudhoe Bay. At the same time, sediments shed off the rising Canadian Rockies built out the large Mackenzie Delta. The rifting apart of the
supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", ...
Pangea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...
, beginning in the Triassic period, opened the early Atlantic Ocean. Rifting then extended northward, opening the Arctic Ocean as
mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...
oceanic crust material erupted out of a branch of Mid-Atlantic Ridge. The Amerasia Basin may have opened first, with the Chukchi Borderland moved along to the northeast by transform faults. Additional spreading helped to create the "triple-junction" of the Alpha-Mendeleev Ridge in the
Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...
. Throughout the
Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...
Era, the subduction of the Pacific plate, the collision of India with Eurasia, and the continued opening of the North Atlantic created new hydrocarbon traps. The seafloor began spreading from the Gakkel Ridge in the
Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), E ...
Epoch and the
Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
Epoch, causing the Lomonosov Ridge to move farther from land and subside. Because of sea ice and remote conditions, the geology of the Arctic Ocean is still poorly explored. The Arctic Coring Expedition drilling shed some light on the Lomonosov Ridge, which appears to be continental crust separated from the Barents-Kara Shelf in the Paleocene and then starved of sediment. It may contain up to 10 billion barrels of oil. The Gakkel Ridge rift is also poorly understand and may extend into the Laptev Sea.


Oceanography


Water flow

In large parts of the Arctic Ocean, the top layer (about ) is of lower salinity and lower temperature than the rest. It remains relatively stable because the salinity effect on density is bigger than the temperature effect. It is fed by the freshwater input of the big Siberian and Canadian rivers ( Ob,
Yenisei The Yenisey (russian: Енисе́й, ''Yeniséy''; mn, Горлог мөрөн, ''Gorlog mörön''; Buryat language, Buryat: Горлог мүрэн, ''Gorlog müren''; Tuvan language, Tuvan: Улуг-Хем, ''Uluğ-Hem''; Khakas language, K ...
,
Lena Lena or LENA may refer to: Places * Léna Department, a department of Houet Province in Burkina Faso * Lena, Manitoba, an unincorporated community located in Killarney-Turtle Mountain municipality in Manitoba, Canada * Lena, Norway, a village in ...
,
Mackenzie Mackenzie, Mckenzie, MacKenzie, or McKenzie may refer to: People * Mackenzie (given name), a given name (including a list of people with the name) * Mackenzie (surname), a surname (including a list of people with the name) * Clan Mackenzie, a Sco ...
), the water of which quasi floats on the saltier, denser, deeper ocean water. Between this lower salinity layer and the bulk of the ocean lies the so-called
halocline In oceanography, a halocline (from Greek ''hals'', ''halos'' 'salt' and ''klinein'' 'to slope') is a Cline (hydrology), cline, a subtype of chemocline caused by a strong, vertical salinity gradient within a body of water. Because salinity (in c ...
, in which both salinity and temperature rise with increasing depth. Because of its relative isolation from other oceans, the Arctic Ocean has a uniquely complex system of water flow. It resembles some hydrological features of the
Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...
, referring to its deep waters having only limited communication through the
Fram Strait The Fram Strait is the passage between Greenland and Svalbard, located roughly between 77°N and 81°N latitudes and centered on the prime meridian. The Greenland and Norwegian Seas lie south of Fram Strait, while the Nansen Basin of the Arctic ...
with the
Atlantic Basin The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and ...
, "where the circulation is dominated by thermohaline forcing". egional Oceanography: An Introduction. Tomczak, Godfrey. Retrieved 18 November 2013./ref> The Arctic Ocean has a total volume of 18.07 × 106 km3, equal to about 1.3% of the World Ocean. Mean surface circulation is predominantly cyclonic on the
Eurasian Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...
side and anticyclonic in the
Canadian Basin The Canada Basin is a deep oceanic basin within the Arctic Ocean. It is part of the Amerasian Basin and lies off the coast of Alaska and northwest Canada between the Chukchi Plateau north of Alaska and the Alpha Ridge north of Ellesmere Island ...
. Water enters from both the Pacific and Atlantic Oceans and can be divided into three unique water masses. The deepest water mass is called Arctic Bottom Water and begins around depth. It is composed of the densest water in the World Ocean and has two main sources: Arctic shelf water and Greenland Sea Deep Water. Water in the shelf region that begins as inflow from the Pacific passes through the narrow Bering Strait at an average rate of 0.8
Sverdrup In oceanography, the sverdrup (symbol: Sv) is a non- SI metric unit of volumetric flow rate, with equal to . It is equivalent to the SI derived unit cubic hectometer per second (symbol: hm3/s or hm3⋅s−1): 1 Sv is equal to 1 hm3/s. It is used ...
s and reaches the
Chukchi Sea Chukchi Sea ( rus, Чуко́тское мо́ре, r=Chukotskoye more, p=tɕʊˈkotskəjə ˈmorʲɪ), sometimes referred to as the Chuuk Sea, Chukotsk Sea or the Sea of Chukotsk, is a marginal sea of the Arctic Ocean. It is bounded on the west b ...
. During the winter, cold Alaskan winds blow over the Chukchi Sea, freezing the surface water and pushing this newly formed ice out to the Pacific. The speed of the ice drift is roughly 1–4 cm/s. This process leaves dense, salty waters in the sea that sink over the continental shelf into the western Arctic Ocean and create a
halocline In oceanography, a halocline (from Greek ''hals'', ''halos'' 'salt' and ''klinein'' 'to slope') is a Cline (hydrology), cline, a subtype of chemocline caused by a strong, vertical salinity gradient within a body of water. Because salinity (in c ...
.Arctic Ocean Circulation
. Polar Discovery
This water is met by Greenland Sea Deep Water, which forms during the passage of winter storms. As temperatures cool dramatically in the winter, ice forms, and intense vertical convection allows the water to become dense enough to sink below the warm saline water below. Arctic Bottom Water is critically important because of its outflow, which contributes to the formation of Atlantic Deep Water. The overturning of this water plays a key role in global circulation and the moderation of climate. In the depth range of is a water mass referred to as Atlantic Water. Inflow from the
North Atlantic Current The North Atlantic Current (NAC), also known as North Atlantic Drift and North Atlantic Sea Movement, is a powerful warm western boundary current within the Atlantic Ocean that extends the Gulf Stream northeastward. The NAC originates from wher ...
enters through the Fram Strait, cooling and sinking to form the deepest layer of the halocline, where it circles the
Arctic Basin The Arctic Basin (also North Polar Basin) is an oceanic basin in the Arctic Ocean, consisting of two main parts separated by the Lomonosov Ridge, a mid-ocean ridge between north Greenland and the New Siberian Islands. It is bordered by the contin ...
counter-clockwise. This is the highest volumetric inflow to the Arctic Ocean, equalling about 10 times that of the Pacific inflow, and it creates the Arctic Ocean Boundary Current. It flows slowly, at about 0.02 m/s. Atlantic Water has the same salinity as Arctic Bottom Water but is much warmer (up to ). In fact, this water mass is actually warmer than the surface water and remains submerged only due to the role of salinity in density. When water reaches the basin, it is pushed by strong winds into a large circular current called the
Beaufort Gyre The Beaufort Gyre is one of the two major ocean currents in the Arctic Ocean. It is roughly located north of the Alaskan and Canadian coast. In the past, Arctic sea-ice would circulate in the Beaufort gyre up to several years, leading to the forma ...
. Water in the Beaufort Gyre is far less saline than that of the Chukchi Sea due to inflow from large Canadian and Siberian rivers. The final defined water mass in the Arctic Ocean is called Arctic Surface Water and is found in the depth range of . The most important feature of this water mass is a section referred to as the sub-surface layer. It is a product of Atlantic water that enters through canyons and is subjected to intense mixing on the
Siberian Shelf The Siberian Shelf is a coastal shelf in the Arctic Ocean and is the largest continental shelf of the Earth, a part of the continental shelf of Russia. It extends from the continent of Eurasia in the general area of North Siberia (hence the name) ...
. As it is entrained, it cools and acts a heat shield for the surface layer on account of weak mixing between layers. However, over the past couple of decades a combination of the warming and the shoaling of Atlantic water are leading to the increasing influence of Atlantic water heat in melting sea ice in the eastern Arctic. The most recent estimates, for 2016–2018, indicate the oceanic heat flux to the surface has now overtaken the atmospheric flux in the eastern Eurasian Basin. Over the same period the weakening halocline stratification has coincided with increasing upper ocean currents thought to be associated with declining sea ice, indicate increasing mixing in this region. In contrast direct measurements of mixing in the western Arctic indicate the Atlantic water heat remains isolated at intermediate depths even under the 'perfect storm' conditions of the
Great Arctic Cyclone of 2012 The Great Arctic Cyclone, or "Great Arctic Cyclone of 2012," was a powerful extratropical cyclone that was centered on the Arctic Ocean in early August 2012. Cyclones of this magnitude are rare in the Arctic summer, although common in the winter. ...
. Waters originating in the Pacific and Atlantic both exit through the Fram Strait between
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...
and
Svalbard Island Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norway, Norwegian archipelago in the Arctic Ocean. North of continental Europe, mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The ...
, which is about deep and wide. This outflow is about 9 Sv. The width of the Fram Strait is what allows for both inflow and outflow on the Atlantic side of the Arctic Ocean. Because of this, it is influenced by the
Coriolis force In physics, the Coriolis force is an inertial or fictitious force that acts on objects in motion within a frame of reference that rotates with respect to an inertial frame. In a reference frame with clockwise rotation, the force acts to the ...
, which concentrates outflow to the East Greenland Current on the western side and inflow to the
Norwegian Current The Norwegian Current (also known as the Norway Coastal Current) is one of two dominant arctic inflows of water. It can be traced from near Shetland, north of Scotland, otherwise from the eastern North Sea at depths of up to 100 metres. It finally ...
on the eastern side. Pacific water also exits along the west coast of Greenland and the
Hudson Strait Hudson Strait (french: Détroit d'Hudson) links the Atlantic Ocean and Labrador Sea to Hudson Bay in Canada. This strait lies between Baffin Island and Nunavik, with its eastern entrance marked by Cape Chidley in Newfoundland and Labrador and ...
(1–2 Sv), providing nutrients to the Canadian Archipelago. As noted, the process of ice formation and movement is a key driver in Arctic Ocean circulation and the formation of water masses. With this dependence, the Arctic Ocean experiences variations due to seasonal changes in sea ice cover. Sea ice movement is the result of wind forcing, which is related to a number of meteorological conditions that the Arctic experiences throughout the year. For example, the Beaufort High—an extension of the
Siberian High The Siberian High (also Siberian Anticyclone; russian: Азиатский антициклон (''Aziatsky antitsiklon'')) is a massive collection of cold dry air that accumulates in the northeastern part of Eurasia from September until April. It ...
system—is a pressure system that drives the anticyclonic motion of the Beaufort Gyre. During the summer, this area of high pressure is pushed out closer to its Siberian and Canadian sides. In addition, there is a
sea level pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The Standard atmosphere (unit), standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equival ...
(SLP) ridge over Greenland that drives strong northerly winds through the Fram Strait, facilitating ice export. In the summer, the SLP contrast is smaller, producing weaker winds. A final example of seasonal pressure system movement is the low pressure system that exists over the Nordic and Barents Seas. It is an extension of the
Icelandic Low The Icelandic Low is a semi-permanent centre of low atmospheric pressure found between Iceland and southern Greenland and extending in the Northern Hemisphere winter into the Barents Sea. In the summer, it weakens and splits into two centres, one ...
, which creates cyclonic ocean circulation in this area. The low shifts to centre over the North Pole in the summer. These variations in the Arctic all contribute to ice drift reaching its weakest point during the summer months. There is also evidence that the drift is associated with the phase of the Arctic Oscillation and Atlantic Multidecadal Oscillation.


Sea ice

Much of the Arctic Ocean is covered by sea ice that varies in extent and thickness seasonally. The mean extent of the Arctic sea ice has been continuously decreasing in the last decades, declining at a rate of currently 12.85% per decade since 1980 from the average winter value of . The seasonal variations are about , with the maximum in April and minimum in September. The sea ice is affected by wind and ocean currents, which can move and rotate very large areas of ice. Zones of compression also arise, where the ice piles up to form pack ice.
Iceberg An iceberg is a piece of freshwater ice more than 15 m long that has broken off a glacier or an ice shelf and is floating freely in open (salt) water. Smaller chunks of floating glacially-derived ice are called "growlers" or "bergy bits". The ...
s occasionally break away from northern
Ellesmere Island Ellesmere Island ( iu, script=Latn, Umingmak Nuna, lit=land of muskoxen; french: île d'Ellesmere) is Canada's northernmost and List of Canadian islands by area, third largest island, and the List of islands by area, tenth largest in the world. ...
, and icebergs are formed from
glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...
s in western Greenland and extreme northeastern Canada. Icebergs are not sea ice but may become embedded in the pack ice. Icebergs pose a hazard to ships, of which the ''Titanic'' is one of the most famous. The ocean is virtually icelocked from October to June, and the
superstructure A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildings, bridges, or ships. Aboard ships and large boats On water craft, the superstruct ...
of ships are subject to icing from October to May. Before the advent of modern
icebreaker An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters, and provide safe waterways for other boats and ships. Although the term usually refers to ice-breaking ships, it may also refer to smaller ...
s, ships sailing the Arctic Ocean risked being trapped or crushed by sea ice (although the '' Baychimo'' drifted through the Arctic Ocean untended for decades despite these hazards).


Climate

The Arctic Ocean is contained in a
polar climate The polar climate regions are characterized by a lack of warm summers but with varying winters. Every month in a polar climate has an average temperature of less than . Regions with polar climate cover more than 20% of the Earth's area. Most of ...
characterized by persistent cold and relatively narrow annual temperature ranges. Winters are characterized by the
polar night The polar night is a phenomenon where the nighttime lasts for more than 24 hours that occurs in the northernmost and southernmost regions of Earth. This occurs only inside the polar circles. The opposite phenomenon, the polar day, or midnig ...
, extreme cold, frequent low-level temperature inversions, and stable weather conditions.
Cyclone In meteorology, a cyclone () is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above (opposite to an anti ...
s are only common on the Atlantic side. Summers are characterized by continuous
daylight Daylight is the combination of all direct and indirect sunlight during the daytime. This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected by Earth and terrestrial objects, like landforms and buildings. Sunligh ...
(
midnight sun The midnight sun is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the Sun remains visible at the local midnight. When the midnight sun is seen in the Arctic, t ...
), and air temperatures can rise slightly above . Cyclones are more frequent in summer and may bring rain or snow. It is cloudy year-round, with mean cloud cover ranging from 60% in winter to over 80% in summer. The temperature of the surface water of the Arctic Ocean is fairly constant at approximately , near the
freezing point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...
of
seawater Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appro ...
. The
density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...
of sea water, in contrast to fresh water, increases as it nears the freezing point and thus it tends to sink. It is generally necessary that the upper of ocean water cools to the freezing point for sea ice to form. In the winter, the relatively warm ocean water exerts a moderating influence, even when covered by ice. This is one reason why the Arctic does not experience the extreme temperatures seen on the
Antarctic continent Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
. There is considerable seasonal variation in how much pack ice of the Arctic ice pack covers the Arctic Ocean. Much of the Arctic ice pack is also covered in snow for about 10 months of the year. The maximum snow cover is in March or April—about over the frozen ocean. The climate of the Arctic region has varied significantly during the Earth's history. During the
Paleocene–Eocene Thermal Maximum The Paleocene–Eocene thermal maximum (PETM), alternatively (ETM1), and formerly known as the "Initial Eocene" or "", was a time period with a more than 5–8 °C global average temperature rise across the event. This climate event o ...
55 million years ago, when the global climate underwent a warming of approximately , the region reached an average annual temperature of . The surface waters of the northernmost Arctic Ocean warmed, seasonally at least, enough to support tropical lifeforms (the
dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...
s ''Apectodinium augustum'') requiring surface temperatures of over . Currently, the Arctic region is warming twice as fast as the rest of the planet.


Biology

Due to the pronounced seasonality of 2–6 months of
midnight sun The midnight sun is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the Sun remains visible at the local midnight. When the midnight sun is seen in the Arctic, t ...
and
polar night The polar night is a phenomenon where the nighttime lasts for more than 24 hours that occurs in the northernmost and southernmost regions of Earth. This occurs only inside the polar circles. The opposite phenomenon, the polar day, or midnig ...
in the Arctic Ocean, the
primary production In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through c ...
of photosynthesizing organisms such as
ice algae Ice algae are any of the various types of algal communities found in annual and multi-year sea or terrestrial ice. On sea ice in the polar oceans, ice algae communities play an important role in primary production. The timing of blooms of the alg ...
and
phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. Ph ...
is limited to the spring and summer months (March/April to September). Important consumers of
primary producers An autotroph or primary producer is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide,Morris, J. et al. (2019). "Biology: How Life Works", ...
in the central Arctic Ocean and the adjacent shelf seas include
zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
, especially
copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...
s (''
Calanus finmarchicus ''Calanus finmarchicus'' is a species of copepods and a part of zooplankton, which is found in enormous amounts in the northern Atlantic Ocean. Distribution and ecology ''Calanus finmarchicus'' is most commonly found in the North Sea and the Nor ...
'', ''
Calanus glacialis ''Calanus glacialis'' is an Arctic copepod found in the north-western Atlantic Ocean, adjoining waters, and the northwestern Pacific and its nearby waters. It ranges from sea level to in depth. Females generally range from about in length, an ...
'', and ''
Calanus hyperboreus ''Calanus hyperboreus'' is a copepod found in the Arctic and northern Atlantic. It occurs from the surface to depths of . Description The size of ''C. hyperboreus'' varies with its geography; individuals located in more temperate waters usually ...
'') and
euphausiids Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are consi ...
, as well as ice-associated
fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zoo ...
(e.g.,
amphipods Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descri ...
). These
primary consumers A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
form an important link between the primary producers and higher
trophic level The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it i ...
s. The composition of higher trophic levels in the Arctic Ocean varies with region (Atlantic side vs. Pacific side) and with the
sea-ice Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oc ...
cover.
Secondary consumer A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...
s in the
Barents Sea The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territo ...
, an Atlantic-influenced Arctic shelf sea, are mainly sub-Arctic species including
herring Herring are forage fish, mostly belonging to the family of Clupeidae. Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Oceans, i ...
, young
cod Cod is the common name for the demersal fish genus '' Gadus'', belonging to the family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gadus'' is commonly not call ...
, and
capelin The capelin or caplin (''Mallotus villosus'') is a small forage fish of the smelt family found in the North Atlantic, North Pacific and Arctic oceans. In summer, it grazes on dense swarms of plankton at the edge of the ice shelf. Larger capelin ...
. In ice-covered regions of the central Arctic Ocean,
polar cod ''Boreogadus saida'', known as the polar cod or as the Arctic cod, is a fish of the cod family Gadidae, related to the true cod (genus ''Gadus''). Another fish species for which both the common names Arctic cod and polar cod are used is ''Arcto ...
is a central predator of primary consumers. The
apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...
s in the Arctic Ocean—
marine mammal Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their reli ...
s such as
seals Seals may refer to: * Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly: ** Earless seal, or "true seal" ** Fur seal * Seal (emblem), a device to impress an emblem, used as a means of a ...
,
whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
s, and
polar bear The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear specie ...
s—prey upon fish. Endangered marine species in the Arctic Ocean include
walrus The walrus (''Odobenus rosmarus'') is a large pinniped, flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in ...
es and
whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
s. The area has a fragile
ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
, and it is especially exposed to
climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
, because it warms faster than the rest of the world.
Lion's mane jellyfish The lion's mane jellyfish (''Cyanea capillata''), also known as the giant jellyfish, arctic red jellyfish, or the hair jelly, is one of the largest known species of jellyfish. Its range is confined to cold, boreal waters of the Arctic, northern ...
are abundant in the waters of the Arctic, and the banded gunnel is the only species of gunnel that lives in the ocean.


Natural resources

Petroleum Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crud ...
and
natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
fields Fields may refer to: Music *Fields (band), an indie rock band formed in 2006 *Fields (progressive rock band), a progressive rock band formed in 1971 * ''Fields'' (album), an LP by Swedish-based indie rock band Junip (2010) * "Fields", a song by ...
,
placer deposit In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation from a specific source rock during sedimentary processes. The name is from the Spanish word ''placer'', meaning "alluvial sand". Placer min ...
s,
polymetallic nodules Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, dep ...
, sand and gravel aggregates, fish, seals and whales can all be found in abundance in the region. The political dead zone near the centre of the sea is also the focus of a mounting dispute between the United States, Russia, Canada, Norway, and Denmark. It is significant for the global
energy market Energy markets are national and international regulated markets that deal specifically with the trade and supply of energy. Energy market may refer to an electricity market, but can also refer to other sources of energy. Typically energy developm ...
because it may hold 25% or more of the world's undiscovered oil and gas resources.


Environmental concerns


Arctic ice melting

The
Arctic ice pack The Arctic ice pack is the sea ice cover of the Arctic Ocean and its vicinity. The Arctic ice pack undergoes a regular seasonal cycle in which ice melts in spring and summer, reaches a minimum around mid-September, then increases during fall a ...
is thinning, and a seasonal hole in the
ozone layer The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in rela ...
frequently occurs. Reduction of the area of Arctic sea ice reduces the planet's average
albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...
, possibly resulting in
global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
in a positive feedback mechanism.Earth – melting in the heat?
Richard Black, 7 October 2005. BBC News. Retrieved 7 December 2006.
Research shows that the Arctic may become ice-free in the summer for the first time in human history by 2040. Estimates vary for when the last time the Arctic was ice-free: 65 million years ago when fossils indicate that plants existed there to as recently as 5,500 years ago; ice and ocean cores going back 8,000 years to the last warm period or 125,000 during the last intraglacial period. Warming temperatures in the Arctic may cause large amounts of fresh melt-water to enter the north Atlantic, possibly disrupting global ocean current patterns. Potentially severe changes in the Earth's
climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...
might then ensue. As the extent of sea ice diminishes and
sea level rise Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...
s, the effect of storms such as the
Great Arctic Cyclone of 2012 The Great Arctic Cyclone, or "Great Arctic Cyclone of 2012," was a powerful extratropical cyclone that was centered on the Arctic Ocean in early August 2012. Cyclones of this magnitude are rare in the Arctic summer, although common in the winter. ...
on open water increases, as does possible salt-water damage to vegetation on shore at locations such as the Mackenzie
Delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D ( NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also ...
as stronger
storm surge A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the n ...
s become more likely.
Global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
has increased encounters between
polar bear The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear specie ...
s and humans. Reduced sea ice due to melting is causing polar bears to search for new sources of food. Beginning in December 2018 and coming to an apex in February 2019, a mass invasion of polar bears into the archipelago of
Novaya Zemlya Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, ...
caused local authorities to declare a state of emergency. Dozens of polar bears were seen entering homes, public buildings and inhabited areas.


Clathrate breakdown

Sea ice Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oce ...
, and the cold conditions it sustains, serves to stabilize
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...
deposits on and near the shoreline, preventing the
clathrate A clathrate is a chemical substance consisting of a lattice that traps or contains molecules. The word ''clathrate'' is derived from the Latin (), meaning ‘with bars, latticed’. Most clathrate compounds are polymeric and completely envelop t ...
breaking down and outgassing
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...
into the atmosphere, causing further warming. Melting of this ice may release large quantities of
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...
, a powerful
greenhouse gas A greenhouse gas (GHG or GhG) is a gas that Absorption (electromagnetic radiation), absorbs and Emission (electromagnetic radiation), emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse ...
, into the
atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
, causing further warming in a strong
positive feedback Positive feedback (exacerbating feedback, self-reinforcing feedback) is a process that occurs in a feedback loop which exacerbates the effects of a small disturbance. That is, the effects of a perturbation on a system include an increase in the ...
cycle and marine genera and species to become extinct.


Other concerns

Other
environmental concerns Environmental issues are effects of human activity on the biophysical environment, most often of which are harmful effects that cause environmental degradation. Environmental protection is the practice of protecting the natural environment on th ...
relate to the
radioactive contamination Radioactive contamination, also called radiological pollution, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is unintended or undesirab ...
of the Arctic Ocean from, for example, Russian
radioactive waste Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons r ...
dump sites in the Kara Sea,
Cold War The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
nuclear test sites Nuclear may refer to: Physics Relating to the nucleus of the atom: *Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space *Nuclear ...
such as Novaya Zemlya,
Camp Century Camp Century was an Arctic United States military scientific research base in Greenland. situated 240 km (150 miles) east of Thule Air Base. When built, Camp Century was publicized as a demonstration for affordable ice-cap military outposts ...
's contaminants in Greenland, and radioactive contamination from the
Fukushima Daiichi nuclear disaster The was a nuclear accident in 2011 at the Fukushima Daiichi Nuclear Power Plant in Ōkuma, Fukushima, Japan. The proximate cause of the disaster was the 2011 Tōhoku earthquake and tsunami, which occurred on the afternoon of 11 March 2011 and ...
. On 16 July 2015, five nations (United States, Russia, Canada, Norway, Denmark/Greenland) signed a declaration committing to keep their fishing vessels out of a 1.1 million square mile zone in the central Arctic Ocean near the North Pole. The agreement calls for those nations to refrain from fishing there until there is better scientific knowledge about the marine resources and until a regulatory system is in place to protect those resources.


See also

*
Arctic Bridge The Arctic Bridge or Arctic Sea Bridge is a seasonal sea route approximately long linking Russia to Canada, specifically the Russian port of Murmansk to the Hudson Bay port of Churchill, Manitoba. Description Churchill is the only principal se ...
*
Arctic cooperation and politics Arctic cooperation and politics are partially coordinated via the Arctic Council, composed of the eight Arctic nations: the United States, Canada, Iceland, Norway, Sweden, Finland, Russia, and Denmark with Greenland and the Faroe Islands. The domi ...
*
Extreme points of the Arctic This is a list of the extreme points of the Arctic, the points of Arctic lands that are farther to the north than any other location classified by continent and country, latitude and longitude, and distance to the North Pole. The list is sorted fro ...
*
International Arctic Science Committee The International Arctic Science Committee (IASC) is a non-governmental organization which is composed of international science groups participating in arctic science research. IASC is an International Scientific Associate of ICSU, and was establ ...
*
List of rivers of the Americas by coastline This list of rivers of the Americas by coastline includes the major coastal rivers of the Americas arranged by country. A link to a map of rivers with known coordinates is listed at right. The ocean coasts are demarcated as follows: *Arctic O ...
*
Nordicity Nordicity () is the degree of northernness. The concept was developed by Canadian geographer Louis-Edmond Hamelin in the 1960s based on previous work done in the Soviet Union. Hamelin's system defined northern territories – like northern Canada ...
*
Seven Seas The "Seven Seas" is a figurative term for all the seas of the known world. The phrase is used in reference to sailors and pirates in the arts and popular culture and can be associated with the Mediterranean Sea, the Arabian Seven Seas east of Afr ...
*
Subarctic The subarctic zone is a region in the Northern Hemisphere immediately south of the true Arctic, north of humid continental regions and covering much of Alaska, Canada, Iceland, the north of Scandinavia, Siberia, and the Cairngorms. Generally, ...


References


Further reading

* Neatby, Leslie H., ''Discovery in Russian and Siberian Waters'' (1973), . * Ray, L., and B. Bacon, eds., ''The Arctic Ocean'' (1982), . * Thorén, Ragnar V.A., ''Picture Atlas of the Arctic'' (1969), .


External links


Arctic Council

Arctic Environmental Atlas
Interactive map
Arctic Great Rivers Observatory (ArcticGRO)

Arctic Ocean
''
The World Factbook ''The World Factbook'', also known as the ''CIA World Factbook'', is a reference resource produced by the Central Intelligence Agency (CIA) with almanac-style information about the countries of the world. The official print version is available ...
''.
Central Intelligence Agency The Central Intelligence Agency (CIA ), known informally as the Agency and historically as the Company, is a civilian foreign intelligence service of the federal government of the United States, officially tasked with gathering, processing, ...
.
Daily Arctic Ocean Rawinsonde Data from Soviet Drifting Ice Stations (1954–1990)
at NSIDC

Images from Web Cams deployed in spring on an ice floe

Data from instruments deployed on an ice floe
International Polar Foundation
* {{Coord, 90, N, 0, E, type:waterbody_scale:50000000, display=title several islands Oceans Extreme points of Earth Articles containing video clips Geography of Northeast Asia Geography of Europe Geography of North America