HOME

TheInfoList



OR:

The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the
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 ...
, generally taken to be south of 60° S latitude and encircling
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 ...
. With a size of , it is regarded as the second-smallest of the five principal oceanic divisions: smaller than 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 ...
,
Atlantic 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 an ...
, and
Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...
oceans but larger than the
Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...
. Over the past 30 years, the Southern Ocean has been subject to rapid climate change, which has led to changes in the marine ecosystem. By way of his voyages in the 1770s,
James Cook James Cook (7 November 1728 Old Style date: 27 October – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean an ...
proved that waters encompassed the southern latitudes of the globe. Since then, geographers have disagreed on the Southern Ocean's northern boundary or even existence, considering the waters as various parts of the Pacific, Atlantic, and Indian oceans, instead. However, according to Commodore John Leech of 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), recent oceanographic research has discovered the importance of Southern Circulation, and the term ''Southern Ocean'' has been used to define the body of water which lies south of the northern limit of that circulation. This remains the current official policy of the IHO, since a 2000 revision of its definitions including the Southern Ocean as the waters south of the 60th parallel has not yet been adopted. Others regard the seasonally-fluctuating
Antarctic Convergence The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. Antarctic waters pr ...
as the natural boundary. This
oceanic zone The oceanic zone is typically defined as the area of the ocean lying beyond the continental shelf (such as the Neritic zone), but operationally is often referred to as beginning where the water depths drop to below 200 meters (660 feet), seaward ...
is where cold, northward flowing waters from the Antarctic mix with warmer
Subantarctic The sub-Antarctic zone is a region in the Southern Hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° and 60° south of the Equator. The subantarctic region includes many islands ...
waters. The maximum depth of the Southern Ocean, using the definition that it lies south of 60th parallel, was surveyed by the
Five Deeps Expedition Victor Lance Vescovo (born 1966) is an American private equity investor, retired naval officer, space tourist and undersea explorer. He is a co-founder and managing partner of private equity company Insight Equity Holdings. Vescovo achieved the ...
in early February 2019. The expedition's multibeam sonar team identified the deepest point at 60° 28' 46"S, 025° 32' 32"W, with a depth of . The expedition leader and chief submersible pilot
Victor Vescovo Victor Lance Vescovo (born 1966) is an American private equity investor, retired naval officer, space tourist and undersea explorer. He is a co-founder and managing partner of private equity company Insight Equity Holdings. Vescovo achieved the ...
, has proposed naming this deepest point in the Southern Ocean the "Factorian Deep", based on the name of the crewed submersible ''DSV Limiting Factor'', in which he successfully visited the bottom for the first time on February 3, 2019.


Definitions and use

Borders and names for oceans and seas were internationally agreed when the
International Hydrographic Bureau 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 ...
, the precursor to the IHO, convened the First International Conference on 24 July 1919. The IHO then published these in its ''Limits of Oceans and Seas'', the first edition being 1928. Since the first edition, the limits of the Southern Ocean have moved progressively southwards; since 1953, it has been omitted from the official publication and left to local hydrographic offices to determine their own limits. The IHO included the ocean and its definition as the waters south of the
60th parallel south The 60th parallel south is a circle of latitude that is 60 degrees south of Earth's equatorial plane. No land lies on the parallel—it crosses nothing but ocean. The closest land is a group of rocks north of Coronation Island (Melson Rocks or ...
in its 2000 revisions, but this has not been formally adopted, due to continuing impasses about some of the content, such as the naming dispute over the
Sea of Japan The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it h ...
. The 2000 IHO definition, however, was circulated in a draft edition in 2002, and is used by some within the IHO and by some other organizations such as the ''
CIA 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 ...
'' and
Merriam-Webster Merriam-Webster, Inc. is an American company that publishes reference books and is especially known for its dictionaries. It is the oldest dictionary publisher in the United States. In 1831, George and Charles Merriam founded the company as ...
. The Australian Government regards the Southern Ocean as lying immediately south of Australia (see ). The
National Geographic Society The National Geographic Society (NGS), headquartered in Washington, D.C., United States, is one of the largest non-profit scientific and educational organizations in the world. Founded in 1888, its interests include geography, archaeology, and ...
recognized the ocean officially in June 2021. Prior to this, it depicted it in a typeface different from the other world oceans; instead, it shows the Pacific, Atlantic, and Indian Oceans extending to Antarctica on both its print and online maps. Map publishers using the term Southern Ocean on their maps include Hema Maps and GeoNova.


Pre-20th century

"Southern Ocean" is an obsolete name for the Pacific Ocean or South Pacific, coined by
Vasco Núñez de Balboa Vasco Núñez de Balboa (; c. 1475around January 12–21, 1519) was a Spanish explorer, governor, and conquistador. He is best known for having crossed the Isthmus of Panama to the Pacific Ocean in 1513, becoming the first European to lead an ...
, the first European to discover it, who approached it from the north. The "South Seas" is a less archaic synonym. A 1745 British
Act of Parliament Acts of Parliament, sometimes referred to as primary legislation, are texts of law passed by the Legislature, legislative body of a jurisdiction (often a parliament or council). In most countries with a parliamentary system of government, acts of ...
established a prize for discovering a
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 "the Western and Southern Ocean of ''America''". Authors using "Southern Ocean" to name the waters encircling the unknown southern polar regions used varying limits.
James Cook James Cook (7 November 1728 Old Style date: 27 October – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean an ...
's account of his second voyage implies
New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...
borders it. Peacock's 1795 ''Geographical Dictionary'' said it lay "to the southward of America and Africa"; John Payne in 1796 used 40 degrees as the northern limit; the 1827 ''Edinburgh Gazetteer'' used 50 degrees. The ''Family Magazine'' in 1835 divided the "Great Southern Ocean" into the "Southern Ocean" and the "Antarctick 'sic''Ocean" along the Antarctic Circle, with the northern limit of the Southern Ocean being lines joining Cape Horn, the Cape of Good Hope, Van Diemen's Land and the south of New Zealand. The United Kingdom's ''
South Australia Act 1834 The ''South Australia Act 1834'', or ''Foundation Act 1834'' and also known as the ''South Australian Colonization Act'', was an Act of the Parliament of the United Kingdom which provided for the settlement of a province or multiple province ...
'' described the waters forming the southern limit of the new province of
South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
as "the Southern Ocean". The
Colony of Victoria In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state'' ...
's ''Legislative Council Act 1881'' delimited part of the division of
Bairnsdale Bairnsdale () ( Ganai: ''Wy-yung'') is a city in East Gippsland, Victoria, Australia in a region traditionally owned by the Tatungalung clan of the Gunaikurnai people. The estimated population of Bairnsdale urban area was 15,411 at Ju ...
as "along the
New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...
boundary to the Southern ocean".


1928 delineation

In the 1928 first edition of ''Limits of Oceans and Seas'', the Southern Ocean was delineated by land-based limits: Antarctica to the south, and South America, Africa, Australia, and
Broughton Island, New Zealand Broughton Island is the second largest island of The Snares, at . It sits just off the South Promontory of the main island North East Island, which itself lies approximately south of New Zealand's South Island. The island is some in size, wi ...
to the north. The detailed land-limits used were from
Cape Horn Cape Horn ( es, Cabo de Hornos, ) is the southernmost headland of the Tierra del Fuego archipelago of southern Chile, and is located on the small Hornos Island. Although not the most southerly point of South America (which are the Diego Ramírez ...
in Chile eastwards to
Cape Agulhas Cape Agulhas (; pt, Cabo das Agulhas , "Cape of the Needles") is a rocky headland in Western Cape, South Africa. It is the geographic southern tip of the African continent and the beginning of the dividing line between the Atlantic and Indian ...
in Africa, then further eastwards to the southern coast of mainland Australia to
Cape Leeuwin Cape Leeuwin is the most south-westerly (but not most southerly) mainland point of the Australian continent, in the state of Western Australia. Description A few small islands and rocks, the St Alouarn Islands, extend further in Flinders Ba ...
,
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
. From Cape Leeuwin, the limit then followed eastwards along the coast of mainland Australia to
Cape Otway Cape Otway is a cape and a bounded locality of the Colac Otway Shire in southern Victoria, Australia on the Great Ocean Road; much of the area is enclosed in the Great Otway National Park. History Cape Otway was originally inhabited by the Gadub ...
,
Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...
, then southwards across
Bass Strait Bass Strait () is a strait separating the island state of Tasmania from the Australian mainland (more specifically the coast of Victoria, with the exception of the land border across Boundary Islet). The strait provides the most direct waterwa ...
to
Cape Wickham Cape Wickham is the most northerly point of King Island, Tasmania, Australia. From here, it is to Cape Otway on the Australian mainland. In the 19th century, ships coming from Europe would sometimes attempt to sail between Cape Wickham and Cap ...
, King Island, along the west coast of King Island, then the remainder of the way south across Bass Strait to
Cape Grim Cape Grim, officially Kennaook / Cape Grim, is the northwestern point of Tasmania, Australia. The Peerapper name for the cape is recorded as ''Kennaook''. It is the location of the Cape Grim Baseline Air Pollution Station and of the Cape Grim ...
,
Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...
. The limit then followed the west coast of Tasmania southwards to the
South East Cape The South East Cape is a cape located at the southernmost point of the main island of Tasmania, the southernmost state of Australia. The cape is situated in the southern and south-eastern corner of the Southwest National Park, part of the Tasma ...
and then went eastwards to Broughton Island, New Zealand, before returning to Cape Horn.


1937 delineation

The northern limits of the Southern Ocean were moved southwards in the IHO's 1937 second edition of the ''Limits of Oceans and Seas''. From this edition, much of the ocean's northern limit ceased to abut land masses. In the second edition, the Southern Ocean then extended from Antarctica northwards to latitude 40°S between
Cape Agulhas Cape Agulhas (; pt, Cabo das Agulhas , "Cape of the Needles") is a rocky headland in Western Cape, South Africa. It is the geographic southern tip of the African continent and the beginning of the dividing line between the Atlantic and Indian ...
in Africa (long. 20°E) and
Cape Leeuwin Cape Leeuwin is the most south-westerly (but not most southerly) mainland point of the Australian continent, in the state of Western Australia. Description A few small islands and rocks, the St Alouarn Islands, extend further in Flinders Ba ...
in Western Australia (long. 115°E), and extended to latitude 55°S between
Auckland Island Auckland Island ( mi, Mauka Huka) is the main island of the eponymous uninhabited archipelago in the Pacific Ocean. It is part of the New Zealand subantarctic area. It is inscribed in the UNESCO World Heritage list together with the other New ...
of New Zealand (165 or 166°E east) and
Cape Horn Cape Horn ( es, Cabo de Hornos, ) is the southernmost headland of the Tierra del Fuego archipelago of southern Chile, and is located on the small Hornos Island. Although not the most southerly point of South America (which are the Diego Ramírez ...
in South America (67°W). As is discussed in more detail below, prior to the 2002 edition the limits of oceans explicitly excluded the seas lying within each of them. The
Great Australian Bight The Great Australian Bight is a large oceanic bight, or open bay, off the central and western portions of the southern coastline of mainland Australia. Extent Two definitions of the extent are in use – one used by the International Hydrog ...
was unnamed in the 1928 edition, and delineated as shown in the figure above in the 1937 edition. It therefore encompassed former Southern Ocean waters—as designated in 1928—but was technically not inside any of the three adjacent oceans by 1937. In the 2002 draft edition, the IHO have designated 'seas' as being subdivisions within 'oceans', so the Bight would have still been within the Southern Ocean in 1937 if the 2002 convention were in place then. To perform direct comparisons of current and former limits of oceans it is necessary to consider, or at least be aware of, how the 2002 change in IHO terminology for 'seas' can affect the comparison.


1953 delineation

The Southern Ocean did not appear in the 1953 third edition of ''Limits of Oceans and Seas'', a note in the publication read: Instead, in the IHO 1953 publication, the Atlantic, Indian and Pacific Oceans were extended southward, the Indian and Pacific Oceans (which had not previously touched pre 1953, as per the first and second editions) now abutted at the meridian of
South East Cape The South East Cape is a cape located at the southernmost point of the main island of Tasmania, the southernmost state of Australia. The cape is situated in the southern and south-eastern corner of the Southwest National Park, part of the Tasma ...
, and the southern limits of the
Great Australian Bight The Great Australian Bight is a large oceanic bight, or open bay, off the central and western portions of the southern coastline of mainland Australia. Extent Two definitions of the extent are in use – one used by the International Hydrog ...
and the
Tasman Sea The Tasman Sea (Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abe ...
were moved northwards.
Alternate location
AWI
(DOI 10013/epic.37175.d00
scanarchived
.


2002 draft delineation

The IHO readdressed the question of the Southern Ocean in a survey in 2000. Of its 68 member nations, 28 responded, and all responding members except Argentina agreed to redefine the ocean, reflecting the importance placed by oceanographers on ocean currents. The proposal for the name ''Southern Ocean'' won 18 votes, beating the alternative ''Antarctic Ocean''. Half of the votes supported a definition of the ocean's northern limit at the
60th parallel south The 60th parallel south is a circle of latitude that is 60 degrees south of Earth's equatorial plane. No land lies on the parallel—it crosses nothing but ocean. The closest land is a group of rocks north of Coronation Island (Melson Rocks or ...
—with no land interruptions at this latitude—with the other 14 votes cast for other definitions, mostly the 50th parallel south, but a few for as far north as the 35th parallel south. Notably the Southern Ocean Observing System collates data from latitudes higher than 40 degrees south. A draft fourth edition of ''Limits of Oceans and Seas'' was circulated to IHO member states in August 2002 (sometimes referred to as the "2000 edition" as it summarized the progress to 2000). It has yet to be published due to 'areas of concern' by several countries relating to various naming issues around the world – primarily the
Sea of Japan naming dispute A dispute exists over the international name for the body of water which is bordered by Japan, Korea (North and South) and Russia. In 1992, objections to the name Sea of Japan were first raised by North Korea and South Korea at the Sixth Unit ...
– and there have been various changes, 60 seas were given new names, and even the name of the publication was changed. A reservation had also been lodged by Australia regarding the Southern Ocean limits. Effectively, the third edition—which did not delineate the Southern Ocean leaving delineation to local hydrographic offices—has yet to be superseded. Despite this, the fourth edition definition has partial ''de facto'' usage by many nations, scientists, and organisations such as the U.S. (the ''
CIA 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 ...
'' uses "Southern Ocean", but none of the other new sea names within the "Southern Ocean", such as the "
Cosmonauts Sea The Cosmonauts Sea (, ''More Kosmonavtov''; sometimes misspelled ''Cosmonaut Sea'') was a proposed sea name as part of the Southern Ocean, off the Prince Olav Coast and Enderby Land, Antarctica, between about 30°E and 50°E. It would have an ...
") and
Merriam-Webster Merriam-Webster, Inc. is an American company that publishes reference books and is especially known for its dictionaries. It is the oldest dictionary publisher in the United States. In 1831, George and Charles Merriam founded the company as ...
, scientists and nations – and even by some within the IHO. Some nations' hydrographic offices have defined their own boundaries; the United Kingdom used the 55th parallel south for example. Other organisations favour more northerly limits for the Southern Ocean. For example, ''
Encyclopædia Britannica The (Latin for "British Encyclopædia") is a general knowledge English-language encyclopaedia. It is published by Encyclopædia Britannica, Inc.; the company has existed since the 18th century, although it has changed ownership various time ...
'' describes the Southern Ocean as extending as far north as South America, and confers great significance on the
Antarctic Convergence The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. Antarctic waters pr ...
, yet its description of the Indian Ocean contradicts this, describing the Indian Ocean as extending south to Antarctica. Other sources, such as the
National Geographic Society The National Geographic Society (NGS), headquartered in Washington, D.C., United States, is one of the largest non-profit scientific and educational organizations in the world. Founded in 1888, its interests include geography, archaeology, and ...
, show the
Atlantic 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 an ...
,
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 ...
, and
Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...
oceans as extending to Antarctica on its maps, although articles on the National Geographic web site have begun to reference the Southern Ocean. A radical shift from past IHO practices (1928–1953) was also seen in the 2002 draft edition when the IHO delineated 'seas' as being subdivisions that lay within the boundaries of 'oceans'. While the IHO are often considered the authority for such conventions, the shift brought them into line with the practices of other publications (e.g. the CIA ''World Fact Book'') which already adopted the principle that seas are contained within oceans. This difference in practice is markedly seen for the Pacific Ocean in the adjacent figure. Thus, for example, previously the
Tasman Sea The Tasman Sea (Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abe ...
between Australia and New Zealand was not regarded by the IHO as being part of the Pacific, but as of the 2002 draft edition it is. The new delineation of seas being subdivisions of oceans has avoided the need to interrupt the northern boundary of the Southern Ocean where intersected by
Drake Passage The Drake Passage (referred to as Mar de Hoces Hoces Sea"in Spanish-speaking countries) is the body of water between South America's Cape Horn, Chile and the South Shetland Islands of Antarctica. It connects the southwestern part of the Atla ...
which includes all of the waters from South America to the Antarctic coast, nor interrupt it for the
Scotia Sea The Scotia Sea is a sea located at the northern edge of the Southern Ocean at its boundary with the South Atlantic Ocean. It is bounded on the west by the Drake Passage and on the north, east, and south by the Scotia Arc, an undersea ridge and i ...
, which also extends below the 60th parallel south. The new delineation of seas has also meant that the long-time named seas around Antarctica, excluded from the 1953 edition (the 1953 map did not even extend that far south), are 'automatically' part of the Southern Ocean.


Australian standpoint

In Australia,
cartographical 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 ...
authorities define the Southern Ocean as including the entire body of water between Antarctica and the south coasts of Australia and New Zealand, and up to 60°S elsewhere. Coastal maps of
Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...
and
South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
label the sea areas as ''Southern Ocean'' and
Cape Leeuwin Cape Leeuwin is the most south-westerly (but not most southerly) mainland point of the Australian continent, in the state of Western Australia. Description A few small islands and rocks, the St Alouarn Islands, extend further in Flinders Ba ...
in
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
is described as the point where the Indian and Southern Oceans meet.


History of exploration


Unknown southern land

Exploration of the Southern Ocean was inspired by a belief in the existence of a ''Terra Australis'' – a vast continent in the far south of the globe to "balance" the northern lands of Eurasia and North Africa – which had existed since the times of
Ptolemy Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...
. The rounding of the
Cape of Good Hope The Cape of Good Hope ( af, Kaap die Goeie Hoop ) ;''Kaap'' in isolation: pt, Cabo da Boa Esperança is a rocky headland on the Atlantic coast of the Cape Peninsula in South Africa. A common misconception is that the Cape of Good Hope is t ...
in 1487 by
Bartolomeu Dias Bartolomeu Dias ( 1450 – 29 May 1500) was a Portuguese mariner and explorer. In 1488, he became the first European navigator to round the southern tip of Africa and to demonstrate that the most effective southward route for ships lay in the o ...
first brought explorers within touch of the Antarctic cold, and proved that there was an ocean separating Africa from any Antarctic land that might exist.
Ferdinand Magellan Ferdinand Magellan ( or ; pt, Fernão de Magalhães, ; es, link=no, Fernando de Magallanes, ; 4 February 1480 – 27 April 1521) was a Portuguese explorer. He is best known for having planned and led the 1519 Spanish expedition to the East ...
, who passed through the
Strait of Magellan The Strait of Magellan (), also called the Straits of Magellan, is a navigable sea route in southern Chile separating mainland South America to the north and Tierra del Fuego to the south. The strait is considered the most important natural pass ...
in 1520, assumed that the islands of
Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of the Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of the main island, Isla G ...
to the south were an extension of this unknown southern land. In 1564,
Abraham Ortelius Abraham Ortelius (; also Ortels, Orthellius, Wortels; 4 or 14 April 152728 June 1598) was a Brabantian cartographer, geographer, and cosmographer, conventionally recognized as the creator of the first modern atlas, the ''Theatrum Orbis Terraru ...
published his first map, ''Typus Orbis Terrarum'', an eight-leaved wall map of the world, on which he identified the ''
Regio Patalis ''Regio Patalis'' is Latin for “the region of Patala”, that is the region around the ancient city of Patala at the mouth of the Indus River in Sindh, Pakistan. The historians of Alexander the Great state that the Indus parted into two branches ...
'' with ''
Locach Lochac, Locach or Locat is a country far south of China mentioned by Marco Polo. The name is widely believed to be a variant of ''Lo-huk'' 罗斛: the Cantonese name for the southern Thai kingdom of Lopburi (also known as Lavapura and Louvo), which ...
'' as a northward extension of the ''
Terra Australis (Latin: '"Southern Land'") was a hypothetical continent first posited in antiquity and which appeared on maps between the 15th and 18th centuries. Its existence was not based on any survey or direct observation, but rather on the idea that ...
'', reaching as far as
New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...
.Joost Depuydt, ‘
Ortelius, Abraham Abraham Ortelius (; also Ortels, Orthellius, Wortels; 4 or 14 April 152728 June 1598) was a Brabantian cartographer, geographer, and cosmographer, conventionally recognized as the creator of the first modern atlas, the ''Theatrum Orbis Terrarum ...
(1527–1598)’,
Oxford Dictionary of National Biography The ''Dictionary of National Biography'' (''DNB'') is a standard work of reference on notable figures from British history, published since 1885. The updated ''Oxford Dictionary of National Biography'' (''ODNB'') was published on 23 September ...
, Oxford University Press, 2004
European geographers continued to connect the coast of Tierra del Fuego with the coast of New Guinea on their globes, and allowing their imaginations to run riot in the vast unknown spaces of the south Atlantic, south Indian and Pacific oceans they sketched the outlines of the ''Terra Australis Incognita'' ("Unknown Southern Land"), a vast continent stretching in parts into the tropics. The search for this great south land was a leading motive of explorers in the 16th and the early part of the 17th centuries. The
Spaniard Spaniards, or Spanish people, are a Romance ethnic group native to Spain. Within Spain, there are a number of national and regional ethnic identities that reflect the country's complex history, including a number of different languages, both ind ...
Gabriel de Castilla Gabriel de Castilla (1577 – c. 1620) was a Spanish explorer and navigator. A native of Palencia, it has been argued that he was an early explorer of Antarctica.Vázquez de Acuña, Isidoro. ''Don Gabriel de Castilla primer avistador de la An ...
, who claimed having sighted "snow-covered mountains" beyond the 64° S in 1603, is recognized as the first explorer that discovered the continent of Antarctica, although he was ignored in his time. In 1606,
Pedro Fernández de Quirós Pedro is a masculine given name. Pedro is the Spanish, Portuguese, and Galician name for '' Peter''. Its French equivalent is Pierre while its English and Germanic form is Peter. The counterpart patronymic surname of the name Pedro, meaning ...
took possession for the king of Spain all of the lands he had discovered in Australia del Espiritu Santo (the
New Hebrides New Hebrides, officially the New Hebrides Condominium (french: link=no, Condominium des Nouvelles-Hébrides, "Condominium of the New Hebrides") and named after the Hebrides Scottish archipelago, was the colonial name for the island group ...
) and those he would discover "even to the Pole".
Francis Drake Sir Francis Drake ( – 28 January 1596) was an English explorer, sea captain, privateer, slave trader, naval officer, and politician. Drake is best known for his circumnavigation of the world in a single expedition, from 1577 to 1580 (t ...
, like Spanish explorers before him, had speculated that there might be an open channel south of Tierra del Fuego. When
Willem Schouten Willem Cornelisz Schouten ( – 1625) was a Dutch navigator for the Dutch East India Company. He was the first to sail the Cape Horn route to the Pacific Ocean. Biography Willem Cornelisz Schouten was born in c. 1567 in Hoorn, Holland, Seven ...
and
Jacob Le Maire Jacob Le Maire (c. 1585 – 22 December 1616) was a Dutch mariner who circumnavigated the earth in 1615 and 1616. The strait between Tierra del Fuego and Isla de los Estados was named the Le Maire Strait in his honour, though not without controvers ...
discovered the southern extremity of Tierra del Fuego and named it
Cape Horn Cape Horn ( es, Cabo de Hornos, ) is the southernmost headland of the Tierra del Fuego archipelago of southern Chile, and is located on the small Hornos Island. Although not the most southerly point of South America (which are the Diego Ramírez ...
in 1615, they proved that the Tierra del Fuego archipelago was of small extent and not connected to the southern land, as previously thought. Subsequently, in 1642,
Abel Tasman Abel Janszoon Tasman (; 160310 October 1659) was a Dutch seafarer, explorer, and merchant, best known for his voyages of 1642 and 1644 in the service of the Dutch East India Company (VOC). He was the first known European explorer to reach New Z ...
showed that even
New Holland (Australia) ''New Holland'' ( nl, Nieuw-Holland) is a historical European name for mainland Australia. The name was first applied to Australia in 1644 by the Dutch seafarer Abel Tasman. The name came for a time to be applied in most European maps to the ...
was separated by sea from any continuous southern continent.


South of the Antarctic Convergence

The visit to South Georgia by
Anthony de la Roché Anthony de la Roché (spelled also ''Antoine de la Roché'', ''Antonio de la Roché'' or ''Antonio de la Roca'' in some sources) was a 17th-century English merchant born in London to a French Huguenot father and an English mother. During a c ...
in 1675 was the first-ever discovery of land south of the
Antarctic Convergence The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. Antarctic waters pr ...
, i.e. in the Southern Ocean/Antarctic. Soon after the voyage cartographers started to depict " Roché Island", honouring the discoverer.
James Cook James Cook (7 November 1728 Old Style date: 27 October – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean an ...
was aware of la Roché's discovery when surveying and mapping the island in 1775.
Edmond Halley Edmond (or Edmund) Halley (; – ) was an English astronomer, mathematician and physicist. He was the second Astronomer Royal in Britain, succeeding John Flamsteed in 1720. From an observatory he constructed on Saint Helena in 1676–77, H ...
's voyage in for magnetic investigations in the South Atlantic met the pack ice in 52° S in January 1700, but that latitude (he reached off the north coast of South Georgia) was his farthest south. A determined effort on the part of the French naval officer
Jean-Baptiste Charles Bouvet de Lozier Jean-Baptiste Charles Bouvet de Lozier (14 January 1705 – 1786) was a French sailor, explorer, and governor of the Mascarene Islands. He was orphaned at the age of seven and after being educated in Paris, he was sent to Saint Malo to study n ...
to discover the "South Land" – described by a half legendary " sieur de Gonneyville" – resulted in the discovery of
Bouvet Island Bouvet Island ( ; or ''Bouvetøyen'') is an island claimed by Norway, and declared an uninhabited protected nature reserve. It is a subantarctic volcanic island, situated in the South Atlantic Ocean at the southern end of the Mid-Atlantic Ri ...
in 54°10′ S, and in the navigation of 48° of longitude of ice-cumbered sea nearly in 55° S in 1730. In 1771, Yves Joseph Kerguelen sailed from
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
with instructions to proceed south from
Mauritius Mauritius ( ; french: Maurice, link=no ; mfe, label=Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It incl ...
in search of "a very large continent". He lighted upon a land in 50° S which he called South France, and believed to be the central mass of the southern continent. He was sent out again to complete the exploration of the new land, and found it to be only an inhospitable island which he renamed the Isle of Desolation, but which was ultimately named after him.


South of the Antarctic Circle

The obsession of the undiscovered continent culminated in the brain of
Alexander Dalrymple Alexander Dalrymple Fellow of the Royal Society, FRS (24 July 1737 – 19 June 1808) was a Scotland, Scottish geographer and the first Hydrographer of the Navy, Hydrographer of the British Admiralty. He was the main proponent of the theory ...
, the brilliant and erratic
hydrographer Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers, as well as with the prediction of their change over time, for the primary p ...
who was nominated by the
Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
to command the
Transit of Venus frameless, upright=0.5 A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and a superior planet, becoming visible against (and hence obscuring a small portion of) the solar disk. During a trans ...
expedition to
Tahiti Tahiti (; Tahitian ; ; previously also known as Otaheite) is the largest island of the Windward group of the Society Islands in French Polynesia. It is located in the central part of the Pacific Ocean and the nearest major landmass is Austr ...
in 1769. The command of the expedition was given by the admiralty to Captain
James Cook James Cook (7 November 1728 Old Style date: 27 October – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean an ...
. Sailing in 1772 with ''Resolution'', a vessel of 462 tons under his own command and ''Adventure'' of 336 tons under Captain
Tobias Furneaux Captain Tobias Furneaux (21 August 173518 September 1781) was an English navigator and Royal Navy officer, who accompanied James Cook on his second voyage of exploration. He was one of the first men to circumnavigate the world in both directions ...
, Cook first searched in vain for
Bouvet Island Bouvet Island ( ; or ''Bouvetøyen'') is an island claimed by Norway, and declared an uninhabited protected nature reserve. It is a subantarctic volcanic island, situated in the South Atlantic Ocean at the southern end of the Mid-Atlantic Ri ...
, then sailed for 20 degrees of longitude to the westward in latitude 58° S, and then 30° eastward for the most part south of 60° S, a lower southern latitude than had ever been voluntarily entered before by any vessel. On 17 January 1773 the
Antarctic Circle The Antarctic Circle is the most southerly of the five major circles of latitude that mark maps of Earth. The region south of this circle is known as the Antarctic, and the zone immediately to the north is called the Southern Temperate Zone. S ...
was crossed for the first time in history and the two ships reached by , where their course was stopped by ice. Cook then turned northward to look for
French Southern and Antarctic Lands The French Southern and Antarctic Lands (french: Terres australes et antarctiques françaises, TAAF) is an Overseas Territory (french: Territoire d'outre-mer or ) of France. It consists of: # Adélie Land (), the French claim on the continent ...
, of the discovery of which he had received news at
Cape Town Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...
, but from the rough determination of his longitude by Kerguelen, Cook reached the assigned latitude 10° too far east and did not see it. He turned south again and was stopped by ice in by 95° E and continued eastward nearly on the parallel of 60° S to 147° E. On 16 March, the approaching winter drove him northward for rest to New Zealand and the tropical islands of the Pacific. In November 1773, Cook left New Zealand, having parted company with the ''Adventure'', and reached 60° S by 177° W, whence he sailed eastward keeping as far south as the floating ice allowed. The Antarctic Circle was crossed on 20 December and Cook remained south of it for three days, being compelled after reaching to stand north again in 135° W. A long detour to served to show that there was no land connection between New Zealand and
Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of the Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of the main island, Isla G ...
. Turning south again, Cook crossed the Antarctic Circle for the third time at before his progress was once again blocked by ice four days later at by . This point, reached on 30 January 1774, was the farthest south attained in the 18th century. With a great detour to the east, almost to the coast of South America, the expedition regained Tahiti for refreshment. In November 1774, Cook started from New Zealand and crossed the South Pacific without sighting land between 53° and 57° S to Tierra del Fuego; then, passing Cape Horn on 29 December, he rediscovered Roché Island renaming it Isle of Georgia, and discovered the
South Sandwich Islands ) , anthem = "God Save the King" , song_type = , song = , image_map = South Georgia and the South Sandwich Islands in United Kingdom.svg , map_caption = Location of South Georgia and the South Sandwich Islands in the southern Atlantic Oce ...
(named ''Sandwich Land'' by him), the only ice-clad land he had seen, before crossing the South Atlantic to the Cape of Good Hope between 55° and 60°. He thereby laid open the way for future Antarctic exploration by exploding the myth of a habitable southern continent. Cook's most southerly discovery of land lay on the temperate side of the 60th parallel, and he convinced himself that if land lay farther south it was practically inaccessible and without economic value. Voyagers rounding Cape Horn frequently met with contrary winds and were driven southward into snowy skies and ice-encumbered seas; but so far as can be ascertained none of them before 1770 reached the Antarctic Circle, or knew it, if they did. In a voyage from 1822 to 1824,
James Weddell James Weddell (24 August 1787 – 9 September 1834) was a British sailor, navigator and seal hunter who in February 1823 sailed to latitude of 74° 15′ S—a record 7.69 degrees or 532 statute miles south of the Antarc ...
commanded the 160-ton
brig A brig is a type of sailing vessel defined by its rig: two masts which are both square rig, square-rigged. Brigs originated in the second half of the 18th century and were a common type of smaller merchant vessel or warship from then until the ...
''Jane'', accompanied by his second ship ''Beaufoy'' captained by Matthew Brisbane. Together they sailed to the South Orkneys where sealing proved disappointing. They turned south in the hope of finding a better sealing ground. The season was unusually mild and tranquil, and on 20 February 1823 the two ships reached
latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
74°15' S and
longitude Longitude (, ) is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter l ...
34°16'45″ W the southernmost position any ship had ever reached up to that time. A few icebergs were sighted but there was still no sight of land, leading Weddell to theorize that the sea continued as far as the South Pole. Another two days' sailing would have brought him to Coat's Land (to the east of the
Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha ...
) but Weddell decided to turn back.


First sighting of land

The first land south of the parallel 60° south latitude was discovered by the
Englishman The English people are an ethnic group and nation native to England, who speak the English language, a West Germanic language, and share a common history and culture. The English identity is of Anglo-Saxon origin, when they were known in ...
William Smith, who sighted
Livingston Island Livingston Island (Russian name ''Smolensk'', ) is an Antarctic island in the Southern Ocean, part of the South Shetlands Archipelago, a group of Antarctic islands north of the Antarctic Peninsula. It was the first land discovered south of 60 ...
on 19 February 1819. A few months later Smith returned to explore the other islands of the
South Shetlands The South Shetland Islands are a group of Antarctic islands with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By the Antarctic Treaty of 19 ...
archipelago, landed on King George Island, and claimed the new territories for Britain. In the meantime, the Spanish Navy ship ''
San Telmo San Telmo ("Saint Pedro González Telmo") is the oldest ''barrio'' (neighborhood) of Buenos Aires, Argentina. It is a well-preserved area of the Argentine metropolis and is characterized by its colonial buildings. Cafes, tango parlors and antiqu ...
'' sank in September 1819 when trying to cross Cape Horn. Parts of her wreckage were found months later by sealers on the north coast of
Livingston Island Livingston Island (Russian name ''Smolensk'', ) is an Antarctic island in the Southern Ocean, part of the South Shetlands Archipelago, a group of Antarctic islands north of the Antarctic Peninsula. It was the first land discovered south of 60 ...
(
South Shetlands The South Shetland Islands are a group of Antarctic islands with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By the Antarctic Treaty of 19 ...
). It is unknown if some survivor managed to be the first to set foot on these Antarctic islands. The first confirmed sighting of mainland Antarctica cannot be accurately attributed to one single person. It can, however, be narrowed down to three individuals. According to various sources, three men all sighted the ice shelf or the continent within days or months of each other:
Fabian Gottlieb von Bellingshausen Fabian Gottlieb Thaddeus von Bellingshausen (russian: Фадде́й Фадде́евич Беллинсга́узен, translit=Faddéy Faddéevich Bellinsgáuzen; – ) was a Russian naval officer, cartographer and explorer, who ultimately ...
, a captain in the
Russian Imperial Navy The Imperial Russian Navy () operated as the navy of the Russian Tsardom and later the Russian Empire from 1696 to 1917. Formally established in 1696, it lasted until dissolved in the wake of the February Revolution of 1917. It developed from a ...
;
Edward Bransfield Edward Bransfield (c. 1785 – 31 October 1852) was an Irish sailor who became an officer in the British Royal Navy, serving as a master on several ships, after being impressed into service in Ireland at the age of 18. He is noted for his par ...
, a captain in the
Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against F ...
; and
Nathaniel Palmer Nathaniel Brown Palmer (August 8, 1799June 21, 1877) was an American seal hunter, explorer, sailing captain, and ship designer. He gave his name to Palmer Land, Antarctica, which he explored in 1820 on his sloop ''Hero''. He was born in Stoning ...
, an American sailor out of
Stonington, Connecticut The town of Stonington is located in New London County, Connecticut in the state's southeastern corner. It includes the borough of Stonington (borough), Connecticut, Stonington, the villages of Pawcatuck, Connecticut, Pawcatuck, Lords Point, and W ...
. It is certain that the expedition, led by von Bellingshausen and Lazarev on the ships ''Vostok'' and ''Mirny'', reached a point within from
Princess Martha Coast Princess Martha Coast ( no, Kronprinsesse Märtha Kyst) is that portion of the coast of Queen Maud Land lying between 05° E and the terminus of Stancomb-Wills Glacier, at 20° W. The entire coastline is bounded by ice shelves with ice cliffs ...
and recorded the sight of an ice shelf at that became known as the
Fimbul Ice Shelf The Fimbul Ice Shelf is an Antarctic ice shelf about long and wide, nourished by Jutulstraumen Glacier, bordering the coast of Queen Maud Land from 3°W to 3°E. It was photographed from the air by the Third German Antarctic Expedition (1938 ...
. On 30 January 1820, Bransfield sighted
Trinity Peninsula Trinity Peninsula is the northernmost part of the Antarctic Peninsula. It extends northeastward for about 130 km (80 mi) to Cape Dubouzet from an imaginary line connecting Cape Kater on the north-west coast and Cape Longing on the sou ...
, the northernmost point of the Antarctic mainland, while Palmer sighted the mainland in the area south of Trinity Peninsula in November 1820. Von Bellingshausen's expedition also discovered
Peter I Island Peter I Island ( no, Peter I Øy) is an uninhabited volcanic island in the Bellingshausen Sea, from continental Antarctica. It is claimed as a dependency of Norway and, along with Bouvet Island and Queen Maud Land, composes one of the three No ...
and Alexander I Island, the first islands to be discovered south of the circle.


Antarctic expeditions

In December 1839, as part of the
United States Exploring Expedition The United States Exploring Expedition of 1838–1842 was an exploring and surveying expedition of the Pacific Ocean and surrounding lands conducted by the United States. The original appointed commanding officer was Commodore Thomas ap Catesby ...
of 1838–42 conducted by the
United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
(sometimes called "the Wilkes Expedition"), an expedition sailed from Sydney, Australia, on the sloops-of-war and , the brig , the full-rigged ship , and two schooners and . They sailed into the Antarctic Ocean, as it was then known, and reported the discovery "of an Antarctic continent west of the
Balleny Islands The Balleny Islands () are a series of uninhabited islands in the Southern Ocean extending from 66°15' to 67°35'S and 162°30' to 165°00'E. The group extends for about in a northwest-southeast direction. The islands are heavily glaciated an ...
" on 25 January 1840. That part of Antarctica was later named "
Wilkes Land Wilkes Land is a large district of land in eastern Antarctica, formally claimed by Australia as part of the Australian Antarctic Territory, though the validity of this claim has been placed for the period of the operation of the Antarctic Treaty, ...
", a name it maintains to this day. Explorer
James Clark Ross Sir James Clark Ross (15 April 1800 – 3 April 1862) was a British Royal Navy officer and polar explorer known for his explorations of the Arctic, participating in two expeditions led by his uncle John Ross, and four led by William Edwa ...
passed through what is now known as the
Ross Sea The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who vi ...
and discovered
Ross Island Ross Island is an island formed by four volcanoes in the Ross Sea near the continent of Antarctica, off the coast of Victoria Land in McMurdo Sound. Ross Island lies within the boundaries of Ross Dependency, an area of Antarctica claimed by New ...
(both of which were named for him) in 1841. He sailed along a huge wall of ice that was later named the
Ross Ice Shelf The Ross Ice Shelf is the largest ice shelf of Antarctica (, an area of roughly and about across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than long, and between hi ...
.
Mount Erebus Mount Erebus () is the second-highest volcano in Antarctica (after Mount Sidley), the highest active volcano in Antarctica, and the southernmost active volcano on Earth. It is the sixth-highest ultra mountain on the continent. With a summ ...
and Mount Terror are named after two ships from his expedition: and . The
Imperial Trans-Antarctic Expedition The Imperial Trans-Antarctic Expedition of 1914–1917 is considered to be the last major expedition of the Heroic Age of Antarctic Exploration. Conceived by Sir Ernest Shackleton, the expedition was an attempt to make the first land crossing ...
of 1914, led by
Ernest Shackleton Sir Ernest Henry Shackleton (15 February 1874 – 5 January 1922) was an Anglo-Irish Antarctic explorer who led three British expeditions to the Antarctic. He was one of the principal figures of the period known as the Heroic Age of ...
, set out to cross the continent via the pole, but their ship, , was trapped and crushed by pack ice before they even landed. The expedition members survived after an epic journey on sledges over pack ice to
Elephant Island Elephant Island is an ice-covered, mountainous island off the coast of Antarctica in the outer reaches of the South Shetland Islands, in the Southern Ocean. The island is situated north-northeast of the tip of the Antarctic Peninsula, west-so ...
. Then Shackleton and five others crossed the Southern Ocean, in an open boat called ''James Caird'', and then trekked over South Georgia to raise the alarm at the whaling station
Grytviken Grytviken ( ) is a settlement on South Georgia in the South Atlantic and formerly a whaling station and the largest settlement on the island. It is located at the head of King Edward Cove within the larger Cumberland East Bay, considered the b ...
. In 1946, US Navy Rear Admiral
Richard E. Byrd Richard Evelyn Byrd Jr. (October 25, 1888 – March 11, 1957) was an American naval officer and explorer. He was a recipient of the Medal of Honor, the highest honor for valor given by the United States, and was a pioneering American aviator, p ...
and more than 4,700 military personnel visited the Antarctic in an expedition called Operation Highjump. Reported to the public as a scientific mission, the details were kept secret and it may have actually been a training or testing mission for the military. The expedition was, in both military or scientific planning terms, put together very quickly. The group contained an unusually high amount of military equipment, including an aircraft carrier, submarines, military support ships, assault troops and military vehicles. The expedition was planned to last for eight months but was unexpectedly terminated after only two months. With the exception of some eccentric entries in Admiral Byrd's diaries, no real explanation for the early termination has ever been officially given. Captain Finn Ronne, Byrd's executive officer, returned to Antarctica with his own expedition in 1947–1948, with Navy support, three planes, and dogs. Ronne disproved the notion that the continent was divided in two and established that East and West Antarctica was one single continent, i.e. that the Weddell Sea and the Ross Sea are not connected. The expedition explored and mapped large parts of Palmer Land and the Weddell Sea coastline, and identified the Ronne Ice Shelf, named by Ronne after his wife Edith "Jackie" Ronne. Ronne covered by ski and dog sled – more than any other explorer in history. The
Ronne Antarctic Research Expedition The Ronne Antarctic Research Expedition (RARE) was an expedition from 1947–1948 which researched the area surrounding the head of the Weddell Sea in Antarctica. Background Finn Ronne led the RARE which was the final privately sponsored exp ...
discovered and mapped the last unknown coastline in the world and was the first Antarctic expedition to ever include women.


Recent history

The
Antarctic Treaty russian: link=no, Договор об Антарктике es, link=no, Tratado Antártico , name = Antarctic Treaty System , image = Flag of the Antarctic Treaty.svgborder , image_width = 180px , caption ...
was signed on 1 December 1959 and came into force on 23 June 1961. Among other provisions, this treaty limits
military activity in the Antarctic As Antarctica has never been permanently settled by humans, there has historically been little military activity in the Antarctic as the Antarctic Treaty, which came into effect on June 23, 1961, bans military activity in Antarctica. Military pers ...
to the support of scientific research. The first person to sail single-handed to Antarctica was the New Zealander
David Henry Lewis David Henry Lewis (1917 – 23 October 2002) was a sailor, adventurer, doctor, and scholar of Polynesian culture. He is best known for his studies on the traditional systems of navigation used by the Pacific Islanders. His studies, published ...
, in 1972, in a steel sloop ''Ice Bird''. A baby, named Emilio Marcos de Palma, was born near
Hope Bay Hope Bay (Spanish: ''Bahía Esperanza'') on Trinity Peninsula, is long and wide, indenting the tip of the Antarctic Peninsula and opening on Antarctic Sound. It is the site of the Argentinian Antarctic settlement Esperanza Base, established i ...
on 7 January 1978, becoming the first baby born on the continent. He also was born further south than anyone in history. The was a
cruise ship Cruise ships are large passenger ships used mainly for vacationing. Unlike ocean liners, which are used for transport, cruise ships typically embark on round-trip voyages to various ports-of-call, where passengers may go on tours known as "s ...
operated by the
Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...
explorer
Lars-Eric Lindblad Lars-Eric Lindblad (January 23, 1927 – July 8, 1994) was a Swedish- American entrepreneur and explorer, who pioneered tourism to many remote and exotic parts of the world. He led the first tourist expedition to Antarctica in 1966 in a chartered ...
. Observers point to ''Explorers 1969 expeditionary cruise to
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 ...
as the frontrunner for today's sea-based tourism in that region. ''Explorer'' was the first cruise ship used specifically to sail the icy waters of the Antarctic Ocean and the first to sink there when she struck an unidentified submerged object on 23 November 2007, reported to be ice, which caused a gash in the hull. ''Explorer'' was abandoned in the early hours of 23 November 2007 after taking on water near the
South Shetland Islands The South Shetland Islands are a group of Antarctic islands with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By the Antarctic Treaty of 195 ...
in the Southern Ocean, an area which is usually stormy but was calm at the time. ''Explorer'' was confirmed by the
Chilean Navy The Chilean Navy ( es, Armada de Chile) is the naval warfare service branch of the Chilean Armed Forces. It is under the Ministry of National Defense. Its headquarters are at Edificio Armada de Chile, Valparaiso. History Origins and the Wars ...
to have sunk at approximately position: 62° 24′ South, 57° 16′ West, in roughly 600 m of water. British engineer
Richard Jenkins Richard Dale Jenkins (born May 4, 1947) is an American actor who is well known for his portrayal of deceased patriarch Nathaniel Fisher on the HBO funeral drama series '' Six Feet Under'' (2001–2005). He began his career in theater at the Tr ...
designed an unmanned "saildrone" that completed the first autonomous circumnavigation of the Southern Ocean on 3 August 2019 after 196 days at sea. The first completely human-powered expedition on the Southern Ocean was accomplished on 25 December 2019 by a team of rowers comprising captain
Fiann Paul Fiann Paul (born 15 August 1980) is an Icelandic explorer, athlete, artist, speaker and Jungian psychoanalyst. He is the world's most record-breaking explorer, and holds the world's highest number of performance-based Guinness World Records ev ...
(Iceland), first mate
Colin O'Brady Colin Timothy O'Brady (born March 16, 1985) is an American professional endurance athlete, motivational speaker and adventurer. He is a former professional triathlete, representing the United States on the ITU Triathlon World Cup circuit, raci ...
(US),
Andrew Towne use both this parameter and , birth_date to display the person's date of birth, date of death, and age at death) --> , death_place = , death_cause = , body_discovered = , resting_place = , resting_place_coordinates ...
(US),
Cameron Bellamy Cameron Bellamy is an endurance athlete from South Africa. He has broken numerous records including being one of six men on a team to row across the Drake Passage in 2019. He also broke the record for the longest ocean channel swim previously held ...
(South Africa), Jamie Douglas-Hamilton (UK) and John Petersen (US).


Geography

The Southern Ocean, geologically the youngest of the oceans, was formed when Antarctica and
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
moved apart, opening the
Drake Passage The Drake Passage (referred to as Mar de Hoces Hoces Sea"in Spanish-speaking countries) is the body of water between South America's Cape Horn, Chile and the South Shetland Islands of Antarctica. It connects the southwestern part of the Atla ...
, roughly 30 million years ago. The separation of the continents allowed the formation of the
Antarctic Circumpolar Current The Antarctic Circumpolar Current (ACC) is an ocean current that flows clockwise (as seen from the South Pole) from west to east around Antarctica. An alternative name for the ACC is the West Wind Drift. The ACC is the dominant circulation feat ...
. With a northern limit at 60°S, the Southern Ocean differs from the other oceans in that its largest boundary, the northern boundary, does not abut a landmass (as it did with the first edition of ''Limits of Oceans and Seas''). Instead, the northern limit is with the Atlantic, Indian and Pacific Oceans. One reason for considering it as a separate ocean stems from the fact that much of the water of the Southern Ocean differs from the water in the other oceans. Water gets transported around the Southern Ocean fairly rapidly because of the
Antarctic Circumpolar Current The Antarctic Circumpolar Current (ACC) is an ocean current that flows clockwise (as seen from the South Pole) from west to east around Antarctica. An alternative name for the ACC is the West Wind Drift. The ACC is the dominant circulation feat ...
which circulates around Antarctica. Water in the Southern Ocean south of, for example, New Zealand, resembles the water in the Southern Ocean south of South America more closely than it resembles the water in the Pacific Ocean. The Southern Ocean has typical depths of between over most of its extent with only limited areas of shallow water. The Southern Ocean's greatest depth of occurs at the southern end of the
South Sandwich Trench The South Sandwich Trench is a deep arcuate trench in the South Atlantic Ocean lying to the east of the South Sandwich Islands. It is the deepest trench of the Southern Atlantic Ocean, and the second deepest of the Atlantic Ocean after the Puert ...
, at 60°00'S, 024°W. The
Antarctic continental shelf The Antarctic continental shelf is a submerged piece of the Antarctic continent that underlies a portion of the Southern Ocean — the ocean which surrounds Antarctica. The shelf is generally narrow and unusually deep, its edge lying at depths aver ...
appears generally narrow and unusually deep, its edge lying at depths up to , compared to a global mean of .
Equinox A solar equinox is a moment in time when the Sun crosses the Earth's equator, which is to say, appears directly above the equator, rather than north or south of the equator. On the day of the equinox, the Sun appears to rise "due east" and se ...
to equinox in line with the sun's seasonal influence, the Antarctic ice pack fluctuates from an average minimum of in March to about in September, more than a sevenfold increase in area.


Sub-divisions of the Southern Ocean

Sub-divisions of oceans are geographical features such as "seas", "straits", "bays", "channels", and "gulfs". There are many sub-divisions of the Southern Ocean defined in the never-approved 2002 draft fourth edition of the IHO publication ''Limits of Oceans and Seas''. In clockwise order these include (with sector): *
Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha ...
(57°18'W – 12°16'E) * King Haakon VII Sea (20°W – 45°E) *
Lazarev Sea The Lazarev Sea (, ''More Lazareva'') is a proposed name for a marginal sea of the Southern Ocean. It would be bordered by two proposals from a 2002 International Hydrographic Organization (IHO) draft, a King Haakon VII Sea to the west and a Ri ...
(0° – 14°E) *
Riiser-Larsen Sea The Riiser-Larsen Sea is one of the marginal seas located in the Southern Ocean off East Antarctica and south of the Indian Ocean. It is delimited Astrid Ridge in the west and the Gunnerus Ridge and the Kainanmaru Bank in the east. It is border ...
(14° – 30°E) *
Cosmonauts Sea The Cosmonauts Sea (, ''More Kosmonavtov''; sometimes misspelled ''Cosmonaut Sea'') was a proposed sea name as part of the Southern Ocean, off the Prince Olav Coast and Enderby Land, Antarctica, between about 30°E and 50°E. It would have an ...
(30° – 50°E) *
Cooperation Sea Cooperation Sea, also called Commonwealth Sea (erratum) or Sodruzhestvo Sea (russian: Море Содружества), is a proposed sea name for part of the Southern Ocean, between Enderby Land (the eastern limit of which is 59°34'E) and West I ...
(59°34' – 85°E) *
Davis Sea Davis Sea is an area of the sea along the coast of East Antarctica between West Ice Shelf in the west and the Shackleton Ice Shelf in the east, or between 82° and 96°E. The name "Davis Sea" appears in most leading geographically authoritati ...
(82° – 96°E) *
Mawson Sea Mawson Sea is a proposed sea name along the Queen Mary Land coast of East Antarctica east of the Shackleton Ice Shelf. West of it, on the western side of Shackleton Ice Shelf, would be the Davis Sea. To the east would be Bowman Island and Vince ...
(95°45' – 113°E) * Dumont D'Urville Sea (140°E) *
Somov Sea Somov Sea (, ''More Somova'') was a proposed name for part of the Southern Ocean. It would be located north of the easternmost part of the Antarctic subcontinent East Antarctica, north of Oates Coast, Victoria Land, and of George V Coast, betwee ...
(150° – 170°E) *
Ross Sea The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who vi ...
(166°E – 155°W) * Amundsen Sea (102°20′ – 126°W) *
Bellingshausen Sea The Bellingshausen Sea is an area along the west side of the Antarctic Peninsula between 57°18'W and 102°20'W, west of Alexander Island, east of Cape Flying Fish on Thurston Island, and south of Peter I Island (there the southern ''Vostokkyste ...
(57°18' – 102°20'W) * Part of the
Drake Passage The Drake Passage (referred to as Mar de Hoces Hoces Sea"in Spanish-speaking countries) is the body of water between South America's Cape Horn, Chile and the South Shetland Islands of Antarctica. It connects the southwestern part of the Atla ...
(54° – 68°W) *
Bransfield Strait Bransfield Strait or Fleet Sea ( es, Estrecho de Bransfield, Mar de la Flota) is a body of water about wide extending for in a general northeast – southwest direction between the South Shetland Islands and the Antarctic Peninsula. History ...
(54° – 62°W) * Part of the
Scotia Sea The Scotia Sea is a sea located at the northern edge of the Southern Ocean at its boundary with the South Atlantic Ocean. It is bounded on the west by the Drake Passage and on the north, east, and south by the Scotia Arc, an undersea ridge and i ...
(26°30' – 65°W) A number of these such as the 2002 Russian-proposed "Cosmonauts Sea", "Cooperation Sea", and "Somov (mid-1950s Russian polar explorer) Sea" are not included in the 1953 IHO document which remains currently in force, because they received their names largely originated from 1962 onward. Leading geographic authorities and atlases do not use these latter three names, including the 2014 10th edition World Atlas from the United States'
National Geographic Society The National Geographic Society (NGS), headquartered in Washington, D.C., United States, is one of the largest non-profit scientific and educational organizations in the world. Founded in 1888, its interests include geography, archaeology, and ...
and the 2014 12th edition of the British
Times Atlas of the World ''The Times Atlas of the World'', rebranded ''The Times Atlas of the World: Comprehensive Edition'' in its 11th edition and ''The Times Comprehensive Atlas of the World'' from its 12th edition, is a world atlas currently published by HarperCol ...
, but Soviet and Russian-issued maps do.


Biggest seas in Southern Ocean

Top large seas: #
Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha ...
– #
Somov Sea Somov Sea (, ''More Somova'') was a proposed name for part of the Southern Ocean. It would be located north of the easternmost part of the Antarctic subcontinent East Antarctica, north of Oates Coast, Victoria Land, and of George V Coast, betwee ...
– #
Riiser-Larsen Sea The Riiser-Larsen Sea is one of the marginal seas located in the Southern Ocean off East Antarctica and south of the Indian Ocean. It is delimited Astrid Ridge in the west and the Gunnerus Ridge and the Kainanmaru Bank in the east. It is border ...
– #
Lazarev Sea The Lazarev Sea (, ''More Lazareva'') is a proposed name for a marginal sea of the Southern Ocean. It would be bordered by two proposals from a 2002 International Hydrographic Organization (IHO) draft, a King Haakon VII Sea to the west and a Ri ...
– #
Scotia Sea The Scotia Sea is a sea located at the northern edge of the Southern Ocean at its boundary with the South Atlantic Ocean. It is bounded on the west by the Drake Passage and on the north, east, and south by the Scotia Arc, an undersea ridge and i ...
– #
Cosmonauts Sea The Cosmonauts Sea (, ''More Kosmonavtov''; sometimes misspelled ''Cosmonaut Sea'') was a proposed sea name as part of the Southern Ocean, off the Prince Olav Coast and Enderby Land, Antarctica, between about 30°E and 50°E. It would have an ...
– #
Ross Sea The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who vi ...
– #
Bellingshausen Sea The Bellingshausen Sea is an area along the west side of the Antarctic Peninsula between 57°18'W and 102°20'W, west of Alexander Island, east of Cape Flying Fish on Thurston Island, and south of Peter I Island (there the southern ''Vostokkyste ...
– #
Mawson Sea Mawson Sea is a proposed sea name along the Queen Mary Land coast of East Antarctica east of the Shackleton Ice Shelf. West of it, on the western side of Shackleton Ice Shelf, would be the Davis Sea. To the east would be Bowman Island and Vince ...
– #
Cooperation Sea Cooperation Sea, also called Commonwealth Sea (erratum) or Sodruzhestvo Sea (russian: Море Содружества), is a proposed sea name for part of the Southern Ocean, between Enderby Land (the eastern limit of which is 59°34'E) and West I ...
– # Amundsen Sea – #
Davis Sea Davis Sea is an area of the sea along the coast of East Antarctica between West Ice Shelf in the west and the Shackleton Ice Shelf in the east, or between 82° and 96°E. The name "Davis Sea" appears in most leading geographically authoritati ...
– # D'Urville Sea # King Haakon VII Sea


Natural resources

The Southern Ocean probably contains large, and possibly giant,
oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...
and
gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...
fields on the
continental margin A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...
.
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, accumulation of valuable minerals such as gold, formed by gravity separation during sedimentary processes are also expected to exist in the Southern Ocean.
Manganese 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, de ...
are expected to exist in the Southern Ocean. Manganese nodules are rock
concretion A concretion is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular ...
s on the
sea The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, ...
bottom formed of concentric layers of
iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
and
manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
hydroxide Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. I ...
s around a core. The core may be microscopically small and is sometimes completely transformed into manganese minerals by
crystallization Crystallization is the process by which solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some ways by which crystals form are precipitating from a solution, freezing, or more rarely deposi ...
. Interest in the potential exploitation of polymetallic nodules generated a great deal of activity among prospective mining consortia in the 1960s and 1970s. The
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 that form each year around in the Southern Ocean hold enough
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 ...
to meet the needs of every person on Earth for several months. For several decades there have been proposals, none yet to be feasible or successful, to tow Southern Ocean icebergs to more arid northern regions (such as Australia) where they can be harvested.


Natural hazards

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 can occur at any time of year throughout the ocean. Some may have drafts up to several hundred meters; smaller icebergs, iceberg fragments and sea-ice (generally 0.5 to 1 m thick) also pose problems for ships. The deep continental shelf has a floor of glacial deposits varying widely over short distances. Sailors know latitudes from 40 to 70 degrees south as the "
Roaring Forties The Roaring Forties are strong westerly winds found in the Southern Hemisphere, generally between the latitudes of 40°S and 50°S. The strong west-to-east air currents are caused by the combination of air being displaced from the Equator ...
", "Furious Fifties" and "Shrieking Sixties" due to high winds and large waves that form as winds blow around the entire globe unimpeded by any land-mass. Icebergs, especially in May to October, make the area even more dangerous. The remoteness of the region makes sources of search and rescue scarce.


Physical oceanography


Antarctic Circumpolar Current and Antarctic Convergence

While the Southern is the second smallest ocean it contains the unique and highly energetic
Antarctic Circumpolar Current The Antarctic Circumpolar Current (ACC) is an ocean current that flows clockwise (as seen from the South Pole) from west to east around Antarctica. An alternative name for the ACC is the West Wind Drift. The ACC is the dominant circulation feat ...
which moves perpetually eastward – chasing and joining itself, and at in length – it comprises the world's longest ocean current, transporting of water – 100 times the flow of all the world's rivers. Several processes operate along the coast of Antarctica to produce, in the Southern Ocean, types of
water mass An oceanographic water mass is an identifiable body of water with a common formation history which has physical properties distinct from surrounding water. Properties include temperature, salinity, chemical - isotopic ratios, and other physical ...
es not produced elsewhere in the oceans of the Southern Hemisphere. One of these is the Antarctic Bottom Water, a very cold, highly saline, dense water that forms under
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 ...
. Another is
Circumpolar Deep Water Circumpolar Deep Water (CDW) is a designation given to the water mass in the Pacific and Indian oceans that is a mixing of other water masses in the region. It is characteristically warmer and saltier than the surrounding water masses, causing CD ...
, a mixture of Antarctic Bottom Water and
North Atlantic Deep Water North Atlantic Deep Water (NADW) is a deep water mass formed in the North Atlantic Ocean. Thermohaline circulation (properly described as meridional overturning circulation) of the world's oceans involves the flow of warm surface waters from the s ...
. Associated with the Circumpolar Current is the
Antarctic Convergence The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. Antarctic waters pr ...
encircling Antarctica, where cold northward-flowing Antarctic waters meet the relatively warmer waters of the
subantarctic The sub-Antarctic zone is a region in the Southern Hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° and 60° south of the Equator. The subantarctic region includes many islands ...
, Antarctic waters predominantly sink beneath subantarctic waters, while associated zones of mixing and
upwelling Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted surface water. The nutr ...
create a zone very high in nutrients. These nurture high levels of
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 ...
with associated copepods and
Antarctic krill Antarctic krill (''Euphausia superba'') is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 ind ...
, and resultant foodchains supporting fish, whales, seals, penguins, albatrosses and a wealth of other species. The Antarctic Convergence is considered to be the best natural definition of the northern extent of the Southern Ocean.


Upwelling

Large-scale
upwelling Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted surface water. The nutr ...
is found in the Southern Ocean. Strong westerly (eastward) winds blow around
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 ...
, driving a significant flow of water northwards. This is actually a type of coastal upwelling. Since there are no continents in a band of open latitudes between
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
and the tip of the
Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...
, some of this water is drawn up from great depths. In many numerical models and observational syntheses, the Southern Ocean upwelling represents the primary means by which deep dense water is brought to the surface. Shallower, wind-driven upwelling is also found off the west coasts of North and South America, northwest and southwest Africa, and southwest and southeast Australia, all associated with oceanic subtropical high pressure circulations. Some models of the ocean circulation suggest that broad-scale upwelling occurs in the tropics, as pressure driven flows converge water toward the low latitudes where it is diffusively warmed from above. The required diffusion coefficients, however, appear to be larger than are observed in the real ocean. Nonetheless, some diffusive upwelling does probably occur.


Ross and Weddell Gyres

The
Ross Gyre The Ross Gyre is one of the two gyres that exist within the Southern Ocean. The gyre is located in the Ross Sea, and rotates clockwise. The gyre is formed by interactions between the Antarctic Circumpolar Current and the Antarctic Continental She ...
and
Weddell Gyre The Weddell Gyre is one of the two gyres that exist within the Southern Ocean. The gyre is formed by interactions between the Antarctic Circumpolar Current (ACC) and the Antarctic Continental Shelf. The gyre is located in the Weddell Sea, and r ...
are two gyres that exist within the Southern Ocean. The gyres are located in the
Ross Sea The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who vi ...
and
Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha ...
respectively, and both rotate clockwise. The gyres are formed by interactions between the
Antarctic Circumpolar Current The Antarctic Circumpolar Current (ACC) is an ocean current that flows clockwise (as seen from the South Pole) from west to east around Antarctica. An alternative name for the ACC is the West Wind Drift. The ACC is the dominant circulation feat ...
and the
Antarctic Continental Shelf The Antarctic continental shelf is a submerged piece of the Antarctic continent that underlies a portion of the Southern Ocean — the ocean which surrounds Antarctica. The shelf is generally narrow and unusually deep, its edge lying at depths aver ...
.
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 ...
has been noted to persist in the central area of the Ross Gyre. There is some evidence that
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 resulted in some decrease of the
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 ...
of the waters of the Ross Gyre since the 1950s. Due to the
Coriolis effect 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 ...
acting to the left in the Southern Hemisphere and the resulting
Ekman transport Ekman transport is part of Ekman motion theory, first investigated in 1902 by Vagn Walfrid Ekman. Winds are the main source of energy for ocean circulation, and Ekman Transport is a component of wind-driven ocean current. Ekman transport occurs w ...
away from the centres of the Weddell Gyre, these regions are very productive due to upwelling of cold, nutrient rich water.


Observations

Observation of the Southern Ocean is coordinated through the
Southern Ocean Observing System (SOOS) SOOS is an international initiative of the Scientific Committee on Antarctic Research (SCAR) and the Scientific Committee on Oceanic Research (SCOR). It was officially launched in 2011. Its International Project Office is hosted by the Institut ...
. This provides access to meta data for a significant proportion of the data collected in the regions over the past decades including hydrographic measurements and ocean currents. The data provision is set up to emphasize records that are related to
Essential Ocean Variables (EOVs) The Global Ocean Observing System (GOOS) is a global system for sustained observations of the ocean comprising the oceanographic component of the Global Earth Observing System of Systems (GEOSS). GOOS is administrated by the Intergovernmental Ocea ...
for the ocean region south of 40°S.


Climate

Sea temperatures vary from about −2 to 10 °C (28 to 50 °F). Cyclonic storms travel eastward around the continent and frequently become intense because of the temperature contrast between ice and
open ocean The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...
. The ocean-area from about latitude 40 south to the Antarctic Circle has the strongest average winds found anywhere on Earth. In winter the ocean freezes outward to 65 degrees south latitude in the Pacific sector and 55 degrees south latitude in the Atlantic sector, lowering surface temperatures well below 0 degrees Celsius. At some coastal points, however, persistent intense drainage winds from the interior keep the shoreline ice-free throughout the winter.


Climate change

The Southern Ocean is one of the regions in which rapid climate change is the most visibly taking place. In this region, small perturbations in temperature lead to major environmental perturbation. The effects of climate change in the Southern Ocean are expected to manifest themselves in a regional and diverse manner. This will include changes in the climate and weather patterns across different time-scales with alterations to the long interdecadal background signals such as the
El Niño–Southern Oscillation El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea te ...
(ENSO). Increasing ocean temperatures and changes in the extent and seasonality of sea ice affect the biological productivity and community of this ecosystem. The magnitude and exact manifestation of these changes could lead to different populations of the same species responding and adapting differently to climate change depending on the region of the Southern Ocean they inhabit. Recent observations and analysis indicate the uptake of heat and carbon is increasing in the
Antarctic Circumpolar Current The Antarctic Circumpolar Current (ACC) is an ocean current that flows clockwise (as seen from the South Pole) from west to east around Antarctica. An alternative name for the ACC is the West Wind Drift. The ACC is the dominant circulation feat ...
, in particular, the Subantarctic Front zone aided by its increasing current strength.


Biodiversity


Animals

A variety of marine animals exist and rely, directly or indirectly, on the phytoplankton in the Southern Ocean. Antarctic sea life includes
penguin Penguins (order (biology), order List of Sphenisciformes by population, Sphenisciformes , family (biology), family Spheniscidae ) are a group of Water bird, aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: on ...
s,
blue whale The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known to have ever existed. The blue whale's long and slender body can ...
s,
orca The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only Extant taxon, extant species in the genus ''Orcinus'' and is recognizable by its black ...
s,
colossal squid The colossal squid (''Mesonychoteuthis hamiltoni'') is part of the family Cranchiidae. It is sometimes called the Antarctic squid or giant cranch squid and is believed to be the largest squid species in terms of mass. It is the only recognized ...
s and
fur seal Fur seals are any of nine species of pinnipeds belonging to the subfamily Arctocephalinae in the family '' Otariidae''. They are much more closely related to sea lions than true seals, and share with them external ears (pinnae), relatively lon ...
s. The
emperor penguin The emperor penguin (''Aptenodytes forsteri'') is the tallest and heaviest of all living penguin species and is endemic to Antarctica. The male and female are similar in plumage and size, reaching in length and weighing from . Feathers of th ...
is the only penguin that breeds during the winter in Antarctica, while the
Adélie penguin The Adélie penguin (''Pygoscelis adeliae'') is a species of penguin common along the entire coast of the Antarctic continent, which is the only place where it is found. It is the most widespread penguin species, and, along with the emperor p ...
breeds farther south than any other penguin. The
rockhopper penguin The rockhopper penguins are three closely related taxa of crested penguins that have been traditionally treated as a single species and are sometimes split into three species. Not all experts agree on the classification of these penguins. Some c ...
has distinctive feathers around the eyes, giving the appearance of elaborate eyelashes.
King penguin The king penguin (''Aptenodytes patagonicus'') is the second largest species of penguin, smaller, but somewhat similar in appearance to the emperor penguin. There are two subspecies: ''A. p. patagonicus'' and ''A. p. halli''; ''patagonicus'' i ...
s, chinstrap penguins, and
gentoo penguin The gentoo penguin ( ) (''Pygoscelis papua'') is a penguin species (or possibly a species complex) in the genus ''Pygoscelis'', most closely related to the Adélie penguin (''P. adeliae'') and the chinstrap penguin (''P. antarcticus''). The ear ...
s also breed in the Antarctic. The
Antarctic fur seal The Antarctic fur seal (''Arctocephalus gazella''), is one of eight seals in the genus '' Arctocephalus'', and one of nine fur seals in the subfamily Arctocephalinae. Despite what its name suggests, the Antarctic fur seal is mostly distributed i ...
was very heavily hunted in the 18th and 19th centuries for its pelt by sealers from the United States and the United Kingdom. The
Weddell seal The Weddell seal (''Leptonychotes weddellii'') is a relatively large and abundant true seal with a circumpolar distribution surrounding Antarctica. The Weddell seal was discovered and named in the 1820s during expeditions led by British sealing ...
, a "
true seal The earless seals, phocids or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia. All true seals are members of the family Phocidae (). They are sometimes called crawling seals to distinguish them from th ...
", is named after Sir James Weddell, commander of British sealing expeditions in the
Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha ...
.
Antarctic krill Antarctic krill (''Euphausia superba'') is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 ind ...
, which congregates in large
schools A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compulsor ...
, is the
keystone species A keystone species is a species which has a disproportionately large effect on its natural environment relative to its abundance, a concept introduced in 1969 by the zoologist Robert T. Paine. Keystone species play a critical role in maintaini ...
of the
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 ...
of the Southern Ocean, and is an important food organism for whales, seals,
leopard seal The leopard seal (''Hydrurga leptonyx''), also referred to as the sea leopard, is the second largest species of seal in the Antarctic (after the southern elephant seal). Its only natural predator is the orca. It feeds on a wide range of prey incl ...
s, fur seals,
squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
, icefish, penguins,
albatross Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North Pacifi ...
es and many other birds. The
benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
communities of the seafloor are diverse and dense, with up to 155,000 animals found in . As the seafloor environment is very similar all around the Antarctic, hundreds of species can be found all the way around the mainland, which is a uniquely wide distribution for such a large community.
Deep-sea gigantism In zoology, deep-sea gigantism or abyssal gigantism is the tendency for species of invertebrates and other deep-sea dwelling animals to be larger than their shallower-water relatives across a large taxonomic range. Proposed explanations for thi ...
is common among these animals. A census of sea life carried out during the
International Polar Year The International Polar Years (IPY) are collaborative, international efforts with intensive research focus on the polar regions. Karl Weyprecht, an Austro-Hungarian naval officer, motivated the endeavor in 1875, but died before it first occurred ...
and which involved some 500 researchers was released in 2010. The research is part of the global
Census of Marine Life The Census of Marine Life was a 10-year, US $650 million scientific initiative, involving a global network of researchers in more than 80 nations, engaged to assess and explain the diversity, distribution, and abundance of life in the oceans. Th ...
(CoML) and has disclosed some remarkable findings. More than 235 marine organisms live in both polar regions, having bridged the gap of . Large animals such as some cetaceans and birds make the round trip annually. More surprising are small forms of life such as mudworms,
sea cucumber Sea cucumbers are echinoderms from the class Holothuroidea (). They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothuria ...
s and free-swimming snails found in both polar oceans. Various factors may aid in their distribution – fairly uniform temperatures of the deep ocean at the poles and the equator which differ by no more than , and the major current systems or marine
conveyor belt A conveyor belt is the carrying medium of a belt conveyor system (often shortened to belt conveyor). A belt conveyor system is one of many types of conveyor systems. A belt conveyor system consists of two or more pulleys (sometimes referred to ...
which transport egg and larva stages. However, among smaller marine animals generally assumed to be the same in the Antarctica and the Arctic, more detailed studies of each population have often—but not always—revealed differences, showing that they are closely related
cryptic species In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...
rather than a single bipolar species.


Birds

The rocky shores of mainland Antarctica and its offshore islands provide nesting space for over 100 million birds every spring. These nesters include species of
albatross Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North Pacifi ...
es,
petrel Petrels are tube-nosed seabirds in the bird order Procellariiformes. Description The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group (all except the albatross f ...
s,
skua The skuas are a group of predatory seabirds with seven species forming the genus ''Stercorarius'', the only genus in the family Stercorariidae. The three smaller skuas, the long-tailed skua, the Arctic skua, and the pomarine skua are called jae ...
s,
gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...
s and
tern Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consists of e ...
s. The insectivorous
South Georgia pipit The South Georgia pipit (''Anthus antarcticus'') is a sparrow-sized bird only found on the South Georgia archipelago off the Antarctic Peninsula. It is the only songbird in Antarctica, South Georgia's only passerine, and one of the few non-seab ...
is
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to South Georgia and some smaller surrounding islands. Freshwater ducks inhabit South Georgia and the
Kerguelen Islands The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the sub-Antarctic constituting one of the two exposed parts of the Kerguelen Plateau, a large ...
. The flightless
penguin Penguins (order (biology), order List of Sphenisciformes by population, Sphenisciformes , family (biology), family Spheniscidae ) are a group of Water bird, aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: on ...
s are all located in the Southern Hemisphere, with the greatest concentration located on and around Antarctica. Four of the 18 penguin species live and breed on the mainland and its close offshore islands. Another four species live on the subantarctic islands.
Emperor penguins The emperor penguin (''Aptenodytes forsteri'') is the tallest and heaviest of all living penguin species and is endemic to Antarctica. The male and female are similar in plumage and size, reaching in length and weighing from . Feathers of th ...
have four overlapping layers of feathers, keeping them warm. They are the only Antarctic animal to breed during the winter.


Fish

There are relatively few fish species in few
families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...
in the Southern Ocean. The most species-rich family are the
snailfish The Liparidae, commonly known as snailfish or sea snails, are a Family (biology), family of Saltwater fish, marine Scorpaeniformes, scorpaeniform fishes. Widely distributed from the Arctic Ocean, Arctic to Antarctic Oceans, including the ocea ...
(Liparidae), followed by the cod icefish (Nototheniidae) and
eelpout The eelpouts are the ray-finned fish family Zoarcidae. As the common name suggests, they are somewhat eel-like in appearance. All of the roughly 300 species are marine and mostly bottom-dwelling, some at great depths. Eelpouts are predominantly ...
(Zoarcidae). Together the snailfish, eelpouts and
notothenioid Notothenioidei is one of 19 suborders of the order Perciformes. The group is found mainly in Antarctic and Subantarctic waters, with some species ranging north to southern Australia and southern South America. Notothenioids constitute approxi ...
s (which includes cod icefish and several other families) account for almost of the more than 320 described fish species of the Southern Ocean (tens of
undescribed species In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. U ...
also occur in the region, especially among the snailfish). Southern Ocean snailfish are generally found in deep waters, while the icefish also occur in shallower waters.


Icefish

Cod icefish (Nototheniidae), as well as several other families, are part of the
Notothenioidei Notothenioidei is one of 19 suborders of the order Perciformes. The group is found mainly in Antarctic and Subantarctic waters, with some species ranging north to southern Australia and southern South America. Notothenioids constitute approx ...
suborder, collectively sometimes referred to as icefish. The suborder contains many species with
antifreeze protein Antifreeze proteins (AFPs) or ice structuring proteins refer to a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival in temperatures below the freezing point of water. AFPs bind to small i ...
s in their blood and tissue, allowing them to live in water that is around or slightly below . Antifreeze proteins are also known from Southern Ocean snailfish. The
crocodile icefish The crocodile icefish or white-blooded fish comprise a family (Channichthyidae) of notothenioid fish found in the Southern Ocean around Antarctica. They are the only known vertebrates to lack hemoglobin in their blood as adults. Icefish populatio ...
(family Channichthyidae), also known as white-blooded fish, are only found in the Southern Ocean. They lack
hemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...
in their blood, resulting in their blood being colourless. One Channichthyidae species, the mackerel icefish (''Champsocephalus gunnari''), was once the most common fish in coastal waters less than deep, but was
overfished Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in t ...
in the 1970s and 1980s. Schools of icefish spend the day at the seafloor and the night higher in the
water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...
eating plankton and smaller fish. There are two species from the genus ''
Dissostichus ''Dissostichus'', the toothfish, is a genus of marine ray-finned fish belonging to the family Nototheniidae, the notothens or cod icefish. These fish are found in the Southern Hemisphere. Toothfish are marketed in the United States as Chilean ...
'', the Antarctic toothfish (''Dissostichus mawsoni'') and the
Patagonian toothfish The Patagonian toothfish (''Dissostichus eleginoides'') is a species of notothen found in cold waters () between depths of in the southern Atlantic, Pacific, and Indian Oceans and Southern Ocean on seamounts and continental shelves around most ...
(''Dissostichus eleginoides''). These two species live on the seafloor deep, and can grow to around long weighing up to , living up to 45 years. The Antarctic toothfish lives close to the Antarctic mainland, whereas the Patagonian toothfish lives in the relatively warmer subantarctic waters. Toothfish are commercially fished, and overfishing has reduced toothfish populations. Another abundant fish group is the genus ''
Notothenia ''Notothenia'' is a genus of marine ray-finned fishes belonging to the family Nototheniidae, the notothens or cod icefishes with the species in this genus often having the common name of rockcod. They are native to the Southern Ocean and other wa ...
'', which like the Antarctic toothfish have antifreeze in their bodies. An unusual species of icefish is the
Antarctic silverfish The Antarctic silverfish (''Pleuragramma antarctica''), or Antarctic herring, is a species of marine ray-finned fish belonging to the family Nototheniidae, the notothens or cod icefishes. It is native to the Southern Ocean and the only truly pela ...
(''Pleuragramma antarcticum''), which is the only truly
pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...
fish in the waters near Antarctica.


Mammals

Seven
pinniped Pinnipeds (pronounced ), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant families Odobenidae (whose only living member is the walru ...
species inhabit Antarctica. The largest, the
elephant seal Elephant seals are very large, oceangoing earless seals in the genus ''Mirounga''. Both species, the northern elephant seal (''M. angustirostris'') and the southern elephant seal (''M. leonina''), were hunted to the brink of extinction for oil ...
(''Mirounga leonina''), can reach up to , while females of the smallest, the
Antarctic fur seal The Antarctic fur seal (''Arctocephalus gazella''), is one of eight seals in the genus '' Arctocephalus'', and one of nine fur seals in the subfamily Arctocephalinae. Despite what its name suggests, the Antarctic fur seal is mostly distributed i ...
(''Arctophoca gazella''), reach only . These two species live north of the sea ice, and breed in
harems Harem (Persian: حرمسرا ''haramsarā'', ar, حَرِيمٌ ''ḥarīm'', "a sacred inviolable place; harem; female members of the family") refers to domestic spaces that are reserved for the women of the house in a Muslim family. A hare ...
on beaches. The other four species can live on the sea ice.
Crabeater seal The crabeater seal (''Lobodon carcinophaga''), also known as the krill-eater seal, is a true seal with a circumpolar distribution around the coast of Antarctica. They are medium- to large-sized (over 2 m in length), relatively slender and pale-c ...
s (''Lobodon carcinophagus'') and
Weddell seal The Weddell seal (''Leptonychotes weddellii'') is a relatively large and abundant true seal with a circumpolar distribution surrounding Antarctica. The Weddell seal was discovered and named in the 1820s during expeditions led by British sealing ...
s (''Leptonychotes weddellii'') form breeding colonies, whereas
leopard seal The leopard seal (''Hydrurga leptonyx''), also referred to as the sea leopard, is the second largest species of seal in the Antarctic (after the southern elephant seal). Its only natural predator is the orca. It feeds on a wide range of prey incl ...
s (''Hydrurga leptonyx'') and
Ross seal The Ross seal (''Ommatophoca rossii'') is a true seal (family Phocidae) with a range confined entirely to the pack ice of Antarctica. It is the only species of the genus ''Ommatophoca''. First described during the Ross expedition in 1841, it is ...
s (''Ommatophoca rossii'') live solitary lives. Although these species hunt underwater, they breed on land or ice and spend a great deal of time there, as they have no terrestrial predators. The four species that inhabit sea ice are thought to make up 50% of the total biomass of the world's seals. Crabeater seals have a population of around 15 million, making them one of the most numerous large animals on the planet. The
New Zealand sea lion The New Zealand sea lion (''Phocarctos hookeri''), once known as Hooker's sea lion, and as or (male) and (female) in Māori, is a species of sea lion that is endemic to New Zealand and primarily breeds on New Zealand's subantarctic Auckland ...
(''Phocarctos hookeri''), one of the rarest and most localised pinnipeds, breeds almost exclusively on the subantarctic
Auckland Islands The Auckland Islands (Māori: ''Motu Maha'' "Many islands" or ''Maungahuka'' "Snowy mountains") are an archipelago of New Zealand, lying south of the South Island. The main Auckland Island, occupying , is surrounded by smaller Adams Island, ...
, although historically it had a wider range. Out of all permanent mammalian residents, the Weddell seals live the furthest south. There are 10
cetacea Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...
n species found in the Southern Ocean: six
baleen whale Baleen whales (systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea (whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their ...
s, and four
toothed whale The toothed whales (also called odontocetes, systematic name Odontoceti) are a parvorder of cetaceans that includes dolphins, porpoises, and all other whales possessing teeth, such as the beaked whales and sperm whales. Seventy-three species of t ...
s. The largest of these, the
blue whale The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known to have ever existed. The blue whale's long and slender body can ...
(''Balaenoptera musculus''), grows to long weighing 84 tonnes. Many of these species are migratory, and travel to
tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...
waters during the Antarctic winter.


Invertebrates


Arthropods

Five species of
krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in n ...
, small free-swimming
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s, have been found in the Southern Ocean. The
Antarctic krill Antarctic krill (''Euphausia superba'') is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 ind ...
(''Euphausia superba'') is one of the most abundant animal species on earth, with a
biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...
of around 500 million tonnes. Each individual is long and weighs over . The swarms that form can stretch for kilometres, with up to 30,000 individuals per , turning the water red. Swarms usually remain in deep water during the day, ascending during the night to feed on
plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...
. Many larger animals depend on krill for their own survival. During the winter when food is scarce, adult Antarctic krill can revert to a smaller juvenile stage, using their own body as nutrition. Many benthic crustaceans have a non-seasonal breeding cycle, and some raise their young in a brood pouch. ''
Glyptonotus antarcticus ''Glyptonotus antarcticus'' is a benthic marine isopod crustacean in the suborder Valvifera. This relatively large isopod is found in the Southern Ocean around Antarctica. It was first described by James Eights in 1852 and the type locality ...
'' is an unusually large benthic
isopod Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...
, reaching in length weighing .
Amphipod 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 descr ...
s are abundant in soft sediments, eating a range of items, from
algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
to other animals. The amphipods are highly diverse with more than 600 recognized species found south of the Antarctic Convergence and there are indications that many undescribed species remain. Among these are several "giants", such as the iconic epimeriids that are up to long. Slow moving
sea spider Sea spiders are marine arthropods of the order Pantopoda ( ‘all feet’), belonging to the class Pycnogonida, hence they are also called pycnogonids (; named after ''Pycnogonum'', the type genus; with the suffix '). They are cosmopolitan, fou ...
s are common, sometimes growing as large as a human hand. They feed on the
coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...
s,
sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...
s, and
bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a l ...
ns that litter the seabed.


Others

Many aquatic
mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000  extant species of molluscs are recognized. The number of fossil species is esti ...
s are present in Antarctica.
Bivalves Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
such as ''
Adamussium colbecki The Antarctic scallop (''Adamussium colbecki'') is a species of bivalve mollusc in the large family of scallops, the Pectinidae. It was thought to be the only species in the genus ''Adamussium'' until an extinct Pliocene species was described ...
'' move around on the seafloor, while others such as '' Laternula elliptica'' live in burrows
filtering Filter, filtering or filters may refer to: Science and technology Computing * Filter (higher-order function), in functional programming * Filter (software), a computer program to process a data stream * Filter (video), a software component tha ...
the water above. There are around 70
cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
species in the Southern Ocean, the largest of which is the
colossal squid The colossal squid (''Mesonychoteuthis hamiltoni'') is part of the family Cranchiidae. It is sometimes called the Antarctic squid or giant cranch squid and is believed to be the largest squid species in terms of mass. It is the only recognized ...
(''Mesonychoteuthis hamiltoni''), which at up to is among the largest invertebrate in the world.
Squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
makes up most of the diet of some animals, such as
grey-headed albatross The grey-headed albatross (''Thalassarche chrysostoma'') also known as the gray-headed mollymawk, is a large seabird from the albatross family. It has a circumpolar distribution, nesting on isolated islands in the Southern Ocean and feeding at h ...
es and
sperm whale The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus ''Physeter'' and one of three extant species in the sperm whale famil ...
s, and the warty squid (''Moroteuthis ingens'') is one of the subantarctic's most preyed upon species by vertebrates. The
sea urchin Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...
genus ''Abatus'' burrow through the sediment eating the nutrients they find in it. Two species of
salp A salp (plural salps, also known colloquially as “sea grape”) or salpa (plural salpae or salpas) is a barrel-shaped, planktic tunicate. It moves by contracting, thereby pumping water through its gelatinous body, one of the most efficient ...
s are common in Antarctic waters: ''Salpa thompsoni'' and ''Ihlea racovitzai''. ''Salpa thompsoni'' is found in ice-free areas, whereas ''Ihlea racovitzai'' is found in the high-latitude areas near ice. Due to their low nutritional value, they are normally only eaten by fish, with larger animals such as birds and marine mammals only eating them when other food is scarce. Antarctic
sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...
s are long-lived and sensitive to environmental changes due to the specificity of the
symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...
microbial communities within them. As a result, they function as indicators of environmental health.


Environment


Current issues

Increased solar
ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
radiation resulting from the Antarctic
ozone hole Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone la ...
has reduced marine primary productivity (
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 ...
) by as much as 15% and has started damaging the DNA of some fish.
Illegal, unreported and unregulated fishing Illegal, unreported and unregulated fishing (IUU) is an issue around the world. Fishing industry observers believe IUU occurs in most fisheries, and accounts for up to 30% of total catches in some important fisheries. Illegal fishing takes pl ...
, especially the landing of an estimated five to six times more
Patagonian toothfish The Patagonian toothfish (''Dissostichus eleginoides'') is a species of notothen found in cold waters () between depths of in the southern Atlantic, Pacific, and Indian Oceans and Southern Ocean on seamounts and continental shelves around most ...
than the regulated fishery, likely affects the sustainability of the stock. Long-line fishing for toothfish causes a high incidence of seabird mortality.


International agreements

All international agreements regarding the world's oceans apply to the Southern Ocean. In addition, it is subject to these agreements specific to the region: * The ''
Southern Ocean Whale Sanctuary The Southern Ocean Whale Sanctuary is an area of 50 million square kilometres surrounding the continent of Antarctica where the International Whaling Commission (IWC) has banned all types of commercial whaling. To date, the IWC has designated two ...
'' of the
International Whaling Commission The International Whaling Commission (IWC) is a specialised regional fishery management organisation, established under the terms of the 1946 International Convention for the Regulation of Whaling (ICRW) to "provide for the proper conservation of ...
(IWC) prohibits commercial
whaling Whaling is the process of hunting of whales for their usable products such as meat and blubber, which can be turned into a type of oil that became increasingly important in the Industrial Revolution. It was practiced as an organized industry ...
south of 40 degrees south (south of 60 degrees south between 50 degrees and 130 degrees west).
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
regularly does not recognize this provision, because the sanctuary violates IWC charter. Since the scope of the sanctuary is limited to commercial whaling, in regard to its whaling permit and whaling for scientific research, a Japanese fleet carried out an annual whale-hunt in the region. On 31 March 2014, the
International Court of Justice The International Court of Justice (ICJ; french: Cour internationale de justice, links=no; ), sometimes known as the World Court, is one of the six principal organs of the United Nations (UN). It settles disputes between states in accordanc ...
ruled that Japan's whaling program, which Japan has long claimed is for scientific purposes, was a cloak for commercial whaling, and no further permits would be granted. * ''
Convention for the Conservation of Antarctic Seals The Convention for the Conservation of Antarctic Seals (CCAS) is part of the Antarctic Treaty System. It was signed at the conclusion of a multilateral conference in London on February 11, 1972. Contents CCAS had the objective "to promote and ac ...
'' is part of the ''
Antarctic Treaty System russian: link=no, Договор об Антарктике es, link=no, Tratado Antártico , name = Antarctic Treaty System , image = Flag of the Antarctic Treaty.svgborder , image_width = 180px , caption ...
''. It was signed at the conclusion of a multilateral conference in London on 11 February 1972. * ''
Convention for the Conservation of Antarctic Marine Living Resources The Convention on the Conservation of Antarctic Marine Living Resources, also known as the Commission for the Conservation of Antarctic Marine Living Resources, and CCAMLR, is part of the Antarctic Treaty System. The convention was opened for s ...
'' (CCAMLR) is part of the ''
Antarctic Treaty System russian: link=no, Договор об Антарктике es, link=no, Tratado Antártico , name = Antarctic Treaty System , image = Flag of the Antarctic Treaty.svgborder , image_width = 180px , caption ...
''. The Convention was entered into force on 7 April 1982 and its goal is to preserve
marine life Marine life, sea life, or ocean life is the plants, animals and other organisms that live in the salt water of seas or oceans, or the brackish water of coastal estuaries. At a fundamental level, marine life affects the nature of the planet. M ...
and environmental integrity in and near
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 ...
. It was established in large part due to concerns that an increase in
krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in n ...
catches in the Southern Ocean could have a serious impact on populations of other marine life which are dependent upon krill for food. Many nations prohibit the exploration for and the exploitation of
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...
resources south of the fluctuating
Antarctic Convergence The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. Antarctic waters pr ...
, which lies in the middle of the Antarctic Circumpolar Current and serves as the dividing line between the very cold polar surface waters to the south and the warmer waters to the north. The
Antarctic Treaty russian: link=no, Договор об Антарктике es, link=no, Tratado Antártico , name = Antarctic Treaty System , image = Flag of the Antarctic Treaty.svgborder , image_width = 180px , caption ...
covers the portion of the globe south of sixty degrees south; it prohibits new claims to Antarctica. The ''Convention for the Conservation of Antarctic Marine Living Resources'' applies to the area south of 60° South latitude as well as the areas further north up to the limit of the Antarctic Convergence.


Economy

Between 1 July 1998 and 30 June 1999, fisheries landed , of which 85% consisted of
krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in n ...
and 14% of
Patagonian toothfish The Patagonian toothfish (''Dissostichus eleginoides'') is a species of notothen found in cold waters () between depths of in the southern Atlantic, Pacific, and Indian Oceans and Southern Ocean on seamounts and continental shelves around most ...
. International agreements came into force in late 1999 to reduce illegal, unreported, and unregulated fishing, which in the 1998–99 season landed five to six times more Patagonian toothfish than the regulated fishery.


Ports and harbors

Major operational ports include: Rothera Station,
Palmer Station Palmer Station is a United States research station in Antarctica located on Anvers Island, the only US station located north of the Antarctic Circle. Initial construction of the station finished in 1968. The station, like the other U.S. Antarcti ...
,
Villa Las Estrellas Villa Las Estrellas (English: "The Stars Village") is a Chilean town and research station on King George Island within the Chilean Antarctic claim, the Chilean Antarctic Territory, and also within the Argentine and British Antarctic claims. ...
,
Esperanza Base ("Permanence, an act of sacrifice") , pushpin_map = Antarctica , pushpin_map_alt = Location of Esperanza Base in Antarctica , pushpin_map_caption = Location of Esperanza Base in Antarctica , pushpin_mapsize ...
,
Mawson Station The Mawson Station, commonly called Mawson, is one of three permanent bases and research outposts in Antarctica managed by the Australian Antarctic Division (AAD). Mawson lies in Holme Bay in Mac. Robertson Land, East Antarctica in the Austra ...
,
McMurdo Station McMurdo Station is a United States Antarctic research station on the south tip of Ross Island, which is in the New Zealand-claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the Unit ...
, and offshore anchorages in Antarctica. Few ports or harbors exist on the southern (Antarctic) coast of the Southern Ocean, since ice conditions limit use of most shores to short periods in midsummer; even then some require
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 ...
escort for access. Most Antarctic ports are operated by government research stations and, except in an emergency, remain closed to commercial or private vessels; vessels in any port south of 60 degrees south are subject to inspection by Antarctic Treaty observers. The Southern Ocean's southernmost port operates at McMurdo Station at . Winter Quarters Bay forms a small harbor, on the southern tip of
Ross Island Ross Island is an island formed by four volcanoes in the Ross Sea near the continent of Antarctica, off the coast of Victoria Land in McMurdo Sound. Ross Island lies within the boundaries of Ross Dependency, an area of Antarctica claimed by New ...
where a floating
ice pier An ice pier or ice wharf is a man-made structure used to assist the unloading of ships in Antarctica. It is constructed by pumping seawater into a contained area and allowing the water to freeze. By repeating this procedure several times, additio ...
makes port operations possible in summer.
Operation Deep Freeze Operation Deep Freeze (OpDFrz or ODF) is codename for a series of United States missions to Antarctica, beginning with "Operation Deep Freeze I" in 1955–56, followed by "Operation Deep Freeze II", "Operation Deep Freeze III", and so on. (There w ...
personnel constructed the first ice pier at McMurdo in 1973."Unique ice pier provides harbor for ships,"
Antarctic Sun. 8 January 2006; McMurdo Station, Antarctica.
Based on the original 1928 IHO delineation of the Southern Ocean (and the 1937 delineation if the
Great Australian Bight The Great Australian Bight is a large oceanic bight, or open bay, off the central and western portions of the southern coastline of mainland Australia. Extent Two definitions of the extent are in use – one used by the International Hydrog ...
is considered integral), Australian ports and harbors between
Cape Leeuwin Cape Leeuwin is the most south-westerly (but not most southerly) mainland point of the Australian continent, in the state of Western Australia. Description A few small islands and rocks, the St Alouarn Islands, extend further in Flinders Ba ...
and
Cape Otway Cape Otway is a cape and a bounded locality of the Colac Otway Shire in southern Victoria, Australia on the Great Ocean Road; much of the area is enclosed in the Great Otway National Park. History Cape Otway was originally inhabited by the Gadub ...
on the Australian mainland and along the west coast of
Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...
would also be identified as ports and harbors existing in the Southern Ocean. These would include the larger ports and harbors of Albany, Thevenard,
Port Lincoln Port Lincoln is a town on the Lower Eyre Peninsula in the Australian state of South Australia. It is situated on the shore of Boston Bay, which opens eastward into Spencer Gulf. It is the largest city in the West Coast region, and is located a ...
,
Whyalla Whyalla was founded as "Hummocks Hill", and was known by that name until 1916. It is the fourth most populous city in the Australian state of South Australia after Adelaide, Mount Gambier and Gawler and along with Port Pirie and Port Augusta ...
,
Port Augusta Port Augusta is a small city in South Australia. Formerly a port, seaport, it is now a road traffic and Junction (rail), railway junction city mainly located on the east coast of the Spencer Gulf immediately south of the gulf's head and about ...
,
Port Adelaide Port Adelaide is a port-side region of Adelaide, approximately northwest of the Adelaide CBD. It is also the namesake of the City of Port Adelaide Enfield council, a suburb, a federal and state electoral division and is the main port for the ...
,
Portland Portland most commonly refers to: * Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States * Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...
,
Warrnambool Warrnambool ( Maar: ''Peetoop'' or ''Wheringkernitch'' or ''Warrnambool'') is a city on the south-western coast of Victoria, Australia. At the 2021 census, Warrnambool had a population of 35,743. Situated on the Princes Highway, Warrnambool (Al ...
, and
Macquarie Harbour Macquarie Harbour is a shallow fjord in the West Coast region of Tasmania, Australia. It is approximately , and has an average depth of , with deeper places up to . It is navigable by shallow-draft vessels. The main channel is kept clear by th ...
. Even though organizers of several yacht races define their routes as involving the Southern Ocean, the actual routes don't enter the actual geographical boundaries of the Southern Ocean. The routes involve instead
South Atlantic 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 an ...
, South Pacific and
Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...
.


See also

* Borders of the oceans * List of Antarctic and subantarctic islands *
List of countries by southernmost point This is a list of countries by southernmost point on land. Where borders are contested, the southernmost point under the control of a nation is listed, excluding points within Antarctica and its outlying islands south of 60°S. Non-UN political en ...
*
List of seamounts in the Southern Ocean This is a list of Seamounts in the Southern Ocean. A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface (sea level), and thus is not an island, islet or Cliff-rock. Seamounts are typically formed from ...
*
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 ...


Notes


References

* * * .


Further reading

* Arndt, JE et al.: ''The International Bathymetric Chart of the Southern Ocean Version 1.0 – A new bathymetric compilation covering circum-Antarctic waters''. Geophysical Research Letters, 40(9), 1–7, 2013. doi:10.1002/grl.50413 * Gille, Sarah T.: ''Warming of the Southern Ocean since the 1950s''. ''
Science Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for ...
'': Vol. 295 (no. 5558), 1275–1277, 2002. doi:10.1126/science.1065863 * Descriptive Regional Oceanography, P. Tchernia, Pergamon Press, 1980, . * Matthias Tomczak and J. Stuart Godfrey. 2003. ''Regional Oceanography: an Introduction''. (se
the site


External links


The CIA World Factbook's
entry on the Southern Ocean

from Geography.About.com * International Hydrographic Organization (IHO):
Limits of Oceans and Seas
' (2nd Edition), extant 1937 to 1953, with limits of ''Southern Ocean''.
NOAA FAQ about the number of oceans

Commission for the Conservation of Antarctic Marine Living Resources
{{Authority control Marine realms Oceans