Southern Ocean

§1. Southern Ocean Introduction

Background:
  A large body of recent oceanographic research has shown that the Antarctic
  Circumpolar Current (ACC), an ocean current that flows from west to east
  around Antarctica, plays a crucial role in global ocean circulation. The
  region where the cold waters of the ACC meet and mingle with the warmer
  waters of the north defines a distinct border - the Antarctic Convergence -
  which fluctuates with the seasons, but which encompasses a discrete body of
  water and a unique ecologic region. The Convergence concentrates nutrients,
  which promotes marine plant life, and which in turn allows for a greater
  abundance of animal life. In the spring of 2000, the International
  Hydrographic Organization decided to delimit the waters within the
  Convergence as a fifth world ocean - the Southern Ocean - by combining the
  southern portions of the Atlantic Ocean, Indian Ocean, and Pacific Ocean.
  The Southern Ocean extends from the coast of Antarctica north to 60 degrees
  south latitude, which coincides with the Antarctic Treaty Limit and which
  approximates the extent of the Antarctic Convergence. As such, the Southern
  Ocean is now the fourth largest of the world's five oceans (after the
  Pacific Ocean, Atlantic Ocean, and Indian Ocean, but larger than the Arctic
  Ocean). It should be noted that inclusion of the Southern Ocean does not
  imply recognition of this feature as one of the world's primary oceans by
  the US Government.

§2. Southern Ocean Geography

Location:
  body of water between 60 degrees south latitude and Antarctica

Geographic coordinates:
  60 00 S, 90 00 E (nominally), but the Southern Ocean has the unique
  distinction of being a large circumpolar body of water totally encircling
  the continent of Antarctica; this ring of water lies between 60 degrees
  south latitude and the coast of Antarctica and encompasses 360 degrees of
  longitude

Map references:
  Antarctic_Region

Area:
  total: 20.327 million kmē
  note: includes Amundsen Sea, Bellingshausen Sea, part of the Drake Passage,
    Ross Sea, a small part of the Scotia Sea, Weddell Sea, and other
    tributary water bodies

Area - comparative:
  slightly more than twice the size of the US

Coastline:
  17,968 km

Climate:
  sea temperatures vary from about 10 degrees Celsius to -2 degrees Celsius;
  cyclonic storms travel eastward around the continent and frequently are
  intense because of the temperature contrast between ice and open ocean; 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 intense
  persistent drainage winds from the interior keep the shoreline ice-free
  throughout the winter

Terrain:
  the Southern Ocean is deep, 4,000 to 5,000 meters over most of its extent
  with only limited areas of shallow water; the Antarctic continental shelf
  is generally narrow and unusually deep, its edge lying at depths of 400 to
  800 meters (the global mean is 133 meters); the Antarctic icepack grows
  from an average minimum of 2.6 million square kilometers in March to about
  18.8 million square kilometers in September, better than a sixfold increase
  in area; the Antarctic Circumpolar Current (21,000 km in length) moves
  perpetually eastward; it is the world's largest ocean current, transporting
  130 million cubic meters of water per second - 100 times the flow of all
  the world's rivers

Elevation extremes:
  lowest point: -7,235 m at the southern end of the South Sandwich Trench
  highest point: sea level 0 m

Natural resources:
  probable large and possible giant oil and gas fields on the continental
  margin, manganese nodules, possible placer deposits, sand and gravel, fresh
  water as icebergs; squid, whales, and seals - none exploited; krill, fishes

Natural hazards:
  huge icebergs with drafts up to several hundred meters; smaller bergs and
  iceberg fragments; sea ice (generally 0.5 to 1 meter thick) with sometimes
  dynamic short-term variations and with large annual and interannual
  variations; deep continental shelf floored by glacial deposits varying
  widely over short distances; high winds and large waves much of the year;
  ship icing, especially May-October; most of region is remote from sources
  of search and rescue

Environment - current issues:
  increased solar ultraviolet radiation resulting from the Antarctic ozone
  hole in recent years, reducing marine primary productivity (phytoplankton)
  by as much as 15% and damaging the DNA of some fish; illegal, unreported,
  and unregulated fishing in recent years, especially the landing of an
  estimated five to six times more Patagonian toothfish than the regulated
  fishery, which is likely to affect the sustainability of the stock; large
  amount of incidental mortality of seabirds resulting from long-line fishing
  for toothfish
  note: the now-protected fur seal population is making a strong comeback
    after severe overexploitation in the 18th and 19th centuries

Environment - international agreements:
  the Southern Ocean is subject to all international agreements regarding the
  world's oceans; in addition, it is subject
  to these agreements specific to the Antarctic region: International Whaling
    Commission (prohibits commercial whaling south of 40 degrees south [south
    of 60 degrees south between 50 degrees and 130 degrees west]); Convention
    on the Conservation of Antarctic Seals (limits sealing); Convention on
    the Conservation of Antarctic Marine Living Resources (regulates fishing)
  note: many nations (including the US) prohibit mineral resource exploration
    and exploitation south of the fluctuating Polar Front (Antarctic
    Convergence) which is 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

Geography - note:
  the major chokepoint is the Drake Passage between South America and
  Antarctica; the Polar Front (Antarctic Convergence) is the best natural
  definition of the northern extent of the Southern Ocean; it is a distinct
  region at the middle of the Antarctic Circumpolar Current that separates
  the very cold polar surface waters to the south from the warmer waters to
  the north; the Front and the Current extend entirely around Antarctica,
  reaching south of 60 degrees south near New Zealand and near 48 degrees
  south in the far South Atlantic coinciding with the path of the maximum
  westerly winds

§3. Southern Ocean Economy

Economy - overview:
  Fisheries in 2003-04 landed 136,262 metric tons, of which 87% (118,166
  tons) was krill and 8% (11,182 tons) Patagonian toothfish, compared to
  142,555 tons in 2002-03 of which 83% (117,728 tons) was krill and 12%
  (16,479 tons) Patagonian toothfish (estimated fishing from the area covered
  by the Convention of the Conservation of Antarctic Marine Living Resources
  (CCAMLR), which extends slightly beyond the Southern Ocean area).
  International agreements were adopted in late 1999 to reduce illegal,
  unreported, and unregulated fishing, which in the 2000-01 season landed, by
  one estimate, 8,376 metric tons of Patagonian and Antarctic toothfish. In
  the 2004-05 Antarctic summer 28,202 tourists, most of them seaborne
  (approximately 97%), visited the Southern Ocean and Antarctica, compared to
  14,762 in 1999-2000.

§4. Southern Ocean Transportation

Ports and terminals:
  McMurdo, Palmer, and offshore anchorages in Antarctica
  note: few ports or harbors exist on southern side of Southern Ocean; ice
    conditions limit use of most to short periods in midsummer; even then
    some cannot be entered without icebreaker escort; most Antarctic ports
    are operated by government research stations and, except in an emergency,
    are not open to commercial or private vessels; vessels in any port south
    of 60 degrees south are subject to inspection by Antarctic Treaty
    observers (see Article 7); Antarctica (HCA), a special hydrographic
    commission of International Hydrographic Organization (IHO), is
    responsible for hydrographic surveying and nautical charting matters in
    Antarctic Treaty area; it coordinates and facilitates provision of
    accurate and appropriate charts and other aids to navigation in support
    of safety of navigation in region; membership of HCA is open to any IHO
    Member State whose government has acceded to the Antarctic Treaty and
    which contributes resources and/or data to IHO Chart coverage of the
    area; members of HCA are Argentina, Australia, Chile, China, France,
    Germany, Greece, India, Italy, New Zealand, Norway, Russia, South Africa,
    Spain and the United Kingdom (2005)

Transportation - note:
  Drake Passage offers alternative to transit through the Panama Canal

§5. Southern Ocean Transnational Issues

Disputes - international:
  Antarctic Treaty defers claims (see Antarctica entry), but Argentina,
  Australia, Chile, France, NZ, Norway, and UK assert claims (some
  overlapping), including the continental shelf in the Southern Ocean;
  several states have expressed an interest in extending those continental
  shelf claims under the United Nations Convention on the Law of the Sea
  (UNCLOS) to include undersea ridges; the US and most other states do not
  recognize the land or maritime claims of other states and have made no
  claims themselves (the US and Russia have reserved the right to do so); no
  formal claims exist in the waters in the sector between 90 degrees west and
  150 degrees west


<Factbook 2006>
