Location:
body of water between 60 degrees south latitude and Antarctica
Geographic coordinates:
65 00 S, 0 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 sq km
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