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 estim