de 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 m 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 m (the global mean is 133 m); the Antarctic
icepack grows from an average minimum of 2.6 million sq km in March
to about 18.8 million sq km 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, fish

Natural hazards:

huge icebergs with drafts up to several hundred meters; smaller
bergs and iceberg fragments; sea ice (generally 0.5 to 1 m 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