llion 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