Australian Antarctic Territory

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The Australian Antarctic Territory (AAT) comprises 42% of the continent of Antarctica. It takes in all islands and territories south of latitude 60°S and between longitudes 45°E and 160°E, except for the French territory of Terre Adélie (which takes in the islands and territories south of 60°S latitude and between longitudes 136° and 142° east). The territory was claimed by Australia between 1933 and 1959.

The AAT, which covers approximately 6.1 million km2, is the largest territorial claim on the continent. Australia is one of seven nations that have claimed territory in Antarctica, the others being Argentina, Chile, France, New Zealand, Norway and the United Kingdom.

Australia operates three stations on the continent — Casey, Davis and Mawson — and another station on Macquarie Island. All have modern facilities including living quarters, research laboratories, powerhouses, stores and workshops. During summer, researches use remote field bases to support their coastal, inland and traverse operations.

Geography

Extent

The Australian Antarctic Territory (AAT) comprise two sectors, the western sector (45°E–136°E, 5.2 million km2) and the eastern sector (142°E–160°E, 0.9 million km2). The coastline of the western sector (including offshore islands) is 12,140 km long, and that of the eastern sector 2,050 km.

Elevation

At its highest point the AAT reaches an altitude of 4,087 m (80°21'S 77°24'E). The highest mountain in the eastern sector is Mt McClintock (3,492 m, 80°13'S 157°26'E), and in the western sector is Mt Menzies (3,328 m, 73°28'S, 61°53'E), in the southern Prince Charles Mountains.

Climate

Antarctica is the driest, coldest, windiest continent on Earth. Average annual temperatures range from around -10°C on the coast to -60°C at the highest elevations in the interior. Adjacent to the coast the temperature can exceed 10°C during summer and fall below -40°C in winter. Over the inland, it can reach about -30°C in summer but plunge to less than -80°C in winter. On 21 July 1983, the temperature at Vostok station reached –89.2°C, the lowest temperature yet recorded on Earth.

Low-pressure systems near the coast can interact with katabatic winds (winds blowing downhill, e.g. caused by falling temperatures at night) to increase their strength. Wind speeds in the territory can exceed 100km/h for days on end, and wind gusts well over 200km/h have been measured.

Air over the interior is usually dry, thus there is little cloud. Cloudy conditions are more common around the coast, particularly the Antarctic Peninsula, because of the greater availability of moisture and the influence of low-pressure systems.

Rain sometimes occurs near the coast, but most precipitation over Antarctica is in the form of snow or ice crystals. The average accumulation of snow over the entire continent is estimated to be the equivalent of around 150 mm of water per year. Over the elevated interior plateau the annual is less than 50 mm, while it usually exceeds 200 mm near the coast. The heaviest recorded fall was 1,000 mm, over an area near the Bellingshausen Sea.

Wildlife

Flora

In general, Antarctica does not provided a suitable habitat for plant growth — total darkness in winter, lack of liquid, virtually no soil. Some plants are able to grow during the summer near the coast, where there is sufficient soil and water for plants to put down their roots. The soils are often ornithogenic ("bird-created"), a product of penguin droppings, feathers and carcases that break down to produce a soil rich in nitrates and phosphates.

Such plants as do grow in Antarctica tend to be low-growing and simple — lichens, mosses and algae are dominant. There are, however, two species of flowering plant, a grass and a pearlwort. Despite 24-hour sunlight in summer, plants are grow extremely slowly, so it is vital that visitors to the region avoid damaging or destroying them.

Fauna

Most of the animal life in the AAT is invertebrate, including microscopic mites, lice, nematodes, tardigrades, rotifers, krill and springtails. The largest land animal is the flightless midge Belgica antarctica, only 12 mm long. The snow petrel is one of only three species of birds that breed exclusively in Antarctica.

Aquatic animals, which rely directly or indirectly on the phytoplankton for their survival, include penguins, blue whales, orcas and fur seals.

A number of species of penguin make their home in Antarctica, including:

Major seal species of the territory include the fur seal, the leopard seal and the Weddell seal.

History

Australia's Antarctic claim is based on a long historical association involving exploration and research. Between 1911 and 1914, Australia's Douglas Mawson led the Australasian Antarctic Expedition (AAE), which established bases at Commonwealth Bay and the Shackleton Ice Shelf, explored the coast near the bases and claimed the land as British territory.

Between 1929 and 1931 the British, Australian and New Zealand Expedition (BANZARE), again led by Mawson, made further extensive claims to sovereignty. During two summer voyages the expedition ship Discovery and the expedition aircraft covered the entire coastline from 45°E to 160°E, defining in the process the limits of what was to become the AAT.

The British government issued an Order-in-Council on 7 February 1933, placing the territory under the authority of the Commonwealth of Australia:

That part of the Territory in the Antarctic seas which comprises all the islands and territories, other than Adelie Land, situated south of the 60th degree south latitude and lying between the 160th degree east longitude and the 45th degree east longitude, is hereby declared to be accepted by the Commonwealth as a Territory under the authority of the Commonwealth, by the name of the Australian Antarctic Territory.

The AAT was permanently occupied from February 1954 when Mawson station — the oldest continually occupied station south of the Antarctic Circle — was established.


References