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Antarctica

Antarctica is the Earths southernmost continent; it contains the geographic South Pole. It’s situated in the Antarctic area of the Southern Hemisphere, almost completely south of the Antarctic Circle, and is bordered by the Southern Ocean. It’s the fifth-largest continent at 5.4 million sq miles.

On average, it is the driest, coldest, and windiest continent as well as having the highest average elevation of all the continents. Considered a desert, the annual precipitation is only 8 inches along the coast and far less inland. There are no permanent human residents, but anywhere between 1,000 and 5,000 people reside throughout the year at research stations scattered across the continent. Only cold-adapted organisms are able to survive there, including many types of algae, bacteria, plants, fungi, protista, and animals such as mites, penguins, seals, nematodes, and tardigrades.

Although there were myths and some speculation about a Terra Australis, meaning “Southern Land” that date back to antiquity, the first established sighting of the continent is commonly accepted to have happened in 1820 by the Russian expedition of Fabian Gottlieb von Bellingshausen and Mikhail Lazarev. However, the continent stayed largely neglected for the rest of the 19th century due to its hostile environment, isolation, and a lack of resourses. The Antarctic Treaty was signed in the year 1959 by 12 countries; today, 49 countries have signed the treaty. It prohibits military activities and mineral mining, prohibits nuclear explosions and nuclear waste disposal, it supports scientific research, and it protects the continents ecozone. Ongoing experimentation by over 4,000 scientists from many nations are conducted.

The initial formal use of the name “Antarctica” as the continental name in the 1890s is attributed to the Scottish cartographer John George Bartholomew. The name is the Romanized version of the Greek compound word antarktike, feminine form of antarktikos, which means “opposite to the Arctic”.

Antarctica is centered asymmetrically around the South Pole. The continent is divided in two by the Transantarctic Mountains which are nearby the neck between the Ross Sea and the Weddell Sea. The part that lies west of the Weddell Sea and east of the Ross Sea is called West Antarctica and the remainder East Antarctica, because they roughly correspond to the Western and Eastern Hemispheres comparative to the Greenwich meridian.

Approximately 98 percent of Antarctica is blanketed by the Antarctic ice sheet, a sheet of ice that averages at least 1 mi thick. The continent has about 90 percent of the world’s ice. If all of this ice were to melt, the sea levels would rise about 200 feet. In the majority of the interior of the continent, precipitation is very low, down to .8 each year; in a few “blue ice” regions, precipitation is lower than mass loss by sublimation and so the balance of local mass is negative.

More than 170 million years ago, the continent was a part of the supercontinent Gondwana. Over a period of time, Gondwana slowly broke apart and Antarctica as we know it today was created around 25 million years ago. This continent was not always dry, cold, and covered in ice sheets. At a number of times in its long history it was farther north, experienced a tropical and temperate climate, was blanketed in forests, and occupied by various ancient life-forms.

The eastern portion of this continent is colder than the western portion due to the higher elevation. Weather fronts rarely ever penetrate far into the continent, leaving the center dry and cold. Despite the lack of rain over the central part, ice there lasts for extended periods of time. Heavy snowfalls are common on the coastal portion of the continent, where snowfalls of up to 48 inches in 48 hours have been documented.

Image Caption: Antarctica: orthographic projection; created with Online Map Creator, et al. Credit: Bosonic dressing/Wikipedia (CC BY-SA 3.0)

Antarctica


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