Antarctica is the fifth largest of the earth’s seven continents. It has an area of nearly 14 million square kilometers. It is located entirely in the Southern Hemisphere, surrounding the South Pole and lies completely within the Antarctic Circle. The continent is surrounded by the southernmost parts of the Pacific, Atlantic and Indian Oceans. Together, the waters of these oceans are knows as ‘Southern Ocean’. This ocean is so cold that its surface temperatures rarely rise over 4o Celsius.
Antarctica originally belonged to the Gondwanaland, a landmass that included Africa, Australia, India and South America. Some 140 million years ago the land broke apart and Antarctica become a separate continent. Fossils of dinosaurs, trees and small mammals have been found buried in the Antarctica. Glaciers began to form in this ice-free continent some 30 million years ago.
The continent was discovered when Captain James Cook sailed all the way around Antarctica in 1968-71 to see if there was any land further south than Australia and South America. He reported on the marine life he saw apart from ice. Since then various polar explorers came to Antarctica. Roald Amundsen, a Norwegian, was the first to reach the South Pole on December 17, 1911. Many explorers and scientists have gone to Antarctica since then. The first Indian expedition to the continent reached on January 9, 1982 and set up a permanent Indian scientific station at Dakshin Gantogri at 70oS Latitude and 12oE Longitude. Later in 1988-89 it was abandoned and a new station was set up at ‘Maitri’ 70 km away from Dakshin Gangotri where 25 people can be accommodated all round the year. Between 1982 and 1989 India sent about nine expeditions to this icy continent. Other major countries that have established camps for scientific study on Antarctica are United Kingdom, Australia, New Zealand, France, Norway, Argentina, Chile, Japan, Russia and the USA. See the map 6.1 which shows how parts of Antarctica have been claimed by various nations for scientific study. However, Antarctica is not owned by any country.
Antarctica is aptly called ‘White Continent’ as it is almost entirely covered by a thick ice sheet which has an average thickness of 1.5 kilometres. The world’s longest glacier called Lambert glacier is found here. The ice sheet does not melt even in summer. Antarctica’s surface is higher in the east than in the west.
Below the ice sheet, East Antarctica faces the Atlantic and Indian Oceans. It is a large compact land area with low plains. Its rocks are as old as 50 million years. Gradually these rise to a height of 2000 metres in the west. The Queen Maud Range divides the continent into almost two equal parts. Trans Antarctic mountains over looking the Ross Sea rise to 4000 metres in places. Mt. Erebus 3794 metres high is the only live volcano on the continent. West Antarctica facing the Pacific Ocean is an archipelago (a group of islands) which consists of three main Islands – the Antarctic Peninsula, Ellsworth Massif and Marie Byrd Massif.
The Antarctica Peninsula, is joined to the tip of South America by a submarine ridge, the peaks of which stand above water level as the islands of Shetland and Sough Orkney. Vinson Massif is the highest point on the Antarctica. It is 5140 metres high and is located on Ellsworth mountain.
The steep shores of Antarctica have high cliffs of ice jutting out into the sea because there is no significant coastal plain, the Ross and Weddell Seas are rather shallow. The seas around Antarctica contain lumps of floating ice called icebergs. These breaks off from large, flat areas called ice shelves which lie across the water of vast bays. Some of these iceberges are nearly 100 km wide. The process of breaking away of icebergs is called calving.
The climate of Antarctica is severe. It is the coldest and stormiest of all continents. Icy winds called blizzards make the air feel colder because they contain snow that is whisked up off the ground by the strong winds. Wind speed may vary from 70 to190 km per hour! The cold air flows down from higher to lower slopes, uninterrupted over the icy smooth surfaces in Antarctica. In between the temperatures in coastal areas and those at the centre of the icecaps. The temperature may fall to -95oC in winter and never rise above 0o in summer. Ice and snow cover 99 per cent of the continent and 70 per cent of world’s supply of fresh water. If this ice melted it would result in a rise of the sea level so that coastal cities around the world would be flooded !
Climate is milder along the coasts but very cold and dry in the interior. Annual coastal rain and snowfall averages 60 cms. The interior of Antarctica is often called a ‘polar desert’ as it only gets about 5 cm of snowfall each year.
Under such severe and harsh conditions there is hardly any vegetation in the Antarctic. Mosses and lichens cling to rocky areas. Black, white and green lichens have been found growing in tiny cracks in dry valleys.
Simpler organisms called algae grow on snow, in lakes and on the ice surrounding the continent. Some flower-bearing plants are found on the northern parts of Antarctica in warmer latitudes. Antarctica is devoid of greenery and any plant life. But in the surrounding sea, floating masses of vegetation that sustains thousands of marine birds and mammals are found.
Despite the cold, there are a surprising number of animals living in the Antarctica, mainly on or near the land around the edges of he continent and in the surrounding seas. Twelve different kinds of whales migrate to Antarctica for the summer. They include the blue whale, fin and humpback whales, killer whales and sperm whales among others. Various kinds of penguins and seals feed on variety of plants and fish that float in the sea. Penguins, whales and seals have a thick layer of fat called ‘blubber’ under their skin to keep them warm. Penguins are flightless birds. They waddle on land awkwardly but they swim very well. The Adelie Penguin, Emperor Penguin, Chinstrap and King Penguins are most common.
Over forty types of sea birds spend their summer in the Antarctica. The albatrosses, petrels, skuas and terns are most common. A small shrimp-like creature called ‘krill’ is found in abundance in the Antarctic water. They are found in swarms of 100 metres or more. Apart from being a major source of food for many Antarctic animals, krill are caught to provide a variety of products as fish-meat and krill paste uses as a bread spread. It is very rich in proteins. In the interior, however, due to extremely low temperature the only creatures living are inspects and tiny spider-like mites that survive in temperatures below 60oC.
Geologists have found coal, oil and natural gas in and around Antarctica. Deposits of gold, lead, zinc, manganese and copper have been discovered as well. However, exploration of minerals under the thick layer of ice in harsh weather conditions including strong winds, icebergs and rough seawaves is very difficult. Moreover the minerals occur in small amounts which makes their exploration uneconomical. ‘Conservationists’ feel that large-scale mining operations would harm Antarctica’s environment. Already they are faced with the problems of disposing off the wastes and scrap on the continent. The damages to the protective ozone layer around the Antarctic atmosphere is also a cause of great concern. What could be of use is the vast quantity of ice on the continent ? Can you think of a way that scientists could utilize the large icebergs of Antarctica some day.
An international Antarctica treaty was signed by twelve nations in 1959 and later six more including India joined it. Today nearly thirty-two countries have signed up this agreement, promising to use the area for peaceful scientific research only. Scientists of the member countries must share any knowledge that results from their studies. The treaty makes Antarctica a military-free and nuclear-free zone. It also preserves and protects the Antarctic environment by restricting the fishing in the seas around Antarctica.
The Antarctica has provided unique opportunities to scientists to learn about the earth’s gravity, earthquakes, magnetism, ice behaviour, rocks, marine flora and fauna, oceans and solar activity. It is because of the keen interest of scientists in this continent that has been called a ‘continent of science’.
Today explorers and scientists from all over the world visit the Antarctica. Several base camps, observation and research stations have been established by various countries. They have created livable conditions within their camps by erecting special kinds of permanent structures which can withstand the strong icy winds and extremely low temperatures. Electric generators facilitate heating and lighting. They use dried, tinned and deep-frozen foods, stoves and special protective clothing. They travel on the snow and ice with snow-mobiles and tow their supplies on trailers; these special vehicles are brought in by ships equipped to cut through the icy seas carefully and then flown in by helicopters. Fresh supplies are dropped by airplanes.