Sunday, 1 May 2011

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Antarctica

Antarctica is Earth's southernmost continent. It is located in the southern hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. It’s the icy continent at the South Pole. At 14.4 million km², it is the fifth-largest continent in area after Asia, Africa, North America, and South America. About 98% of Antarctica is covered by ice, which averages at least 1.6 kilometers in thickness.  It is surrounded by water and is about 1 1/2 times larger than Australia or the United States.
There are no permanent human residents. Most visitors travel to Antarctica by ship from the southern tip of South America (Argentina or Chile) or from Australia or New Zealand.

Here in the World

Click here to see a map of the Antarctic Region

Really Cold! Really Dry!!

On average, Antarctica is the coldest, driest and windiest continent, and it has the highest average elevation of all the continents. Since there is little precipitation, except at the coasts, the interior of the continent is technically the largest desert in the world. A desert is anyenvironment that receives less than 25cm of precipitation per year. On average, most of Antarctica gets less than 5cm of snow fall each year. 98 percent of the land is covered with a thick continental ice sheet; the remaining 2 percent of land is barren rock. Antarctica has about 87% of the world's ice.
The coldest temperature ever recorded on Earth was at the South Pole where it reached -88.0°C!

Before It Was Cold

Antarctica hasn't always been cold and situated at the South Pole. It has drifted, like the other continents, and has ranged from theequator (during the Cambrian period, about 500 million years ago) to the present day South Pole. During the time of the dinosaurs (the Mesozoic Era, about 65 million to 248 million years ago), Antarctica had a more temperate climate and was connected to other landforms like Australia. It was the home of dinosaurs and many other life forms. Scientists know this from fossils of plants and animals found all over Antarctica.

Exploring a Land of Mystery

The name Antarctica is a version of the Greek word Αntarktikí which means "opposite to the north". The word “Antarctica” has several meanings. One is that it is the opposite of the Arctic. Antarctica and the Arctic Region are on opposite poles of the Earth. Another meaning is “without bears”. Polar bears do not live in Antarctica. They are native only to the Arctic, and the word “arctic” comes from the Classical Greek word arktos, which means bear.
For centuries the unknown southern land was a magical place called Terra Australis ("Southern Land"). The first confirmed sighting of the continent is commonly accepted to have occurred in 1820 by the Russian expedition of Mikhail Lazarev and Fabian Gottlieb von Bellingshausen. However, even after discovery the continent remained largely unexplored for the rest of the 19th century because of its icy hostile environment, lack of resources, and isolation. The first formal use of the name "Antarctica" as a continental name in the 1890s is attributed to the Scottish cartographer John George Bartholomew.
The Antarctic Treaty was created to help insure Antarctica remained open to all nations.  It was originally signed in 1959 by twelve countries; today forty-six countries have signed the treaty. The treatyhelps Antarctica remain open to all nations. It bans military activities and mineral mining, supports scientific research, and protects the continent's environment. A few nations like Chile, Argentina, USA, Australia, New Zealand and Russia have permanent research bases located on Antarctica. Ongoing experiments are performed at these bases by scientists of many nationalities and with different research interests.
Although scientific expeditions visit Antarctica, some even over the long winter months, there are no permanent cities. There are no cities because of the extreme weather, which includes freezingtemperatures, strong winds, and blizzards. There are about 4,000 seasonal (summer) visitors to Antarctica.

Plenty of Penguins!!

Only a handful of tiny invertebrates, and not one single landvertebrate, can survive the whole Antarctic winter. Most visit the continent during the summer months, November through early March. The southern continent's permanent resident is a 12mm midge (a kind of very small biting fly). Only cold-adapted plants and animals survive in Antarctica including seabirds, seals, sea lions, mosses, lichen, and many types of algae. Antarctica’s most famous visitors are the flightless birds called penguins.
Most of the world’s penguins live around Antarctica’s coast or on sub-Antarctic islands. Only here the ice melts just long enough each summer to allow penguins to build nests and raise their chicks. These include, Emperor, King, Gentoo, Adelie, Chinstrap, Rockhopper, and Macaroni.
Seals are the other animals that share the Antarctic summer with seabirds. The famous leopard seal grows to over 2m long and swims through the water like a torpedo hunting fish, penguins and smaller seals. Weddell and Crabeater seals also share the frigid ocean. Giant elephant seals and southern fur seals also visit ice-free coasts in summer.
Marine life under the Antarctic ice includes some of the strangest creatures in the ocean. Scientists have even discovered “icefish” that have special blood that isn’t red, with a kind of anti-freeze so they can survive the extreme cold.

Shrimp for Lunch… Breakfast and Dinner

The most numerous animal in Antarctic waters is a 1cm to 3cm long shrimp-like invertebrate called krill. Krill live in all the world’s oceans but are especially abundant in the cold nutrient rich waters surrounding Antarctica. Krill swim in giant schools of millions of individuals called balls.  Krill is the food most other Antarctic wildlife depends on for survival – from tiny penguins to giant whales.  Even humans fish for krill.

Watch the Antarctic Environment

Even though Antarctica has no cities or permanent residents, people still have a huge impact on the region. In 1998, a NASA satellite showed that the Antarctic ozone hole was the largest on record, covering 27 million square kilometers. Ozone naturally occurs in Earth’s atmosphere and protects life from too much ultraviolet lightpassing from the Sun. Changes in the ozone layer are caused by increases in gases like carbon dioxide (CO2) from automobiles and burning coal and from methane (CH4) from cows and burning natural gas.
In the past few years significant areas of ice shelves have beenmelting in response to global warming. Scientists are monitoring the Antarctic ice very carefully to help understand the impacts we humans may be having on the whole planet.

Antarctic FastFACTS

  • Full name: Antarctica
  • Population: 4,000 seasonal visitors
  • Capital: none, only communities are scientific research bases
  • Area: 14.4 million sq km (about 13.72 million sq km ice-covered)
  • Highest point: Vinson Massif 4,897 m
  • Lowest point: Bentley Subglacial Trench -2,555 m
  • Coastline17,968 km
  • Natural Resources: iron ore, chromium, copper, gold, nickel, platinum and other minerals, and coal and oil have been found in small quantities (Antarctic Treaty prohibits mining by any country); krill, finfish, and crab have been taken by commercial fisheries

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