补充阅读 Cool Antarctica

Cool AntarcticaAntarctica is an amazing place. It may be cold and remote, but this frozen land is home to some great wildlife. Read the article to find out more about this incredible continent. Introduction Antarctica is a frozen continent. It is as far south as you can get and it surrounds the south pole. Antarctica is covered by a great icesheet and is about the toughest place you could choose to live. The continent is divided in two parts by the Transantarctic Mountains. This mountain chain is 3,540km long and contains an active volcano: Mount Erebus. The highest mountain on Antarctica is the Vinson Massif (5,140m) in the Ellesworth Mountains. The eastern part of the continent is the largest, and the western part has a peninsula that sticks out as far as 965km (600 miles) from the pole. Antarctica is the least populated and least polluted of the worlds continents, but is not untouched. In fact, it is where the hole in the ozone layer is found. In 1959 the Antarctic Treaty was signed in order to try and preserve the unique features of the continent. Exploration Antarctica was the last continent to be discovered by modern man. Ancient peoples had long passed down legends of a mysterious southern land but it was first officially sighted in 1820. During the 19th century, people started to exploit its resources, by hunting whales and seals. Then in the early 1900s, the great explorers, including Scott, Shackleton and Amundsen took up the challenge to reach the south pole. Amundsen actually got there first in December 1911, but Scotts expedition is perhaps more famous. His team made it to the pole just a month later, only to find the Norwegian flag already in place. Scott and his companions all died on the return journey. Mawson and Byrd were the first explorers to consider flying to the south pole. Now that we have modern aircraft equipped with the latest technology, its much easier to find out about Antarctica. There have been a number of scientific studies in the last 50 years. Climate Antarctica is colder and drier than any other continent. The coldest temperature ever recorded was -89.2C (-128.6 F) at Vostock research station. Although Antarctica is the worlds smallest continent, it is large enough for the climate to vary from one area to the next. In summer, temperatures can rise to +15C (59F) in the peninsula but only reach about -20C (-4F) in the interior. Because of the orbit of the earth in relation to the sun, Antarctica has very long days in the summer and very long nights in the winter. At the south pole you get six months of light followed by six months of darkness. This change in light has a big effect on the temperature. The rise in temperature in the summer causes huge volumes of sea ice to melt. In September there is 22,000 000 square km of sea ice, but in March, it is reduced to a mere 3,000 000 square km. Antarctica has two thirds of all the fresh water on Earth. Wildlife Most of Antarcticas wildlife is found in the sea because the land is so inhospitable. The Antarctic seas are full of nutrients that support large numbers of fish and krill. Krill provides food for many of the other marine animals. It is estimated that whales eat 150 million tons of krill a year. Antarctica whales include the southern right whale, the humpback whale, the blue whale, fin whale, sei whale and minke whale. Sperm whales, killer whales, porpoises and dolphins are also found there. Antarctica has many seal species including the Weddell seal, the crabeater seal, the rarely seen Ross seal and the solitary and aggressive leopard seal. Elephant seals and sealions can be found on islands in the Southern Ocean. The Antarctic coasts also boast huge rookeries of birds. There can be as many as a million birds in some penguin colonies. The only true land animals in Antarctica are a few species of invertebrates. Plants Most of Antarctica is covered by ice and snow. Less than 1 per cent of the land is ice-free. The ice can be a massive 2,700m thick at the South Pole. You might think no plants could grow in Antarctica, but amazingly, they can. In some valleys theres little snow fall and strong winds do not allow what snow there is to build up. In summer, plants pop up in a number of places around the coast, especially on the milder peninsula. There are about 800 species of land plants in Antarctica, mostly lichens and mosses. The plants usually exist because they are in an area that has its own microclimate, for example, they grow on dark rocks, which absorb heat from the sun. Lichens are very slo