Antarctica continent

Geographic location

Antarctica is a continent located in the very south of the Earth, the center of Antarctica roughly coincides with the south geographic pole. Antarctica is washed by the waters of the Southern Ocean.

The continent covers about 14,107,000 km² (including 930,000 km² of ice shelves and 75,500 km² of islands).

Antarctica is also referred to as the part of the world consisting of the continent Antarctica and the adjacent islands.

Antarctica is washed by the waters of the Pacific, Indian and Atlantic Oceans, it is shaded by the Ross Sea, the Amundsen Sea, the Bellingshausen Sea and the Weddell Sea, the latter two are separated by the Antarctic Peninsula.

Antarctica is almost entirely covered by a layer of glaciers, reaching 4 km. in thickness, so Antarctica is the highest continent, its average height is 2,040 m. Only near the coasts are isolated “oases” – land areas free of ice. In general, Antarctica glaciers contain 90% of fresh water reserves on Earth, if they melt all at once, the water level of the oceans rises by 70 meters.

According to the specificity of the relief can be divided into two parts of the continent – eastern (located in the eastern hemisphere) and western (respectively, in the western). The eastern part is flatter, with the following plains: Eastern, Schmidt, Western and the flat Eastern Plateau. The western part is separated by the Transarctic Ridge, there is a more diverse terrain, the low-lying Baird Plain neighbors with small mountain ranges, including Mount Ellsworth (the highest point of the continent-5140 m). Deposits of hard coal and ores of ferrous and non-ferrous metals have been found in Antarctica.

Topography

Antarctica is the highest continent on Earth, with an average surface altitude of more than 2,000 m above sea level and 4,000 m in the center of the continent. Most of this height is a permanent ice sheet of the continent, under which the continental relief is hidden and only 0.3% (about 40 thousand square kilometers) of its area are free of ice – mainly in West Antarctica and the Transantarctic Mountains: islands, coastal areas, the so-called “dry valleys” and some ridges and mountain peaks (nunataks) that rise above the ice surface. Transantarctic mountains that cross almost the entire continent divide Antarctica into two parts – West Antarctica and East Antarctica, which have different origins and geological structure. In the east there is a high (the highest elevation of the ice surface ~4,100 m above sea level) ice-covered plateau. The western part consists of a group of mountainous islands connected by ice. On the Pacific coast there are the Antarctic Andes, the height of which exceeds 4000 m; the highest point of the continent – 4892 m above sea level – the Vinson massif in the Elsworth Mountains. West Antarctica is also home to the continent’s deepest depression, the Bentley Trench, probably of rift origin. Bentley Depression, filled with ice, reaches 2,555 m below sea level.

Subglacial relief

Research using modern methods made it possible to learn more about the subglacial relief of the southern continent. As a result of research, it was found that about one-third of the continent lies below sea level, the study also showed the presence of mountain ranges and massifs.

The western part of the continent has a complex relief and large height differences. Here is the highest mountain (Mount Vinson 4,892 m) and the deepest depression (Bentley Trough -2,555 m) in Antarctica. The Antarctic Peninsula is a continuation of the South American Andes, which stretches toward the south pole, sloping slightly away from it into the western sector.

The eastern part of the continent has a predominantly smoothed relief, with individual plateaus and mountain ranges up to 3-4 km high. In contrast to the western part, formed by young Cenozoic rocks, the eastern part is a protrusion of the crystalline basement of the platform, previously part of Gondwana.

The continent has relatively low volcanic activity. The largest volcano is Mount Erebus on Ross Island in the sea of the same name.

NASA’s subglacial topography studies have found a crater of asteroidal origin in Antarctica. The crater is 482 kilometers in diameter. The crater was formed when an asteroid with a diameter of about 48 kilometers (larger than Eros) fell to Earth about 2 50 million years ago, in Permian-Triassic time. The dust raised by the asteroid’s impact and explosion led to centuries of cooling and the death of much of the flora and fauna of that era. This crater is considered to be the largest on Earth today.

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In the case of complete melting of the glaciers, the area of Antarctica would be reduced by one-third: western Antarctica would become an archipelago, while the east would remain a continent. According to other data, all of Antarctica would become an archipelago.

Climate

The climate of Antarctica is very harsh In winter, extremely cold, the average temperature is -70 ° C, the average temperature of the warmest month of +2 0 ° C. Antarctica has the lowest temperature in the world – 80 ° C. The average amount of precipitation that falls as snow in Antarctica is 2 00 mm per year, more on the coast and less inland. Because of the difference in pressure and temperature in Antarctica there are constant winds from the mainland, on the coast the strongest winds on Earth, reaching speeds of 90 m/s.

Life in Antarctica exists mainly in oases. There are several species of seals, whales, many birds petrels, skuas, albatrosses, gulls, penguins. Produce mostly mosses, lichens.

Antarctica has no permanent population, it does not belong to any country and is not an independent state. On the mainland there are research stations, scientists study the relief and climate.

A number of international treaties regulate the situation regarding Antarctica, military testing is prohibited here, 1991 in Antarctica it is forbidden to develop minerals.

Antarctica is characterized by an extremely severe cold climate. In East Antarctica at the Soviet Antarctic station Vostok 2 on July 1, 1983, the lowest air temperature on Earth for the entire history of meteorological measurements was recorded: 89.2 degrees below zero. The area is considered to be the Earth’s cold pole. On December 9, 2 013, at a conference of the American Geophysical Union, a group of American researchers reported that on August 10, 2 010, the air temperature at a point in Antarctica dropped to -93.2 °C (-135.8 F). This information was revealed as a result of analysis of satellite data from NASA. However, according to one of the authors of the message Ted Scambos, the value obtained will not be registered as a record, as it was determined as a result of satellite measurements, rather than using a thermometer. Average temperatures in winter months are from -60 to -75 °С, and from -30 to -50 °С in summer; on the coast in winter from -8 to -35 °С, and 0-5 °С in summer. It should be noted that winter months in Antarctica (as throughout the southern hemisphere) are June, July and August, and summer months – December, January and February.

Animal and plant life

Most of Antarctica is a desert, devoid of both vegetation and animal life. Vegetation in Antarctica is found almost exclusively on the fringes of the continent and on sub-Antarctic islands, and the rich and distinctive animal life is associated mainly with Antarctic water basins and partly with the marginal strip of the continent.

Antarctica and adjacent parts of other continents stand out as a special floristic kingdom. In the Mesozoic, the Antarctic continent was a major center of flora formation, but changes in climatic conditions led to its drastic impoverishment and migration northward.

Of the land plants on the continent itself, only mosses, lichens, lower algae, fungi and bacteria can be found. Lichens are the most richly represented, of which there are about 300 species. They can be found in all ice-free areas of land. Mosses are also quite widespread, especially on islands, where even small peatlands are formed. In total, there are about 80 species of mosses in Antarctica.

Freshwater algae settle in ponds in summer, as well as on the surface of snow that thaws in summer under the rays of the sun. Clusters of red, green and yellow microscopic algae create colorful patches on the surface. Colonies of microscopic green algae resemble lawns from afar.

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There are no flowering plants on the mainland. The southern border of distribution of higher plants is 64°S on the Antarctic Peninsula. Up to 10 species of stunted flowering plants are common there, including pike grass (Deschampsia flexuosa) and carnation colobanthus (Colobanthus quitensis) with small, unsightly flowers and pale green leaves. Here and there they form small meadows. On the islands the vegetation is much richer. More than two dozen species of flowering plants can be found there, including the Kerguelen cabbage (Pringlea antiscorbutica), which is a tasty and nutritious vegetable and an effective remedy for scurvy. Also widespread is a cereal of the bluegrass genus, the tussock (Roa flabellata), a good fodder for sheep. All plants of the islands are herbaceous; their flowers and leaves are almost colorless, since pollination is not by insects but by the wind.

Antarctica is poor in terrestrial animals. There are no terrestrial mammals, but there are some worms, primitive crustaceans and wingless insects. The lack of wings can be explained by the fact that insects cannot take to the air due to constantly blowing strong winds. Several species of beetles, spiders, freshwater mollusks, and one type of flightless butterfly were found on Antarctic islands. Freshwater fish are absent. Of the birds living on land, the White Plover, Pipit and one species of duck nesting on South Georgia Island are known.

Animal life in Antarctica is associated with the ocean waters that bathe the continent. Dozens of bird species – petrels, albatrosses, black-headed gulls and penguins – nest on the coast and coastal cliffs in summer. Among the latter, the most typical are Adelie penguins, making long journeys inland, and large emperor penguins. Coastal waters are inhabited by whales, sperm whales, killer whales, and various species of seals. In coastal waters there is a lot of plankton, especially small crustaceans (krill). Fish, whales, pinnipeds, and birds feed on it.

Conclusion

Antarctica has no permanent population. Its international status is such that it does not belong to any state. Only scientists from all countries can carry out scientific research on the continent, and some tourist and sport expeditions break the ice silence of the vast expanses of the continent. Antarctica is a continent covered by an ice sheet, which has important ecological significance, unique flora and fauna and huge reserves of fresh water.

Antarctica is the common heritage of mankind which should be protected and preserved as a great relic.

Antarctica is a treasure trove of useful scientific information and an undeniable candidate for scientific research only, not for destruction.

Antarctica

Antarctica is a continent located in the very south of the Earth, the center of Antarctica roughly coincides with the south geographic pole. Antarctica is washed by the waters of the Southern Ocean (previously this ocean was considered the southern parts of the Indian, Pacific and Atlantic Oceans). The area of the continent is about 14.4 million km² (of which 1.6 million km² are ice shelves). Antarctica is also called the part of the world consisting of the continent Antarctica and the adjacent islands.

Antarctica was discovered on January 16 (28), 1820 by the Russian expedition led by Thaddeus Bellingshausen and Mikhail Lazarev, who, on sloops Vostok and Mirny, approached it at 69°21′ S. 2°14′ W. (area of the modern Bellingshausen Ice Shelf). The first to enter the continental part were the captain of the Norwegian ship “Antarctica” Christensen and the science teacher Karlsten Borchgrevink on January 24, 1895.

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Video: Antarctica.

Topography and Ice Sheet.

Antarctica is the highest continent on Earth, with an average surface elevation of more than 2,000 meters above sea level and reaching 4,000 meters in the center of the continent. Most of this height is the continent’s permanent ice sheet, under which the continental relief is hidden and only~5% of its area is ice-free – mainly in West Antarctica and the Transantarctic Mountains: islands, coastal areas, the so-called “dry valleys” and individual ridges and mountain peaks (nunataks) rising above the ice surface. Transantarctic mountains that cross almost the entire continent divide Antarctica into two parts – West Antarctica and East Antarctica, which have different origins and geological structure. In the east there is a high (the highest elevation of the ice surface ~4,100 m above sea level) ice-covered plateau. The western part consists of a group of mountainous islands connected by ice. On the Pacific coast there are the Antarctic Andes, the height of which exceeds 4000 m; the highest point of the continent – 4892 m above sea level – the Vinson Massif of the Sentinel Ridge. West Antarctica is also home to the continent’s deepest depression, the Bentley Trench, probably of rift origin. The Bentley Depression, filled with ice, reaches a depth of 2555 m below sea level.

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The Antarctic ice sheet is the largest on our planet and exceeds the nearest in size Greenland ice sheet by approximately 10 times in area. It contains ~30 million km³ of ice, that is 90% of all land ice. It has the form of a dome with increasing steepness of surface towards the coast, where in many places it is framed by shelf glaciers. The average thickness of the ice layer is 2500-2800 m, reaching a maximum value in some areas of East Antarctica – 4800 m. Ice accumulation on the ice sheet leads, as in the case of other glaciers, to ice flow into the ablation (destruction) zone, which is the continental coast (see Fig. 3); the ice is broken away in the form of icebergs. The annual volume of ablation is estimated at 2500 km³.

A specific feature of Antarctica is the large area of ice shelves (low (blue) areas of West Antarctica), amounting to ~10% of the area above sea level; these glaciers are the sources of icebergs of record sizes, significantly exceeding the size of icebergs of Greenland’s outlet glaciers; for example, in 2000, the largest known at this time (2005) iceberg B-15 of over 10,000 km² broke away from the Ross Ice Shelf Glacier. In winter (northern hemisphere summer), the area of sea ice around Antarctica increases to 18 million km² and decreases to 3-4 million km² in summer.

The ice cover of Antarctica was formed about 14 million years ago, apparently facilitated by the rupture of the seal connecting South America and the Antarctic Peninsula, which led in turn to the formation of the Antarctic Circumpolar Current (Western Winds Current) and the isolation of Antarctic waters from the World Ocean – these waters form the so-called Southern Ocean.

Seismic activity

Antarctica is a tectonically calm continent with little seismic activity, the manifestations of volcanism are concentrated in West Antarctica and are associated with the Antarctic Peninsula, which arose during the Andean Period of mountain building. Some of the volcanoes, especially the island ones, have erupted in the last 200 years. The most active volcano in Antarctica is Erebus. It has been called “the volcano guarding the way to the South Pole.”

Climate

Antarctica has an extremely harsh cold climate. In East Antarctica there is an absolute pole of cold, where temperatures as low as -89.2 °C were recorded (Vostok Station area).

Another peculiarity of East Antarctica meteorology is runoff (catabatic) winds due to its dome-shaped topography. These stable southerly winds arise on sufficiently steep slopes of the ice sheet due to cooling of the air layer near the ice surface, the density of the surface layer increases, and it flows down the slope under the action of gravity. The thickness of the air flow layer is usually 200-300 m; due to the large amount of ice dust carried by the wind, horizontal visibility in such winds is very low. The strength of the runoff wind is proportional to the steepness of the slope and reaches its greatest strength in coastal areas with a high slope toward the sea. Runoff winds reach their maximum strength in Antarctic winter – from April to November they blow almost continuously around the clock, from November to March – at night or when the Sun is low above the horizon. In summer, during the daytime hours, due to the warming of the surface layer of air by the sun, the runoff winds near the coast stop.

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Data on temperature changes from 1981 to 2007 show that the temperature background in Antarctica changed unevenly. For West Antarctica, in general, there was an increase in temperature, whereas no warming was found for East Antarctica, and even some negative trend was noted. It is unlikely that the process of melting of Antarctica will increase significantly in the 21st century. On the contrary, the amount of snow falling on the Antarctic ice sheet is expected to increase with rising temperatures. However, due to warming, more intense destruction of ice shelves and acceleration of movement of Antarctic outlet glaciers that release ice into the world’s oceans is possible.

Inland Waters

Due to the fact that not only average annual temperatures, but in most areas even summer temperatures in Antarctica do not exceed zero degrees Celsius, precipitation there falls only in the form of snow (rain is an extremely rare phenomenon). It forms a glacial (snow is compressed under its own weight) cover with a thickness of more than 1700 m, reaching 4300 m in some places. Antarctic ice concentrates up to 90% of all fresh water on Earth.

In the 1990s, Russian scientists discovered an ice-free subglacial lake Vostok – the largest of the Antarctic lakes, with a length of 250 km and a width of 50 km, the lake holds about 5400 thousand km³ of water.

In January 2006, geophysicists Robin Bell and Michael Studinger of the U.S. Lamont-Dogerty Geophysical Observatory discovered the second and third largest subglacial lakes, 2,000 km² and 1,600 km² respectively, located at a depth of about 3 km from the continental surface. They said it could have been done earlier if data from the 1958-1959 Soviet expedition had been analyzed more thoroughly. In addition to these data, satellite data, radar readings and measurements of the gravitational force on the surface of the continent were used.

In total, more than 140 subglacial lakes were discovered in Antarctica in 2007.

Biosphere

The biosphere in Antarctica is represented in four “life arenas”: coastal islands and ice, coastal oases on the mainland (such as the “Banger Oasis”), nunatak arenas (Mount Amundsen near Mirny, Mount Nansen on Victoria Land, etc.) and the ice sheet arena.

Plants and animals are most common in the littoral zone. Terrestrial vegetation in ice-free areas exists mainly in the form of various moss and lichen species and does not form a closed cover (Antarctic moss-lichen deserts).

Antarctic animals are completely dependent on the coastal ecosystem of the Southern Ocean: due to the scarcity of vegetation, all significant food chains of coastal ecosystems begin in the waters surrounding Antarctica. Antarctic waters are particularly rich in zooplankton, primarily krill. Krill directly or indirectly form the basis of the food chain of many species of fish, cetaceans, squids, seals, penguins and other animals; there are no land mammals entirely in Antarctica; invertebrates are represented by about 70 species of arthropods (insects and spiders) and soil-dwelling nematodes.

Of the land animals are seals (Weddell’s seals, crab seals, sea leopards, Ross’s seals, sea elephants) and birds (several species of petrels, two species of skuas, Adelie penguins and emperor penguins).

In freshwater lakes of mainland coastal oases – “dry valleys” – there are oligotrophic ecosystems inhabited by blue-green algae, roundworms, paddlefish (cyclops) and daphnia, while birds (petrels and skuas) arrive here occasionally.

Nunataks are characterized only by bacteria, algae, lichens and strongly depressed mosses, while only skuas occasionally fly into the ice sheet, following humans.

There is a suggestion that subglacial lakes in Antarctica, such as Lake Vostok, have extremely oligotrophic ecosystems that are virtually isolated from the outside world.

In 1994, scientists reported a rapid increase in the number of plants in Antarctica, which seems to confirm the hypothesis of global climate warming on the planet.

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The Antarctic Peninsula with its adjacent islands has the most favorable climatic conditions on the continent. It is here that the region’s only flowering plants, the Antarctic meadowsweet and kito colobanthus, grow.

Exploring Antarctica

The first ship to cross the southern polar circle belonged to the Dutch; it was commanded by Dirk Heeritz, who sailed in Jacob Mague’s squadron. In 1559, in the Strait of Magellan, Geeritz’s vessel lost sight of the squadron after a storm and sailed south. When it went down to 64° S., high land was discovered there. In 1671 La Roche discovered South Georgia; in 1739 Bouvet Island was discovered; in 1772 in the Indian Ocean Yves-Joseph Kerglen, a French naval officer, discovered an island named after him.

Almost simultaneously with the Kerglen voyage from England, James Cook set out on his first voyage to the southern hemisphere, and already in January 1773 his vessels Adventure and Resolution crossed the southern polar circle at the meridian 37°33′ E. After a difficult struggle with the ice, he reached 67°15′ S., where he was forced to turn north. In December 1773 Cook sailed again to the southern ocean, crossed it on December 8, and on the parallel of 67°5′ S. was wiped out by ice. Cook then proceeded southward and at the end of January 1774 reached 71°15′S, just SSW of Tierra del Fuego. Here an impenetrable wall of ice prevented him from proceeding further. Cook was one of the first to reach the South Polar Seas and, encountering solid ice at several points, declared that it was impossible to penetrate further. He was believed, and for 45 years no polar expeditions were undertaken.

In 1819 the Russian sailors F. F. Bellingshausen and M. P. Lazarev, on the military sloops Vostok and Mirny, visited South Georgia and attempted to penetrate deep into the Southern Arctic Ocean. For the first time, in January 1820, almost on the Greenwich meridian, they reached 69°21′ S.; then, having gone beyond the polar circle, Bellingshausen passed along it eastward to 19° E., where he crossed it again and reached almost the same latitude (69°6′) again in February 1820. Further eastward it ascended only to the 62° parallel and continued its way along the edge of the floating ice. Then, on the meridian of the Balleny Islands, Bellingshausen reached 64°55′, in December 1820 reached 161°W, passed the southern polar circle and reached 67°15′ S., and in January 1821 reached 69°53′ S. Near the meridian of 81° he discovered the high shore of Peter I Island, and passing further eastward, inside the southern polar circle – the coast of Alexander I. Thus, Bellingshausen was the first to make a complete voyage around Antarctica at latitudes from 60° to 70°.

After that the study of the coast of the continent and its interior began. Numerous explorations were made by British expeditions led by Ernest Shackleton (about them he wrote the book “The Most Terrible Crusade”). In 1911-1912 between the expeditions of the Norwegian explorer Roald Amundsen and the Englishman Robert Scott there was a real race to conquer the South Pole. Amundsen was the first to reach the South Pole, a month after him, Robert Scott’s party arrived at the cherished point and died on the way back.

Since the middle of the XX century the study of Antarctica on an industrial basis began. Numerous permanent bases were established on the continent by different countries, conducting meteorological, glaciological and geological research all year round. December 14, 1958 the third Soviet Antarctic expedition, led by Evgeny Tolstikov, reached the South Pole of Inaccessibility and founded there a temporary station “Pole of Inaccessibility.

Population

Because of the harshness of the climate, Antarctica has no permanent population. However, scientific stations are located there. The temporary population of Antarctica varies from 4,000 people in summer (Russians about 150) to 1,000 people in winter (Russians about 100).

Antarctica is assigned a top-level Internet domain of .aq and a telephone prefix of +672.

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