Antarctica
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| surface | 14,000,000 km² |
|---|---|
| population | 1106 (mainly scientists and tourists ) |
| Population density | 0.0001-0.0003 inhabitants / km² |
| countries | no |
| Regions | West Antarctica , East Antarctica |
Antarctica (from ancient Greek ἀνταρκτικός antarktikos , the Arctic over ') is the South continent of the Earth that is also the South Pole is itself. It is located in the middle of the Antarctic (zone beyond 66.6 ° latitude ), with which it is often identified in everyday language. Further names are the southern continent and the Antarctic continent . Antarctica has an area of about 14 million square kilometers and is almost completely covered by the Antarctic ice sheet . Geographically one differentiates between the regions West Antarctica and East Antarctica .
The existence of an undiscovered southern continent has been suspected since ancient times and it was called Terra Australis ("southern land"). With the exploration of the southern Pacific , New Zealand and Australia by Abel Tasman in the 17th century and James Cook in the 18th century, its possible location was restricted to the high southern latitudes. However, the pack ice of the Southern Ocean and the extreme weather conditions made exploring this region impossible for a long time.
It was not until the end of the 19th century that discoveries made it clear that the interior of the southern polar region, for which the name Antarctica was coined, actually contained land of continental proportions.
Surname
Antarctica has the same linguistic root as Antarctica: Greek ἀνταρκτικός antarktikos , "the Arctic over". “Arctic” is derived from the ancient Greek word Άρκτος arktós for “bear”, which goes back to the constellation Great Bear . There is no comparable polar land mass in the Arctic.
In German usage , however, the name Antarctica became uncommon, especially after 1920, unlike in other languages. Instead, it became established to use “Antarctica” to refer to both the entire southern polar region and the continent within.
The double meaning of the word Antarctica results in a lack of distinction between region and continent. This was criticized among others by the German polar researcher and marine biologist Leonid Breitfuß in 1946 in the journal Polarforschung . He called for the terms to be differentiated as is customary in other languages and to continue to use Antarctica for the region, but the name Antarctica for the continent.
geography
Antarctica is entirely south of the 60th southern latitude and the Southern Ocean surrounding it. In addition to the Antarctic mainland, the continent includes numerous offshore islands on the continental shelf as well as the numerous shelf tables .
The northernmost point of the Antarctic mainland is Prime Head 23 km northwest of Hope Bay in the north of the Antarctic Peninsula , at 61 ° 0 '3.6 "S. The northernmost point of the Antarctic continent is on one of the tiny Seal Islands (at 60 ° 56 ′ 5 ″ S), one of the numerous offshore sub-Antarctic islands , around eight kilometers north of Cape Yelcho , the northern point of Elephant Island , one of the South Shetland Islands . The southern Orkney Islands , which are still further north, are generally no longer counted as part of the continent of Antarctica, although they are still completely south of the 60th parallel south.
The southernmost point of the continent is the geographic South Pole in East Antarctica .
The closest larger land masses are Tierra del Fuego at the southern tip of South America , followed by Cape Agulhas in South Africa and the islands of Tasmania and New Zealand .
West and East Antarctica
The continent of Antarctica is divided into the subcontinent West Antarctica , which lies mostly west of the meridian of Greenwich and east of the 180th longitude, and East Antarctica , which lies east of the meridian of Greenwich and west of the 180th longitude. The two large landscapes are geographically divided by the Transantarctic Mountains .
West Antarctica
West Antarctica has a rugged surface, divided into several peninsulas, which is mainly covered with an ice sheet. The climate is more oceanic, which is why the temperatures are not as extremely low as in East Antarctica.
East Antarctica
The surface of East Antarctica consists of a single, huge ice sheet. The climate is continental and only slightly influenced by the sea, which leads to extreme temperatures of up to −89.4 ° C (measured on July 21, 1983).
- Adélieland
- American highlands
- Antarctic dry valleys
- Coatsland
- Enderbyland
- Gamburzew Mountains
- Kaiser-Wilhelm-II.-Land with Gaußberg
- Queen Maud Land
- New Swabia
- Polar plateau
- Princess Elizabeth Land
- Prince Charles Mountains
- Victoria Land
- Wilkesland
In addition to the South Pole, East Antarctica also has the center of the continent, which is known as the “ South Pole of Inaccessibility ”.
Islands
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Some of the islands of Antarctica are completely surrounded by the sea, others are connected to the continent via the ice shelf, so that their island character is only recognizable under the ice. Some of the islands are of volcanic origin.
Some islands off the coast of Antarctica and in the Southern Ocean:
- Alexander I Island (the largest island in Antarctica)
- Berkner Island (second largest island in Antarctica, completely enclosed by the Filchner-Ronne Ice Shelf)
- Joinville Islands
- Roosevelt Island (largest island in the Ross Ice Shelf)
- Ross Island (southernmost island that can be reached from the sea)
- South Shetland Islands
- Thurston Island (third largest island in Antarctica)
Mountains
The mountains of Antarctica, especially inland, are partly completely buried under the ice sheet (subglacial mountains, up to 3500 m high). However, there are also mountains that are not or only partially covered by the ice sheet.
The highest mountain in Antarctica is Mount Vinson (4892 m), located in the Sentinel Range in West Antarctica. The second highest mountain range is the Queen Alexandra Range in East Antarctica with the 4528 m high Mount Kirkpatrick .
There are also volcanoes in Antarctica that are partly extinct and partly active. At 4181 m the highest is the extinct Mount Sidley in the Executive Committee Range . The 3794 m high Mount Erebus , which is located on Ross Island in the west of the Ross Sea , is the southernmost active volcano on earth.
The volcanic island of Deception Island has the only known thermal springs in Antarctica.
particularities
Antarctic ice sheet
- shades of blue show the ice thickness in steps of 1000 m
- thick lines: ice divisions
- thin lines: flow lines of the ice
- turquoise: ice shelf
- red: land not covered by ice
The most striking feature of the Antarctic continent is that it is almost completely frozen. The Antarctic Ice Sheet is the largest ice mass on earth. Around 90% of the earth's ice and 70% of the world's freshwater reserves are contained in the ice sheet , which is up to 4500 m thick . A comparable large-scale glaciation on earth is currently only found in Greenland .
Only around 280,000 km² of the continent are ice-free, which corresponds to around two to three percent of the total area. The thickest layers of ice are in Marie-Byrd-Land in the western part. Only about 400 km from the coast there is a deep subglacial ditch at this point, above the bottom of which the ice rises 4776 m high. The thinnest layers of ice can be found over the up to 3500 m high subglacial mountains in the interior of the continent.
When the Antarctic ice sheet formed a few million years ago, the continent subsided due to the enormous weight of the ice masses in the earth's crust. If the ice melts, it is expected that the land will rise again. At the same time, if the sea level melted completely, it would rise by around 61 meters.
The ice is in constant flow from the inland towards the coasts. Geographical lines on which the ice flows in different directions are called ice divides , analogous to watersheds .
The ice accumulation and outflow are not exactly in balance. While the ice sheet increased an average of 112 billion tons between 1992 and 2001 and grew 82 billion tons between 2003 and 2008, Antarctica lost around 183 billion tons of ice per year between 2008 and 2015, and the trend is rising. This is known as glacial melt . The Antarctic Peninsula in particular is currently affected by the retreat of glaciers. The loss of ice became particularly dramatic when large parts of the Larsen Ice Shelf dissolved .
The Glaciology studies the structure, history and the internal dynamics of the ice sheet. The aim of the investigations is to understand the future development of the Antarctic and the influence of possible changes on the world climate. The most important findings are obtained from the investigation of ice cores .
"Land" under and over the sea
The freshwater ice of Antarctica forms the majority of the “land” surface and is therefore included in the continent. Large parts of Antarctica are below sea level, but are covered in ice to above sea level and are commonly considered part of the continent.
The deepest point is the Bentley subglacial rift, located 2,496 m below sea level, in West Antarctica ( 80 ° 19 ′ S , 110 ° 5 ′ W ). It is considered to be the deepest non-submarine point on earth.
Without the ice cover, the contours of the continent would look completely different from what they are usually shown. West Antarctica would be divided into three large parts: the Antarctic Peninsula , Marie Byrd Land, and the Vinson Massif . East Antarctica would consist of a land mass with huge bays (e.g. Aurora Subglacial Basin and Wilkes Subglacial Basin ) and fjords (e.g. at the site of today's Amery Glacier or under the South Pole). The East Antarctic land mass would be littered with many lakes and inland seas, the bottom of which sometimes extends far below sea level.
Lakes under the ice
In Antarctica there are lakes of liquid water under the ice called subglacial lakes . These consist primarily of fresh water.
To date, more than 150 subglacial lakes have been found. The largest of these is Lake Vostok , which was discovered in 1996 by satellite imagery near the Russian Vostok station . It is about 250 km long, 50 km wide, has a water depth of up to 1200 m and lies at a depth of 3700 to 4100 meters under the ice. The fact that the lake is not frozen despite its average temperature of −3 ° C is due to the high pressure of around 30 to 40 megapascals under the ice cover, as the melting point of the ice falls at high pressure .
In addition, there are surface lakes in Antarctica (with surfaces that are partially frozen all year round) such as the Fryxell Lake and hypersaline lakes such as the Don Juan Lake , which is considered to be the most salty body of water on earth with a salt content of over 40%.
Rivers
Another geographical peculiarity of Antarctica is the extensive lack of surface rivers . The largest river in Antarctica, the Onyx River , is a 30 km long meltwater river that only flows during the late Antarctic summer (February, March).
However, it was discovered in 2006 that the subglacial lakes are presumably linked by a network of subglacial rivers and that pressure equalization and water transport take place between them. The subglacial rivers are partly above and partly below sea level.
Discovered in 1911, the red-colored Blood Falls consist of iron-containing hypersaline water that comes from a subglacial lake.
Antarctic oases
As Antarctic oasis large are (largely) designated ice-free regions in Antarctica. The largest Antarctic oases are formed by the dry valleys in Victoria Land. Antarctic oases are rocky and often contain freshwater lakes. The Antarctic flora and fauna can be explored in these areas. They are also important for finding fossils.
Examples:
Glaciers and ice streams
The Antarctic ice sheets are constantly moving towards the coasts of the Southern Ocean. There are areas in which the ice moves significantly faster than in adjacent areas, these are called ice flows . They are a special form of glacier .
The ice streams can be hundreds of kilometers long, 50 km wide, 2 km high, and their speed can be up to 1000 meters per year. At the edges of the ice streams, shear forces occur that deform the ice and make it softer. Numerous crevasses form there .
Most of Antarctica's ice flows are called glaciers, but not every glacier is an ice flow. Where ice streams flow into the sea, glacier tongues ("ice tongues") can protrude far into the sea.
Examples:
- Lambert Glacier - around 400 km long and 100 km wide, the longest and largest glacier in the world, the most important ice flow in East Antarctica
- Denman Glacier - at 3500 meters below sea level, the deepest point on any continent on earth
- Axel Heiberg Glacier - discovered in 1911 by Roald Amundsen , who was the first person to reach the South Pole via him on December 14, 1911
- Beardmore Glacier - Robert Falcon Scott reached the South Pole via it on January 18, 1912
- Pine Island Glacier - the most heavily draining glacier in West Antarctica
- Mertz Glacier - its tongue was rammed by the iceberg B-9B in February 2010 and then broke in two
Ice shelf
About 44% of Antarctica's coastline is ice shelf . These are freshwater ice sheets from 100 to 1000 meters thick that do not rest on land, but float as a rigid structure on the sea water. They are fed by glaciers and are firmly connected to them. The glacier ice glides over the continental rock until, from a certain point, the touchdown line , seawater flows under it. From this line on it is called an ice shelf and pushes out into the sea as a continuous plate. Icebergs of various sizes continually break off at its edge ; this is known as " calving ". Large icebergs originating from ice shelves, which are typical for Antarctica, are called tabular icebergs because of their flat shape.
The largest Antarctic ice shelves include:
- Amery Ice Shelf
- Filchner-Ronne Ice Shelf
- Fimbul Ice Shelf
- George VI Ice Shelf
- Larsen Ice Shelf
- Riiser Larsen Ice Shelf
- Ross Ice Shelf
- Shackleton Ice Shelf
- West Ice Shelf
- Wilkins Ice Shelf
In contrast to the ice shelf, the saltwater pack ice that surrounds Antarctica over a large area, especially in winter, is not included in the continent.
By definition, the ice shelf areas are included in the continent. The exact position of their touchdown lines is difficult to determine and map, as is their constantly changing breakoff edges. As large icebergs calve, the contours of the continent and its size are constantly changing. The largest continuous iceberg measured to date, which was sighted in 1956, had dimensions of 335 km × 97 km and an area of about 31,000 km², making it larger than Belgium.
geology
Today, Antarctica lies in the center of a continental plate ( Antarctic plate ) and is surrounded on all sides by mid-ocean ridges . Only the South Shetland Islands off the Antarctic Peninsula are on their own microplate ( Scotia plate ).
East Antarctica in Enderbyland contains the oldest rocks on the continent, at three billion years old, and is a Precambrian craton that has not undergone any significant transformation in the past 500 million years. West Antarctica is geologically much younger and more heterogeneous. It originated when microcontinents were attached to East Antarctica beginning in the Jurassic . In the middle of the Cretaceous there was a rift , Marie-Byrd-Land moved several hundred kilometers away from East Antarctica and the Bentley Trench was formed . The youngest part of Antarctica is the Antarctic Peninsula. It is a fold of the Andes and was formed 80 to 60 million years ago.
A belt of volcanoes , some of which are still active, stretches through the Antarctic continent, from Victoria Land to Ross Island and Marie Byrd Land to the Antarctic Peninsula , including Mount Erebus , which is almost 3800 m high on Ross Island . This belt is continued on the South Shetland Islands and the Balleny Islands .
Projects that have contributed significantly to the geological exploration of Antarctica include: a. the GANOVEX expeditions of the Federal Institute for Geosciences and Natural Resources , the Polarstern expeditions of the Alfred Wegener Institute and the Cape Roberts Project .
Geological development
For most of the Earth's history , Antarctica was fertile land and free of ice. More than 170 million years ago, Antarctica was part of the land mass of the great continent of Gondwana . On the basis of fossils , the former arrangement of the now separate continents in Gondwana can be reconstructed. The illustration on the right shows this using the reptiles Cynognathus , Mesosaurus and Lystrosaurus as well as the fern Glossopteridales .
In the late Jurassic , Gondwana began to disintegrate. At first, Antarctica and Australia were still connected and together formed a continent of Eastern Gondwana in the chalk . A large part of this double continent was already very far south within the Arctic Circle. However, the earth's climate in the Cretaceous was significantly warmer than today and the South Pole was not glaciated. In the early Cretaceous, 145-100 million years ago, dinosaurs also lived on the continent, for example Cryolophosaurus and Leaellynasaura , as evidenced by fossil finds. The habitat of that time has no equivalent to any existing habitat on earth: The flora and fauna were particularly adapted to the long darkness of the polar night.
For the time after the global mass extinction at the end of the Cretaceous , in the Paleogene , it is assumed that Antarctica was home to a rich marsupial fauna, even if there are so far only few fossil finds to prove this. Even terror birds lived during this time in Antarctica. About 45 million years ago, Antarctica and Australia separated.
Glacial and interglacial
Antarctica in Glacial (Cold Age)
Antarctica in the interglacial (warm period)
About 30 million years ago, with the beginning of the current Neogen Ice Age , the first significant ice fields appeared. Some 25 million years ago, at the turn of the geological ages of Oligocene and Miocene , opened between Antarctica and South America, the Drake Passage . The resulting formation of the circumpolar current intensified the icing process. The forests that had previously covered the continent were displaced. For about five million years, in the Pliocene , the continent was permanently iced, which is still there today. The icing led to the death of almost all plant and land-living animal species in Antarctica and to a worldwide drop in sea levels .
During the freezing period, cold periods (glacials) and warm periods (interglacials) alternate. During the glacial, Antarctic glaciation is much greater than during the interglacial. The sea level also fluctuates according to the varying degrees of glaciation. In the last glacial 18,000 years ago, it was around 135 meters lower than it is today. For about 12,000 years we have been in a warm period, the Holocene , with comparatively little glaciation.
By analyzing ice cores , detailed information about the climate history of the earth could be obtained. The oldest ice core dates go back to 900,000 years and encompass more than eight ice age cycles.
Cartographic representation
Due to the polar position of Antarctica, maps showing this continent usually use a polar azimuthal map . The point of contact of the image plane is in the south pole. Meridians are shown as straight lines emanating from the south pole in a star shape, and circles of latitude as concentric circles around the south pole. There are several such images, e.g. B .:
- the stereographic projection (true to angle and true to circle)
- the gnomonic projection , in which the projection center is in the center of the earth (true to the line)
- the orthographic azimuthal projection (true to length along the parallels)
- the azimuthal equidistant projection (equidistant in the distances from the south pole)
- the azimuthal equal area projection (equal area)
Since with a central mapping of the geographic South Pole, every direction away from there is a northerly one, a different convention is required for a uniform orientation of Antarctic maps. The map is oriented according to a longitude. Often the prime meridian is at the top. This has the advantage that West Antarctica is to the left of East Antarctica. Occasionally, however, the prime meridian is also oriented to the right, so that the western longitudes as angles correspond to the coordinate system commonly used in mathematics (90 ° W above, etc.).
Detailed maps of Antarctica that do not contain the South Pole are often again oriented north upwards.
climate
Due to its polar position on all continents, Antarctica is an extreme climatic case in every respect .
Seasons and lengths of day
Antarctica is characterized by two seasons called winter and summer.
In the Antarctic winter (around March to September) the sun only shines a few hours a day or not at all ( polar night ) , depending on the latitude . In the Antarctic summer (around September to March), on the other hand, it appears almost or actually 24 hours a day ( polar day ) , depending on the latitude, and circles the entire sky to the left. In the transition period the sun shuttles below and above the horizon; these weeks are characterized by twilight. See also the article day length .
Weather
Temperatures
Antarctica is the coldest continent on earth. The domestic annual average temperature is −55 ° C. The monthly mean temperatures vary due to the length of the day. On the polar plateau , temperatures reach between −40 and −68 ° C and on the coast between around −18 ° C in June and a few degrees above zero in the warmest month of January. The lowest temperature ever recorded on earth in the wild is −89.2 ° C, it was recorded on July 21, 1983 by the Soviet Vostok station on the polar plateau.
In December 2013, a new negative record was discovered in satellite measurement data. The data from NASA's "Landsat" satellite, which regularly flies over the southern continent, from August 10, 2010, showed a more than 2000 km long cold valley behind an extensive 3800 meter high mountain ridge: the temperatures there were almost everywhere below −80 ° C . Within the measurement area, in an ice depression, a new cold record of −93.2 ° C was found for that polar night.
The cold record was measured by the satellite directly on the ice, while the old minimum at the Vostok station was two meters above the ground, where it is a little warmer. The height difference between the ground and the air is only one to a maximum of two degrees. Nevertheless, official temperatures are always measured in the air by meteorologists. Thus the new value is considered technically proven, but is not meteorologically accepted.
There are several reasons for the extremely low temperatures in Antarctica:
- Due to the high geographical latitude, the country receives only little solar radiation.
- The Antarctic Circumpolar Current separates the continent from warm ocean currents.
- Snow and ice have a high albedo , which reflects most of the sun's energy.
- The low air temperatures result in extremely low humidity. Since water vapor is the most effective way of preventing heat radiation, the land loses a great deal of heat to space.
- Antarctica is the continent with the highest average elevation.
- Over the poles, the troposphere is only 8 km thick.
Rainfall and winds
Usually the Antarctic precipitation is snow . The annual average is a little over 40 l / m² in the interior of the continent. According to the precipitation-oriented definition, these areas are therefore a desert - the largest in the world. However, the snowfall increases significantly towards the coast.
The polar position and the katabatic downdraft winds blowing from the polar plateau to the coast not only have a determining effect on the continent itself, but also on the adjacent polar sea. In July 1972 a wind speed of 327 km / h (91 m / s) was measured at the Dumont-d'Urville station .
Flora and fauna
While the Southern Ocean and the huge pack ice zone that surrounds Antarctica, as well as the offshore islands are full of life, the interior of the continent is barren and empty, as hardly any more highly developed life forms are found here. Instead, these areas are predominantly populated by microorganisms , mosses and lichens, as well as some invertebrates. But these ecosystems are unique on earth. On the one hand there are very extreme environmental conditions, on the other hand the region is - due to the former - still largely free from human influences.
An unusual and at the same time very simple ecosystem can be found in the dry valleys near the McMurdo station , which is predominantly populated by microorganisms, mosses and lichens and a few invertebrates. Due to the few organisms that occur, the connections and mutual relationships as well as their adaptation to extreme living conditions can be examined very comprehensively.
Surprisingly, it was found that life is not only limited to the few ice-free regions, but can also be detected in unexpected places. In the dry valleys, for example, algae and lichens have been found that live within sandstone rocks . Even in the vast expanse of the Antarctic ice sheet, various algae and other organisms have been found in smaller ice crevices and meltwater lakes on the glaciers.
flora
Together with the neighboring areas, Antarctica forms its own flora kingdom , the Antarctic flora kingdom . It includes Antarctica, the South Island of New Zealand and the southwestern part of Patagonia and is home to 13 different plant genera , such as the southern beech ( Nothafagus ), Gunnera or Fuchsia , most of which, however, are not native to Antarctica itself.
There are only two indigenous flowering plants in the entire Antarctic: the Antarctic Schmiele ( Deschampsia antarctica ) and the clove family Antarctic Perlwurz ( Colobanthus quitensis ). The creeping buttercup ( Ranunculus repens ), the water sedge ( Carex aquatilis ), the bluegrass Poa annua and Poa pratensis and the chickweed ( Stellaria media ) were also introduced by humans .
In addition to various algae , more than 200 types of lichen, more than 100 types of moss and liverwort and about 30 macrofungi have been found.
fauna
Character animals of Antarctica are the penguins , sea birds that only come ashore to breed. Of the 18 penguin species, however, only five breed on Antarctica and its immediately offshore islands, the largest species emperor penguin , the Adelie penguin , the gentoo penguin , the chinstrap penguin and the golden crested penguin, the last three species only on the Antarctic peninsula. Other breeding birds on the Antarctic mainland are the snow petrel , the Antarctic petrel , the Antarctic skua ( Stercorarius maccormicki ), the Dominican gull and the white-faced sheath-beak (also here the last two species only on the Antarctic peninsula).
Live on the coast and on islands four seal species , all from the family of earless seals (Phocidae), the crab-eater , with several million copies one of the individuals most large animal species on Earth, the Weddell , who lives further south than any other mammal, the leopard seal , a Predator of the penguins, and the rare horse seal , which is the smallest Antarctic seal. The largest seal, the southern elephant seal, is only found on Antarctic islands. The seals mate and raise their pups on land or on the pack ice.
A 12 millimeter large, wingless species of mosquito called Belgica antarctica is one of the only two Diptera species that live on the islands surrounding the mainland. Only about 0.5% of the continental area is ice-free. These areas include so-called nunataks , e.g. B. in Queen Maud Land or in the Prince Charles Mountains , but on the other hand also ice-free areas at lower altitudes, the Antarctic dry valleys . Not all ice-free areas are inhabited by life. This is probably due, on the one hand, to the fact that the environmental conditions are often too harsh to allow life. On the other hand, these areas are very isolated, and it is therefore possible that life could not spread over hundreds of kilometers of ice. The characteristic fauna of the ice-free inland areas include roundworms , mites and tardigrade . The largest land-dwelling animals in the ice-free inland areas are various species of springtails .
history
Since the continent was discovered very late in the course of human history and has been explored in recent times, but not settled, history is comparatively uneventful. The chronological table of human history offers a chronological and geographical overview .
Assumptions and approximation
Long before the discovery of Antarctica in 1820, the existence of a vast southern continent was assumed to act as a counterweight to the land masses of the northern hemisphere. This continent called Terra Australis is depicted on numerous world maps from the early modern period . Since some of these representations, for example the map by Piri Reis from 1513, the map by Orontius Finaeus from 1531, the map from Gerhard Mercator from 1569 or the map from Philippe Buache from 1754, show certain similarities with the actual location and shape of Antarctica, there are authors who suspect that the continent was discovered long before the official date of 1820. However, especially for the map by Piri Reis, this is neither the only nor the most plausible possible interpretation.
However, the world map by Samuel Dunn (1794) contradicts an earlier assumption of an Antarctic continent. The map shows a Southern Icy Ocean that extends to the South Pole.
In fact, there is no evidence of human presence in Antarctica before the 19th century. However, voyages of discovery have already been undertaken in the southern polar region, for example the southern Shetland Islands were probably discovered as early as 1599 by Dirck Gerritz Pomp or Gabriel de Castilla in 1603. James Cook crossed the Southern Ocean between 1772 and 1775 and was probably the first person to cross the Arctic Circle in 1773 , but pack ice prevented him from seeing Antarctica himself.
Discovery and polar exploration
The first sighting of Antarctica cannot be linked to an event with absolute certainty: Captain Fabian von Bellingshausen of the Russian Navy , Captain Edward Bransfield of the British Navy and the American seal hunter Nathaniel Palmer sighted Antarctica within a few days or weeks, probably Bellingshausen on January 16, Jul. / January 28, 1820 greg. the first. The first landing took place just a year later by the American seal hunter John Davis on February 7, 1821. In good weather conditions, the English navigator James Weddell was able to advance to 74 ° 15 ′ south in the Weddell Sea named after him in 1823 . The French king then commissioned Jules Dumont d'Urville to break this record, but his trip from 1837–1838 was only successful on the second attempt when he sighted the Adelie land.
After the Arctic magnetic pole was located in 1831 , James Clark Ross set off for the Antarctic magnetic pole in 1839 with his ships HMS Erebus and HMS Terror . While looking for it, Ross was able to determine its approximate position, but could not reach it. He also mapped the Ross Sea , a lake region that was later named after him.
The actual conquest of Antarctica began in 1895 with the 6th International Geographical Congress, which took place in London's Imperial Institute. On August 3rd, a resolution was passed at this congress calling on the world's scientists to undertake expeditions: "The exploration of the Antarctic regions is the greatest piece of geographical exploration still to be undertaken". At a time when the whole world seemed to be discovered, Antarctica was felt to be the last unknown part of the world, and the conquest of this part of the world became a metaphor for the triumph of imperialism . With this in mind, Leonard Darwin , President of the Royal Geographical Society , said during a farewell dinner for Robert Falcon Scott before he left for his Antarctic expedition : “ Scott is going to prove once again that the manhood of our nation is not dead and that the characteristics of our ancestors who won the Empire still flourish among us. "
Until 1900, only the Belgica expedition led by Adrien de Gerlache de Gomery and the Southern Cross expedition led by Carsten Egeberg Borchgrevink took place. Scott's first Antarctic expedition ( Discovery Expedition 1901-1904) approached the South Pole to within 480 miles.
Simultaneously with Scott Otto Nordenskjöld led the Swedish Antarctic Expedition and Erich von Drygalski led the first German south polar expedition, the Gauss expedition . Equipped with the Gauß ship , the researchers discovered Kaiser Wilhelm II Land and sighted the Gaußberg from the basket of a tethered balloon .
The Nimrod Expedition (1907-1909) of Ernest Shackleton , a former member of Scott's crew, approached the South Pole within 97 miles before it was forced to turn back.
On December 14, 1911, Roald Amundsen was the first to reach the South Pole as part of the Norwegian Fram expedition . It wasn't until a month later that Robert Falcon Scott and his companions arrived at the pole, even though they had landed in Antarctica first. Scott was stopped on his way back by a snow storm - he and all his companions died in the cold (see Terra Nova Expedition ).
In addition to Amundsen, Scott and Shackleton, Douglas Mawson is the fourth great Antarctic explorer of this time. He was only a member of the Nimrod Expedition, led by Shackleton, before he led the Aurora Expedition to Antarctica from 1911 to 1914 .
The second German south polar expedition, led by Wilhelm Filchner, discovered the Filchner-Ronne-Ice Shelf and the Prinzregent-Luitpold-Land in 1912 with the expedition ship Deutschland, which was trapped in the pack ice for nine months .
One of the most legendary expeditions in Antarctica, however, is the Expedition Endurance , which began in 1914 and had the goal of crossing Antarctica, but just like the expedition ship Deutschland was trapped in the pack ice.
Systematic exploration from the air
A new era of Antarctic discovery began in 1928 with the expeditions of the American Richard Evelyn Byrd and the Australian Hubert Wilkins . Wilkins became the first person to fly over the Antarctic Peninsula on December 20, 1928. On the second Wilkins-Hearst expedition, Wilkins and other pilots were able to complete several flights over the Antarctic mainland between December 1929 and January 1930. However, Byrd was able to achieve greater success on his first of five Antarctic expeditions when the Floyd Bennett aircraft, controlled by Bernt Balchen , reached the South Pole on November 29, 1929.
In his explorations, Byrd put the main focus on research . In Operation Highjump , which took place from December 1946 to April 1947 , the largest Antarctic expedition of all time, Byrd brought 4,700 people, 13 ships and 23 aircraft to the Little America base in McMurdo Sound and had more than 70,000 aerial photographs taken . Byrd's expeditions laid the foundation for modern mapping and exploration of the continent.
In the southern summer of 1938/39 the German Reich sent an expedition to the Antarctic under the direction of the experienced polar captain Alfred Ritscher . The aim was to explore the coastal areas of a previously barely explored sector of Antarctica for commercial whale hunting. The chosen ship was the Schwabenland catapult ship , the floating aircraft base of Lufthansa , from which Dornier whale- type flying boats weighing 10 t could take off with the help of steam catapults . Lufthansa has been using this revolutionary technology for mail with South America since 1934. The Schwabenland was made ready for the expedition to the Antarctic in the fall of 1938 in Hamburg shipyards. After the reconstruction of the Schwabenland (it had previously been used mainly in tropical waters ), she left Hamburg on December 17, 1938 and reached Antarctica on January 19, 1939. In the following weeks, the two flying boats Boreas and Passat made almost 600,000 flights km² overflown and documented by 11,600 oblique aerial photographs . The dropping of aluminum poles with national emblems at the turning points of the flight polygons should form a basis for German sovereignty claims . The newly discovered land was after the expedition ship Swabia as Neuschwabenland referred.
1950s until today
In 1952 there was the first and so far only fighting over territorial claims: In 1952, Argentine soldiers shot at British researchers when they tried to rebuild a destroyed research station. Argentina claimed the Antarctic Peninsula, as this headland is only about 1480 km away from the southern tip of South America at its northern end.
After Amundsen and Scott, a person was not standing on the South Pole again until October 31, 1956, when the American Rear Admiral George J. Dufek landed there in an R4D Skytrain aircraft .
A large number of expeditions took place during the International Geophysical Year 1957-1958. Among others, a team reached to the New Zealander Sir Edmund Hillary with converted tractors first after Scott overland to the South Pole, where on January 20, the team led by the British Vivian Fuchs on Shackleton's route added poked and researchers together as British Commonwealth Transantarctic Expedition to completed the first crossing of the Antarctic on March 2nd. In addition, on December 14, 1958, a Soviet expedition reached the south pole of inaccessibility and set up a research station there, which was operated until December 26.
Reinhold Messner and Arved Fuchs were able to cross the entire continent on foot for the first time from November 13, 1989 to February 12, 1990 in 92 days via the South Pole. In 2001, the two Antarctic adventurers Ann Bancroft and Liv Arnesen followed them on skis.
Political status
Antarctica is not a separate state. Different nations have raised territorial claims, some of which overlap. Currently seven nations are making claims to eight territories in Antarctica: Argentina , Australia , Chile , France , New Zealand , Norway and the United Kingdom :
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Argentine Antarctic Territory |
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Australian Antarctic Territory |
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Chilean Antarctic Territory |
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Adélieland , district of the French Southern and Antarctic Lands |
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Ross Sub-Area ( New Zealand ) |
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Queen Maud Land , Peter I Island |
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British Antarctic Territory |
The Marie Byrd Land , located in West Antarctica between the Chilean and New Zealand claimed territory is claimed by any country.
In 1961 the Antarctic Treaty came into force, which excludes all territorial claims made until then and grants all interested nations free access for scientific purposes. The Antarctic Treaty was supplemented by additional protocols in order to guarantee the protection of natural resources for the future. The Antarctic Treaty prohibits economic activities other than research and tourism. Tourism has grown significantly in recent years, and the largest employer in Antarctica is the Raytheon Polar Services Company , which is responsible for the US stations . The Antarctic Treaty will expire in 2041.
Since Antarctica is neither a state nor a government, the continent does not have its own flag . However, recently there have been some attempts to create a flag for Antarctica. The two relatively popular proposals come from Graham Bartram and Whitney Smith .
Flag proposed by Graham Bartram
Flag proposed by Whitney Smith
Flag of the Antarctic Treaty
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population
Antarctica has no real population. However, around 4,000 people live in the over 80 research stations in summer and around 1,000 in winter, although the exact number varies greatly. At the largest station alone, the McMurdo station , there were 79 women and 162 men in July 2005 (in the middle of the Antarctic winter).
On January 7, 1978 in Argentina's Esperanza Base near Hope Bay with Emilio Palma the first baby born on the Antarctic mainland. In 1986/1987 a boy and a girl were born in the Chilean town of Villa Las Estrellas . The first sacred buildings have existed in Antarctica since 1956 . The Buromski Island cemetery, now towered over by a Russian Orthodox cross, is one of the protected Antarctic monuments with over 60 people buried there .
Research stations and zone times
According to COMNAP , there are 82 research stations in the southern area within the 60th parallel , 37 of which are in use all year round and 36 stations only in the summer months.
The American stations Palmer and McMurdo , whose ports form the logistical basis of most activities in the Antarctic, as well as the Amundsen-Scott South Pole Station and, from the German point of view, Neumayer Station III, deserve special mention .
Antarctica has no defined time zones . It has been proposed to put all of Antarctica under a single time zone, UTC . In practice, the individual research stations often use the time zone of their respective home country or the time zone of the airport with which they are logistically closely connected, for example the US stations use New Zealand time. UTC is used in the mutual communication between the stations, as is usual with amateur and aviation radio.
Since the time zone situation is unclear, it is also unclear whether the date line extends along the 180th degree of longitude to the South Pole, or whether it ends at the Arctic Circle .
Infrastructure and communication
Most of the transportation of people and material is done by air with planes and helicopters. 27 stations have flight strips and / or heliports. The slopes consist partly of gravel, partly of ice or compressed snow. One runway is longer than three kilometers and six others are between two and three kilometers long. The mainland stations are mainly supplied by Lockheed C-130 Hercules aircraft belonging to the New York Air National Guard . In December 2007, civil scheduled flights to Casey Station began .
The US Navy maintains two seaports , McMurdo and Palmer , but their use is strictly regulated by the US government. There are also anchorages off the coast, from where goods are brought ashore by smaller boats, barges or helicopters to coastal stations.
There are few, poor quality and often snow-drifted roads in Antarctica. The most important longer route is the 1,500-kilometer South Pole Traverse , which was completed in 2006/2007 and connects the American stations McMurdo on the coast and Amundsen-Scott on the South Pole. It was built by leveling snow and filling crevasses. Land transport is carried out with tracked vehicles, in the past with dog sleds, and on foot with skis or snowshoes.
Apart from military communication channels and amateur radio , the Iridium system can be used.
Although Antarctica is not a state, the continent has its own country-specific top-level domain " .aq ", as well as the ISO codes AQ, ATA and 010. Postcodes are divided into 3 different systems, depending on the state to which the territories belong: British Antarctic Territory : BIQQ 1ZZ, Australian Antarctic Territory: 7151. ZIP code for McMurdo Station: 96599, full address: PSC 469 Box 700, APO AP 96599-1035, (optional :) Antarctica. However, the address “McMurdo Station, Air Post Office, Private Bag 4747, Christchurch 8140, New Zealand” does not route via the USA. The Amundsen-Scott South Pole Station has the US ZIP code 96598.
Natural resources
So far, various ore minerals of non-ferrous metals , industrial minerals and precious metals have been found in Antarctica . Such finds of ore minerals in mostly insignificant concentrations have been summarized by various authors into maps of the "Mineral Resources of Antarctica". Deposits in the mining sense are only formed by coal deposits in the Transantarctic Mountains and the Prince Charles Mountains , as well as iron ores in the Prince Charles Mountains.
In the southern Transantarctic Mountains and the Queen Alexandra Range between 10 and 30 seams with thicknesses of 0.1 to 3.6 m occur; one seam even reaches a thickness of 11 m locally. It is gas coal with an average ash content of 11%. In the Permian sedimentary basin around Beaver Lake in the Prince Charles Mountains, 63 seams with a thickness of 0.1 to 2.2 m have been counted, 17 of which are over 0.7 m thick. The total known reserves amount to 16.9 billion tons, other reserves under the ice are assumed in the order of a few hundred billion tons of coal.
The iron ore deposits of the Prince Charles Mountains are exposed at Mount Ruker , they can be traced under the ice as 5 to 10 km wide magnetic anomalies over more than 120 km. With iron oxide (FeO) contents of 33.7 to 57.4%, the quality of these ores is below the deposits currently considered worth building worldwide.
In general, the estimates of the raw material potential of Antarctica are based on statistical extrapolations in which the average frequency of certain raw materials in the continents formerly neighboring Gondwana Australia, India, southern Africa and South America are compared to the area of Antarctica. According to this, around 45 billion barrels of oil and 326 trillion cubic meters of natural gas would be expected in the sedimentary basins of Antarctica and on the continental shelf. However, none of these theoretically expected deposits has yet been discovered.
The environmental protection protocol to the Antarctic Treaty of 1991 forbids the prospecting , development or extraction of mineral resources in the Antarctic. This mining moratorium can only be implemented 50 years after it came into force, i.e. H. in 2041, to be renegotiated by a three-quarters majority of the consultative states of the Antarctic Treaty.
Web links
Wikinews: Antarctica - In The News
- Database of indexed literature on the social, political and economic situation in Antarctica
- deutschlandfunk.de , Wissenschaft im Brennpunkt , January 1, 2018, Dagmar Röhrlich : Survival under ice
literature
- German Research Foundation: German research in the Antarctic. Scientific progress and perspectives. Wiley-VCH, Weinheim 2005, ISBN 3-527-31251-X .
- John May: The Greenpeace Book of Antarctica. Ravensburger Buchverlag, Ravensburg 1991, ISBN 3-473-46166-0 .
- Norbert W. Roland: Antarctica. Research in the Eternal Ice. Spektrum Akademischer Verlag, Heidelberg 2009, ISBN 978-3-8274-1875-3 .
Individual evidence
- ^ Duden online: Antarctica
- ^ Bertelsmann: the new Universal Lexicon. Wissenmedia Verlag, Gütersloh 2006, p. 247 .
- ↑ Google Ngram Viewer "Antarctica"
- ^ Leonid Breitfuß : Antarctica - Antarctica. In: Polarforschung , Volume 16, 1946, p. 102 ( PDF ).
- ↑ If polar ice caps melted how much would the oceans rise? , HowStuffWorks
- ^ Rob Garner: NASA Study: Mass Gains of Antarctic Ice Sheet Greater than Losses . In: NASA . October 30, 2015 ( nasa.gov [accessed January 23, 2018]).
- ↑ Alex S. Gardner et al .: Increased West Antarctic and unchanged East Antarctic ice discharge over the last 7 years . In: The Cryosphere . tape 12 , 2018, p. 521-547 , doi : 10.5194 / tc-12-521-2018 .
- ↑ Antarctica in Context (PDF; 9.5 MB)
- ↑ phase diagram of water , (engl.)
- ↑ Polar Times, Volume 43, p. 18 ( online version (reprint) from USA Today )
- ↑ Georg Kleinschmidt (1999) The plate tectonic role of the Antarctic. Carl Friedrich von Siemens Stiftung, Munich, 85 p. ( Pdf 14 MB )
- ↑ Why is Antarctica so cold? Information from www.antarcticconnection.com ( Memento from January 8, 2007 in the Internet Archive )
- ↑ New findings on the genetic diversity of a virus community in an Antarctic lake. Universidad Autónoma de Madrid, November 11, 2009.
- ↑ Alberto López-Bueno u. a .: High Diversity of the Viral Community from an Antarctic Lake. In: Science. November 6, 2009, Vol. 326. no. 5954, pp. 858-861, abstract, accessed December 26, 2009
- ↑ Christoph Zinsius: The fauna of the Antarctic. July 23, 2013, accessed April 23, 2019 .
- ↑ Gerald Tuck, Hermann Heinzel: The sea birds of the world. Parey, Hamburg / Berlin 1980, ISBN 3-490-07818-7 .
- ^ Rüdiger Wandrey: Wale and Seals of the World . Franckh-Kosmos Verlag, 1997, ISBN 3-440-07047-6 .
- ^ Peter Convey, John AE Gibson, Claus-Dieter Hillenbrand, Dominic A. Hodgson, Philip JA Pugh, John L. Smellie, Mark I. Stevens: Antarctic terrestrial life - challenging the history of the frozen continent? In: Biological Reviews 83 (2), 2008, pp. 103-117, doi: 10.1111 / j.1469-185X.2008.00034.x
- ^ Samuel Dunn Wall Map of the World in Hemispheres (1794)
- ↑ Hubert Wilkins on southpole.com. Retrieved June 24, 2011.
- ^ Eugene Rodgers: Beyond the Barrier: The Story of Byrd's first Expedition to Antarctica . 1st edition. United States Naval Institute, Annapolis 1990, ISBN 0-87021-022-X , pp. 186 .
- ↑ www.polar.org ( Memento from September 21, 2005 in the Internet Archive )
- ↑ HSM 9: Buromsky Island Cemetery in the Antarctic Protected Areas Database on the Antarctic Treaty Secretariat website (English, Spanish, French, Russian), accessed November 16, 2019
- ↑ Time zones of all and especially Australian ( Memento from September 18, 2006 in the Internet Archive ) stations.
- ^ British Antarctic Territory Postal Codes postal-codes.net, February 5, 2014, accessed February 10, 2019.
- ^ APO = Army / Air Force Post Office. See: en: Military mail
- ↑ Bertrand Imbert: The Poles. Expeditions into the eternal ice. Ravensburger Buchverlag, Ravensburg 1990, ISBN 3-473-51005-X , p. 175.
- ↑ The Fischer World Almanac. 1998, Map XVI, Fischer Taschenbuch Verlag, Frankfurt am Main 1997, ISBN 3-596-19098-3 .
- ↑ GI Kameneva, YV Mikhal'skiy: Major features of the distribution of coal-bearing deposits in Antarctica. In: Antarctica. Volume 24, Leningrad 1985, pp. 65-75.
- ↑ Central Intelligence Agency: Polar Regions. Atlas. National Foreign Assessment Center.
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