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The geography of Antarctica is dominated by its south polar location and, thus, by ice. The Antarctic continent, located in the Earth's southern hemisphere, is centered asymmetrically around the South Pole and largely south of the Antarctic Circle. It is washed by the Southern Ocean or, depending on definition, the southern Pacific, Atlantic, and Indian Oceans. It has an area of more than 14 million km2. Antarctica is the largest ice desert in the world.
Lake Vostok is the largest of Antarctica's almost 400 known subglacial lakes. Lake Vostok is located at the southern Pole of Cold, beneath Russia's Vostok Station under the surface of the central East Antarctic Ice Sheet, which is at 3,488 m (11,444 ft) above mean sea level. The surface of this fresh water lake is approximately 4,000 m (13,100 ft) under the surface of the ice, which places it at approximately 500 m (1,600 ft) below sea level.
An ice shelf is a large floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Ice shelves are only found in Antarctica, Greenland, Northern Canada, and the Russian Arctic. The boundary between the floating ice shelf and the anchor ice that feeds it is the grounding line. The thickness of ice shelves can range from about 100 m (330 ft) to 1,000 m (3,300 ft).
Vostok Station is a Russian research station in inland Princess Elizabeth Land, Antarctica. Founded by the Soviet Union in 1957, the station lies at the southern Pole of Cold, with the lowest reliably measured natural temperature on Earth of −89.2 °C. Research includes ice core drilling and magnetometry. Vostok was named after Vostok, the lead ship of the First Russian Antarctic Expedition captained by Fabian von Bellingshausen. The Bellingshausen Station was named after this captain.
The Amundsen Sea is an arm of the Southern Ocean off Marie Byrd Land in western Antarctica. It lies between Cape Flying Fish to the east and Cape Dart on Siple Island to the west. Cape Flying Fish marks the boundary between the Amundsen Sea and the Bellingshausen Sea. West of Cape Dart there is no named marginal sea of the Southern Ocean between the Amundsen and Ross Seas. The Norwegian expedition of 1928–1929 under Captain Nils Larsen named the body of water for the Norwegian polar explorer Roald Amundsen while exploring this area in February 1929.
The Byrd Polar and Climate Research Center (BPCRC) is a polar, alpine, and climate research center at The Ohio State University founded in 1960.
A subglacial lake is a lake that is found under a glacier, typically beneath an ice cap or ice sheet. Subglacial lakes form at the boundary between ice and the underlying bedrock, where gravitational pressure decreases the pressure melting point of ice. Over time, the overlying ice gradually melts at a rate of a few millimeters per year. Meltwater flows from regions of high to low hydraulic pressure under the ice and pools, creating a body of liquid water that can be isolated from the external environment for millions of years.
A subglacial volcano, also known as a glaciovolcano, is a volcanic form produced by subglacial eruptions or eruptions beneath the surface of a glacier or ice sheet which is then melted into a lake by the rising lava. Today they are most common in Iceland and Antarctica; older formations of this type are found also in British Columbia and Yukon Territory, Canada.
Prydz Bay is a deep embayment of Antarctica between the Lars Christensen Coast and Ingrid Christensen Coast. The Bay is at the downstream end of a giant glacial drainage system that originates in the East Antarctic interior. The Lambert Glacier flows from Lambert Graben into the Amery Ice Shelf on the south-west side of Prydz Bay. Other major glaciers drain into the southern end of the Amery Ice Shelf at 73° S where the marine part of the system starts at the modern grounding zone.
Thwaites Glacier is an unusually broad and vast Antarctic glacier located east of Mount Murphy, on the Walgreen Coast of Marie Byrd Land. It was initially sighted by polar researchers in 1940, mapped in 1959–1966 and officially named in 1967, after the late American glaciologist Fredrik T. Thwaites. The glacier flows into Pine Island Bay, part of the Amundsen Sea, at surface speeds which exceed 2 kilometres (1.2 mi) per year near its grounding line. Its fastest-flowing grounded ice is centered between 50 and 100 kilometres east of Mount Murphy. Like many other parts of the cryosphere, it has been adversely affected by climate change, and provides one of the more notable examples of the retreat of glaciers since 1850.
Hodgson Lake is a perennially ice-covered freshwater lake, which is about 2 km (1.2 mi) long by about 1.5 km (0.93 mi) wide. It is located within the southern part of Alexander Island, west of Palmer Land in Antarctica, at approximately 72°S latitude and 68°W longitude. This lake has a 93.4 m (306 ft) deep water column that lies sealed beneath a 3.6 to 4.0 m thick perennial lake ice. The lake is an ultra-oligotrophic lake with very low nutrient content and very low productivity. There is no detectable life living in Hodgson Lake. The lake extends eastward into George VI Sound and the George VI Ice Shelf making it adjacent to the sound. The northern side of this lake is bounded by the Saturn Glacier, which flows east into George VI Sound. The lake lies next to and southeast of Citadel Bastion, a pre-eminent mountain on Alexander Island.
Lake Ellsworth is a natural freshwater liquid subglacial lake located in West Antarctica under approximately 3.4 km (2.1 mi) of ice. It is approximately 10 km long and is estimated to be 150 m (490 ft) in depth. The lake is named after the American explorer Lincoln Ellsworth. The surface of the lake itself is located over 4,593 feet (1,400 m) below sea level.
Totten Glacier is a large glacier draining a major portion of the East Antarctic Ice Sheet, through the Budd Coast of Wilkes Land in the Australian Antarctic Territory. The catchment drained by the glacier is estimated at 538,000 km2 (208,000 sq mi), extending approximately 1,100 km (680 mi) into the interior and holds the potential to raise sea level by at least 3.5 m (11 ft). Totten drains northeastward from the continental ice but turns northwestward at the coast where it terminates in a prominent tongue close east of Cape Waldron. It was first delineated from aerial photographs taken by USN Operation Highjump (1946–47), and named by Advisory Committee on Antarctic Names (US-ACAN) for George M. Totten, midshipman on USS Vincennes of the United States Exploring Expedition (1838–42), who assisted Lieutenant Charles Wilkes with correction of the survey data obtained by the expedition.
The Gamburtsev Mountain Range is a subglacial mountain range located in East Antarctica, just underneath the lofty Dome A, near the Southern Pole of Inaccessibility. The range was discovered by the 3rd Soviet Antarctic Expedition in 1958 and is named for Soviet geophysicist Grigoriy A. Gamburtsev. It is approximately 1,200 kilometres (750 mi) long, and the mountains are believed to be about 2,700 metres (8,900 ft) high, although they are completely covered by over 600 metres (2,000 ft) of ice and snow. The Gamburtsev Mountain Range is about the same size as the European Alps. As of 2008, it was unknown how the mountains were formed due to the lack of data. Studies conducted during the International Polar year demonstrated that ancient plate collisions produced a core that was rejuvenated in the early to mid-Mesozoic. The main features of the range formed before 34 million years ago, when the area was covered by the present ice sheet. Current models suggest that the East Antarctic ice sheet was formed from the glaciers that began sliding down the Gamburtsev range at the end of the Eocene. Vostok Subglacial Highlands form an east extension of Gamburtsev Subglacial Mountains.
Ice sheet dynamics describe the motion within large bodies of ice such as those currently on Greenland and Antarctica. Ice motion is dominated by the movement of glaciers, whose gravity-driven activity is controlled by two main variable factors: the temperature and the strength of their bases. A number of processes alter these two factors, resulting in cyclic surges of activity interspersed with longer periods of inactivity, on both hourly and centennial time scales. Ice-sheet dynamics are of interest in modelling future sea level rise.
Andrey Petrovich Kapitsa was a Soviet and Russian geographer and Antarctic explorer, discoverer of Lake Vostok, the largest subglacial lake in Antarctica. He was a member of the Kapitsa family, a scientific dynasty in Russia.
An ice cap climate is a polar climate where no mean monthly temperature exceeds 0 °C (32 °F). The climate generally covers areas at high latitudes and polar regions, such as Antarctica and some of the northernmost islands of Canada and Russia. Most of Greenland is under the influence of an ice cap climate, although the coasts are prone to more influence from the sea, providing more ET climates. Some regions on the islands of Norway's Svalbard Archipelago facilitate an EF climate. Areas with ice cap climates are normally covered by a permanent layer of ice and have no vegetation. There is limited animal life in most ice cap climates, which are usually found near the oceanic margins. Although ice cap climates are inhospitable to human life, there are some research stations scattered in Antarctica and interior Greenland.
Lake Whillans is a subglacial lake in Antarctica. The lake is located under the Whillans Ice Stream at the southeastern edge of the Ross Ice Shelf in the west of the continent. The lake surface is 800 m (2,600 ft) beneath the surface of the ice and the lake covers an estimated area of 60 km2 (20 sq mi). Lake depths measured thus far have been around 2 metres. Its temperature is −0.49 °C, below 0 °C because of the high pressure.
Mercer Subglacial Lake is a subglacial lake in Antarctica covered by a sheet of ice 1,067 m (3,501 ft) thick; the water below is hydraulically active, with water replacement times on the order of a decade from the Ross Sea. Studies suggest that Mercer Subglacial Lake as well as other subglacial lakes appear to be linked, with drainage events in one reservoir causing filling and follow-on drainage in adjacent lakes.
Igor Alekseevich Zotikov was a Russian glaciologist, polar explorer and academic. Zotikov was best known for predicting the existence of fresh water lakes under the Antarctic ice sheet, later to be discovered as Lake Vostok. For his efforts he was awarded a glacier named after him, Zotikov Glacier.
References
- 1 2 "Appeal to the Duma on Lake Vostok, Antarctica" (PDF). Antarctic and Southern Ocean Coalition . 14 April 2008. Archived from the original (PDF) on 4 March 2016. Retrieved 10 February 2011.
- 1 2 3 Quirin Schiermeier (2010-03-23). "Teams set for first taste of Antarctic lakes". Nature . Retrieved 2018-12-06.
Over the past 40 years, radar imagery has revealed around 150 freshwater lakes of various sizes and ages beneath the massive Antarctic ice sheet. Some have been isolated from the outside world for millions of years, raising the possibility that they hold unique life forms. The dark, nutrient-deprived environment of the lakes could resemble conditions on Jupiter's moon Europa, which is assumed to hold a large ocean beneath its frozen surface.
- 1 2 3 Peter Aldhous (2014-08-20). "First samples of Antarctic lake reveal thriving life". New Scientist magazine . Retrieved 2018-12-06.
Antarctica is home to about 400 subglacial lakes, many of which are linked in drainage basins. Priscu calls it 'the planet's largest wetland'.
- ↑ "Lakes Drain under Antarctic Ice Sheet". NASA . Retrieved 2018-12-06.
- ↑ Bethan Davies (2018-06-11). "Glacier hydrology". Antarctic Glaciers . Retrieved 2018-12-06.
Beneath the Antarctic Ice Sheet, these subglacial drainage channels are connected to numerous subglacial lakes.
- ↑ Becky Oskin (2014-08-20). "Cold, Dark and Alive! Life Discovered in Buried Antarctic Lake". Livescience magazine . Retrieved 2018-12-06.
Nearly 4,000 species of microbes inhabit Lake Whillans, which lies beneath 2,625 feet (800 meters) of ice in West Antarctica, researchers report today (Aug. 20) in the journal Nature. These are the first organisms ever retrieved from a subglacial Antarctic lake.
- ↑ "Far fewer lakes below the East Antarctic Ice Sheet than previously believed". Science Daily magazine . 2018-11-07. Retrieved 2018-12-06.
Thanks to our data, we can now fill in some of the blank spots on the map of Antarctica." However, when it comes to large lakes – they had expected to find ones as large as Lake Constance – the scientists came up empty-handed, even though they analysed the radar data for every known lake criterion.
- ↑ R.B. Heywood (1977-05-26). "A Limnological survey of the Ablation Point area, Alexander Island, Antarctica". Philosophical Transactions of the Royal Society of London . 279 (963): 39–54. Bibcode:1977RSPTB.279...39H. doi:10.1098/rstb.1977.0070. JSTOR 2417750.
Two of the lakes are unusual in that they are in contact with seawater from George VI Sound which is covered by an ice shelf, 100-500 m thick, and which separates Alexander Island from the Antarctic mainland.
- ↑ "Antarctica Detail: Ablation Lake". US Geographic Service . Retrieved 2018-12-06.
A pro-glacial tidal lake in Ablation Valley, Alexander Island, with stratified saline and fresh water and depths exceeding 117 meters. The feature is dammed in the upper portion by ice that pushes into the lake from the adjacent George VI Ice Shelf. Named after the valley following British Antarctic Survey (BAS) limnological research from 1973.
- ↑ "Antarctica Detail: Concordia Subglacial Lake". US Geographic Service . Retrieved 2018-12-06.
First located in Dec. 1999. The name derives from the nearby Italian Concordia research station.
- ↑ Malte Thoma; Klaus Grosfeld; Irina Filina; Christoph Mayer (2009-08-30). "Modelling flow and accreted ice in subglacial Lake Concordia, Antarctica, Author links open overlay panelb". Science Direct magazine . doi:10.1016/j.epsl.2009.06.037.
This paper focuses on Lake Concordia — the second largest subglacial lake in Antarctica over which substantial geophysical data has been collected. This lake is covered by about 4000 m ice and is located near Dome C.
- ↑ "Antarctica Detail: Forlidas Pond". US Geographic Service . Retrieved 2018-12-06.
The only pond in the northern Pensacola Mountains, it is of much interest to biologists.