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Mercer Lake (Antarctica)
Mercer Subglacial Lake is a subglacial lake in Antarctica covered by a sheet of ice 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. Exploration Helen Amanda Fricker from the Scripps Institution of Oceanography discovered Mercer Subglacial Lake in 2007, while using satellite laser altimetry to search for the grounding line of a glacier. The lake is named after [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual Climate of Antarctica#Precipitation, precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the Lowest temperature recorded on Earth, lowest measured temperature on Earth, . The coastal regions can reach temperatures over in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Cycling
The carbon cycle is a part of the biogeochemical cycle where carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycle. Carbon is the main component of biological compounds as well as a major component of many rocks such as limestone. The carbon cycle comprises a sequence of events that are key to making Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration (storage) to and release from carbon sinks. To describe the dynamics of the carbon cycle, a distinction can be made between the ''fast'' and ''slow'' carbon cycle. The fast cycle is also referred to as the ''biological carbon cycle''. Fast cycles can complete within years, moving substances from atmosphere to biosphere, then back to the atmosphere. Slow or geological cycles (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underground Lake
An underground lake or subterranean lake is a lake underneath the surface of the Earth. Most naturally occurring underground lakes are found in areas of karst topography, where limestone or other soluble rock has been weathered away, leaving a cave where water can flow and accumulate. Natural underground lakes are an uncommon hydrogeological feature. More often, groundwater gathers in formations such as aquifers or springs. The largest underground lake in the world is in Dragon's Breath Cave in Namibia, with an area of almost ; the second largest is The Lost Sea, located inside Craighead Caverns in Tennessee, United States, with an area of Characteristics An underground lake is any body of water that is similar in size to a surface lake and exists mostly or entirely underground; though, a precise scientific definition of what may be considered a "lake" is not yet well-established. underground lakes could be classified as either "lakes" or "ponds", depending on charac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supraglacial Lake
A supraglacial lake is any pond of liquid water on the top of a glacier. Although these pools are ephemeral, they may reach kilometers in diameter and be several meters deep. They may last for months or even decades at a time, but can empty in the course of hours. Lifetime Lakes may be created by surface melting during summer months, or over the period of years by rainfall, such as monsoons. They may dissipate by overflowing their banks, or creating a moulin. Effects on ice masses Lakes of a diameter greater than ~300 m are capable of driving a fluid-filled crevasse to the glacier/bed interface, through the process of hydrofracture. A surface-to-bed connection made in this way is referred to as a moulin. When these crevasses form, it can take a mere 2–18 hours to empty a lake, supplying warm water to the base of the glacier - lubricating the bed and causing the glacier to surge. The rate of emptying such a lake is equivalent to the rate of flow of the Niagara Fal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Antarctic Subglacial Lakes ...
An ongoing inventory of subglacial lakes in Antarctica. Compiled from: * Discoveries from the 1970's to 2012 via: Wright, A., and Siegert, M. (2012)A fourth inventory of Antarctic subglacial lakes Antarctic Science 24, 659-664 References {{portal, Lakes Antarctice subglacial lakes Antarctic subglacial lakes subglacial lakes 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 liquid water can exist above the lower melting point of ice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Untersee
Lake Untersee ( "Lower Lake") is the largest surface freshwater lake in the interior of the Gruber Mountains of central Queen Maud Land in East Antarctica. It is situated to the southeast of the Schirmacher Oasis. The lake is approximately long and wide, with a surface area of , and a maximum depth of . The lake is permanently covered with ice and is partly bounded by glacier ice. Lake Untersee is an unusual lake, with pH between 9.8 and 12.1, dissolved oxygen at 150 per cent supersaturation, and very low primary production in the water column. Despite the high oxygen supersaturation in most of the lake, there is a small sub-basin at the southern end that is anoxic, and its sediments may have a higher methane concentration than those of any other known lake on Earth. Much of the primary production is in microbial communities that grow on the floor of the lake as stromatolites. The water temperature varies between and and the ice cover on the lake is thick. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hodgson Lake
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 (12 to 13 ft) 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.Stewart, J. (2011) ''Antarctic An Encyclopedia'' McFarland & Company Inc, New York. 1776 pp. . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Ellsworth (Antarctica)
Lake Ellsworth is a natural freshwater liquid subglacial lake located in West Antarctica under approximately of ice. It is approximately long and is estimated to be in max. depth. The lake is named after the American explorer Lincoln Ellsworth. The surface of the lake itself is located, approximately below mean sea level. Elevation of icecap covering, the lake: m.a.s.l. Exploration Lake Ellsworth was discovered in 1996 by British scientist Professor Martin Siegert of the University of Bristol; it is one of 387 known subglacial Antarctic lakes and it is a target site for exploration due to the speculation that new forms of microbial life could have evolved in the unique habitats of Antarctica's sub-glacial lakes after half a million years of isolation.Siegert, Martin J. and the Lake Ellsworth Consortium, "Exploration of Subglacial Lake Ellsworth", Poster, University of Bristol, September 2004 Life in subglacial lakes would have to adapt to total darkness, low nutrient levels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Vostok
Lake Vostok () is the largest of Antarctica's 675 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 above mean sea level. The surface of this fresh water lake is approximately under the surface of the ice, which places it at approximately below sea level. The lake is named after the Vostok Station, which derives its name from '' Vostok'' (Восток), a sloop-of-war, which means "East" in Russian (the lake is also located in East Antarctica). The existence of a subglacial lake was first suggested by Russian geographer Andrey Kapitsa based on seismic soundings made during the Soviet Antarctic Expeditions in 1959 and 1964 to measure the thickness of the ice sheet. The continued research by Russian and British scientists led to the final confirmation of the existence of the lake in 1993 by J. P. Ridley using ERS-1 laser altimetry. The overlying i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Lake
A glacial lake is a body of water with origins from glacier activity. They are formed when a glacier erodes the land and then melts, filling the depression created by the glacier. Formation Near the end of the last glacial period, roughly 10,000 years ago, glaciers began to retreat. A retreating glacier often left behind large deposits of ice in hollows between drumlins or hills. As the ice age ended, these melted to create lakes. These lakes are often surrounded by drumlins, along with other evidence of the glacier such as moraines, eskers and erosional features such as glacial striations, striations and chatter marks. These lakes are clearly visible in aerial photos of landforms in regions that were glaciated during the last ice age. The formation and characteristics of glacial lakes vary between location and can be classified into glacial erosion lake, ice-blocked lake, moraine-dammed lake, other glacial lake, supraglacial lake, and subglacial lake. Glacial lakes and chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biodiversity
Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distributed evenly on Earth. It is greater in the tropics as a result of the warm climate and high primary productivity in the region near the equator. Tropical forest ecosystems cover less than one-fifth of Earth's terrestrial area and contain about 50% of the world's species. There are latitudinal gradients in species diversity for both marine and terrestrial taxa. Since Abiogenesis, life began on Earth, six major mass extinctions and several minor events have led to large and sudden drops in biodiversity. The Phanerozoic aeon (the last 540 million years) marked a rapid growth in biodiversity via the Cambrian explosion. In this period, the majority of Multicellular organism, multicellular Phylum, phyla first appeared. The next 400 mil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subglacial Lake
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 liquid water can exist above the lower melting point of ice under high pressure. 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. Since the first discoveries of subglacial lakes under the Antarctic Ice Sheet, more than 400 subglacial lakes have been discovered in Antarctica, beneath the Greenland Ice Sheet, and under Iceland's Vatnajökull ice cap. Subglacial lakes contain a substantial proportion of Earth's liquid freshwater, with the volume of Antarctic subglacial lakes alone estimated to be about 10,000 km3, or about 15% of all liquid freshwater on Earth. As ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
