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Antarctic Zone
The Antarctic realm is one of eight terrestrial biogeographic realms. The ecosystem includes Antarctica and several island groups in the southern Atlantic and Indian oceans. The continent of Antarctica is so cold that it has supported only 2 vascular plants for millions of years, and its flora presently consists of around 250 lichens, 100 mosses, 25–30 liverworts, and around 700 terrestrial and aquatic algal species, which live on the areas of exposed rock and soil around the shore of the continent. Antarctica's two flowering plant species, the Antarctic hair grass (''Deschampsia antarctica'') and Antarctic pearlwort (''Colobanthus quitensis''), are found on the northern and western parts of the Antarctic Peninsula. Antarctica is also home to a diversity of animal life, including penguins, seals, and whales. Several Antarctic and sub-Antarctic island groups are considered part of the Antarctic realm, including Bouvet Island, the Crozet Islands, Heard Island, the Kerguelen Isl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heard Island And McDonald Islands
The Territory of Heard Island and McDonald Islands (HIMI) is an Australian States and territories of Australia, external territory comprising a volcanic group of mostly barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall land area is and it has of coastline. Discovered in the mid-19th century, the islands lie on the Kerguelen Plateau in the Indian Ocean and have been an Australian territory since 1947. Heard Island and McDonald Islands contain Australia's only two active volcanoes. The summit of one, Mawson Peak, is higher than any mountain in all other Australian states, territories or land claim, claimed territories, except Dome Argus, Mount McClintock and Mount Menzies in the Australian Antarctic Territory. This Antarctic territory is a land claim unrecognised by most other countries, meaning that Mawson Peak is the highest mountain with undisputed Australian Westphalian sovereignty, sovereignty. The islands are among th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fur Seal
Fur seals are any of nine species of pinnipeds belonging to the subfamily Arctocephalinae in the family Otariidae. They are much more closely related to sea lions than Earless seal, true seals, and share with them external ears (Pinna (anatomy), pinnae), relatively long and muscular foreflippers, and the ability to walk on all fours. They are marked by their dense pelage, underfur, which made them a long-time object of commercial Seal hunting, hunting. Eight species belong to the genus ''Arctocephalus'' and are found primarily in the Southern Hemisphere, while a ninth species also sometimes called fur seal, the Northern fur seal (''Callorhinus ursinus''), belongs to a different genus and inhabits the North Pacific. The fur seals in ''Arctocephalus'' are more closely related to sea lions than they are to the Northern fur seal, but all three groups are more closely related to one another than they are to true seals. Taxonomy Fur seals and sea lions make up the family Otariidae. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leopard Seal
The leopard seal (''Hydrurga leptonyx''), also referred to as the sea leopard, is the second largest species of seal in the Antarctic (after the southern elephant seal). It is a top order predator, feeding on a wide range of prey including cephalopods, other pinnipeds, krill, fish, and birds, particularly penguins, and its only natural predator being the orca. It is the only species in the genus ''Hydrurga''. Its closest relatives are the Ross seal, the crabeater seal and the Weddell seal, which are all Antarctic seals of the tribe Lobodontini. Research history and taxonomy Henri Marie Ducrotay de Blainville, a French zoologist, described the leopard seal in 1820 from a stuffed specimen from the collection of one M. Hauville, in Le Havre. The skin that produced this work of taxidermy was sourced from "the southern seas", that he ascertained to be from around the Falkland Islands. Blainville describes the specimen as "beautiful", 7-8 "pieds" long ( long) and elongated, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seal (mammal)
Pinnipeds (pronounced ), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals), with 34 extant species and more than 50 extinct species described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic group (descended from one ancestor). Pinnipeds belong to the suborder Caniformia of the order Carnivora; their closest living relatives are musteloids (weasels, raccoons, skunks and red pandas), having diverged about 50 million years ago. Seals range in size from the and Baikal seal to the and southern elephant seal. Several species exhibit sexual dimorphism. They have streamlined bodies and four limbs that ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Ocean
The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the world ocean, generally taken to be south of 60th parallel south, 60° S latitude and encircling Antarctica. With a size of , it is the second-smallest of the five principal oceanic divisions, smaller than the Pacific Ocean, Pacific, Atlantic Ocean, Atlantic and Indian Ocean, Indian oceans, and larger than the Arctic Ocean. The maximum depth of the Southern Ocean, using the definition that it lies south of 60th parallel, was surveyed by the Five Deeps Expedition in early February 2019. The expedition's multibeam sonar team identified the deepest point at 60° 28' 46"S, 025° 32' 32"W, with a depth of . The expedition leader and chief submersible pilot Victor Vescovo, has proposed naming this deepest point the "Factorian Deep", based on the name of the crewed submersible ''DSV Limiting Factor'', in which he successfully visited the bottom for the first time on February 3, 2019 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keystone Species
A keystone species is a species that has a disproportionately large effect on its natural environment relative to its abundance. The concept was introduced in 1969 by the zoologist Robert T. Paine. Keystone species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and numbers of various other species in the community. Without keystone species, the ecosystem would be dramatically different or cease to exist altogether. Some keystone species, such as the wolf and lion, are also apex predators. The role that a keystone species plays in its ecosystem is analogous to the role of a keystone in an arch. While the keystone is under the least pressure of any of the stones in an arch, the arch still collapses without it. Similarly, an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by measur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Krill
Antarctic krill (''Euphausia superba'') is a species of krill found in the Antarctica, Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 animals per cubic metre. It feeds directly on minute phytoplankton, thereby using the primary production energy that phytoplankton originally derive from the sun in order to sustain its pelagic biological life cycle, life cycle. It grows to a length of , weighs up to , and can live for up to six years. A key species in the Antarctic ecosystem and in terms of biomass (ecology), biomass, ''E. superba'' is one of the most abundant animal species on the planet, with a cumulative biomass of approximately . Life cycle The main spawn (biology), spawning season of Antarctic krill is from January to March, both above the continental shelf and also in the upper region of deep sea oceanic areas. In the typical way of all krill, the male at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tundra
In physical geography, a tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: #Arctic, Arctic, Alpine tundra, Alpine, and #Antarctic, Antarctic. Tundra vegetation is composed of dwarf shrubs, Cyperaceae, sedges, Poaceae, grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline. The tundra soil is rich in nitrogen and phosphorus. The soil also contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide in the permafrost, making the tundra soil a carbon sink. As global warming heats the ecosystem and causes soil thawing, the permafrost carbon cycle accelerates and releases much of these soil-contained greenhouse gases into the atmosphere, creating Climate change feedback, a feedback cycle t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Shetland Islands
The South Shetland Islands are a group of List of Antarctic and subantarctic islands, Antarctic islands located in the Drake Passage with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By the Antarctic Treaty System, Antarctic Treaty of 1959, the islands' sovereignty is neither recognized nor disputed by the signatories. According to British government language on the topic, "the whole of Antarctica is protected in the interests of peace and science." The islands have been claimed by three countries, beginning with the United Kingdom since 1908 (since 1962 as part of the equally unrecognized British Antarctic Territory). The islands are also claimed by the governments of Chile (since 1940, as part of the Antártica Chilena province), and by Argentina (since 1943, as part of Argentine Antarctica, Tierra del Fuego Province, Argentina, Tierra del Fuego Province). Several countries ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Orkney Islands
The South Orkney Islands are a group of List of Antarctic and sub-Antarctic islands, islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsula''Antarctica: Secrets of the Southern Continent'' p. 122 , David McGonigal, 2009 and south-west of South Georgia Island. They have a total area of about . The islands are claimed both by Britain (as part of the British Antarctic Territory since 1962, previously as a Falkland Islands Dependencies, Falkland Islands Dependency) and by Argentina (as part of Argentine Antarctica). Under the 1959 Antarctic Treaty, sovereignty claims are held in abeyance. Britain and Argentina both maintain bases on the islands. The Argentine base, Orcadas Base, Orcadas, established in 1904, is sited on Laurie Island. The 11 buildings ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Georgia And The South Sandwich Islands
South Georgia and the South Sandwich Islands (SGSSI) is a British Overseas Territory in the southern Atlantic Ocean. It is a remote and inhospitable collection of islands, consisting of South Georgia and a chain of smaller islands known as the South Sandwich Islands. South Georgia is long and wide and is by far the largest island in the territory. The South Sandwich Islands lie about southeast of South Georgia. The territory's total land area is . The Falkland Islands are about west from its nearest point. The South Sandwich Islands are uninhabited, and a very small non-permanent population resides on South Georgia. There are no scheduled passenger flights or ferries to or from the territory, although visits by cruise liners to South Georgia are increasingly popular, with several thousand visitors each summer. The United Kingdom claimed sovereignty over South Georgia in 1775 and the South Sandwich Islands in 1908. The territory of "South Georgia and the South Sandwich Islan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
