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Polynya
A polynya () is an area of open water surrounded by sea ice. It is now used as a geographical term for an area of unfrozen seawater within otherwise contiguous pack ice or fast ice. It is a loanword from the Russian language, Russian (), which refers to a natural ice hole and was adopted in the 19th century by polar explorers to describe navigable portions of the sea. There are two main types of polynyas: coastal polynyas, which can be found year-round near the Antarctic and Arctic coasts and are mainly created by strong winds pushing the ice away from the coast, and mid-sea or open-ocean polynyas, which may be found more sporadically in the middle of ice pack in certain locations, especially around Antarctica. These locations are generally preconditioned by certain oceanic dynamics. One of the most famous mid-sea polynyas is the Weddell Polynya, also known as the Maud Rise Polynya, which occurs in the Lazarev Sea over the Maud Rise seamount. It was first spotted in September ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Water Polynya
The North Water Polynya (NOW), or ''Pikialasorsuaq'' to Inuit in Greenland and ''Sarvarjuaq'' to Inuit in Canada, is a polynya (area of year-round open water surrounded by sea ice) that lies between Greenland and Canada in northern Baffin Bay. The world's largest Arctic polynya at about , it creates a warm microclimate that provides a refuge for narwhal, beluga whale, beluga, walrus, and bowhead whales to feed and rest. While thin ice forms in some areas, the polynya is kept open by wind, tides and an ice bridge on its northern edge. Named the "North Water" by 19th century whalers who relied on it for spring passage, this polynya is one of the most biologically productive marine areas in the Arctic Ocean. Fauna Polynyas are often compared to oasis, oases as their open waters allow for an unusually early spring plankton bloom and an open water wintering area in a frozen world. This provides food for Arctogadus glacialis, Arctic cod, a species that plays a critical role in suppo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weddell Polynya
The Weddell Polynya, or Weddell Sea Polynya, is a polynya, or irregular area of open water surrounded by sea ice, in the Weddell Sea of the Southern Ocean off Antarctica and near the Maud Rise. The formation of the polynya exposes relatively warmer ocean waters (at surface freezing temperatures of –1.9 °C) to a cold atmosphere, leading to a large exchange of heat which drives deep convection in the ocean, often reaching depths of 1,000 to 2,000 meters. Occurrences The size of New Zealand, it re-occurred each winter between 1974 and 1976. These were the first three austral winters observed by the Nimbus 5 Electrically Scanning Microwave Radiometer (ESMR). From 1976 to 2015, this polynya was rarely observed. The polynya reoccurred in 2016, and has since appeared in 2017. The 2010s occurrence has been smaller than the 1970s occurrence, being about the size of Maine in 2017, or roughly . Since the 1970s, the polar Southern Ocean south of the Antarctic Circumpolar Current has fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Ice
Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the Arctic ecology, including the Arctic sea ice ecology and history, ocean's ecosystems. Due to the action of winds, currents and temperature fluctuations, sea ice is very dynamic, leading to a wide variety of ice types and features. Sea ice may be contrasted with icebergs, which are chunks of ice shelf, ice shelves or glaciers that Ice calving, calve into the ocean. Depending on location, sea ice expanses may also incorporate icebergs. General features and dynamics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Bottom Water
The Antarctic bottom water (AABW) is a type of water mass in the Southern Ocean surrounding Antarctica with temperatures ranging from −0.8 to 2 °C (35 °F) and absolute salinities from 34.6 to 35.0 g/kg. As the densest water mass of the oceans, AABW is found to occupy the depth range below 4000 m of all ocean basins that have a connection to the Southern Ocean at that level. AABW forms the lower branch of the large-scale movement in the world's oceans through thermohaline circulation. AABW forms near the surface in coastal polynyas along the coastline of Antarctica, where high rates of sea ice formation during winter leads to the densification of the surface waters through brine rejection. Since the water mass forms near the surface, it is responsible for the exchange of large quantities of heat and gases with the atmosphere. AABW has a high oxygen content relative to the rest of the oceans' deep waters, but this depletes over time. This water sinks at four dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Shelf Ice Hg
The Antarctic (, ; commonly ) is the polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is diametrically opposite of the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau, and other island territories located on the Antarctic Plate or south of the Antarctic Convergence. The Antarctic region includes the ice shelves, waters, and all the island territories in the Southern Ocean situated south of the Antarctic Convergence, a zone approximately wide and varying in latitude seasonally. The region covers some 20 percent of the Southern Hemisphere, of which 5.5 percent (14 million km2) is the surface area of the Antarctica continent itself. All of the land and ice shelves south of 60°S latitude are administered under the Antarctic Treaty System. Biogeographically, the Antarctic realm is one of eight biogeographic realms on Earth's land surface. Climate change in Antarcti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brine Rejection
Brine rejection is a process that occurs when salty water freezes. The salts do not fit in the crystal structure of water ice, so the salt is expelled. Since the oceans are salty, this process is important in nature. Salt rejected by the forming sea ice drains into the surrounding seawater, creating saltier, denser brine. The denser brine sinks, influencing ocean circulation. Formation As water reaches the temperature where it begins to crystallize and form ice, salt ions are rejected from the lattices within the ice and are either forced out into the surrounding water, or trapped among the ice crystals in pockets called brine cells. Generally, sea ice has a salinity ranging from 0 psu at the surface to 4 psu at the base. The faster that this freezing process occurs, the more brine cells are left in the ice. Once the ice reaches a critical thickness, roughly 15 cm, the concentration of salt ions in the liquid around the ice begins to increase, as leftover brine is rejecte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Narwhal
The narwhal (''Monodon monoceros'') is a species of toothed whale native to the Arctic. It is the only member of the genus ''Monodon'' and one of two living representatives of the family Monodontidae. The narwhal is a stocky cetacean with a relatively blunt snout, a large Melon (whale), melon, and a shallow ridge in place of a dorsal fin. Males of this species have a large () long tusk, which is a protruding left Canine tooth, canine thought to function as a weapon, a tool for feeding, in sexual selection, attracting mates or sensing water salinity. Specially adapted slow-twitch muscles, along with the jointed neck vertebrae and shallow dorsal ridge allow for easy movement through the Arctic environment, where the narwhal spends extended periods at great depths. The narwhal's geographic range overlaps with that of the similarly built and closely related beluga whale, and the animals are known to interbreed. Narwhals inhabit the Arctic waters of Canada, Greenland and Russia. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walrus
The walrus (''Odobenus rosmarus'') is a large pinniped marine mammal with discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. It is the only extant species in the family Odobenidae and genus ''Odobenus''. This species is subdivided into two subspecies: the Atlantic walrus (''O. r. rosmarus''), which lives in the Atlantic Ocean, and the Pacific walrus (''O. r. divergens''), which lives in the Pacific Ocean. Adult walrus are characterised by prominent tusks and whiskers, and considerable bulk: adult males in the Pacific can weigh more than and, among pinnipeds, are exceeded in size only by the two species of elephant seals. Walrus live mostly in shallow waters above the continental shelves, spending significant amounts of their lives on the sea ice looking for benthic bivalve molluscs. Walruses are relatively long-lived, social animals, and are considered to be a " keystone species" in the Arctic marine regio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Mammal
Marine mammals are mammals that rely on marine ecosystems for their existence. They include animals such as cetaceans, pinnipeds, sirenians, sea otters and polar bears. They are an informal group, unified only by their reliance on marine environments for feeding and survival. Marine mammal adaptation to an aquatic lifestyle varies considerably between species. Both cetaceans and sirenians are fully aquatic and therefore are obligate water dwellers. Pinnipeds are semiaquatic; they spend the majority of their time in the water but need to return to land for important activities such as mating, breeding in the wild, breeding and molting. Sea otters tend to live in kelp forests and estuaries. In contrast, the polar bear is mostly terrestrial and only go into the water on occasions of necessity, and are thus much less adapted to aquatic living. The diets of marine mammals vary considerably as well; some eat zooplankton, others eat fish, squid, shellfish, or seagrass, and a few eat ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenland
Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenland are full Danish nationality law, citizens of Denmark and European Union citizenship, of the European Union. Greenland is one of the Special territories of members of the European Economic Area#Overseas countries and territories, Overseas Countries and Territories of the European Union and is part of the Council of Europe. It is the List of islands by area, world's largest island, and lies between the Arctic Ocean, Arctic and Atlantic oceans, east of the Arctic Archipelago, Canadian Arctic Archipelago. It is the location of the northernmost point of land in the world; Kaffeklubben Island off the northern coast is the world's Northernmost point of land, northernmost undisputed point of land—Cape Morris Jesup on the mainland was thought to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of countries and dependencies by area, second-largest country by total area, with the List of countries by length of coastline, world's longest coastline. Its Canada–United States border, border with the United States is the world's longest international land border. The country is characterized by a wide range of both Temperature in Canada, meteorologic and Geography of Canada, geological regions. With Population of Canada, a population of over 41million people, it has widely varying population densities, with the majority residing in List of the largest population centres in Canada, urban areas and large areas of the country being sparsely populated. Canada's capital is Ottawa and List of census metropolitan areas and agglomerations in Canada, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
