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Callianira Antarctica
''Callianira antarctica'' is a species of ctenophore that physically resembles ''Mertensia ovum,'' but lacks the oil sacs. Just like other ctenophores, over 95% of its body mass and composition is water. Physical description ''Callianira antarctica'' studied in 2002 ranged in size from 35mm to 83.6mm in Autumn months, and from 8.5mm to 98mm in Winter months. Their weight ranged from 150 mg to 758 mg in Autumn, and in Winter they ranged from 2.8 mg to 1366 mg. Distribution ''Callianira antarctica'' has been found in the waters of Southern Chile and Argentina, specifically the Strait of Magellan and Beagle Channel. It has also been studied and observed in Antarctic waters in the Croker Passage and Marguerite Bay. It resides in water depths ranging from 30m to 400m, but through sampling it was seen that the highest abundance of ctenophores was found to be between 120-150m during the day, and about 250m at night. Ecology ''Callianira antarctica'' is carnivo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mertensia Ovum
''Mertensia ovum'', also known as the Arctic comb jelly or sea nut, is a cydippid comb jelly or ctenophore first described as ''Beroe ovum'' by Johan Christian Fabricius in 1780. It is the only species in the genus ''Mertensia''. Unusually among ctenophores, which normally prefer warmer waters, it is found in the Arctic and adjacent polar seas, mostly in surface waters down to . In addition to being weakly bioluminescent in blues and greens, comb jellies produce a rainbow effect similar to that seen on an oil slick, and which is caused by interference of incident light on the eight rows of moving cilia or comb rows which propel the organism. The comb rows beat sequentially, rather like the action of a Mexican wave. The comb rows also function as chemical sense organs, serving the same role as insect antennae. ''Mertensia ovum'' is the major source of bioluminescence from Arctic gelatinous zooplankton. This species, like other ctenophores, has a large body cavity and is carni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strait Of Magellan
The Strait of Magellan (), also called the Straits of Magellan, is a navigable sea route in southern Chile separating mainland South America to the north and Tierra del Fuego to the south. The strait is considered the most important natural passage between the Atlantic and Pacific oceans. It was discovered and first traversed by the Spanish expedition of Ferdinand Magellan in 1520, after whom it is named. Prior to this, the strait had been navigated by canoe-faring indigenous peoples including the Kawésqar. Magellan's original name for the strait was ''Estrecho de Todos los Santos'' ("Strait of All Saints"). The King of Spain, Emperor Charles V, who sponsored the Magellan-Elcano expedition, changed the name to the Strait of Magellan in honor of Magellan. The route is difficult to navigate due to frequent narrows and unpredictable winds and currents. Maritime piloting is now compulsory. The strait is shorter and more sheltered than the Drake Passage, the often stormy open sea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beagle Channel
Beagle Channel (; Yahgan: ''Onašaga'') is a strait in the Tierra del Fuego Archipelago, on the extreme southern tip of South America between Chile and Argentina. The channel separates the larger main island of Isla Grande de Tierra del Fuego from various smaller islands including the islands of Picton, Lennox and Nueva; Navarino; Hoste; Londonderry; and Stewart. The channel's eastern area forms part of the border between Chile and Argentina and the western area is entirely within Chile. The Beagle Channel, the Straits of Magellan to the north, and the open-ocean Drake Passage to the south are the three navigable passages around South America between the Pacific and Atlantic Oceans. Most commercial shipping uses the open-ocean Drake Passage. The Beagle Channel is about long and wide at its narrowest point. It extends from Nueva Island in the east to Darwin Sound and Cook Bay in the Pacific Ocean in the west. Some from its western end, it divides into two branches, north ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Croker Passage
Hoseason Island is an island long and wide, lying west of Trinity Island Trinity Island or Île de la Trinité or Isla Trinidad is an island long and wide in the northern part of the Palmer Archipelago, Antarctica. It lies east of Hoseason Island, south of Deception Island in the South Shetland Islands, and nor ... in the Palmer Archipelago, Antarctica. This name, which has appeared on charts for over 100 years, commemorates James Hoseason, first mate on the ''Sprightly'', an Enderby Brothers sealing ship which operated in these waters in 1824–25. See also * Angot Point * List of Antarctic and sub-Antarctic islands References Islands of the Palmer Archipelago {{PalmerArchipelago-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marguerite Bay
Marguerite Bay or Margaret Bay is an extensive bay on the west side of the Antarctic Peninsula, which is bounded on the north by Adelaide Island and on the south by Wordie Ice Shelf, George VI Sound and Alexander Island. The mainland coast on the Antarctic Peninsula is Fallières Coast. Islands within the bay include Pourquoi Pas Island, Horseshoe Island, Terminal Island, and Lagotellerie Island. Marguerite Bay was discovered in 1909 by the French Antarctic Expedition under Jean-Baptiste Charcot, who named the bay for his wife. Named features Toadstool Rocks are a group of insular, ice-covered rocks that rise to about 250 cm above sea level in the southwest part of Marguerite Bay, east-southeast of Terminal Island. The rocks were roughly charted from RRS association with Mushroom Island and Puffball Islands. Endurance Reef is a reef in Marguerite Bay, lying west of Red Rock Ridge. The name is after HMS ''Endurance'' which at this position in February 1972 struck a ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calanoides Acutus
''Calanoides acutus'' is a copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ... found in Antarctica and the surrounding waters. Description The female ranges from about , and the male has an average length of about . Distribution ''C. acutus'' is found in Antarctic and sub-Antarctic waters, from sea level to in depth. Ecology Life history and reproduction While ''C. acutus'' is only confirmed to breed from November to March, it likely starts breeding in early October, as a study observed females without eggs and late-stage nauplii presumably belonging to this copepod in mid-November. Stage I through III copepodites are generally found from sea level to of depth. Older stages, on the other hand, are found in the top during the summer, except during December, when they ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limacina Helicina
''Limacina helicina'' is a species of small swimming planktonic sea snail in the family Limacinidae, which belong to the group commonly known as sea butterflies (Thecosomata). ''Limacina helicina'' is a keystone species of mesozooplankton in Arctic pelagic ecosystems. The first written record of this species was by Friderich Martens from Spitsbergen in 1675. ''Limacina helicina'' was also observed during a 1773 expedition to the Arctic led by Constantine John Phipps on the ships HMS ''Racehorse'' and on HMS ''Carcass'' and the species was described one year later, in 1774. ''Limacina helicina'' is the type species of the genus ''Limacina''. In contrast to the traditional view, it was shown in 2010 that the distribution of this species is not bipolar; Arctic and Antarctic individuals belong to two genetically distinct species: ''Limacina helicina'' in the Arctic, and ''Limacina antarctica'' in the Antarctic. Subspecies * ''Limacina helicina helicina'' (Phipps, 1774)Bouc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calanus Propinquus
''Calanus propinquus'' is a copepod found in Antarctica, and the surrounding waters. Description The female averages about in length, whereas the male has an average of about . The female usually ranges between around , and the male ranges from about . Distribution ''C. propinquus'' is found off Antarctica, southern Africa, and southern South America. Ecology Life cycle and reproduction Reproduction occurs from October to March. In February, the population of ''C. propinquus'' greatly increases. During this time, the population is mostly concentrated in the top of the sea. The next month, the population shifts, with stages I through III found from sea level to in depth. The females, on the other hand, are usually found deeper than . In the Southern Hemisphere autumn, some stage III through V copepodites migrate to overwinter below depths of (probably in diapause). Most of these copepodites, however, stay at the surface, overwintering in an active state. During October and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metridia Gerlachei
''Metridia gerlachei'' is a copepod found primarily in Antarctic and sub-Antarctic waters. Description In length, the female ''M. gerlachei'' is between about with a mean of . The male is smaller, between about and averaging in length. Distribution ''M. gerlachei'' is found primarily in Antarctic and sub-Antarctic waters, in addition to records from the southern Atlantic, Pacific, and Indian Oceans. Ecology Life cycle and reproduction ''M. gerlachei'' may start to reproduce during late winterAll seasons are for the Southern Hemisphere. or early spring and stops during mid-winter (although a more conservative estimate gives from December to April). Breeding peaks in December and January due to the abundance of phytoplankton. It has a relatively low egg production rate of about 6 eggs per day at saturated food concentrations. Vertical distribution During summer, most of the population is found from the surface to in depth. The population is evenly distributed throughout t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Krill
Antarctic krill (''Euphausia superba'') is a species of krill found in the 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 individual animals per cubic metre. It feeds directly on minute phytoplankton, thereby using the primary production energy that the phytoplankton originally derived from the sun in order to sustain their pelagic (open ocean) life cycle. It grows to a length of , weighs up to , and can live for up to six years. It is a key species in the Antarctic ecosystem and in terms of biomass, is one of the most abundant animal species on the planet (approximately 500 million tons, corresponding to 300 to 400 trillion individuals). Life cycle The main 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 attaches a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colloblast
Colloblasts are unique, multicellular structures found in ctenophores. They are widespread in the tentacles of these animals and are used to capture prey. Colloblasts consist of a collocyte containing a coiled spiral filament, internal granules and other organelles. Like the cnidocytes of cnidarians, colloblasts are discharged from the animals’ tentacles, and are used to capture prey. However, unlike cnidocytes, which are venomous cells, colloblasts contain adhesives which stick to, rather than sting the prey. Form, function, and occurrence Colloblasts were first described in 1844. The apical surface of colloblasts consist of numerous cap cells that secrete eosinophilic granules that are thought to be the source of adhesion. On contact, these granules rupture, and release an adhesive substance onto the prey. The spiral filament absorbs the impact of the rupture, preventing the ensnared prey from escaping. Colloblasts are found in all ctenophores except those of the order Beroid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wikipedia Student Program
Wikipedia is a multilingual free online encyclopedia written and maintained by a community of volunteers, known as Wikipedians, through open collaboration and using a wiki-based editing system. Wikipedia is the largest and most-read reference work in history. It is consistently one of the 10 most popular websites ranked by Similarweb and formerly Alexa; Wikipedia was ranked the 5th most popular site in the world. It is hosted by the Wikimedia Foundation, an American non-profit organization funded mainly through donations. Wikipedia was launched by Jimmy Wales and Larry Sanger on January 15, 2001. Sanger coined its name as a blend of ''wiki'' and ''encyclopedia''. Wales was influenced by the "spontaneous order" ideas associated with Friedrich Hayek and the Austrian School of economics after being exposed to these ideas by the libertarian economist Mark Thornton. Initially available only in English, versions in other languages were quickly developed. Its combined editions com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
