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Tetrapygus
''Tetrapygus'' is a genus of sea urchins in the family Arbaciidae. It is a monotypic genus and the only species is ''Tetrapygus niger'' which was first described by the Chilean naturalist Juan Ignacio Molina in 1782. It is found in the southeastern Pacific Ocean on the coasts of South America. Description The oral (under) surface of the test is flattened while the aboral (upper) surface is shallowly domed. There is a small apical disc and the ambulacral areas are straight. There are up to five large primary tubercles in rows in the inter-ambulacral areas, interspersed with smaller secondary tubercles. The mouth is surrounded by a sunken subpentagonal peristome which is half as wide as the test. The primary spines are moderately long while the secondary spines are short. The colour of this sea urchin is purplish-black. Distribution ''T. niger'' is found in the southeastern Pacific Ocean on the coasts of Peru and Chile, its range extending from northern Peru to the Strait of Mage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luidia Magellanica
''Luidia magellanica'' is a species of starfish in the family Luidiidae. It is found in the southeastern Pacific Ocean on the coast of South America. Distribution and habitat ''Luidia magellanica'' occurs subtidally in the southeastern Pacific Ocean, on the coasts of Peru and Chile. Its typical habitat is on rock bottoms with encrusting red algae, ''Lithophyllum'', or soft sediments composed of coarse sand and shell fragments. Ecology ''Luidia magellanica'' is a large and aggressive specialist predator of other echinoderms. Its diet includes brittle stars such as '' Ophiactis'', sea urchins such as '' Tetrapygus niger'' and starfish such as '' Patiria''. In the subtidal zone of temperate Chile it feeds on eight different species of echinoderm, and with '' Meyenaster gelatinosus'' is the dominant predator. Many of the starfish in this zone have missing or regenerating arms, and this is likely to be as a result of a near-lethal encounter with either ''L. magellanica'' or ''M. ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arbaciidae
Arbacioida are an order of sea urchins, consisting of a single family, the Arbaciidae. They are distinguished from other sea urchins by the presence of five separate plates around the anus. Unlike their close relatives, the Salenioida, all of the tubercles on their tests are of similar size. Genera: *''Arbacia'' Gray, 1835 *''Arbaciella'' Mortensen, 1910a *'' Arbia'' Cooke, 1948† *'' Baueria'' Noetling, 1885† *'' Codiopsis'' Agassiz, in Agassiz & Desor, 1846† *''Coelopleurus'' Agassiz, 1840a *'' Cottaldia'' Desor, 1856 † *'' Dialithocidaris'' Agassiz, 1898 *'' Habrocidaris'' Agassiz & Clark, 1907b *'' Podocidaris'' Agassiz, 1869 *'' Pygmaeocidaris'' Döderlein, 1905 *'' Sexpyga'' Shigei, 1975 *''Tetrapygus'' Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he rec ..., 1841b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Agassiz
Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he received a PhD at Erlangen and a medical degree in Munich. After studying with Georges Cuvier and Alexander von Humboldt in Paris, Agassiz was appointed professor of natural history at the University of Neuchâtel. He emigrated to the United States in 1847 after visiting Harvard University. He went on to become professor of zoology and geology at Harvard, to head its Lawrence Scientific School, and to found its Museum of Comparative Zoology. Agassiz is known for observational data gathering and analysis. He made institutional and scientific contributions to zoology, geology, and related areas, including multivolume research books running to thousands of pages. He is particularly known for his contributions to ichthyological classification, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stipe (botany)
In botany, a stipe is a stalk that supports some other structure. The precise meaning is different depending on which taxonomic group is being described. file:Helicteres-Yucatán-Flowers.jpg, The long stipe of a '' Helicteres'' flower. file:Helicteres-Yucatán-Fruits.jpg, remains as each flower forms a fruit. In the case of ferns, the stipe is only the petiole from the rootstock to the beginning of the leaf tissue, or lamina. The continuation of the structure within the lamina is then termed a rachis. In flowering plants, the term is often used in reference to a stalk that sometimes supports a flower's ovary. In orchids, the stipe or caudicle is the stalk-like support of the pollinia. It is a non-viscid band or strap connecting the pollinia with the viscidium (the viscid part of the rostellum or beak). A stipe is also a structure found in organisms that are studied by botanists but that are no longer classified as plants. It may be the stem-like part of the thallus of a mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coralline Algae
Coralline algae are red algae in the order Corallinales. They are characterized by a thallus that is hard because of calcareous deposits contained within the cell walls. The colors of these algae are most typically pink, or some other shade of red, but some species can be purple, yellow, blue, white, or gray-green. Coralline algae play an important role in the ecology of coral reefs. Sea urchins, parrot fish, and limpets and chitons (both mollusks) feed on coralline algae. In the temperate Mediterranean Sea, coralline algae are the main builders of a typical algal reef, the ''Coralligène'' ("coralligenous"). Many are typically encrusting and rock-like, found in marine waters all over the world. Only one species lives in freshwater. Unattached specimens ( maerl, rhodoliths) may form relatively smooth compact balls to warty or fruticose thalli. A close look at almost any intertidal rocky shore or coral reef will reveal an abundance of pink to pinkish-grey patches, distributed throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urchin Barren
An urchin barren is an area of the shallow part of the ocean where the population growth of sea urchins has gone unchecked, causing destructive grazing of kelp forests. Process Sea urchins eat kelp holdfasts. This can be caused by a lack of sea otters or other predators in the area, which makes it extremely important to protect the ecological balance in a kelp forest. Keystone species such as the sea otter help maintain healthy kelp communities; however, likely because of increased killer whale predation, their numbers are in decline in areas of Western Alaska. Off the California coast, storm runoff, erosion and polluted water allow less light to penetrate, weakening the kelp. Sea urchins then can move in and settle. Despite their name, urchin barrens are usually abundant with marine invertebrate life, echinoderms in particular. Species such as the sunflower starfishes, brittle stars, and the purple sea urchin are common. Although macrofauna such as these are aplenty, there is l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
El Niño
El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date Line and 120°W), including the area off the Pacific coast of South America. The ENSO is the cycle of warm and cold sea surface temperature (SST) of the tropical central and eastern Pacific Ocean. El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific. El Niño phases are known to last close to four years; however, records demonstrate that the cycles have lasted between two and seven years. During the development of El Niño, rainfall develops between September–November. The cool phase of ENSO is es, La Niña, translation=The Girl, with SSTs in the eastern Pacific below average, and air pressure high in the eastern Pacific and low in the western Pacific. The ENSO cycle, including bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliaster Helianthus
The sun star ''(Heliaster helianthus)'' is a species of Asteroidea (starfish) in the family Heliasteridae. It is found in shallow water rocky habitats and in the kelp forests off the Pacific coast of Ecuador, Peru and Chile. Description ''H. helianthus'' is a multi-armed starfish, the number of arms usually being in the range 28 to 39, and the diameter typically being between . The aboral (upper) surface is brown with reddish tubercles while the oral (under) surface is white or yellowish-white. The disc is broad and the ossicles (plate-like components in the skin) in the proximal parts of the arms (closest to the disc) are connected to those of the neighbouring arms by connective tissue, forming inter-arm septa. This means that only a small part of each arm is free, the rest appearing to form part of the disc. Distribution and habitat This species is present in the southeastern Pacific Ocean, along the west coast of South America. Its range includes Ecuador, Peru and Chile, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stichaster Striatus
''Stichaster striatus'', the common light striated star, is a species of starfish in the family Stichasteridae, found in the southeastern Pacific Ocean. It was first described by the German zoologists Johannes Peter Müller and Franz Hermann Troschel in 1840. Distribution and habitat ''Stichaster striatus'' is native to the southeastern Pacific Ocean, along the coast of South America. It occurs on rocky and sandy seabeds and among kelp in intertidal areas, with a maximum depth of . Ecology This starfish is gregarious and a predator. Although it has been recorded in Chile as feeding on twenty-eight different species of invertebrate, the majority of these were sessile organisms. It was not found to engage in cannibalism of its own species or to feed on other species of starfish. Many individuals were found to have missing or regenerating arms. This is likely the result of attacks by the dominant predatory starfish in the region '' Meyenaster gelatinosus'' and ''Luidia magell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meyenaster
''Meyenaster'' is a genus of starfish in the family Asteriidae. It is a monotypic genus and the only species is ''Meyenaster gelatinosus'' which was first described by the Prussian botanist and zoologist Franz Julius Ferdinand Meyen in 1834. It is found in the southeastern Pacific Ocean on the coasts of South America. Description ''M. gelatinosus'' is a white starfish with six arms and a mean radius ranging from . Distribution and habitat ''M. gelatinosus'' is native to the southeastern Pacific Ocean where it is found on the coasts of Chile. It is abundant in kelp forests in the subtidal zone as well as being found on sand and gravel bottoms, and among seagrasses. It is usually found in areas with strong surge away from quiet locations. Ecology In the kelp forests, ''M. gelatinosus'' is one of the dominant predators along with the starfish ''Stichaster striatus'', ''Luidia magellanica'' and ''Heliaster helianthus'', the fish ''Pinguipes chilensis'', '' Semicossyphus darwini'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelp
Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms. Kelp grows in "underwater forests" (kelp forests) in shallow oceans, and is thought to have appeared in the Miocene, 5 to 23 million years ago. The organisms require nutrient-rich water with temperatures between . They are known for their high growth rate—the genera ''Macrocystis'' and '' Nereocystis'' can grow as fast as half a metre a day, ultimately reaching .Thomas, D. 2002. ''Seaweeds.'' The Natural History Museum, London, p. 15. Through the 19th century, the word "kelp" was closely associated with seaweeds that could be burned to obtain soda ash (primarily sodium carbonate). The seaweeds used included species from both the orders Laminariales and Fucales. The word "kelp" was also used directly to refer to these processed ashes. Description In most kelp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lessonia Trabeculata
''Lessonia trabeculata'' is a species of kelp, a brown alga in the genus '' Lessonia''. It grows subtidally off the coasts of Peru and northern and central Chile, with the closely related ''Lessonia nigrescens'' tending to form a separate zone intertidally. Lessonia trabeculata kelp have gained a great economic importance for alginate production, and its harvest has greatly intensified along the Chilean coast during past two decades Description This kelp can grow to a length of . It is distinguished from all other members of the genus by the presence of trabeculae (cross struts) in the hollow centres of the blades and stipes (stems), and by the massive and irregular holdfast by which the kelp is attached to the rocks. Distribution and habitat ''Lessonia trabeculata'' occurs in the southeastern Pacific Ocean, in the subtidal zone off the coasts of Peru and northern and central Chile. Its range extends from Antofagasta to Puerto Montt and its depth range is between . It forms sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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