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Porites Lutea
''Porites lutea'' is a species of stony coral in the family Poritidae. It is found growing in very shallow water on reefs in the Indo-Pacific region. It sometimes forms "microatolls" in the intertidal zone and these massive structures have been used to study trends in sea levels and sea water temperature. Description ''Porites lutea'' forms massive, smooth, hemispherical mounds or helmet-shaped colonies up to across. The corallites have thin walls and are closely packed, some in diameter. In contrast to ''Porites lobata'', the corallites are well-filled with skeletal elements, including five tall pali near the centre. The colour of this coral is usually cream or yellow, but other bright colours sometimes occur in shallow-water habitats. Distribution and habitat ''Porites lutea'' is native to the tropical Indo-Pacific region. Its range extends from Madagascar and the east coast of Africa to Malaysia, Indonesia, the Philippines, Japan and northern and eastern Australia. It occurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Réunion
Réunion (; ; ; known as before 1848) is an island in the Indian Ocean that is an overseas departments and regions of France, overseas department and region of France. Part of the Mascarene Islands, it is located approximately east of the island of Madagascar and southwest of the island of Mauritius. , it had a population of 896,175. Its capital and largest city is Saint-Denis, La Réunion, Saint-Denis. Réunion was uninhabited until French immigrants and colonial subjects settled the island in the 17th century. Its tropical climate led to the development of a plantation economy focused primarily on sugar; slaves from East Africa were imported as fieldworkers, followed by Malays, Annamite, Vietnamese, Chinese, and Indians as indentured laborers. Today, the greatest proportion of the population is of mixed descent, while the predominant language is Réunion Creole, though French remains the sole official language. Since 1946, Réunion has been governed as a regions of France, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium–thorium Dating
Uranium–thorium dating, also called thorium-230 dating, uranium-series disequilibrium dating or uranium-series dating, is a radiometric dating technique established in the 1960s which has been used since the 1970s to determine the age of calcium carbonate materials such as speleothem or coral. Unlike other commonly used radiometric dating techniques such as rubidium–strontium or uranium–lead dating, the uranium-thorium technique does not measure accumulation of a stable end-member decay product. Instead, it calculates an age from the degree to which secular equilibrium has been restored between the radioactive isotope thorium-230 and its radioactive parent uranium-234 within a sample. Background Thorium is not soluble in natural water under conditions found at or near the surface of the earth, so materials grown in or from this water do not usually contain thorium. In contrast, uranium is soluble to some extent in all natural water, so any material that precipitates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corals Described In 1851
Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral reef, reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many cloning, genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cnidarians Of The Pacific Ocean
Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in freshwater and marine environments (predominantly the latter), including jellyfish, hydroids, sea anemones, corals and some of the smallest marine parasites. Their distinguishing features are an uncentralized nervous system distributed throughout a gelatinous body and the presence of cnidocytes or cnidoblasts, specialized cells with ejectable flagella used mainly for envenomation and capturing prey. Their bodies consist of mesoglea, a non-living, jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick. Cnidarians are also some of the few animals that can reproduce both sexually and asexually. Cnidarians mostly have two basic body forms: swimming medusae and sessile polyps, both of which are radially symmetrical with mouths surrounded by tentacles that bear cnidocytes, which are specialized stinging cells used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zooxanthellae
Zooxanthellae (; zooxanthella) is a colloquial term for single-celled photosynthetic organisms that are able to live in symbiosis with diverse marine invertebrates including corals, jellyfish, demosponges, and nudibranchs. Most known zooxanthellae are in the dinoflagellate genus '' Symbiodinium'', but some are known from the genus '' Amphidinium'', and other taxa, as yet unidentified, may have similar endosymbiont affinities. "Zooxanthella" was originally a genus name (meaning literally "little yellow animal") given in 1881 by Karl Brandt to '' Zooxanthella nutricula'' (a mutualist of the radiolarian '' Collozoum inerme'') which has been placed in the Peridiniales. Another group of unicellular eukaryotes that partake in similar endosymbiotic relationships in both marine and freshwater habitats are green algae zoochlorellae. Zooxanthellae are photosynthetic organisms, which contain chlorophyll a and chlorophyll c, as well as the dinoflagellate pigments peridinin and diadi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symbiosis
Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biological interaction, between two organisms of different species. The two organisms, termed symbionts, can for example be in Mutualism (biology), mutualistic, commensalism, commensalistic, or parasitism, parasitic relationships. In 1879, Heinrich Anton de Bary defined symbiosis as "the living together of unlike organisms". The term is sometimes more exclusively used in a restricted, mutualistic sense, where both symbionts contribute to each other's subsistence. This means that they benefit each other in some way. Symbiosis can be ''obligate'' (or ''obligative''), which means that one, or both of the organisms depend on each other for survival, or ''facultative'' (optional), when they can also subsist independently. Symbiosis is also classified by physical attachment. Symbionts forming a single body live ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
El Niño
EL, El or el may refer to: Arts and entertainment Fictional entities * El, a character from the manga series ''Shugo Chara!'' by Peach-Pit * Eleven (''Stranger Things'') (El), a fictional character in the TV series ''Stranger Things'' * El, family name of Kal-El (Superman) and his father Jor-El in the Superman dynasty * E.L. Faldt, character in the road comedy film '' Road Trip'' Music * Él Records, an independent record label from the UK founded by Mike Alway * ''Él ''(Lucerito album), a 1982 album by Lucerito * "Él", Spanish song by Rubén Blades from the album '' Caminando'' * "Él" (Lucía song), the Spanish entry performed by Lucía in the Eurovision Song Contest 1982 Other media * ''Él'', 1926 autobiographical novel by Mercedes Pinto * ''Él'' (film), a 1953 film by Luis Buñuel based on the 1926 novel * ''Él'' (visual novel), a 1991 Japanese adult visual novel * EL TV, an Azerbaijani regional television channel Companies and organizations * Estée Lauder Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Carbonate
Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skeletons and pearls. Materials containing much calcium carbonate or resembling it are described as calcareous. Calcium carbonate is the active ingredient in agricultural lime and is produced when calcium ions in hard water react with carbonate ions to form limescale. It has medical use as a calcium supplement or as an antacid, but excessive consumption can be hazardous and cause hypercalcemia and digestive issues. Chemistry Calcium carbonate shares the typical properties of other carbonates. Notably, it: *reacts with acids, releasing carbonic acid which quickly disintegrates into carbon dioxide and water: : *releases carbon dioxide upon heating, called a thermal decomposition reaction, or calcination (to above 840 °C in the case of ), t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clathria Aceratoobtusa
''Clathria aceratoobtusa'' is a species of sponge in the family Microcionidae. The genus ''Clathria'' is subdivided into a number of subgenera, and it is in the subgenus '' Microciona''. It is native to shallow water habitats in the Indo-Pacific region. The type locality is the Gulf of Thailand. Description ''Clathria aceratoobtusa'' is an encrusting sponge forming patches thick. The oscula (exhalent pores) are up to in diameter and appear to have membranous lips. They are either flush with the smooth surface or slightly raised. The inhalant pores are tiny and scattered over the surface, giving a net-like effect. The texture is firm and the living sponge is a bright orange-red colour. Distribution ''Clathria aceratoobtusa'' occurs in the tropical Indo-Pacific region, its range including Myanmar, Malaysia, Thailand, the Philippines, Micronesia and northern Australia. In the 21st century, it has appeared for the first time in Gulf of Mannar Marine National Park in southern Indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyp (zoology)
A polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa (biology), medusa. Polyps are roughly cylindrical in shape and elongated at the axis of the vase-shaped body. In solitary polyps, the aboral (opposite to oral) end is attached to the substrate (biology), substrate by means of a disc-like holdfast (biology), holdfast called a pedal disc, while in colony (biology), colonies of polyps it is connected to other polyps, either directly or indirectly. The oral end contains the mouth, and is surrounded by a circlet of tentacles. Classes In the class Anthozoa, comprising the sea anemones and corals, the individual is always a polyp; in the class Hydrozoa, however, the individual may be either a polyp or a medusa (biology), medusa, with most species undergoing a biological life cycle, life cycle with both a polyp stage and a medusa stage. In the class Scyphozoa, the medusa stage is dominant, and the polyp stage may or may not be present, depen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
