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Occultammina
''Occultammina'' is a genus of xenophyophorean foraminifera known from the Atlantic and Pacific oceans. It is notable for being the first known infaunal xenophyophore as well as for being a possible identity for the enigmatic trace fossil ''Paleodictyon''. Distribution and habitat Like all other known xenophyophores, ''Occultammina'' is found in the deep ocean; the first known specimen was first discovered in 1980 at a depth of in the Izu–Ogasawara Trench, Ogasawara Trench, off the coast of Japan and described in 1982 by a joint research team from the University of Copenhagen and the University of Tokyo. Further specimens referred to ''Occultammina'' sp. have been found at a depth of in the Porcupine Abyssal Plain, in the North Atlantic. Further studies have expanded its geographical and bathymetric range from in the Ogasawara Trench and from in the North Atlantic, and also recorded its presence at in the Japan Trench, Japan trench. ''Occultammina'' sp. has also been rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenophyophorea
Xenophyophorea is a clade of foraminiferans. Members of this class are multinucleate unicellular organisms found on the ocean floor throughout the world's oceans, at depths of . They are a kind of foraminiferan that extract minerals from their surroundings and use them to form an exoskeleton known as a test. They were first described by Henry Bowman Brady in 1883. They are abundant on abyssal plains, and in some regions are the dominant species. Fifteen genera and 75 species have been described, varying widely in size. The largest, ''Syringammina fragilissima'', is among the largest known coenocytes, reaching up to in diameter. Naming and classification The name Xenophyophora means "bearer of foreign bodies", from the Greek. This refers to the sediments, called xenophyae, which are cemented together to construct their tests. In 1883, Henry Bowman Brady classified them as primitive Foraminifera. Later they were placed within the sponges. In the beginning of the 20th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleodictyon
''Paleodictyon'' is a trace fossil, usually interpreted to be a burrow, which appears in the geologic marine record beginning in the Precambrian/Early Cambrian and in modern ocean environments.Swinbanks, D. D., 1982: ''Paleodictyon'': the traces of infaunal xenophyophores? Science, v. 218, 47-49. ''Paleodictyon'' were first described by Giuseppe Meneghini in 1850. The origin of the trace fossil is enigmatic and numerous candidates have been proposed. Description ''Paleodictyon'' consist of thin tunnels or ridges that usually form hexagonal or polygonal-shaped honeycomb-like network.KU Ichnology - Studying the Traces of Life IBGS Research Group Both irregular and regular nets are known throughout the stratigraphic range of ''Paleodictyon'', but it is the striking regular honeycomb patte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleodictyon P
''Paleodictyon'' is a trace fossil, usually interpreted to be a burrow, which appears in the geologic marine record beginning in the Precambrian/Early Cambrian and in modern ocean environments.Swinbanks, D. D., 1982: ''Paleodictyon'': the traces of infaunal xenophyophores? Science, v. 218, 47-49. ''Paleodictyon'' were first described by Giuseppe Meneghini in 1850. The origin of the trace fossil is enigmatic and numerous candidates have been proposed. Description ''Paleodictyon'' consist of thin tunnels or ridges that usually form hexagonal or polygonal-shaped honeycomb-like network.KU Ichnology - Studying the Traces of Life IBGS Research Group Both irregular and regular nets are known throughout the stratigraphic range of ''Paleodictyon'', but it is the striking regular honeycomb patte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraminifera
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and other uses; and commonly an external shell (called a "Test (biology), test") of diverse forms and materials. Tests of chitin (found in some simple genera, and Textularia in particular) are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthos, benthic), while a smaller number float in the water column at various depths (i.e., are planktonic), which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA. Foraminifera typically produce a test (biology), test, or shell, which can have eithe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraminifera Genera
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell (called a "test") of diverse forms and materials. Tests of chitin (found in some simple genera, and Textularia in particular) are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthic), while a smaller number float in the water column at various depths (i.e., are planktonic), which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA. Foraminifera typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate in struc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Izu–Ogasawara Trench
The , also known as Izu–Bonin Trench, is an oceanic trench in the western Pacific Ocean, consisting of the Izu Trench (at the north) and the Bonin Trench (at the south, west of the Ogasawara Plateau). It stretches from Japan to the northernmost section of Mariana Trench. The Izu–Ogasawara Trench is an extension of the Japan Trench. Here, the Pacific Plate is being subducted beneath the Philippine Sea Plate, creating the Izu Islands and Bonin Islands on the Izu–Bonin–Mariana Arc system. It is at its deepest. The xenophyophore ''Occultammina'' was first discovered at a depth of 8260 metres in the trench. See also * Oceanic trench * Izu–Bonin–Mariana Arc The Izu–Bonin–Mariana (IBM) arc system is a plate tectonics, tectonic plate convergent boundary in Micronesia. The IBM arc system extends over 2800 km south from Tokyo, Japan, to beyond Guam, and includes the Izu Islands, the Bonin Island ... References Oceanic trenches of the Pacific Ocean Geolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porcupine Abyssal Plain
The Porcupine Abyssal Plain (PAP) is located in international waters, adjacent to the Irish continental margin. The PAP lies beyond the Porcupine Bank's deepest point and is southwest of it. It has a muddy seabed, with scattered abyssal hills that covers an area approximately half the size of Europe's landmass. Its depth ranges from to . Characteristics The Porcupine Abyssal Plain is a vast, relatively level stretch of seabed with a depth range of . It has a muddy floor in the abyssopelagic zone and scattered rocky abyssal hills that rise into the bathypelagic zone forming seamounts and knolls. The water at this depth is relatively stable and moving slowly towards the south and southeast. There is a downward flow of organic detritus derived from primary production in the upper layers of ocean that settles on the sea floor. Fauna A large number of marine invertebrates inhabit the abyssal plain. About 90% by number and biomass of the macrobenthos are sea cucumbers and some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead-210
Lead (82Pb) has four stable isotopes: 204Pb, 206Pb, 207Pb, 208Pb. Lead-204 is entirely a primordial nuclide and is not a radiogenic nuclide. The three isotopes lead-206, lead-207, and lead-208 represent the ends of three decay chains: the uranium series (or radium series), the actinium series, and the thorium series, respectively; a fourth decay chain, the neptunium series, terminates with the thallium isotope 205Tl. The three series terminating in lead represent the decay chain products of long-lived primordial 238U, 235U, and 232Th, respectively. However, each of them also occurs, to some extent, as primordial isotopes that were made in supernovae, rather than radiogenically as daughter products. The fixed ratio of lead-204 to the primordial amounts of the other lead isotopes may be used as the baseline to estimate the extra amounts of radiogenic lead present in rocks as a result of decay from uranium and thorium. (See lead–lead dating and uranium–lead dating). The longes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexactinellid
Hexactinellid sponges are sponges with a skeleton made of four- and/or six-pointed siliceous spicules, often referred to as glass sponges. They are usually classified along with other sponges in the phylum Porifera, but some researchers consider them sufficiently distinct to deserve their own phylum, Symplasma. Some experts believe glass sponges are thlongest-lived animals on earth these scientists tentatively estimate a maximum age of up to 15,000 years. Biology Glass sponges are relatively uncommon and are mostly found at depths from below the sea level. Although the species '' Oopsacas minuta'' has been found in shallow water, others have been found much deeper. They are found in all oceans of the world, although they are particularly common in Antarctic and Northern Pacific waters. They are more-or-less cup-shaped animals, ranging from in height, with sturdy lattice-like internal skeletons made up of fused spicules of silica. The body is relatively symmetrical, with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mid-Atlantic Ridge
The Mid-Atlantic Ridge is a mid-ocean ridge (a divergent or constructive plate boundary) located along the floor of the Atlantic Ocean, and part of the longest mountain range in the world. In the North Atlantic, the ridge separates the North American from the Eurasian Plate and the African Plate, north and south of the Azores Triple Junction respectively. In the South Atlantic, it separates the African and South American plates. The ridge extends from a junction with the Gakkel Ridge (Mid-Arctic Ridge) northeast of Greenland southward to the Bouvet Triple Junction in the South Atlantic. Although the Mid-Atlantic Ridge is mostly an underwater feature, portions of it have enough elevation to extend above sea level, for example in Iceland. The ridge has an average spreading rate of about per year. Discovery A ridge under the northern Atlantic Ocean was first inferred by Matthew Fontaine Maury in 1853, based on soundings by the USS ''Dolphin''. The existence of the ridge and its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radium-226
Radium (88Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given. The longest lived, and most common, isotope of radium is 226Ra with a half-life of . 226Ra occurs in the decay chain of 238U (often referred to as the radium series). Radium has 33 known isotopes from 202Ra to 234Ra. In 2013 it was discovered that the nucleus of radium-224 is pear-shaped. This was the first discovery of an asymmetric nucleus. List of isotopes , - , 202Ra , , style="text-align:right" , 88 , style="text-align:right" , 114 , 202.00989(7) , 2.6(21) ms .7(+33−3) ms, , , 0+ , , - , rowspan=2, 203Ra , rowspan=2, , rowspan=2 style="text-align:right" , 88 , rowspan=2 style="text-align:right" , 115 , rowspan=2, 203.00927(9) , rowspan=2, 4(3) ms , α , 199Rn , rowspan=2, (3/2−) , rowspan=2, , - , β+ (rare) , 203Fr , - , rowspan=2 style="text-indent:1em" , 203mRa , rowspan=2, , rowspan=2 colspan="3" style="text-i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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