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Hypostomus Commersoni
''Hypostomus commersoni'' is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Paraná River drainage, including the Iguazu River, the Paraguay River, the Río de la Plata, and the Dulce River. It is typically found in rivers with muddy substrates and moderate currents. The water that ''H. commersoni'' inhabits usually has a temperature of 16.8 to 27.8 °C (62.2 to 82.0 °F), a pH of 7.2 to 9.2, a turbidity of 23.7 to 442 NTU, an oxygen concentration of 6.1 to 9.1 mg/L, and a conductivity of 1.087 to 2.654 μS/cm. ''H. commersoni'' reaches 60.5 cm (23.8 inches) in total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ... and can reportedly weigh at least 1.8 kg (4 lbs). It appears in the aquarium trade, where it is of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achille Valenciennes
Achille Valenciennes (9 August 1794 – 13 April 1865) was a French zoologist. Valenciennes was born in Paris, and studied under Georges Cuvier. His study of parasitic worms in humans made an important contribution to the study of parasitology. He also carried out diverse systematic classifications, linking fossil and current species. He worked with Cuvier on the 22-volume "'' Histoire Naturelle des Poissons''" (Natural History of Fish) (1828–1848), carrying on alone after Cuvier died in 1832. In 1832, he succeeded Henri Marie Ducrotay de Blainville (1777–1850) as chair of ''Histoire naturelle des mollusques, des vers et des zoophytes'' at the Muséum national d'histoire naturelle. Early in his career, he was given the task of classifying animals described by Alexander von Humboldt (1769–1859) during his travels in the American tropics (1799 to 1803), and a lasting friendship was established between the two men. He is the binomial authority for many species of fish, such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbidity
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can contain suspended solid matter consisting of particles of many different sizes. While some suspended material will be large enough and heavy enough to settle rapidly to the bottom of the container if a liquid sample is left to stand (the settable solids), very small particles will settle only very slowly or not at all if the sample is regularly agitated or the particles are colloidal. These small solid particles cause the liquid to appear turbid. Turbidity (or haze) is also applied to transparent solids such as glass or plastic. In plastic production, haze is defined as the percentage of light that is deflected more than 2.5° from the incoming light direction. Causes and effects Turbidity in open water may be caused by growth of phyto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Described In 1836
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Most fis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypostomus
''Hypostomus'' is a genus of catfish in the family Loricariidae. They are native to tropical and subtropical South America. '' H. plecostomus'' is the popular freshwater aquarium fish formerly known as ''Plecostomus plecostomus''. The taxonomic structure of the Loricariidae is still being expanded by scientists. ''Hypostomus'' is a highly species-rich and widely distributed catfish genus. [Baidu] |
Fish Measurement
Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish measured from the tip of the snout to the posterior end of the last vertebra or to the posterior end of the midlateral portion of the hypural plate. Simply put, this measurement excludes the length of the caudal (tail) fin. * Total length (TL) is the length of a fish measured from the tip of the snout to the tip of the longer lobe of the caudal fin, usually measured with the lobes compressed along the midline. It is a straight-line measure, not measured over the curve of the body. Standard length measurements are used with Teleostei (most bony fish), while total length measurements are used with Myxini (hagfish), Petromyzontiformes (lampreys), and (usually) Elasmobranchii (sharks and rays), as well as some other fishes. Total length meas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siemens (unit)
The siemens (symbol: S) is the unit of electric conductance, electric susceptance, and electric admittance in the International System of Units (SI). Conductance, susceptance, and admittance are the reciprocals of resistance, reactance, and impedance respectively; hence one siemens is redundantly equal to the reciprocal of one ohm () and is also referred to as the '' mho''. The 14th General Conference on Weights and Measures approved the addition of the siemens as a derived unit in 1971. The unit is named after Ernst Werner von Siemens. In English, the same word ''siemens'' is used both for the singular and plural. Like other SI units named after people, the symbol is capitalized but the name of the unit is not. For the siemens this is particularly important to distinguish it from the second, symbol (lower case) s. The related property, electrical conductivity, is measured in units of siemens per metre (S/m). Definition For an element conducting direct current, electrica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conductivity (electrolytic)
Conductivity (or specific conductance) of an electrolyte solution is a measure of its ability to conduct electricity. The SI unit of conductivity is Siemens per meter (S/m). Conductivity measurements are used routinely in many industrial and environmental applications as a fast, inexpensive and reliable way of measuring the ionic content in a solution. For example, the measurement of product conductivity is a typical way to monitor and continuously trend the performance of water purification systems. In many cases, conductivity is linked directly to the total dissolved solids (TDS). High quality deionized water has a conductivity of about 0.05 μS/cm at 25 °C, typical drinking water is in the range of 200–800 μS/cm, while sea water is about 50 mS/cm ncorrect according to source(or 50,000 μS/cm). Conductivity is traditionally determined by connecting the electrolyte in a Wheatstone bridge. Dilute solutions follow Kohlrausch's Laws of concentrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is Earth's most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula . Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. Many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nephelometric Turbidity Unit
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can contain suspended solid matter consisting of particles of many different sizes. While some suspended material will be large enough and heavy enough to settle rapidly to the bottom of the container if a liquid sample is left to stand (the settable solids), very small particles will settle only very slowly or not at all if the sample is regularly agitated or the particles are colloidal. These small solid particles cause the liquid to appear turbid. Turbidity (or haze) is also applied to transparent solids such as glass or plastic. In plastic production, haze is defined as the percentage of light that is deflected more than 2.5° from the incoming light direction. Causes and effects Turbidity in open water may be caused by growth of phytopla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dulce River (Argentina)
The Dulce River (in Spanish ''Río Dulce'', in Quechua ''Misky Mayu'') is the most important river in the Argentine province of Santiago del Estero. The Dulce River's source is in Tucumán Province under the name of Salí River, though it receives tributaries from Salta Province, and changes names when reaching Santiago del Estero. It runs southeast throughout the province, and then feeds the Río Hondo in Córdoba Province before emptying into the Mar Chiquita salt lake. There is also a dam in the limit with Tucumán Province called Río Hondo dam, with a lake formatted with the connection of four rivers of Tucumán. This lake is experiencing pollution due to the lack of control of the emissions of polluting substances into the Salí River, caused mainly by the pulpmills located in Tucumán. The river runs through the Argentine Espinal ecoregion. It is the main source of water for irrigation Irrigation (also referred to as watering) is the practice of applying control ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Río De La Plata
The Río de la Plata (, "river of silver"), also called the River Plate or La Plata River in English, is the estuary formed by the confluence of the Uruguay River and the Paraná River at Punta Gorda. It empties into the Atlantic Ocean and forms a funnel-shaped indentation on the southeastern coastline of South America. Depending on the geographer, the Río de la Plata may be considered a river, an estuary, a gulf, or a marginal sea. If considered a river, it is the widest in the world, with a maximum width of . The river is about long and widens from about at its source to about at its mouth. It forms part of the border between Argentina and Uruguay. The name Río de la Plata is also used to refer to the populations along the estuary, especially the main port cities of Buenos Aires and Montevideo, where Ríoplatense Spanish is spoken and tango culture developed. The coasts of the river are the most densely-populated areas of Uruguay and Argentina. Geography The Río d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
