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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 and can reportedly weigh at least 1.8 kg (4 lbs). It appears in the aquarium trade, where it is often known as Commerson's pleco. Etymology The fish is named in honor of French naturalist Philibert Commerçon Philibert Commerson (; 18 November 1727 – 14 March 1773), sometimes spelled Commerçon by contemporaries, was a French natural history, nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achille Valenciennes
Achille Valenciennes (9 August 1794 – 13 April 1865) was a French zoology, 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, ... [...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 both water clarity and 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 caus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Described In 1836
A fish (: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians. In a break to the long tradition of grouping all fish into a single class (Pisces), modern phylogenetics views fish as a paraphyletic group. Most fish are cold-blooded, their body temperature varying with the surrounding water, though some large active swimmers like white shark and tuna can hold a higher core temperature. Many fish can communicate acoustically with each other, such as during courtship displays. The study of fish is known as ichthyology. The earliest fish appeared during the Cambrian as small filter feeders; they continued to evolve through the Paleozoic, diversifying into many forms. The earliest fish wi ... [...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] |
Philibert Commerçon
Philibert Commerson (; 18 November 1727 – 14 March 1773), sometimes spelled Commerçon by contemporaries, was a French natural history, naturalist, best known for accompanying Louis Antoine de Bougainville on his voyage of circumnavigation in 1766–1769. Biography Commerson was born at Châtillon-les-Dombes in France. He studied in Montpellier, and for a time was a practicing physician. He was in contact with Carl Linnaeus, who encouraged him to study fish of the Mediterranean. Commerson returned to live at Châtillon-les-Dombes, where he occupied himself in creating a botanical garden in 1758. After the death of his wife in 1762, he moved to Paris. In 1766, Commerson joined Bougainville on his voyage of circumnavigation after being recommended for the position of naturalist by the Paris Academy of Sciences. He had previously drawn up an extensive programme of nature studies for the Marine Ministry, in which he elaborated the "three natural kingdoms" which a naturalist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Measurement
Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery 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. 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 (shark Sharks are a group of elasmobranch cartilaginous fish characterized by ... [...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 equal to the reciprocal of one ohm () and is also referred to as the '' mho''. The siemens was adopted by the IEC in 1935, and 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 name of the unit (siemens) is not capitalized. Its symbol (S), however, ''is'' capitalized to distinguish it from the '' second'', whose symbol (s) is lower case. The related property, electrical conductivity, is measured in units of siemens per metre (S/m). Definition For an ... [...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 : \kappa = 0.05501 \pm 0.0001 μS/cm at 25 °C. This corresponds to a specific resistivity of : \rho = 18.18 \pm 0.03 MΩ⋅cm. The preparation of salt solutions often takes place in unsealed beakers. In this case the conductivity of purified water often is 10 to 20 times higher. A discussion can be found below. Typical drinking water is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is abundance of elements in Earth's crust, the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides and silicates.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. It is abundance of chemical elements, the third-most abundant element in the universe after hydrogen and helium. At standard temperature and pressure, two oxygen atoms will chemical bond, bind covalent bond, covalently to form dioxygen, a colorless and odorless diatomic gas with the chemical formula ... [...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 both water clarity and 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 ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
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. It is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour, or ecological niche. In addition, palaeontologists 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. About 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomen". The first part of a binomen is the name of a genus to which the species belongs. The second part is called the specific name (zoology), specific name or the specific ... [...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 Tucumán Province called Río Hondo dam, with a lake formed 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 pulp mills 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 of plants) is the practice of applying controlled amou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
