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Salinity

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	Salinity
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	Topics Salinity Topic Home Salinity is the saltSalt In chemistry, a salt is any ionic compound composed of cations and anions so that the product is neutral .... iness or dissolved salt content of a body of waterWater Water is a tasteless, odorless substance that is essential to all known forms of life and is known as the universal solve... . Salinity in Australian EnglishAustralian English Australian English is the form of the English language used in Australia.... and North American EnglishNorth American English Summary North American English is a collective term used for the varieties of the English language that are spoken in the United Sta... may also refer to the salt in soilSoil Soil is the collection of natural bodies that form in earthy material on the land surface.... (see soil salinationSoil salination Summary Soil salination is the accumulation of free salts to such an extent that it leads to degradation of soils and vegetation.... ). Definitions The technical term for saltiness in the ocean is halinity, from the fact that halideHalide A halide is a binary compound, of which one part is a halogen atom and the other part is an element or radical that is less... s - chlorideChloride The chloride ion is formed when the element chlorine picks up one electron to form an anion Cl−.... specifically - are the most abundant anions in the mix of dissolved elements. In oceanographyOceanography Oceanography , also called oceanology or marine science is the study of the Earth's oceans and seas.... , it has been traditional to express salinity not as percent, but as parts per thousand (ppt or ‰Permille Overview A permille or per mille is a tenth of a percent or one part per thousand.... ), which is approximately grams of salt per liter of solution. Other disciplines use chemical analyses of solutions, and thus salinity is frequently reported in mg/L or ppm (parts per million). Prior to 1978, salinity or halinity was expressed as ‰ usually based on the electrical conductivityElectrical conductivity Summary Electrical conductivity is a measure of a material's ability to conduct an electric current.... ratio of the sample to "Copenhagen water", an artificial sea water manufactured to serve as a world "standard". In 1978, oceanographers redefined salinity in the Practical Salinity Scale (PSSPSS The initialism PSS has several meanings, including: ... ) as the conductivity ratio of a sea water sample to a standard KCl solution. Ratios have no units, so it is not the case that a salinity of 35 exactly equals 35 grams of salt per litre of solution. These seemingly esoteric approaches to measuring and reporting salt concentrations may appear to obscure their practical use; but it must be remembered that salinity is the sum weight of many different elements within a given volume of water. It has always been the case that to get a precise salinity as a concentration and convert this to an amount of substance (sodium chloride, for instance) required knowing much more about the sample and the measurement than just the weight of the solids upon evaporation (one method of determining "salinity"). For example, volume is influenced by water temperature; and the composition of the salts is not a constant (although generally very much the same throughout the world ocean). Saline waters from inland seas can have a composition that differs from that of the ocean. For the latter reason, these waters are termed saline as differentiated from ocean waters, where the term haline applies (although is not universally used). Contour lineContour line A contour line for a function of two variables is a curve connecting points where the function has a same particular value.... s of constant salinity are called isohales. Environmental considerations Salinity is an ecological factor of considerable importance, influencing the types of organisms that live in a body of water. As well, salinity influences the kinds of plantPlant Plants are a major group of living things including familiar organisms such as trees, flowers, herbs, ferns, and mosses.... s that will grow either in a water body, or on land fed by a water (or by a groundwaterGroundwater Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of geologic formations.... ). A plant adapted to saline conditions is called a halophyteHalophyte A halophyte is a plant that naturally grows where it is affected by salinity in the root area or by salt spray, such as in s... . Organisms (mostly bacteria) that can live in very salty conditions are classified as extremophileExtremophile An extremophile is an organism, usually unicellular, which thrives in or requires 'extreme' conditions that would exceed opt... s, halophileHalophile Halophiles are extremophiles that thrive in environments with very high concentrations of salt .... s specifically. An organism that can withstand a wide range of salinities is euryhalineEuryhaline Euryhaline organisms are able to adapt to a wide range of salinities.... . Salt is difficult to remove from water, and salt content is an important factor in water use (such as potabilityDrinking water Drinking water is water that is intended to be drunk by humans.... ). See also Salinity controlSalinity control alinity control relates to controlling the problem of soil salinity and reclaiming salinized agricultural land.... DesalinationDesalination Desalination refers to any of several processes that remove the excess salt and other minerals from water in order to obtain... Fresh waterFresh water Fresh water is water with less than 0.5 parts per thousand dissolved salts.... SeawaterSeawater Seawater is water from a sea or ocean.... Soil salinationSoil salination Soil salination is the accumulation of free salts to such an extent that it leads to degradation of soils and vegetation.... Stenohaline fishStenohaline Stenohaline describes an organism, usually fish, that cannot handle a wide fluctuation in the salt content of water.... Euryhaline fishEuryhaline Euryhaline organisms are able to adapt to a wide range of salinities....