fbpx
Wikipedia

Salinity

January 08, 2024

Salinity (/səˈlɪnɪti/) is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal to ‰).

Annual mean sea surface salinity for the World Ocean. Data from the World Ocean Atlas 2009.[1]
International Association for the Physical Sciences of the Oceans (IAPSO) standard seawater.

Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it, and is a thermodynamic state variable that, along with temperature and pressure, governs physical characteristics like the density and heat capacity of the water.

A contour line of constant salinity is called an isohaline, or sometimes isohale.

Definitions edit

Salinity in rivers, lakes, and the ocean is conceptually simple, but technically challenging to define and measure precisely. Conceptually the salinity is the quantity of dissolved salt content of the water. Salts are compounds like sodium chloride, magnesium sulfate, potassium nitrate, and sodium bicarbonate which dissolve into ions. The concentration of dissolved chloride ions is sometimes referred to as chlorinity. Operationally, dissolved matter is defined as that which can pass through a very fine filter (historically a filter with a pore size of 0.45 μm, but nowadays[when?] usually 0.2 μm).[2] Salinity can be expressed in the form of a mass fraction, i.e. the mass of the dissolved material in a unit mass of solution.

Seawater typically has a mass salinity of around 35 g/kg, although lower values are typical near coasts where rivers enter the ocean. Rivers and lakes can have a wide range of salinities, from less than 0.01 g/kg[3] to a few g/kg, although there are many places where higher salinities are found. The Dead Sea has a salinity of more than 200 g/kg.[4] Precipitation typically has a TDS of 20 mg/kg or less.[5]

Whatever pore size is used in the definition, the resulting salinity value of a given sample of natural water will not vary by more than a few percent (%). Physical oceanographers working in the abyssal ocean, however, are often concerned with precision and intercomparability of measurements by different researchers, at different times, to almost five significant digits.[6] A bottled seawater product known as IAPSO Standard Seawater is used by oceanographers to standardize their measurements with enough precision to meet this requirement.

Composition edit

Measurement and definition difficulties arise because natural waters contain a complex mixture of many different elements from different sources (not all from dissolved salts) in different molecular forms. The chemical properties of some of these forms depend on temperature and pressure. Many of these forms are difficult to measure with high accuracy, and in any case complete chemical analysis is not practical when analyzing multiple samples. Different practical definitions of salinity result from different attempts to account for these problems, to different levels of precision, while still remaining reasonably easy to use.

For practical reasons salinity is usually related to the sum of masses of a subset of these dissolved chemical constituents (so-called solution salinity), rather than to the unknown mass of salts that gave rise to this composition (an exception is when artificial seawater is created). For many purposes this sum can be limited to a set of eight major ions in natural waters,[7][8] although for seawater at highest precision an additional seven minor ions are also included.[6] The major ions dominate the inorganic composition of most (but by no means all) natural waters. Exceptions include some pit lakes and waters from some hydrothermal springs.

The concentrations of dissolved gases like oxygen and nitrogen are not usually included in descriptions of salinity.[2] However, carbon dioxide gas, which when dissolved is partially converted into carbonates and bicarbonates, is often included. Silicon in the form of silicic acid, which usually appears as a neutral molecule in the pH range of most natural waters, may also be included for some purposes (e.g., when salinity/density relationships are being investigated).

Seawater edit

See also: Ocean § Salinity
Full 3 minute NASA video Feb 27,2013 The NASA Aquarius instrument aboard Argentina's SAC-D satellite is designed to measure global sea surface salinity. This movie shows salinity patterns as measured by Aquarius from December 2011 through December 2012. Red colors represent areas of high salinity, while blue shades represent areas of low salinity.

The term 'salinity' is, for oceanographers, usually associated with one of a set of specific measurement techniques. As the dominant techniques evolve, so do different descriptions of salinity. Salinities were largely measured using titration-based techniques before the 1980s. Titration with silver nitrate could be used to determine the concentration of halide ions (mainly chlorine and bromine) to give a chlorinity. The chlorinity was then multiplied by a factor to account for all other constituents. The resulting 'Knudsen salinities' are expressed in units of parts per thousand (ppt or ‰).

The use of electrical conductivity measurements to estimate the ionic content of seawater led to the development of the scale called the practical salinity scale 1978 (PSS-78).[9][10] Salinities measured using PSS-78 do not have units. The suffix psu or PSU (denoting practical salinity unit) is sometimes added to PSS-78 measurement values.[11] The addition of PSU as a unit after the value is "formally incorrect and strongly discouraged".[2]

In 2010 a new standard for the properties of seawater called the thermodynamic equation of seawater 2010 (TEOS-10) was introduced, advocating absolute salinity as a replacement for practical salinity, and conservative temperature as a replacement for potential temperature.[6] This standard includes a new scale called the reference composition salinity scale. Absolute salinities on this scale are expressed as a mass fraction, in grams per kilogram of solution. Salinities on this scale are determined by combining electrical conductivity measurements with other information that can account for regional changes in the composition of seawater. They can also be determined by making direct density measurements.

A sample of seawater from most locations with a chlorinity of 19.37 ppt will have a Knudsen salinity of 35.00 ppt, a PSS-78 practical salinity of about 35.0, and a TEOS-10 absolute salinity of about 35.2 g/kg. The electrical conductivity of this water at a temperature of 15 °C is 42.9 mS/cm.[6][12]

On the global scale, it is extremely likely that human-caused climate change has contributed to observed surface and subsurface salinity changes since the 1950s, and projections of surface salinity changes throughout the 21st century indicate that fresh ocean regions will continue to get fresher and salty regions will continue to get saltier.[13]

Lakes and rivers edit

Limnologists and chemists often define salinity in terms of mass of salt per unit volume, expressed in units of mg/L or g/L.[7] It is implied, although often not stated, that this value applies accurately only at some reference temperature because solution volume varies with temperature. Values presented in this way are typically accurate to the order of 1%. Limnologists also use electrical conductivity, or "reference conductivity", as a proxy for salinity. This measurement may be corrected for temperature effects, and is usually expressed in units of μS/cm.

A river or lake water with a salinity of around 70 mg/L will typically have a specific conductivity at 25 °C of between 80 and 130 μS/cm. The actual ratio depends on the ions present.[14] The actual conductivity usually changes by about 2% per degree Celsius, so the measured conductivity at 5 °C might only be in the range of 50–80 μS/cm.

Direct density measurements are also used to estimate salinities, particularly in highly saline lakes.[4] Sometimes density at a specific temperature is used as a proxy for salinity. At other times an empirical salinity/density relationship developed for a particular body of water is used to estimate the salinity of samples from a measured density.

Water salinity
Fresh water Brackish water Saline water Brine
< 0.05% 0.05 – 3% 3 – 5% > 5%
< 0.5 ‰ 0.5 – 30 ‰ 30 – 50 ‰ > 50 ‰

Classification of water bodies based upon salinity edit

Thalassic series
> 300 ‰
hyperhaline
60–80 ‰
metahaline
40 ‰
mixoeuhaline
30 ‰
polyhaline
18 ‰
mesohaline
5 ‰
oligohaline
0.5 ‰

Marine waters are those of the ocean, another term for which is euhaline seas. The salinity of euhaline seas is 30 to 35 ‰. Brackish seas or waters have salinity in the range of 0.5 to 29 ‰ and metahaline seas from 36 to 40 ‰. These waters are all regarded as thalassic because their salinity is derived from the ocean and defined as homoiohaline if salinity does not vary much over time (essentially constant). The table on the right, modified from Por (1972),[15][16] follows the "Venice system" (1959).[17]

In contrast to homoiohaline environments are certain poikilohaline environments (which may also be thalassic) in which the salinity variation is biologically significant.[18] Poikilohaline water salinities may range anywhere from 0.5 to greater than 300 ‰. The important characteristic is that these waters tend to vary in salinity over some biologically meaningful range seasonally or on some other roughly comparable time scale. Put simply, these are bodies of water with quite variable salinity.

Highly saline water, from which salts crystallize (or are about to), is referred to as brine.

Environmental considerations edit

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 plants that will grow either in a water body, or on land fed by a water (or by a groundwater).[19] A plant adapted to saline conditions is called a halophyte. A halophyte which is tolerant to residual sodium carbonate salinity are called glasswort or saltwort or barilla plants. Organisms (mostly bacteria) that can live in very salty conditions are classified as extremophiles, or halophiles specifically. An organism that can withstand a wide range of salinities is euryhaline.

Salts are expensive to remove from water, and salt content is an important factor in water use, factoring into potability and suitability for irrigation. Increases in salinity have been observed in lakes and rivers in the United States, due to common road salt and other salt de-icers in runoff.[20]

The degree of salinity in oceans is a driver of the world's ocean circulation, where density changes due to both salinity changes and temperature changes at the surface of the ocean produce changes in buoyancy, which cause the sinking and rising of water masses. Changes in the salinity of the oceans are thought to contribute to global changes in carbon dioxide as more saline waters are less soluble to carbon dioxide. In addition, during glacial periods, the hydrography is such that a possible cause of reduced circulation is the production of stratified oceans. In such cases, it is more difficult to subduct water through the thermohaline circulation.

Not only is salinity a driver of ocean circulation, but changes in ocean circulation also affect salinity, particularly in the subpolar North Atlantic where from 1990 to 2010 increased contributions of Greenland meltwater were counteracted by increased northward transport of salty Atlantic waters.[13][21][22][23] However, North Atlantic waters have become fresher since the mid-2010s due to increased Greenland meltwater flux.[13][24]

See also edit

References edit

  1. ^ World Ocean Atlas 2009. nodc.noaa.gov
  2. ^ a b c Pawlowicz, R. (2013). "Key Physical Variables in the Ocean: Temperature, Salinity, and Density". Nature Education Knowledge. 4 (4): 13.
  3. ^ Eilers, J. M.; Sullivan, T. J.; Hurley, K. C. (1990). "The most dilute lake in the world?". Hydrobiologia. 199: 1–6. doi:10.1007/BF00007827. S2CID 30279782.
  4. ^ a b Anati, D. A. (1999). "The salinity of hypersaline brines: concepts and misconceptions". Int. J. Salt Lake. Res. 8 (1): 55–70. Bibcode:1999IJSLR...8...55A. doi:10.1007/bf02442137.
  5. ^ "Learn about salinity and water quality". Retrieved 21 July 2018.
  6. ^ a b c d IOC, SCOR, and IAPSO (2010). The international thermodynamic equation of seawater – 2010: Calculation and use of thermodynamic properties. Intergovernmental Oceanographic Commission, UNESCO (English). pp. 196pp.{{cite book}}: CS1 maint: multiple names: authors list (link)
  7. ^ a b Wetzel, R. G. (2001). Limnology: Lake and River Ecosystems, 3rd ed. Academic Press. ISBN 978-0-12-744760-5.
  8. ^ Pawlowicz, R.; Feistel, R. (2012). "Limnological applications of the Thermodynamic Equation of Seawater 2010 (TEOS-10)". Limnology and Oceanography: Methods. 10 (11): 853–867. Bibcode:2012LimOM..10..853P. doi:10.4319/lom.2012.10.853. S2CID 93210746.
  9. ^ Unesco (1981). The Practical Salinity Scale 1978 and the International Equation of State of Seawater 1980. Tech. Pap. Mar. Sci., 36
  10. ^ Unesco (1981). Background papers and supporting data on the Practical Salinity Scale 1978. Tech. Pap. Mar. Sci., 37
  11. ^ Millero, F. J. (1993). "What is PSU?". Oceanography. 6 (3): 67.
  12. ^ Culkin, F.; Smith, N. D. (1980). "Determination of the Concentration of Potassium Chloride Solution Having the Same Electrical Conductivity, at 15C and Infinite Frequency, as Standard Seawater of Salinity 35.0000‰ (Chlorinity 19.37394‰)". IEEE J. Oceanic Eng. OE-5 (1): 22–23. Bibcode:1980IJOE....5...22C. doi:10.1109/JOE.1980.1145443.
  13. ^ a b c Fox-Kemper, B.; Hewitt, H.T.; Xiao, C.; Aðalgeirsdóttir, G.; Drijfhout, S.S.; Edwards, T.L.; Golledge, N.R.; Hemer, M.; Kopp, R.E.; Krinner, G.; Mix, A. (2021). Masson-Delmotte, V.; Zhai, P.; Pirani, A.; Connors, S.L.; Péan, C.; Berger, S.; Caud, N.; Chen, Y.; Goldfarb, L. (eds.). "Ocean, Cryosphere and Sea Level Change" (PDF). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK and New York, New York, US: Cambridge University Press. 2021: 1211–1362. doi:10.1017/9781009157896.011. ISBN 9781009157896.
  14. ^ van Niekerk, Harold; Silberbauer, Michael; Maluleke, Mmaphefo (2014). "Geographical differences in the relationship between total dissolved solids and electrical conductivity in South African rivers". Water SA. 40 (1): 133. doi:10.4314/wsa.v40i1.16.
  15. ^ Por, F. D. (1972). "Hydrobiological notes on the high-salinity waters of the Sinai Peninsula". Marine Biology. 14 (2): 111–119. Bibcode:1972MarBi..14..111P. doi:10.1007/BF00373210. S2CID 86601297.
  16. ^ "Salinity | Freshwater Inflows". www.freshwaterinflow.org. Retrieved 2020-10-25.
  17. ^ Venice system (1959). The final resolution of the symposium on the classification of brackish waters. Archo Oceanogr. Limnol., 11 (suppl): 243–248.
  18. ^ Dahl, E. (1956). "Ecological salinity boundaries in poikilohaline waters". Oikos. 7 (1): 1–21. Bibcode:1956Oikos...7....1D. doi:10.2307/3564981. JSTOR 3564981.
  19. ^ Kalcic, Maria, Turowski, Mark; Hall, Callie (2010-12-22). "Stennis Space Center Salinity Drifter Project. A Collaborative Project with Hancock High School, Kiln, MS". Stennis Space Center Salinity Drifter Project. NTRS. Retrieved 2011-06-16.{{cite web}}: CS1 maint: multiple names: authors list (link)
  20. ^ "Hopes To Hold The Salt, And Instead Break Out Beet Juice And Beer To Keep Roads Clear". www.wbur.org.
  21. ^ Dukhovskoy, D.S.; Myers, P.G.; Platov, G.; Timmermans, M.L.; Curry, B.; Proshutinsky, A.; Bamber, J.L.; Chassignet, E.; Hu, X.; Lee, C.M.; Somavilla, R. (2016). "Greenland freshwater pathways in the sub‐Arctic Seas from model experiments with passive tracers". Journal of Geophysical Research: Oceans. 121 (1): 877–907. Bibcode:2016JGRC..121..877D. doi:10.1002/2015JC011290. hdl:1912/7922. S2CID 603982.
  22. ^ Dukhovskoy, D.S.; Yashayaev, I.; Proshutinsky, A.; Bamber, J.L.; Bashmachnikov, I.L.; Chassignet, E.P.; Lee, M.; Tedstone, A.J. (2019). "Role of Greenland freshwater anomaly in the recent freshening of the subpolar North Atlantic". Journal of Geophysical Research: Oceans. 124 (5): 3333–3360. Bibcode:2019JGRC..124.3333D. doi:10.1029/2018JC014686. PMC 6618073. PMID 31341755.
  23. ^ Stendardo, I.; Rhein, M.; Steinfeldt, R. (2020). "The North Atlantic Current and its volume and freshwater transports in the subpolar North Atlantic, time period 1993–2016". Journal of Geophysical Research: Oceans. 125 (9). Bibcode:2020JGRC..12516065S. doi:10.1029/2020JC016065. S2CID 225238073.
  24. ^ Holliday, N. Penny; Bersch, Manfred; Berx, Barbara; Chafik, Léon; Cunningham, Stuart; Florindo-López, Cristian; Hátún, Hjálmar; Johns, William; Josey, Simon A.; Larsen, Karin Margretha H.; Mulet, Sandrine (2020-01-29). "Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic". Nature Communications. 11 (1): 585. Bibcode:2020NatCo..11..585H. doi:10.1038/s41467-020-14474-y. ISSN 2041-1723. PMC 6989661. PMID 31996687.

Further reading edit

  • Mantyla, A.W. (1987). "Standard Seawater Comparisons updated". J. Phys. Oceanogr. 17 (4): 543–548. Bibcode:1987JPO....17..543M. doi:10.1175/1520-0485(1987)017<0543:sscu>2.0.co;2.
  • MIT page of seawater properties, with Matlab, EES and Excel VBA library routines
  • Equations and algorithms to calculate fundamental properties of sea water.
  • History of the salinity determination
  • Practical Salinity Scale 1978.
  • Salinity calculator
  • Lewis, E. L. 1982. The practical salinity scale of 1978 and its antecedents. Marine Geodesy. 5(4):350–357.
  • Equations and algorithms to calculate salinity of inland waters

January 08, 2024
salinity, saltiness, amount, salt, dissolved, body, water, called, saline, water, also, soil, salinity, usually, measured, grams, salt, liter, kilogram, water, latter, dimensionless, equal, annual, mean, surface, salinity, world, ocean, data, from, world, ocea. Salinity s e ˈ l ɪ n ɪ t i is the saltiness or amount of salt dissolved in a body of water called saline water see also soil salinity It is usually measured in g L or g kg grams of salt per liter kilogram of water the latter is dimensionless and equal to Annual mean sea surface salinity for the World Ocean Data from the World Ocean Atlas 2009 1 International Association for the Physical Sciences of the Oceans IAPSO standard seawater Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it and is a thermodynamic state variable that along with temperature and pressure governs physical characteristics like the density and heat capacity of the water A contour line of constant salinity is called an isohaline or sometimes isohale Contents 1 Definitions 1 1 Composition 1 2 Seawater 1 3 Lakes and rivers 2 Classification of water bodies based upon salinity 3 Environmental considerations 4 See also 5 References 6 Further readingDefinitions editSalinity in rivers lakes and the ocean is conceptually simple but technically challenging to define and measure precisely Conceptually the salinity is the quantity of dissolved salt content of the water Salts are compounds like sodium chloride magnesium sulfate potassium nitrate and sodium bicarbonate which dissolve into ions The concentration of dissolved chloride ions is sometimes referred to as chlorinity Operationally dissolved matter is defined as that which can pass through a very fine filter historically a filter with a pore size of 0 45 mm but nowadays when usually 0 2 mm 2 Salinity can be expressed in the form of a mass fraction i e the mass of the dissolved material in a unit mass of solution Seawater typically has a mass salinity of around 35 g kg although lower values are typical near coasts where rivers enter the ocean Rivers and lakes can have a wide range of salinities from less than 0 01 g kg 3 to a few g kg although there are many places where higher salinities are found The Dead Sea has a salinity of more than 200 g kg 4 Precipitation typically has a TDS of 20 mg kg or less 5 Whatever pore size is used in the definition the resulting salinity value of a given sample of natural water will not vary by more than a few percent Physical oceanographers working in the abyssal ocean however are often concerned with precision and intercomparability of measurements by different researchers at different times to almost five significant digits 6 A bottled seawater product known as IAPSO Standard Seawater is used by oceanographers to standardize their measurements with enough precision to meet this requirement Composition edit Measurement and definition difficulties arise because natural waters contain a complex mixture of many different elements from different sources not all from dissolved salts in different molecular forms The chemical properties of some of these forms depend on temperature and pressure Many of these forms are difficult to measure with high accuracy and in any case complete chemical analysis is not practical when analyzing multiple samples Different practical definitions of salinity result from different attempts to account for these problems to different levels of precision while still remaining reasonably easy to use For practical reasons salinity is usually related to the sum of masses of a subset of these dissolved chemical constituents so called solution salinity rather than to the unknown mass of salts that gave rise to this composition an exception is when artificial seawater is created For many purposes this sum can be limited to a set of eight major ions in natural waters 7 8 although for seawater at highest precision an additional seven minor ions are also included 6 The major ions dominate the inorganic composition of most but by no means all natural waters Exceptions include some pit lakes and waters from some hydrothermal springs The concentrations of dissolved gases like oxygen and nitrogen are not usually included in descriptions of salinity 2 However carbon dioxide gas which when dissolved is partially converted into carbonates and bicarbonates is often included Silicon in the form of silicic acid which usually appears as a neutral molecule in the pH range of most natural waters may also be included for some purposes e g when salinity density relationships are being investigated Seawater edit See also Ocean Salinity source source source source source source source source Full 3 minute NASA video Feb 27 2013 The NASA Aquarius instrument aboard Argentina s SAC D satellite is designed to measure global sea surface salinity This movie shows salinity patterns as measured by Aquarius from December 2011 through December 2012 Red colors represent areas of high salinity while blue shades represent areas of low salinity The term salinity is for oceanographers usually associated with one of a set of specific measurement techniques As the dominant techniques evolve so do different descriptions of salinity Salinities were largely measured using titration based techniques before the 1980s Titration with silver nitrate could be used to determine the concentration of halide ions mainly chlorine and bromine to give a chlorinity The chlorinity was then multiplied by a factor to account for all other constituents The resulting Knudsen salinities are expressed in units of parts per thousand ppt or The use of electrical conductivity measurements to estimate the ionic content of seawater led to the development of the scale called the practical salinity scale 1978 PSS 78 9 10 Salinities measured using PSS 78 do not have units The suffix psu or PSU denoting practical salinity unit is sometimes added to PSS 78 measurement values 11 The addition of PSU as a unit after the value is formally incorrect and strongly discouraged 2 In 2010 a new standard for the properties of seawater called the thermodynamic equation of seawater 2010 TEOS 10 was introduced advocating absolute salinity as a replacement for practical salinity and conservative temperature as a replacement for potential temperature 6 This standard includes a new scale called the reference composition salinity scale Absolute salinities on this scale are expressed as a mass fraction in grams per kilogram of solution Salinities on this scale are determined by combining electrical conductivity measurements with other information that can account for regional changes in the composition of seawater They can also be determined by making direct density measurements A sample of seawater from most locations with a chlorinity of 19 37 ppt will have a Knudsen salinity of 35 00 ppt a PSS 78 practical salinity of about 35 0 and a TEOS 10 absolute salinity of about 35 2 g kg The electrical conductivity of this water at a temperature of 15 C is 42 9 mS cm 6 12 On the global scale it is extremely likely that human caused climate change has contributed to observed surface and subsurface salinity changes since the 1950s and projections of surface salinity changes throughout the 21st century indicate that fresh ocean regions will continue to get fresher and salty regions will continue to get saltier 13 Lakes and rivers edit Limnologists and chemists often define salinity in terms of mass of salt per unit volume expressed in units of mg L or g L 7 It is implied although often not stated that this value applies accurately only at some reference temperature because solution volume varies with temperature Values presented in this way are typically accurate to the order of 1 Limnologists also use electrical conductivity or reference conductivity as a proxy for salinity This measurement may be corrected for temperature effects and is usually expressed in units of mS cm A river or lake water with a salinity of around 70 mg L will typically have a specific conductivity at 25 C of between 80 and 130 mS cm The actual ratio depends on the ions present 14 The actual conductivity usually changes by about 2 per degree Celsius so the measured conductivity at 5 C might only be in the range of 50 80 mS cm Direct density measurements are also used to estimate salinities particularly in highly saline lakes 4 Sometimes density at a specific temperature is used as a proxy for salinity At other times an empirical salinity density relationship developed for a particular body of water is used to estimate the salinity of samples from a measured density Water salinityFresh water Brackish water Saline water Brine lt 0 05 0 05 3 3 5 gt 5 lt 0 5 0 5 30 30 50 gt 50 Classification of water bodies based upon salinity editThalassic series gt 300 hyperhaline60 80 metahaline40 mixoeuhaline30 polyhaline18 mesohaline5 oligohaline0 5 Marine waters are those of the ocean another term for which is euhaline seas The salinity of euhaline seas is 30 to 35 Brackish seas or waters have salinity in the range of 0 5 to 29 and metahaline seas from 36 to 40 These waters are all regarded as thalassic because their salinity is derived from the ocean and defined as homoiohaline if salinity does not vary much over time essentially constant The table on the right modified from Por 1972 15 16 follows the Venice system 1959 17 In contrast to homoiohaline environments are certain poikilohaline environments which may also be thalassic in which the salinity variation is biologically significant 18 Poikilohaline water salinities may range anywhere from 0 5 to greater than 300 The important characteristic is that these waters tend to vary in salinity over some biologically meaningful range seasonally or on some other roughly comparable time scale Put simply these are bodies of water with quite variable salinity Highly saline water from which salts crystallize or are about to is referred to as brine Environmental considerations editSalinity 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 plants that will grow either in a water body or on land fed by a water or by a groundwater 19 A plant adapted to saline conditions is called a halophyte A halophyte which is tolerant to residual sodium carbonate salinity are called glasswort or saltwort or barilla plants Organisms mostly bacteria that can live in very salty conditions are classified as extremophiles or halophiles specifically An organism that can withstand a wide range of salinities is euryhaline Salts are expensive to remove from water and salt content is an important factor in water use factoring into potability and suitability for irrigation Increases in salinity have been observed in lakes and rivers in the United States due to common road salt and other salt de icers in runoff 20 The degree of salinity in oceans is a driver of the world s ocean circulation where density changes due to both salinity changes and temperature changes at the surface of the ocean produce changes in buoyancy which cause the sinking and rising of water masses Changes in the salinity of the oceans are thought to contribute to global changes in carbon dioxide as more saline waters are less soluble to carbon dioxide In addition during glacial periods the hydrography is such that a possible cause of reduced circulation is the production of stratified oceans In such cases it is more difficult to subduct water through the thermohaline circulation Not only is salinity a driver of ocean circulation but changes in ocean circulation also affect salinity particularly in the subpolar North Atlantic where from 1990 to 2010 increased contributions of Greenland meltwater were counteracted by increased northward transport of salty Atlantic waters 13 21 22 23 However North Atlantic waters have become fresher since the mid 2010s due to increased Greenland meltwater flux 13 24 See also editDesalination for economic purposes Desalination of water Desalination of soil soil salinity control Sodium adsorption ratio Measuring salinity Salinometer Salinity by biologic context In organisms generally with particular emphasis on human health Electrolytes Fluid balance Hypernatremia Hyponatremia Salt poisoning In plants Arabidopsis thaliana responses to salinity In fish Stenohaline fish Euryhaline fish Salinity by geologic context Fresh water Seawater Soil salinity Thermohaline circulation Paleosalinity CORA dataset data on salinity of global oceans General cases of solute concentration Osmotic concentration TonicityReferences edit World Ocean Atlas 2009 nodc noaa gov a b c Pawlowicz R 2013 Key Physical Variables in the Ocean Temperature Salinity and Density Nature Education Knowledge 4 4 13 Eilers J M Sullivan T J Hurley K C 1990 The most dilute lake in the world Hydrobiologia 199 1 6 doi 10 1007 BF00007827 S2CID 30279782 a b Anati D A 1999 The salinity of hypersaline brines concepts and misconceptions Int J Salt Lake Res 8 1 55 70 Bibcode 1999IJSLR 8 55A doi 10 1007 bf02442137 Learn about salinity and water quality Retrieved 21 July 2018 a b c d IOC SCOR and IAPSO 2010 The international thermodynamic equation of seawater 2010 Calculation and use of thermodynamic properties Intergovernmental Oceanographic Commission UNESCO English pp 196pp a href Template Cite book html title Template Cite book cite book a CS1 maint multiple names authors list link a b Wetzel R G 2001 Limnology Lake and River Ecosystems 3rd ed Academic Press ISBN 978 0 12 744760 5 Pawlowicz R Feistel R 2012 Limnological applications of the Thermodynamic Equation of Seawater 2010 TEOS 10 Limnology and Oceanography Methods 10 11 853 867 Bibcode 2012LimOM 10 853P doi 10 4319 lom 2012 10 853 S2CID 93210746 Unesco 1981 The Practical Salinity Scale 1978 and the International Equation of State of Seawater 1980 Tech Pap Mar Sci 36 Unesco 1981 Background papers and supporting data on the Practical Salinity Scale 1978 Tech Pap Mar Sci 37 Millero F J 1993 What is PSU Oceanography 6 3 67 Culkin F Smith N D 1980 Determination of the Concentration of Potassium Chloride Solution Having the Same Electrical Conductivity at 15C and Infinite Frequency as Standard Seawater of Salinity 35 0000 Chlorinity 19 37394 IEEE J Oceanic Eng OE 5 1 22 23 Bibcode 1980IJOE 5 22C doi 10 1109 JOE 1980 1145443 a b c Fox Kemper B Hewitt H T Xiao C Adalgeirsdottir G Drijfhout S S Edwards T L Golledge N R Hemer M Kopp R E Krinner G Mix A 2021 Masson Delmotte V Zhai P Pirani A Connors S L Pean C Berger S Caud N Chen Y Goldfarb L eds Ocean Cryosphere and Sea Level Change PDF Climate Change 2021 The Physical Science Basis Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge UK and New York New York US Cambridge University Press 2021 1211 1362 doi 10 1017 9781009157896 011 ISBN 9781009157896 van Niekerk Harold Silberbauer Michael Maluleke Mmaphefo 2014 Geographical differences in the relationship between total dissolved solids and electrical conductivity in South African rivers Water SA 40 1 133 doi 10 4314 wsa v40i1 16 Por F D 1972 Hydrobiological notes on the high salinity waters of the Sinai Peninsula Marine Biology 14 2 111 119 Bibcode 1972MarBi 14 111P doi 10 1007 BF00373210 S2CID 86601297 Salinity Freshwater Inflows www freshwaterinflow org Retrieved 2020 10 25 Venice system 1959 The final resolution of the symposium on the classification of brackish waters Archo Oceanogr Limnol 11 suppl 243 248 Dahl E 1956 Ecological salinity boundaries in poikilohaline waters Oikos 7 1 1 21 Bibcode 1956Oikos 7 1D doi 10 2307 3564981 JSTOR 3564981 Kalcic Maria Turowski Mark Hall Callie 2010 12 22 Stennis Space Center Salinity Drifter Project A Collaborative Project with Hancock High School Kiln MS Stennis Space Center Salinity Drifter Project NTRS Retrieved 2011 06 16 a href Template Cite web html title Template Cite web cite web a CS1 maint multiple names authors list link Hopes To Hold The Salt And Instead Break Out Beet Juice And Beer To Keep Roads Clear www wbur org Dukhovskoy D S Myers P G Platov G Timmermans M L Curry B Proshutinsky A Bamber J L Chassignet E Hu X Lee C M Somavilla R 2016 Greenland freshwater pathways in the sub Arctic Seas from model experiments with passive tracers Journal of Geophysical Research Oceans 121 1 877 907 Bibcode 2016JGRC 121 877D doi 10 1002 2015JC011290 hdl 1912 7922 S2CID 603982 Dukhovskoy D S Yashayaev I Proshutinsky A Bamber J L Bashmachnikov I L Chassignet E P Lee M Tedstone A J 2019 Role of Greenland freshwater anomaly in the recent freshening of the subpolar North Atlantic Journal of Geophysical Research Oceans 124 5 3333 3360 Bibcode 2019JGRC 124 3333D doi 10 1029 2018JC014686 PMC 6618073 PMID 31341755 Stendardo I Rhein M Steinfeldt R 2020 The North Atlantic Current and its volume and freshwater transports in the subpolar North Atlantic time period 1993 2016 Journal of Geophysical Research Oceans 125 9 Bibcode 2020JGRC 12516065S doi 10 1029 2020JC016065 S2CID 225238073 Holliday N Penny Bersch Manfred Berx Barbara Chafik Leon Cunningham Stuart Florindo Lopez Cristian Hatun Hjalmar Johns William Josey Simon A Larsen Karin Margretha H Mulet Sandrine 2020 01 29 Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic Nature Communications 11 1 585 Bibcode 2020NatCo 11 585H doi 10 1038 s41467 020 14474 y ISSN 2041 1723 PMC 6989661 PMID 31996687 Further reading editMantyla A W 1987 Standard Seawater Comparisons updated J Phys Oceanogr 17 4 543 548 Bibcode 1987JPO 17 543M doi 10 1175 1520 0485 1987 017 lt 0543 sscu gt 2 0 co 2 MIT page of seawater properties with Matlab EES and Excel VBA library routines Equations and algorithms to calculate fundamental properties of sea water History of the salinity determination Practical Salinity Scale 1978 Salinity calculator Lewis E L 1982 The practical salinity scale of 1978 and its antecedents Marine Geodesy 5 4 350 357 Equations and algorithms to calculate salinity of inland waters Retrieved from https en wikipedia org w index php title Salinity amp oldid 1192682581, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.