The green crab (Carcinus maenas) is an example of a euryhaline invertebrate that can live in salt and brackish water. Euryhaline organisms are commonly found in habitats such as estuaries and tide pools where the salinity changes regularly. However, some organisms are euryhaline because their life cycle involves migration between freshwater and marine environments, as is the case with salmon and eels.
The opposite of euryhaline organisms are stenohaline ones, which can only survive within a narrow range of salinities. Most freshwater organisms are stenohaline, and will die in seawater, and similarly most marine organisms are stenohaline, and cannot live in fresh water.
Osmoregulation is the active process by which an organism maintains its level of water content. The osmotic pressure in the body is homeostatically regulated in such a manner that it keeps the organism's fluids from becoming too diluted or too concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis.
Two major types of osmoregulation are osmoconformers and osmoregulators. Osmoconformers match their body osmolarity to their environment actively or passively. Most marine invertebrates are osmoconformers, although their ionic composition may be different from that of seawater.
Osmoregulators tightly regulate their body osmolarity, which always stays constant, and are more common in the animal kingdom. Osmoregulators actively control salt concentrations despite the salt concentrations in the environment. An example is freshwater fish. The gills actively uptake salt from the environment by the use of mitochondria-rich cells. Water will diffuse into the fish, so it excretes a very hypotonic (dilute) urine to expel all the excess water. A marine fish has an internal osmotic concentration lower than that of the surrounding seawater, so it tends to lose water (to the more negative surroundings) and gain salt. It actively excretes salt out from the gills. Most fish are stenohaline, which means they are restricted to either salt or fresh water and cannot survive in water with a different salt concentration than they are adapted to. However, some fish show a tremendous ability to effectively osmoregulate across a broad range of salinities; fish with this ability are known as euryhaline species, e.g., salmon. Salmon has been observed to inhabit two utterly disparate environments — marine and fresh water — and it is inherent to adapt to both by bringing in behavioral and physiological modifications.
Some marine fish, like sharks, have adopted a different, efficient mechanism to conserve water, i.e., osmoregulation. They retain urea in their blood in relatively higher concentration. Urea is damaging to living tissue so, to cope with this problem, some fish retain trimethylamine oxide. This provides a better solution to urea's toxicity. Sharks, having slightly higher solute concentration (i.e., above 1000 mOsm which is sea solute concentration), do not drink water like marine fish.
The level of salinity in intertidal zones can also be quite variable. Low salinities can be caused by rainwater or river inputs of freshwater. Estuarine species must be especially euryhaline, or able to tolerate a wide range of salinities. High salinities occur in locations with high evaporation rates, such as in salt marshes and high intertidal pools. Shading by plants, especially in the salt marsh, can slow evaporation and thus ameliorate salinity stress. In addition, salt marsh plants tolerate high salinities by several physiological mechanisms, including excreting salt through salt glands and preventing salt uptake into the roots.
Despite having a regular freshwater presence, the Atlantic stingray is physiologically euryhaline and no population has evolved the specialized osmoregulatory mechanisms found in the river stingrays of the family Potamotrygonidae. This may be due to the relatively recent date of freshwater colonization (under one million years), and/or possibly incomplete genetic isolation of the freshwater populations, as they remain capable of surviving in salt water. Freshwater Atlantic stingrays have only 30-50% the concentration of urea and other osmolytes in their blood compared to marine populations. However, the osmotic pressure between their internal fluids and external environment still causes water to diffuse into their bodies, and they must produce large quantities of dilute urine (at 10 times the rate of marine individuals) to compensate.[2]
^Thorson, T.B. (1983). "Observations on the morphology, ecology and life history of the euryhaline stingray, Dasyatis guttata (Bloch and Schneider) 1801". Acta Biologica Venezuelica. 11 (4): 95–126.
^Piermarini, P.M.; Evans, D.H. (1998). (PDF). Physiological and Biochemical Zoology. 71 (5): 553–560. doi:10.1086/515973. PMID 9754532. S2CID 1980147. Archived from the original (PDF) on 2020-07-31.
February 16, 2024
euryhaline, organisms, able, adapt, wide, range, salinities, example, euryhaline, fish, short, finned, molly, poecilia, sphenops, which, live, fresh, water, brackish, water, salt, water, green, crab, carcinus, maenas, example, euryhaline, invertebrate, that, l. Euryhaline organisms are able to adapt to a wide range of salinities An example of a euryhaline fish is the short finned molly Poecilia sphenops which can live in fresh water brackish water or salt water The green crab Carcinus maenas is an example of a euryhaline invertebrate that can live in salt and brackish water Euryhaline organisms are commonly found in habitats such as estuaries and tide pools where the salinity changes regularly However some organisms are euryhaline because their life cycle involves migration between freshwater and marine environments as is the case with salmon and eels The opposite of euryhaline organisms are stenohaline ones which can only survive within a narrow range of salinities Most freshwater organisms are stenohaline and will die in seawater and similarly most marine organisms are stenohaline and cannot live in fresh water Contents 1 Osmoregulation 2 Euryhaline fish 3 Other euryhaline organisms 4 See also 5 ReferencesOsmoregulation editOsmoregulation nbsp Movement of water and ions in a saltwater fish yellow jack nbsp Movement of water and ions in a freshwater fish brown trout See also Osmoregulation Osmoregulation is the active process by which an organism maintains its level of water content The osmotic pressure in the body is homeostatically regulated in such a manner that it keeps the organism s fluids from becoming too diluted or too concentrated Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis Two major types of osmoregulation are osmoconformers and osmoregulators Osmoconformers match their body osmolarity to their environment actively or passively Most marine invertebrates are osmoconformers although their ionic composition may be different from that of seawater Osmoregulators tightly regulate their body osmolarity which always stays constant and are more common in the animal kingdom Osmoregulators actively control salt concentrations despite the salt concentrations in the environment An example is freshwater fish The gills actively uptake salt from the environment by the use of mitochondria rich cells Water will diffuse into the fish so it excretes a very hypotonic dilute urine to expel all the excess water A marine fish has an internal osmotic concentration lower than that of the surrounding seawater so it tends to lose water to the more negative surroundings and gain salt It actively excretes salt out from the gills Most fish are stenohaline which means they are restricted to either salt or fresh water and cannot survive in water with a different salt concentration than they are adapted to However some fish show a tremendous ability to effectively osmoregulate across a broad range of salinities fish with this ability are known as euryhaline species e g salmon Salmon has been observed to inhabit two utterly disparate environments marine and fresh water and it is inherent to adapt to both by bringing in behavioral and physiological modifications Some marine fish like sharks have adopted a different efficient mechanism to conserve water i e osmoregulation They retain urea in their blood in relatively higher concentration Urea is damaging to living tissue so to cope with this problem some fish retain trimethylamine oxide This provides a better solution to urea s toxicity Sharks having slightly higher solute concentration i e above 1000 mOsm which is sea solute concentration do not drink water like marine fish Euryhaline fish editSome euryhaline fish nbsp Short finned molly nbsp Round goby nbsp Atlantic stingray nbsp Bat ray nbsp Longnose stingray 1 nbsp Big scale sand smelt nbsp Moonyfishes nbsp Pink salmon nbsp Barramundi nbsp Green sawfish nbsp Spanish toothcarp nbsp Atlantic threadfin nbsp Desert pupfish nbsp Mayan cichlid nbsp Crevalle jacksThe level of salinity in intertidal zones can also be quite variable Low salinities can be caused by rainwater or river inputs of freshwater Estuarine species must be especially euryhaline or able to tolerate a wide range of salinities High salinities occur in locations with high evaporation rates such as in salt marshes and high intertidal pools Shading by plants especially in the salt marsh can slow evaporation and thus ameliorate salinity stress In addition salt marsh plants tolerate high salinities by several physiological mechanisms including excreting salt through salt glands and preventing salt uptake into the roots Despite having a regular freshwater presence the Atlantic stingray is physiologically euryhaline and no population has evolved the specialized osmoregulatory mechanisms found in the river stingrays of the family Potamotrygonidae This may be due to the relatively recent date of freshwater colonization under one million years and or possibly incomplete genetic isolation of the freshwater populations as they remain capable of surviving in salt water Freshwater Atlantic stingrays have only 30 50 the concentration of urea and other osmolytes in their blood compared to marine populations However the osmotic pressure between their internal fluids and external environment still causes water to diffuse into their bodies and they must produce large quantities of dilute urine at 10 times the rate of marine individuals to compensate 2 Partial listAtlantic stingray Bull shark Green chromide Herring Lamprey Mummichog Molly Guppy Puffer fish Salmon Shad Striped bass Sturgeon Tilapia Trout Barramundi Mangrove jack White perch Killifish Desert pupfish nbsp Cobia nbsp Flathead mullet nbsp Bull sharkOther euryhaline organisms editother euryhaline organisms nbsp the seagrass Halodule uninervis nbsp Green sea urchin nbsp White spotted jellyfish nbsp Lagoon cockle nbsp New Zealand mud snail nbsp Amphipods of the family Gammaridae nbsp Irrawaddy dolphin nbsp Asian shore crab nbsp Shore crab nbsp Crab eating frog nbsp Diamondback terrapinSee also editFish migration Osmoregulation Stenohaline OsmoconformerReferences edit Thorson T B 1983 Observations on the morphology ecology and life history of the euryhaline stingray Dasyatis guttata Bloch and Schneider 1801 Acta Biologica Venezuelica 11 4 95 126 Piermarini P M Evans D H 1998 Osmoregulation of the Atlantic Stingray Dasyatis sabina from the Freshwater Lake Jesup of the St Johns River Florida PDF Physiological and Biochemical Zoology 71 5 553 560 doi 10 1086 515973 PMID 9754532 S2CID 1980147 Archived from the original PDF on 2020 07 31 Retrieved from https en wikipedia org w index php title Euryhaline amp oldid 1193620384, wikipedia, wiki, book, books, library,
