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Euryhaline Fish Of Nicaragua
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the 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. Osmoregulation Osmoregulation is the active process by which an organism maintains its level of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salinity
Salinity () 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 ‰). 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 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmotic Pressure
Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane. It is also defined as the measure of the tendency of a solution to take in a pure solvent by osmosis. Potential osmotic pressure is the maximum osmotic pressure that could develop in a solution if it were separated from its pure solvent by a semipermeable membrane. Osmosis occurs when two solutions containing different concentrations of solute are separated by a selectively permeable membrane. Solvent molecules pass preferentially through the membrane from the low-concentration solution to the solution with higher solute concentration. The transfer of solvent molecules will continue until equilibrium is attained. Theory and measurement Jacobus van 't Hoff found a quantitative relationship between osmotic pressure and solute concentration, expressed in the following equation: :\Pi = icRT where \Pi is osmotic p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moonyfish
Monodactylidae is a family of perciform bony fish commonly referred to as monos, moonyfishes or fingerfishes. All are strongly laterally compressed with disc-shaped bodies and tall anal and dorsal fins. Unusually for fish, scales occur on their dorsal fins and sometimes on the anal fins. The pelvic fins are small, sometimes vestigial. They are of moderate size, typically around in length, and ''Monodactylus sebae'' can be taller than it is long, measuring up to from the tip of the dorsal fin down to the tip of the anal fin. These long, scaly fins have given them the name "fingerfishes". Most are silvery with yellow and black markings; the juveniles are especially attractive, and most species are popular as aquarium fish. The family contains six extant species in two genera, ''Monodactylus'' and ''Schuettea''. They are distributed along the coastlines of Africa, India, and southern Asia, and as far west as Australia. Species of ''Monodactylus'' in particular commonly occur in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Big-scale Sand Smelt
The big-scale sand smelt (''Atherina boyeri'') is a species of fish in the family Atherinidae. It is a euryhaline amphidromous fish, up to 20 cm in length. Description It is a small pelagic fish species which occurs near the surface in the littoral estuarine zone: in lagoons, salt marshes (77 psu), shallow brackish areas (2 psu) and inland waters which are rather unsuitable for other fish species, due to their high ionic strength and salinity. Body is rather long, slender, moderately flattened. Eyes are large. Head and body are scaly. Mouth is protractible, upwardly directed, with small teeth. Lower jaw has an upper expansion within mouth (high dentary bone). There are two separate dorsal fins, with all rays of first and 1-2 anterior rays of second dorsal fin being unsegmented. The anal fin is similar to the second dorsal fin, while the caudal fin is forked. The first dorsal fin has 6-10 flexible spines. It is an omnivorous species feeding on zoo-plankton and small bottom-l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longnose Stingray
The longnose stingray (''Dasyatis guttata'') is a species of stingray in the family Dasyatidae, native to the western Atlantic Ocean from the southern Gulf of Mexico to Brazil. Found in coastal waters no deeper than , this demersal species favors muddy or sandy habitats. The longnose stingray is characterized by its angular, rhomboid pectoral fin disc, moderately projecting snout, and whip-like tail with a dorsal keel and ventral fin fold. It typically grows to across and is brownish above and light-colored below. Longnose stingrays feed mainly on bottom-dwelling invertebrates and small bony fishes. Reproduction is aplacental viviparous, with females bearing two litters of 1–2 pups per year. The young are born in relatively fresh water, move into saltier water as juveniles, and then back into fresher water as adults. This species is valued by commercial and recreational fishers in many parts of its range, and utilized for meat, gelatin, oil, and even the aquarium trade. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bat Ray
The bat ray (''Myliobatis californica'')Gill, T.N. (1865). "Note on the family of myliobatoids, and on a new species of ''Aetobatis''". ''Ann. Lyc. Nat. Hist. N. Y.'' 8, 135–138. is an eagle ray found in muddy or sandy sloughs, estuaries and bays, kelp beds and rocky-bottomed shoreline in the eastern Pacific Ocean, between the Oregon coast and the Gulf of California. It is also found in the area around the Galápagos Islands.Florida Museum of Natural HistoryBat Ray Biological Profile Retrieved 2006-01-16. The largest specimens can grow to a wingspan of and a mass of .Monterey Bay Aquarium Online Field GuideBat Ray Retrieved 2012-06-14. They more typically range from . The size of the bat ray is dependent on many factors, such as habitat alterations, different oceanographic and environmental conditions. Bat rays have one to three venomous barbed spines at the base of its tail. Some bat rays are solitary while others form schools numbering in the thousands. The sexual maturit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Stingray
The Atlantic stingray (''Dasyatis sabina'') is a species of stingray in the family Dasyatidae, common along the Atlantic coast of North America from Chesapeake Bay to Mexico, including brackish and freshwater habitats. It may be distinguished from other stingrays in the area by its relatively elongated snout. This species is of little commercial importance, other than for sale in the aquarium industry. Taxonomy and phylogeny The Atlantic stingray was described by French naturalist Charles Alexandre Lesueur as ''Trygon sabina'', in an 1824 volume of the ''Journal of the Academy of Natural Sciences of Philadelphia''. He based his account on a damaged male specimen collected by American naturalist Titian Ramsay Peale during the Academy's 1817 expedition to Florida. Since then, various authors have included this species in the obsolete genera ''Pastinaca'', ''Dasybatus'' (or the variants ''Dasibatis'' and ''Dasybatis''), and ''Amphotistius'', all of which were eventually synonymi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Round Goby
The round goby (''Neogobius melanostomus'') is a fish. Defined as a euryhaline bottom-dwelling goby of the family Gobiidae, it is native to Central Eurasia, including the Black Sea and the Caspian Sea. Round gobies have established large non-native populations in the Baltic Sea, several major Eurasian rivers, and the North American Great Lakes. Characteristics Round gobies are small, soft-bodied fish characterized by a distinctive black spot on the first dorsal fin. The eyes are large and protrude slightly from the top of the head and, like most gobies, the pelvic fins are fused to form a single disc (shaped like a suction cup) on the belly. Round gobies range in length from , with a maximum size of . They weigh between , their weight increasing with age. Male round gobies are larger than females. Juvenile round gobies (less than one year old) are grey. Upon maturation, round gobies become mottled with grey, black, brown, and olive green markings. Adult male round gobies turn ink ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylamine Oxide
Trimethylamine ''N''-oxide (TMAO) is an organic compound with the formula (CH3)3NO. It is in the class of amine oxides. Although the anhydrous compound is known, trimethylamine ''N''-oxide is usually encountered as the dihydrate. Both the anhydrous and hydrated materials are white, water-soluble solids. TMAO is found in the tissues of marine crustaceans and marine fish, where it prevents water pressure from distorting proteins and thus killing the animal. The concentration of TMAO increases with the depth at which the animal lives; TMAO is found in high concentrations in the deepest-living described fish species, ''Pseudoliparis swirei'', which was found in the Mariana Trench, at a recorded depth of . TMAO is a product of the oxidation of trimethylamine, a common metabolite of choline in animals. Marine animals Trimethylamine ''N''-oxide is an osmolyte found in molluscs, crustaceans, and all marine fishes and bony fishes. It is a protein stabilizer that serves to counteract the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill
A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia (pl. branchiae) is the zoologists' name for gills (from Ancient Greek ). With the exception of some aquatic insects, the filaments and lamellae (folds) contain blood or coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including mollusks, crustaceans, insects, fish, and amphibians. Semiterrestrial marine animals such as crabs and mudskippers have gill cham ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantities in seawater. The open ocean has about of solids per liter of sea water, a salinity of 3.5%. Salt is essential for life in general, and saltiness is one of the basic human tastes. Salt is one of the oldest and most ubiquitous food seasonings, and is known to uniformly improve the taste perception of food, including otherwise unpalatable food. Salting, brining, and pickling are also ancient and important methods of food preservation. Some of the earliest evidence of salt processing dates to around 6,000 BC, when people living in the area of present-day Romania boiled spring water to extract salts; a salt-works in China dates to approximately the same period. Salt was also prized by the ancient Hebrews, Greeks, Romans, Byzantines, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonicity
In chemical biology, tonicity is a measure of the effective osmotic pressure gradient; the water potential of two solutions separated by a partially-permeable cell membrane. Tonicity depends on the relative concentration of selective membrane-impermeable solutes across a cell membrane which determine the direction and extent of osmotic flux. It is commonly used when describing the swelling-versus-shrinking response of cells immersed in an external solution. Unlike osmotic pressure, tonicity is influenced only by solutes that cannot cross the membrane, as only these exert an effective osmotic pressure. Solutes able to freely cross the membrane do not affect tonicity because they will always equilibrate with equal concentrations on both sides of the membrane without net solvent movement. It is also a factor affecting imbibition. There are three classifications of tonicity that one solution can have relative to another: ''hypertonic'', ''hypotonic'', and ''isotonic''.A hypotonic s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
