Artemia salina
Encyclopedia
Artemia salina is a species of brine shrimp
– aquatic crustacean
s that are more closely related to Triops
and cladocera
ns than to true shrimp
. It is a very old species that does not appear to have changed in .
, which is also found in vertebrate
s. Males differ from females by two large antennae
on the head.
. There are two types of eggs: thin–shelled eggs that hatch immediately and thick–shelled eggs, which can remain in a dormant state
. These cyst
s can last for a number of years, and will hatch when they are placed in water. Thick–shelled eggs are produced when the body of water is drying out, raising the salt concentration. If the female dies, the eggs develop further. Eggs hatch into nauplii that are about 0.5 mm in length. They have one single simple eye that only senses the presence and direction of light. Nauplii swim towards the light but adult individuals swim away from it. Later, the two more capable eyes develop but the initial eye also stays, resulting in three-eyed creatures.
s. They are almost never found in an open sea, most likely because of the lack of food and relative defenselessness. However, Artemia have been observed in Elkhorn Slough
, which is connected to the sea. Unlike most aquatic species, Artemia swims upside down.
Artemia can live in water having much more or much less salt content than normal seawater. They tolerate salt amounts as high as 50%, which is nearly a saturated solution, and can live for several days in solutions very different from the sea water, such as potassium permanganate
or silver nitrate
, while iodine
– a frequent addition to edible salt
– is harmful to them. The animal's color depends on the salt concentration, with high concentrations giving them a slightly red appearance. In fresh water, Artemia salina dies after about an hour. These shrimp feed mainly on green algae
.
of chemicals. In addition, the eggs survive for years. Hence it is possible to buy eggs and also "Artemia growing kits" for children, containing eggs, salt, food and most necessary tools. These have been most popularly marketed under the name Sea Monkeys. Children have the possibility to observe the life cycle of this interesting organism. Aquaristic
shops also sell frozen Artemia as fish food. Artemia occurs in vast numbers in the Great Salt Lake
where it is commercially important. However, nowadays it is believed that this lake is inhabited by a second brine shrimp species, Artemia franciscana.
, England
. That population is now extinct
, although specimens collected there are retained in zoological museums.
Brine shrimp
Artemia is a genus of aquatic crustaceans known as brine shrimp. Artemia, the only genus in the family Artemiidae, has changed little externally since the Triassic period...
– aquatic crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s that are more closely related to Triops
Triops
Triops is a genus of small crustaceans in the order Notostraca . They are considered living fossils, with a fossil record that reaches back to the Carboniferous, .-Relatives and fossil record:...
and cladocera
Cladocera
Cladocera is an order of small crustaceans commonly called water fleas. Around 620 species have been recognised so far, with many more undescribed. They are ubiquitous in inland aquatic habitats, but rare in the oceans. Most are long, with a down-turned head, and a carapace covering the apparently...
ns than to true shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
. It is a very old species that does not appear to have changed in .
Description
Adults have three eyes and 11 pairs of legs and can grow to about 15 millimetre (0.590551181102362 in) in size. Their blood contains the pigment hemoglobinHemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...
, which is also found in vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s. Males differ from females by two large antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
on the head.
Life cycle
Males have two reproductive organs. The females can produce eggs either in the usual way or via parthenogenesisParthenogenesis
Parthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...
. There are two types of eggs: thin–shelled eggs that hatch immediately and thick–shelled eggs, which can remain in a dormant state
Dormancy
Dormancy is a period in an organism's life cycle when growth, development, and physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions...
. These cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...
s can last for a number of years, and will hatch when they are placed in water. Thick–shelled eggs are produced when the body of water is drying out, raising the salt concentration. If the female dies, the eggs develop further. Eggs hatch into nauplii that are about 0.5 mm in length. They have one single simple eye that only senses the presence and direction of light. Nauplii swim towards the light but adult individuals swim away from it. Later, the two more capable eyes develop but the initial eye also stays, resulting in three-eyed creatures.
Ecology
In nature, they live in salt lakeSalt lake
A salt lake or saline lake is a landlocked body of water which has a concentration of salts and other dissolved minerals significantly higher than most lakes . In some cases, salt lakes have a higher concentration of salt than sea water, but such lakes would also be termed hypersaline lakes...
s. They are almost never found in an open sea, most likely because of the lack of food and relative defenselessness. However, Artemia have been observed in Elkhorn Slough
Elkhorn Slough
Elkhorn Slough is a tidal slough and estuary on Monterey Bay in Monterey County, California. The community of Moss Landing and the huge Moss Landing Power Plant are located at the mouth of the slough on the bay....
, which is connected to the sea. Unlike most aquatic species, Artemia swims upside down.
Artemia can live in water having much more or much less salt content than normal seawater. They tolerate salt amounts as high as 50%, which is nearly a saturated solution, and can live for several days in solutions very different from the sea water, such as potassium permanganate
Potassium permanganate
Potassium permanganate is an inorganic chemical compound with the formula KMnO4. It is a salt consisting of K+ and MnO4− ions. Formerly known as permanganate of potash or Condy's crystals, it is a strong oxidizing agent. It dissolves in water to give intensely purple solutions, the...
or silver nitrate
Silver nitrate
Silver nitrate is an inorganic compound with chemical formula . This compound is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides...
, while iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
– a frequent addition to edible salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
– is harmful to them. The animal's color depends on the salt concentration, with high concentrations giving them a slightly red appearance. In fresh water, Artemia salina dies after about an hour. These shrimp feed mainly on green algae
Green algae
The green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic...
.
Uses
The resilience of these creatures make them ideal test samples in experiments. Artemia is one of the standard organisms for testing the toxicityToxicity
Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
of chemicals. In addition, the eggs survive for years. Hence it is possible to buy eggs and also "Artemia growing kits" for children, containing eggs, salt, food and most necessary tools. These have been most popularly marketed under the name Sea Monkeys. Children have the possibility to observe the life cycle of this interesting organism. Aquaristic
Fishkeeping
Fishkeeping is a popular hobby concerned with keeping fish in a home aquarium or garden pond. There is also a fishkeeping industry, as a branch of agriculture.-Types of fishkeeping systems:...
shops also sell frozen Artemia as fish food. Artemia occurs in vast numbers in the Great Salt Lake
Great Salt Lake
The Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt water lake in the western hemisphere, the fourth-largest terminal lake in the world. In an average year the lake covers an area of around , but the lake's size fluctuates substantially due to its...
where it is commercially important. However, nowadays it is believed that this lake is inhabited by a second brine shrimp species, Artemia franciscana.
Taxonomy
Artemia salina was first described (as Cancer salinus) by Carl Linnaeus in his in 1758. This was based on a report by a German called Schlosser, who had found Artemia at LymingtonLymington
Lymington is a port on the west bank of the Lymington River on the Solent, in the New Forest district of Hampshire, England. It is to the east of the South East Dorset conurbation, and faces Yarmouth on the Isle of Wight which is connected to it by a car ferry, operated by Wightlink. The town...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. That population is now extinct
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
, although specimens collected there are retained in zoological museums.