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| Brine shrimp | ||||||||||||||
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 Artemia salina
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Artemia franciscana |
Brine shrimp are a species of aquatic crustaceans of the genus Artemia. Artemia, the only genus in the family Artemiidae, have evolved little since the Triassic period. First discovered in Lymington, England, in 1755,[1] Artemia are found worldwide in inland saltwater lakes, but not in oceans.
Artemia is a well known genus as one variety (sometimes identified as a new species Artemia salina x nyos), a cultivated subspecies of Artemia salina and is sold as novelty gifts most commonly under the marketing name Sea-Monkeys.
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Life cycle
Brine shrimp eggs are metabolically inactive and can remain in total stasis for several years while in a dry, oxygen-free environment, even at temperatures below freezing. This characteristic is called cryptobiosis meaning "hidden life" (also called diapause). Once placed in water the cyst-like eggs hatch within a few hours, and will grow to a mature length of around one cm on average. Brine shrimp have a biological life cycle of one year. This short life span and other characteristics such as their ability to remain dormant for long periods have made them invaluable in scientific research, including space experiments.
Diet
The nauplii, or larvae, of brine shrimp are less than 0.5mm when they first hatch. They eat micro-algae, but will also eat yeast, wheat flour, soybean powder, or egg yolk.[2]
Tolerance to salinity
Brine shrimp can tolerate varying levels of salinity. A common biology experiment in school is to investigate the effect of salinity levels on the growth of these creatures.
Nutritional benefits
The nutritional properties of newly hatched brine shrimp make them particularly suitable to be sold as aquarium food as they are high in lipids and unsaturated fatty acids (but low in calcium). These nutritional benefits are likely to be one reason that brine shrimp are found only in highly salinated waters with reasonable temperatures. This makes sense as these areas are uninhabitable for potential predators.
'Threatened'
Artemia monica, the variety commonly known as Mono Lake brine shrimp, are found only in Mono Lake, Mono County, California. In 1987, Dr. Dennis D. Murphy from Stanford University petitioned the United States Fish and Wildlife Service to add Artemia monica to the endangered species list under the Endangered Species Act 1973. Despite there being trillions of these creatures in Mono Lake, it was felt that rising levels of salinity and sodium hydroxide concentration of the lake would endanger them because of the increase in pH. However, the US Fish and Wildlife Service reported in the Federal Register on 7 September 1995 that this brine shrimp did not warrant listing after the threat to the lake was removed following a revised policy by the California State Water Resources Control Board.[3]
References
- ^ Eads, Brian D. (2004). "SALTY SURVIVORS: Artemia: Basic and Applied Biology". J Exp Biol 207 (11): 1757–8. doi:. Retrieved on 2008-03-20.
- ^ Schumann, Kai (1997-08-10). "Artemia (Brine Shrimp) FAQ 1.1". Portland State University. Archived from the original on 2007-08-14. Retrieved on 2008-03-20.
- ^ United States Fish and Wildlife Service (1995). Endangered and Threatened Wildlife and Plants; 12-Month Finding for a Petition to List the Mono Lake Brine Shrimp as Endangered. Federal Register 60 (173): 46571–46572.
Bibliography
- Salty Survivors: Artemia: Basic and Applied Biology, Edited by Th. J. Abatzopoulos, J. A. Beardmore, J. S. Clegg and P. Sorgeloos , Kluwer Academic Publishers (2002). ISBN 1402007469
External links
- http://sn2000.taxonomy.nl/Taxonomicon/TaxonTree.aspx?id=33062 "Genus Artemia", The Taxonomicon & Systema Naturae 2000
- http://web.archive.org/web/20060423082302/http://www.lander.edu/rsfox/310artemiaLab.html "Artemia franciscana" Invertebrate Anatomy Online
- http://ut.water.usgs.gov/shrimp/index.html "Brine Shrimp and Ecology of Great Salt Lake", United States Geological Survey
