Brine shrimp, also known as fairy shrimp, are remarkable crustaceans that inhabit highly saline lakes, ponds, and other waters throughout the world. Some brine shrimp can thrive in water that's 10 times saltier than ocean water, where little else can survive.

Brine shrimp (Order Anostraca) are small crustaceans without shells. Their bodies are clearly segmented and elongated. Brine shrimp use 11 pairs of swimming legs to propel themselves through the water, but they swim upside down, feeding on microalgae in the water.


Several adaptations enable brine shrimp to survive in a high saline environment. The brine shrimp's body is covered with a special lining that makes it impermeable to water, and prevents excess salt from being absorbed through its skin. Salt water enters the brine shrimp's body only through the mouth during feeding. Immature brine shrimp have a special gland in the neck, which is believed to function as a salt pump, eliminating any excess salt from the body. In adult brine shrimp, a special stomach lining absorbs salt water, and the salt is then excreted through the gills.

Even with these adaptations, environmental conditions can become too severe for brine shrimp to survive. Extreme changes in temperate, salinity, or other environmental conditions can trigger a change in the life cycle. Instead of producing live, free-swimming offspring (called nauplii), the brine shrimp produces special embryos called cysts, which can remain dormant for years through drought and temperature extremes. The cysts remain in diapause until conditions become favorable again, when they hatch and a new generation of nauplii emerges.

Brine shrimp are harvested commercially, usually as egg cysts, for use as fish food and as a novelty item. Do you remember Sea Monkeys? In 1957, an enterprising fellow named Harold von Braunhut started packaging brine shrimp cysts and selling them as a magical product called "Instant Life." Just add water! A few years later, he changed the name to Sea Monkeys and started marketing them as instant pets in comic books. In 1998, John Glenn took Sea Monkeys on the space shuttle Discovery. After 9 days in space, the Sea Monkeys landed back on Earth, and they hatched 8 weeks later. Sea Monkey enthusiasts celebrate their beloved brine shrimp every May 16^th, which has been designated National Sea Monkey Day.

 

_Sources:

• _{What is a brine shrimp?, Great Salt Lake Ecosystem Program website. Accessed online July 28, 2015.}
• _{Introduction to the Branchiopoda, University of California Museum of Paleontology website. Accessed online July 28, 2015.}
• _{Toys and American Culture: An Encyclopedia, by Sharon M. Scott.}