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Smithsonian National Museum of Natural History
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Mid-Oceanic Ridge Shrimp - Rimicaris exoculata Williams & Rona, 1986

Ridge ShrimpLine drawing adapted from Williams & Rona, 1986, USNM 310708

Volcanic vents along the Mid-Atlantic Ridge, where superheated water and dissolved gases spew out from cracks in the earth's surface at the bottom of the sea, are recognized as sites of extraordinary assemblages of animals - giant tube worms, giant clams, vent crabs, and blind shrimp. These vent systems were discovered in 1977, and since then more than 500 fully identified species have been described or recorded living in these remarkable environments. The shrimp, Rimicaris exoculata, is so abundant in some vent areas that swarms of about 2,500 individuals per square meter have been documented on active chimney walls were water temperature ranges from 10° to 30° C. These shrimp lack eyestalks and pigmented eyes, and were originally presumed to be blind. However, close examination revealed a pair of large dorsal organs just beneath the transparent carapace that contain visual pigment but lacking any image-forming structures like lenses. It has been proposed that the shrimp can detect thermal radiation (very dim light) given off by the superheated water coming from the hydrothermal vents. The shrimp feed on bacteria that are “cultivated” on their mouthparts or on the mineral particles ingested. The carapace length of these shrimp varies in length from 22.0 to 55.0 mm.

The Smithsonian crustacean holdings contain one of the most complete collection of hydrothermal vent invertebrate species, and is used by scientists from all over the world to study many biological aspects of the unique fauna from these deep-sea environments.

ON THE WEB:

Search "hydrothermal vents" and "deep ocean" for many interesting sites, among them:
http://www.ocean.udel.edu/deepsea/home/home.html
Click on "Creature Features" to learn about a vent crab.

AT YOUR LIBRARY OR BOOKSTORE:

Readers Age 12 and above may like:
Kate Madin. Down to a Sunless Sea: The Strange World of Hydrothermal Vents. 1999.

High school students may enjoy:
Cindy Lee Van Dover. The Octopus's Garden: Hydrothermal Vents and Other Mysteries of the Deep Sea. 1996. Addison Wesley.

Daniel Desbruyeres, Michel Segonzac and Monica Bright (Eds). Handbook of Deep-Sea Hydrothermal Vent Fauna, Series: DENISIA 18. 2006. 544 pages, illus.

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