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Archaea: Ecology

Archaeans include inhabitants of some of the most extreme environmentson the planet. Some live near rift vents in the deep sea at temperatureswell over 100 degrees Centigrade. Others live in hot springs, in extremelyalkaline or acid waters, or in extremely saline water. Thesepictures show an immense bloom of ahalophilic ("salt-loving"; dependent on high salt concentrations)archaean species, in a saline pond at a saltworks near San Quintin, Baja California Norte, Mexico.This archaean,Halobacterium,also lives in enormous numbers in salt ponds at the south end ofSan Francisco Bay; interested residents of this area should take theDumbarton Bridge for the best views. An interesting fact aboutHalobacterium is that the red light-sensitive pigment that givesHalobacterium its color, which is a simple photosynthetic systemthat provides the archaean with chemical energy, is known asbacteriorhodopsin -- and is chemically very similarto the light-detecting pigmentrhodopsin, found in the vertebrate retina.

General Links :

• An impressive set of links to all things Archaean may be found atLife in Extreme Environments: Archaea on the Astrobiology Web.
• Get a general introduction to themajor groups of prokaryotes from Kenneth Todar at the University of Wisconsin--Madison.

• Read about undersea black smoker vents at the American Museum of Natural History'sBlack Smokers page.
• TheMicrobe Zoo features several methane-producing organisms, including some Archaea.
• For more information on Halobacteria, including lesson information for teachers, go toThe HaloEd Project.

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