Archaea: Ecology

Salt-lovers : immense bloom of a halophilic ("salt-loving") archaean species at a salt works near San Quentin, Baja California Norte, Mexico. This archaean, Halobacterium, also lives in enormous numbers in salt ponds at the south end of San Francisco Bay; interested residents of this area should take the Dumbarton Bridge for the best views.

Archaeans include inhabitants of some of the most extreme environments on the planet. Some live near rift vents in the deep sea at temperatures well over 100 degrees Centigrade. Others live in hot springs, in extremely alkaline or acid waters, or in extremely saline water. These pictures show an immense bloom of a halophilic ("salt-loving"; dependent on high salt concentrations) archaean species, in a saline pond at a salt works near San Quintin, Baja California Norte, Mexico. This archaean, Halobacterium, also lives in enormous numbers in salt ponds at the south end of San Francisco Bay; interested residents of this area should take the Dumbarton Bridge for the best views. An interesting fact about Halobacterium is that the red light-sensitive pigment that gives Halobacterium its color, which is a simple photosynthetic system that provides the archaean with chemical energy, is known as bacteriorhodopsin -- and is chemically very similar to the light-detecting pigment rhodopsin, found in the vertebrate retina.

General Links :

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

Links to specific Archaeal lifestyles :

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

Pictures of Norm Pace and Pyrodictium courtesy Norm Pace and the Dept. of Plant Biology at UC Berkeley. Picture of black smoker by Prof. Iver Duedall at Florida Tech, and courtesy the Norm Pace Lab.
Images of methanogens on ciliate, chemostat, and Methanosarcina kindly provided by the Dept. of Microbiology, University of Nijmegen, The Netherlands.

Sources:

T. D. Brock, M. T. Madigan, J. M. Martinko, & J. Parker. 1994. Biology of Microorganisms, 7th ed. (New Jersey: Prentice Hall).
Kai-Uwe Hinrichs, J. M. Hayes, S. P. Sylva, P. G. Brewer, & E. F. DeLong. 1999. Methane-consuming archaebacteria in marine sediments. Nature 398: 802-805.
K. Horikoshi & W. D. Grant (eds.). 1998. Extremophiles -- Microbial Life in Extreme Environments (New York: Plenum).
John L. Howland. 2000. The Surprising Archaea (New York & Oxford: Oxford University Press).
M. Kates, D. J. Kushner, & A. T. Matheson (eds.). 1993. The Biochemistry of Archaea (Archaebacteria) (Amsterdam: Elsevier Science Publishers.
M. T. Madigan & B. L. Marrs, 1997. Extremophiles. Scientific American (Apr): 82-87.
C. R. Woese, 1981. Archaebacteria. Scientific American (Jun): 98-122.