Prokaryotes

Prokaryotes are living organisms, including the domains Bacteria and Archaea, which lack "a unit membrane-bound nucleus" and usually lack other cell organelles as well. Unlike eukaryotes, the other major category of living organisms, some prokaryotes are able to fix atmospheric nitrogen.


 * "Despite the apparent, relative simplicity of prokaryotic cells, as a group they have the greater taxanomic and functional diversity. Globally, organic C in prokaryotes is equivalent to that in plants and they contain 10-fold more N. They also possess the most efficient dispersal and survival mechanisms. As a result, prokaryotes are of enormous importance in creating, maintaining, and functioning of the soil."

Prokaryotes are capable of lateral (horizontal) gene transfer.

New Methods of Research
A past limitation to studying prokaryotes was that most studies focused on those that could be cultured in the lab. Now that new, molecular approaches have replaced cultivation-based techniques, scientists are learning much more about prokaryotes - including the revelation that many previous theories were wrong.


 * "For example, organisms that were previously considered to be "typical" soil organisms (bacilli, pseudomonads, actinobacteria) are often found at relatively low abundance, while some of the novel, "yet-to-be-cultured" organisms are ubiquitous and presence at high relative abundance (e.g., planctomycetes; Rappe and Giovannoni, 2003)."

Related Sourcewatch

 * Soil Life
 * Synthetic Fertilizer
 * Mycorrhizal Fungi

External Resources

 * Janice S. Snow, Misunderstanding Soil Ecosystems: How flawed conceptions of soil have lead to flawed U. S. land, water and climate policies, Masters Thesis, Tufts University, November 2009.
 * J. Prosser and Ken Killham. "Prokaryotes." In Soil Microbiology, Ecology, and Biochemistry, edited by Eldor A. Paul. Burlington, MA: Academic Press (Elsevier), 2007.
 * Lynn Margulis and Karlene V. Schwartz, Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth, Third ed. (New York: W.H. Freeman and Company, 1997).