DESCRIPTION OF THE PHYLUM CRENARCHAEOTA
| ARCHAEA> CRENARCHAEA> CRENARCHAEOTA |
PHYLUM CRENARCHAEOTA LINKS
| Crenarchaeota (kren-ar-ke-O-ta) is formed from two Greek roots that mean “fountain” (krene -κρήνη) and “ancient” (archaios -αρχαίος). The reference is to the occurrence of many members of this kingdom in geothermal springs. It was first defined as a kingdom by Woese et al. (1990). |
| INTRODUCTION TO THE CRENARCHAEOTA Hyperthermophilic archaea (Figures 1 and 2) occur in areas that are rich in sulfur and very hot. Such environments are associated with geothermal sites (geothermally heated soils and surface hot springs). They are the producers that form the foundation of the productive deep ocean geothermal vent environments, called sulfotara (text with tooltip) Solfatara are environments that have elevated temperatures and are rich in sulfur compounds. Examples are deep ocean vents and hot volcanic springs. (Figure 3). This is a problematic group of Archaea (indeed, almost all Archaea are problematic). They metabolize sulfur and generally grow at temperatures approaching the boiling point of water, both of which likely are primitive characters. Although, the fundamental synapomorphies do not seem to have been defined for the Crenarchaeota, the group seems to be well supported by 16S rRNA sequence trees. Mindful of that, we have followed the system of Garrity et al. (2001 and 2003) for this phylum. Still, we recognize that the group as it is defined likely is paraphyletic. |
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| FIGURE 1. A TEM micrograph of Thermoproteus. Image from http://hanskrause.de/HKHPE/hkhpe_02_06.htm | FIGURE 2. A TEM micrograph of Sulfolobus. Image from http://web.pdx.edu/~kstedman/research.html | FIGURE 3. A hot sulfur spring in Yellowstone National Park, an environment in which Sulfolobus thrives. Image from the National Park Service, in the Public Domain |
| FURTHER READING: DISCOVERY OF THE DOMAINS OF LIFE |
| LITERATURE CITED Black, J. G. 2002. Microbiology, Principles and Explorations. 5th ed. John Wiley and Sons, Inc. New York. Gao, B. and R. S. Gupta. 2007. Phylogenetic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis. BMC Genomics. 8:86. http://www.biomedcentral.com/1471-2164/8/86. Garrity, G. M., M. Winters, and D. Searles. 2001. Bergey’s manual of systematic bacteriology. 2nd ed. Springer-Verlag. New York. Garrity, G. M., J. A. Bell, and T. G. Lilburn. 2003. Taxonomic Outline of the Prokaryotes. Bergey’s Manual of Systematic Bacteriology. 2nd edition. Release 4.0. Springer-Verlag. New York. pp. 1-397. Margulis, L. and K. Schwartz. 1988. Five kingdoms, an illustrated guide to the phyla of life on earth. 2nd Edition. W. H. Freeman and Co. New York. Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3rd Edition. W. H. Freeman and Co. New York. Woese, C. R. and G. E. Fox. 1977. Phylogenetic structure of the prokaryotic domain: the primary kingdoms. Proceedings of the National Academy of Sciences USA. 74:5088-5090. Woese, C. R., O. Kandler, and M. L. Wheelis. 1990. Towards a natural system of organisms: Proposal for the domains Archaea, Bacteria, and Eucarya. Proc. Natl. Acad. Sci. USA. 87: 4576-4579. |
| By Jack R. Holt. Last revised: 02/11/2013 |
