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Science 25 September 1970:
Vol. 169. no. 3952, pp. 1316 - 1318
DOI: 10.1126/science.169.3952.1316
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Articles

Limits of Microbial Existence: Temperature and pH

Thomas D. Brock 1 and Gary K. Darland 1

1 Department of Microbiology, Indiana University, Bloomington 47401

A microscopic survey made to detect the presence of bacteria in hot springs of varying temperature and pH characteristics revealed that in neutral and alkaline hot springs bacteria are found at temperatures up to the boiling point of water (92° to 100°C, depending on the altitude). In hot springs of increasing acidity the upper temperature limit at which bacteria are found decreases; at pH 2 to 3 the upper temperature limit is 75° to 80°C. Bacteria have thus been able to evolve with the ability to grow at either high temperature or high acidity, but not at both high temperature and high acidity. These results suggest that there are physicochemical limitations of the environment beyond which life is impossible.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
CO2 Uptake and Fixation by a Thermoacidophilic Microbial Community Attached to Precipitated Sulfur in a Geothermal Spring.
E. S. Boyd, W. D. Leavitt, and G. G. Geesey (2009)
Appl. Envir. Microbiol. 75, 4289-4296
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Science. ISSN 0036-8075 (print), 1095-9203 (online)