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Earth microbes may contaminate the search for life on Mars

Date:
April 28, 2010
Source:
American Society for Microbiology
Summary:
Bacteria common to spacecraft may be able to survive the harsh environs of Mars long enough to inadvertently contaminate Mars with terrestrial life, according to new research.
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Mars viewed by the Hubble Space Telescope.
Credit: Jim Bell (Cornell) et al., Hubble Heritage Team (AURA/STScI/NASA)

Bacteria common to spacecraft may be able to survive the harsh environs of Mars long enough to inadvertently contaminate Mars with terrestrial life, according to research published in the April 2010 issue of the journal Applied and Environmental Microbiology.

The search for life on Mars remains a stated goal of NASA's Mars Exploration Program and Astrobiology Institutes. To preserve the pristine environments, the bioloads on spacecraft headed to Mars are subject to sterilization designed to prevent the contamination of the Martian surface.

Despite sterilization efforts made to reduce the bioload on spacecraft, recent studies have shown that diverse microbial communities remain at the time of launch. The sterile nature of spacecraft assembly facilities ensures that only the most resilient species survive, including acinetobacter, bacillus, escherichia, staphylococcus and streptococcus.

Researchers from the University of Central Florida replicated Mars-like conditions by inducing desiccation, hypobaria, low temperatures, and UV irradiation. During the week-long study they found that Escherichia coli a potential spacecraft contaminant, may likely survive but not grow on the surface of Mars if it were shielded from UV irradiation by thin layers of dust or UV-protected niches in spacecraft.

"If long-term microbial survival is possible on Mars, then past and future explorations of Mars may provide the microbial inoculum for seeding Mars with terrestrial life," say the researchers. "Thus, a diversity of microbial species should be studied to characterize their potential for long term survival on Mars."


Story Source:

The above story is based on materials provided by American Society for Microbiology. Note: Materials may be edited for content and length.


Journal Reference:

  1. B. J. Berry, D. G. Jenkins, A. C. Schuerger. Effects of Simulated Mars Conditions on the Survival and Growth of Escherichia coli and Serratia liquefaciens. Applied and Environmental Microbiology, 2010; 76 (8): 2377 DOI: 10.1128/AEM.02147-09

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American Society for Microbiology. "Earth microbes may contaminate the search for life on Mars." ScienceDaily. ScienceDaily, 28 April 2010. <www.sciencedaily.com/releases/2010/04/100427111252.htm>.
American Society for Microbiology. (2010, April 28). Earth microbes may contaminate the search for life on Mars. ScienceDaily. Retrieved May 24, 2015 from www.sciencedaily.com/releases/2010/04/100427111252.htm
American Society for Microbiology. "Earth microbes may contaminate the search for life on Mars." ScienceDaily. www.sciencedaily.com/releases/2010/04/100427111252.htm (accessed May 24, 2015).

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