FAYETTEVILLE,
Ark. — University
of Arkansas researchers have shown
that methane-producing microorganisms can survive for up to 25 days without
water, which might make such creatures even more likely candidates for the type
of life that could be found on Mars.
Tim Kral, professor of biological
sciences in the J. William Fulbright College of Arts and Sciences, and honors
student Michael Kendrick will report their findings today, May 23, at the
American Society for Microbiology annual meeting in Orlando,
Fla.
For years Kral has studied
methanogens, ancient microorganisms from the biological kingdom Archaea, as
potential candidates for what life might look like on Mars. Methanogens produce
methane and live in anaerobic environments, such as the guts of animals, in deep
parts of the ocean or in the Earth’s crust. Kral has grown the microorganisms
on Mars soil simulant under some of the conditions of temperature and pressure
found on Mars. His experiments with Kendrick tested yet another parameter for
the possible growth of such creatures on the red planet.
“Mars is very dry, at least on
the surface,” Kral said. “So the question for us was how would methanogens on
Earth handle periods of dryness.”
Kendrick and Kral grew different
methanogen species on Mars soil simulant in anaerobic culture, then transferred
the soil simulant containing the microorganisms from these tubes into beakers,
which were left in a desiccator in the anaerobic chamber. Every day thereafter,
Kendrick would remove a beaker from the desiccator, transfer the soil to a test
tube, add buffer, anaerobically seal the tubes, and incubate them under the
organism's ideal growth conditions.
“We were looking to see if
anything had survived,” Kral said. The researchers tested for methane
production, an indicator of the microorganisms’ survival.
Two species of methanogens
produced methane up to 25 days later, while another species produced methane up
to 10 days later, the researchers report.
“What that means is at least two
of these organisms could survive almost a month” in extremely arid conditions,
Kral said. “This is an important addition to our knowledge base.”
The next step would be to look at
desiccation at reduced pressure and temperatures to re-create more of the
environment found on Mars.
Kral has a new planetary
environmental chamber that will be devoted to the methanogen research that will
be up and running in the near future through the Arkansas
Center for Space and Planetary
Sciences.
ASM Presentation : “Survival of
Methanogens During Periods of Desiccation” (Session 132/N)