[meteorite-list] Otherworldly Bacteria Discovered Two Miles Down in South Africa

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri Oct 20 12:33:27 2006
Message-ID: <200610201633.JAA18848_at_zagami.jpl.nasa.gov>

http://www.carnegieinstitution.org/news_releases/news_2006_1019.html

Thursday, October 19, 2006

Contact Dr. Douglas Rumble; 202-478-8990 or rumble_at_gl.ciw.edu
or Li-Hung Lin at lhlin_at_ntu.edu.tw

For a copy of the paper, please contact:

AAAS Office of Public Programs; (202) 326-6440 or scipak_at_aaas.org

Otherworldly Bacteria Discovered Two Miles Down
Carnegie Institution

Washington, D.C. - Researchers have discovered an isolated,
self-sustaining, bacterial community living under extreme conditions
almost two miles deep beneath the surface in a South African gold mine.
It is the first microbial community demonstrated to be exclusively
dependent on geologically produced sulfur and hydrogen and one of the
few ecosystems found on Earth that does not depend on energy from the
Sun in any way. The discovery, appearing in the October 20 issue of
Science, raises the possibility that similar bacteria could live beneath
the surface of other worlds, such as Mars or Jupiter's moon Europa.

"These bacteria are truly unique, in the purest sense of the word," said
lead author Li-Hung Lin, now at National Taiwan University, who
performed many of the analyses as a doctoral student at Princeton and as
a postdoctoral researcher at the Carnegie Institution's Geophysical
Laboratory.

As Lin explained: "We know how isolated the bacteria have been because
our analyses show that the water they live in is very old and hasn't
been diluted by surface water. In addition, we found that the
hydrocarbons in the local environment did not come from living
organisms, as is usual, and that the source of the hydrogen (H2) needed
for their respiration comes from the decomposition of water (H2O) by
radioactive decay of uranium, thorium, and potassium."

Humans and most other land-dwelling organisms ultimately get their
energy from the Sun, with photosynthetic plants forming the base of the
food web. But in dark places where sunlight doesn't reach, life has to
depend on other energy sources. Other communities of "chemoautotrophs" - a
word chained together from Greek roots meaning "chemical
self-nourishment" - have been found in exotic places such as aquifers,
petroleum reservoirs, and vents linked to deep-sea volcanoes. Yet these
communities all depend at least in part on nutrients that can be traced
back to photosynthetic plants or bacteria.

The international team led by T. C. Onstott of Princeton University,*
which also includes Carnegie staff scientist Douglas Rumble and former
Carnegie postdoctoral researcher Pei-Ling Wang, also now at National
Taiwan University, found the community in a rock fracture that
intersects the Mponeng gold mine near Johannesburg, South Africa. Water
trapped in the fracture is home to the otherworldly bacteria.

Using genetic tools, the team discovered that there is very little
species diversity in the rock fracture community. Compared with bacteria
in the water used for mining, the fracture water is dominated by one
type of bacteria related to Desulfotomaculum, which is known to get
energy from the reduction of sulfur compounds.

"We also believe that the sulfate used by these creatures is left-over
from ancient groundwater mixed with ancient hydrothermal fluid. We can
detect that because the chemical signature arises from interacting with
the fracture's wall rock," commented Rumble. "It is possible that
communities like this can sustain themselves indefinitely, given enough
input from geological processes. Time will tell how many more we might
find in Earth's crust, but it is especially exciting to ponder whether
they exist elsewhere in the solar system."

------------------------------------------------------------------------

*Other authors of this work include: Johanna Lipmann-Pipke of
GeoForschungsZentrum Potsdam, Germany; Erik Boice and Lisa M. Pratt of
Indiana University, Bloomington, IN; Barbara Sherwood Lollar of the
University of Toronto, ON, Canada; Eoin L. Brodie, Terry C. Hazen, Gary
L. Andersen, and Todd Z. DeSantis of Lawrence Berkeley National
Laboratory, Berkeley, CA; Duane P. Moser of the Desert Research
Institute, Las Vegas, NV; Dave Kershaw of the Mponeng Mine, Anglo Gold,
Johannesburg, South Africa; and T.C. Onstott of Princeton University,
Princeton, NJ.

This work was supported by grants from the National Science Foundation,
the National Aeronautics and Space Administration, the U.S. Department
of Energy, the National Science Council of Taiwan, the Natural Sciences
and Engineering Research Council of Canada, Deutsche
Forschungsgemeinschaft (DFG; the German Research Foundation), and the
Killam Fellowships Program. Granting divisions include the NASA/NSF Life
in Extreme Environments (LExEN) Program, the NASA Astrobiology
Institute's teams at Indiana-Princeton-Tennessee Astrobiology Institute
(IPTAI) and the Carnegie Institution of Washington, the NASA
Cosmochemistry Program, the NSF Division of Earth Sciences (EAR),and the
DOE Genomics:GTL program.

The Carnegie Institution of Washington (www.carnegieinstitution.org),
a private nonprofit organization, has been a pioneering force in basic
scientific research since 1902. It has six research departments: the
Geophysical Laboratory and the Department of Terrestrial Magnetism,
both located in Washington, D.C.; The Observatories, in Pasadena,
California, and Chile; the Department of Plant Biology and the
Department of Global Ecology, in Stanford, California; and the
Department of Embryology, in Baltimore, Maryland.
Received on Fri 20 Oct 2006 12:33:24 PM PDT