http://www.colorado.edu/news/releases/2005/183.html

University of Colorado at Boulder News Release

Yellowstone Discovery Bodes Well For Detecting Evidence Of Life on
Mars,
Says CU-Boulder Study
April 20, 2005

University of Colorado at Boulder researchers say a bizarre group of
microbes found living inside rocks in an inhospitable geothermal
environment at Wyoming's Yellowstone National Park could provide
tantalizing clues about ancient life on Earth and help steer the hunt
for evidence of life on Mars.

The CU-Boulder research team reported the microbes were discovered in
the pores of rocks in a highly acidic environment with high
concentrations of metals and silicates at roughly 95 degrees F in
Yellowstone's Norris Geyser Basin. The new study shows the microbe
communities are subject to fossilization and have the potential to
become preserved in the geologic record.

Scientists believe similar kinds of geothermal environments may once
have existed on Mars, where astrobiologists have intensified the search
for past and present life forms in recent years.

A paper by CU-Boulder doctoral student Jeffrey Walker, postdoctoral
fellow John Spear and Professor Norman Pace of CU-Boulder's molecular,
cellular and developmental biology department and the Center for
Astrobiology appears in the April 21 issue of Nature.

The research was funded by the National Science Foundation and NASA.

"This is the first description of these microbial communities, which
may
be a good diagnostic indicator of past life on Mars because of their
potential for fossil preservation," said Walker. "The prevalence of
this
type of microbial life in Yellowstone means that Martian rocks
associated with former hydrothermal systems may be the best hope for
finding evidence of past life there."

Located about 20 miles northwest of Yellowstone Lake, Norris Geyser
Basin is considered to be the hottest and most active geyser basin in
Yellowstone and perhaps the world. It also is extremely acidic,
according to the researchers.

"The pores in the rocks where these creatures live has a pH value of
one, which dissolves nails," said Pace. "This is another example that
life can be robust in an environment most humans view as inhospitable."

The process used to identify the organisms developed by Pace is much
more sensitive than standard lab-culturing techniques that typically
yield a small, biased fraction of organisms from any environment, said
Walker. In this method, the researchers detected and identified
organisms by reading gene sequences.

"Each kind of organism has a unique sequence, which is used to map its
position in the tree of life," said Walker. "It's a family tree of
sorts
that describes the genetic relationship between all known organisms."

Walker discovered the new microbe community in 2003 after breaking
apart
a chunk of sandstone-like rock in the Norris Geyser Basin. "I
immediately noticed a distinctive green band just beneath the surface,"
he said. "It was one of those 'eureka' moments."

An analysis determined the green band was caused by a new species of
photosynthetic microbes in the Cyanidium group, a kind of alga that is
among the most acid-tolerant photosynthetic organisms known, said
Walker. Cyanidium organisms made up about 26 percent of the microbes
identified in the Norris Geyser Basin study by the CU-Boulder team,
Walker said.

Surprisingly, the most abundant microbes identified by the team were a
new species of Mycobacterium, a group of microbes best known for
causing
human illnesses like tuberculosis and leprosy, Walker said. Extremely
rare and never before identified in such extreme hydrothermal
environments, Mycobacterium made up 37 percent of the total number of
microbes identified by the CU-Boulder team.

Pace described the new life form in the Norris Geyser Basin as "pretty
weird." "It may well be a new type of lichen-like symbiosis," said
Pace,
who won a MacArthur Fellowship, or "genius grant," in 2001. "It
resembles a lichen, but instead of being comprised of a symbiosis
between a fungus and an alga, it seems to be an association of the
Mycobacterium with an alga."

While photosynthesis appears to be a key energy source for most of the
creatures, at least some Yellowstone microbes are believed to get
energy
from the dissolved metals and hydrogen found in the pore water of the
rock, Walker said. A study by the CU-Boulder team published by the
National Academy of Sciences in January 2005 indicated Yellowstone
microbe populations living in hot springs at temperatures more than 158
degrees F use hydrogen as their primary fuel source.

The research effort in the Norris Geyser Basin shows that rock
formation
processes occurring in the hydrothermal environment under study make
very real fossil imprints of the organisms embedded in the rock at
various stages, showing how the distinctive fossils develop over time,
according to the research team.

"Remnants of these communities could serve as 'biosignatures' and
provide important clues about ancient life associated with geothermal
environments on Earth or elsewhere in the Solar System," the authors
wrote in Nature.

Note to Editors: Contents embargoed until 1 p.m. EDT on Wednesday,
April
20. Images of the Yellowstone project are available on request.