[meteorite-list] Biological Potential Seen for Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:07:00 2004
Message-ID: <200210111709.KAA04204_at_zagami.jpl.nasa.gov>

http://www.space.com/scienceastronomy/mars_biological_021011.html

Biological Potential Seen for Mars
By Leonard David
space.com
11 October 2002

BOULDER, COLORADO -- Mix Mars rock, water, and a heat source. What do have?
Perhaps a suitable environment to support Martian life.

A source of energy to power metabolism has been regarded as a limiting
factor if life is to have thrived, or now exists, on the red planet.

New research by a team of researchers here at the University of Colorado's
Laboratory for Atmospheric and Space Physics (LASP) suggests that there's
hope in discovering still-alive organisms on Mars.

Weathering reactions

Researchers Bruce Jakosky, Stacy Varnes, and Thomas McCollom have looked at
the biological potential of Martian hydrothermal systems, presenting their
findings this week at a meeting of the Division for Planetary Sciences (DPS)
of the American Astronomical Society in Birmingham, Alabama.

"We've been working on this for several years. What we've done is look at
the availability of geochemical energy in the environment of Mars as a
source of energy that might support metabolism of organisms," Jakosky told
SPACE.com.

On Earth there are organisms that use that source of energy - energy given
off by chemical weathering reactions like oxidation of iron and minerals,
Jakosky said.

Organisms on Mars could, in a figurative sense, stick their finger into that
reaction, mediate it, and take advantage of the energy, Jakosky said. "What
we've done is to look at the types of environments that occur on Mars and
use them as a constraint to calculate how much energy could be available,"
he added.

Survival of organisms

Jakosky and his colleagues used data about the soil and rock composition on
the red planet. That information was gleaned from the Mars Pathfinder in
July 1997 and studies of Mars meteorites recovered on Earth.

While the makeup of groundwater on Mars is presently unknown, knowledge of
the planet's crust and atmosphere was reviewed to help guide the team to
their research conclusions.

Depending on what assumptions you make about the composition of the water
and what rock you start with, you get different amounts of energy coming out
of the weathering of the rock, Jakosky said. In some cases you get amounts
similar to systems on Earth where organisms thrive. In some cases you get
less, he said.

"Even in the worst case, however, our general conclusion is that there's
lots of energy on Mars to be had. These sorts of systems are places where
organisms could survive," Jakosky said.

In particular, there's lots of chemical energy available in hydrothermal
systems connected with hot volcanic water flowing through rock. "That's
where you get the most energy available - and there's lots of evidence for
those sorts of systems on Mars," Jakosky explained.

"What I think we've done is to show that the availability of chemical energy
on Mars is not going to be a seriously limiting factor. The energy on Mars
is available for organisms, if those organisms are there," Jakosky said.
Received on Fri 11 Oct 2002 01:09:44 PM PDT