[meteorite-list] New Model Is Proposed to Explain Absence of Organic Compounds on Surface of Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 10 Jun 2010 16:46:33 -0700 (PDT)
Message-ID: <201006102346.o5ANkXZP026945_at_zagami.jpl.nasa.gov>

Mary Ann Liebert, Inc., Publishers
Contact: Vicki Cohn
Mary Ann Liebert, Inc.
(914) 740-2100, ext. 2156
vcohn at liebertpub.com

For Immediate Release

New Model Is Proposed to Explain Absence of Organic Compounds on Surface of Mars

New Rochelle, June 10, 2010 - The ongoing search for evidence of past or
present life on Mars includes efforts to identify organic compounds such
as proteins in Martian soil, but their absence to date remains a
mystery. A new theory to explain what happens to these carbon-based
molecules is presented in an article published in Astrobiology, a
peer-reviewed journal published by *Mary Ann Liebert, Inc
<http://cl.exct.net/?qs=97fedff095471e983a892ac0dc3aad36dafafbb1325782a25edc67ddec013666>.*
The article is available free online
<http://cl.exct.net/?qs=97fedff095471e98ccccc9761f9002c96987c594a653787d99cfa30a353d28cd>.

"There may be no 'safe haven' for these organic molecules on Mars,"
conclude Ilya Shkrob, Sergey Chemerisov, and Timothy Marin, from
Argonne National Laboratory and Benedictine University, in Illinois, in
their article entitled "Photocatalytic Decomposition of Carboxylated
Molecules on Light-Exposed Martian Regolith and its Relation to Methane
Production on Mars."

Unlike on Earth, where plants and other organisms convert carbon dioxide
and water into organic compounds via photosynthesis, the authors propose
that the opposite happens on the surface of Mars. The iron oxides that
make up Martian soil and give the planet its distinctive red color are
photocatalysts. They use energy from ultraviolet light absorbed through
the thin Martian atmosphere to oxidize carbon-containing organic
molecules trapped in soil particles, converting them to carbon dioxide
and gases such as methane.

The authors present study data to support this model and to explain why
it might not be realistic to rely on the discovery of proteins, amino
acids, and other carbon-containing compounds in the upper soil layers of
Mars to determine whether life forms are or have been present on the planet.

"This is an interesting result and may be an important step in solving
the enduring mystery of organics on Mars," says Christopher P. McKay,
Senior Editor of Astrobiology and Research Scientist at NASA Ames
Research Center. "We see organics in many places in the solar system but
have not been able to detect them on Mars - the planet that we think had
the most Earth-like conditions. Why? Could it be our instrument approach
has been wrong? Or could it be that there is some chemistry on Mars that
is actively destroying organics? This work points toward this latter
explanation. Mars may have a self cleaning surface. If so, we may have
to dig deeply to find any organic materials."

"The importance of drilling below the Martian surface for rocks and
soils that might retain preserved organics is certainly on the minds of
future mission scientists," says Sherry L. Cady, PhD, Editor of
Astrobiology and Associate Professor in the Department of Geology at
Portland State University. "The possible 2018 joint ESA-NASA mission is
a case in point."

Astrobiology is an authoritative peer-reviewed journal published 10
times a year in print and online. The Journal provides a forum for
scientists seeking to advance our understanding of life's origins,
evolution, distribution, and destiny in the universe. The complete
tables of content and the full text for this issue may be viewed online
<http://cl.exct.net/?qs=97fedff095471e98ccccc9761f9002c96987c594a653787d99cfa30a353d28cd>.

Mary Ann Liebert, Inc. is a privately held, fully integrated media
company known for establishing authoritative peer-reviewed journals in
many promising areas of science and biomedical research. Its
biotechnology trade magazine, Genetic Engineering & Biotechnology News
(GEN), was the first in its field and is today the industry's most
widely read publication worldwide. A complete list of the firm's 60
journals, books, and newsmagazines is available at our website
<http://cl.exct.net/?qs=97fedff095471e983a892ac0dc3aad36dafafbb1325782a25edc67ddec013666>.
Received on Thu 10 Jun 2010 07:46:33 PM PDT