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Atmospheric energy for subsurface life on Mars?

Weiss, Benjamin P. and Yung, Yuk L. and Nealson, Kenneth H. (2000) Atmospheric energy for subsurface life on Mars? Proceedings of the National Academy of Sciences of the United States of America, 97 (4). pp. 1395-1399. ISSN 0027-8424. PMCID PMC26444.

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The location and density of biologically useful energy sources on Mars will limit the biomass, spatial distribution, and organism size of any biota. Subsurface Martian organisms could be supplied with a large energy flux from the oxidation of photochemically produced atmospheric H2 and CO diffusing into the regolith. However, surface abundance measurements of these gases demonstrate that no more than a few percent of this available flux is actually being consumed, suggesting that biological activity driven by atmospheric H2 and CO is limited in the top few hundred meters of the subsurface. This is significant because the available but unused energy is extremely large: for organisms at 30-m depth, it is 2,000 times previous estimates of hydrothermal and chemical weathering energy and far exceeds the energy derivable from other atmospheric gases. This also implies that the apparent scarcity of life on Mars is not attributable to lack of energy. Instead, the availability of liquid water may be a more important factor limiting biological activity because the photochemical energy flux can only penetrate to 100- to 1,000-m depth, where most H2O is probably frozen. Because both atmospheric and Viking lander soil data provide little evidence for biological activity, the detection of short-lived trace gases will probably be a better indicator of any extant Martian life.

Item Type:Article
Related URLs:
URLURL TypeDescription CentralArticle
Yung, Yuk L.0000-0002-4263-2562
Nealson, Kenneth H.0000-0001-5189-3732
Additional Information:© 2000 by the National Academy of Sciences. Communicated by Richard M. Goody, Harvard University, Cambridge, MA, December 10, 1999 (received for review July 19, 1999). Article published online before print: Proc. Natl. Acad. Sci. USA, 10.1073/pnas.030538097. We thank A. Haldemann, M. Allen, H. Holland, B. Jakosky, and E. Gaidos for helpful discussions. We also thank R. Goody for reviewing and communicating this work to PNAS. This research is supported in part by NASA Grant NAG5-4022 and the NASA Astrobiology Institute grant to the California Institute of Technology.
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Issue or Number:4
PubMed Central ID:PMC26444
Record Number:CaltechAUTHORS:WEIpnas00
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9129
Deposited By: Archive Administrator
Deposited On:31 Oct 2007
Last Modified:09 Mar 2020 13:19

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