Water activity and the challenge for life on early mars

Tosca, N. J. and Knoll, A. H. and McLennan, S. M. (2008) Water activity and the challenge for life on early mars. Science, 320 (5880). pp. 1204-1207. DOI https://doi.org/10.1126/science.1155432

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Abstract

In situ and orbital exploration of the martian surface has shown that acidic, saline liquid water was intermittently available on ancient Mars. The habitability of these waters depends critically on water activity (a H2O), a thermodynamic measure of salinity, which, for terrestrial organisms, has sharply defined limits. Using constraints on fluid chemistry and saline mineralogy based on martian data, we calculated the maximum a H2O for Meridiani Planum and other environments where salts precipitated from martian brines. Our calculations indicate that the salinity of well-documented surface waters often exceeded levels tolerated by known terrestrial organisms.

Item Type:	Article
Subjects:	01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions:	01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title:	Science
Volume:	320
Page Range:	pp. 1204-1207
Identification Number:	https://doi.org/10.1126/science.1155432
Depositing User:	Sarah Humbert
Date Deposited:	17 Dec 2009 12:11
Last Modified:	23 Jul 2013 09:56
URI:	http://eprints.esc.cam.ac.uk/id/eprint/1248

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