Publication Date:
2008-05-31
Description:
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 (aH2O), 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 aH2O 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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tosca, Nicholas J -- Knoll, Andrew H -- McLennan, Scott M -- New York, N.Y. -- Science. 2008 May 30;320(5880):1204-7. doi: 10.1126/science.1155432.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA. ntosca@fas.harvard.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18511686" target="_blank"〉PubMed〈/a〉
Keywords:
*Exobiology
;
Extraterrestrial Environment
;
Life
;
*Mars
;
Salinity
;
*Water
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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