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Atmospheric biomarkers of subsurface life on Mars
Author(s) -
Summers Michael E.,
Lieb B. Joseph,
Chapman Emily,
Yung Yuk L.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl015377
Subject(s) - martian , atmosphere of mars , mars exploration program , astrobiology , atmosphere (unit) , martian surface , trace gas , environmental science , atmospheric escape , flux (metallurgy) , atmospheric sciences , geology , physics , chemistry , meteorology , organic chemistry
If life exists beneath the Martian surface similar to terrestrial bacteria that rely upon chemical reactions involving H 2 and/or CO as energy sources, then it may be possible to infer its existence by observing metabolic by‐products that would appear as trace gases in the Martian atmosphere. We have studied the fate of organic trace gases in the Martian atmosphere and find that most have very short chemical lifetimes, however CH 4 has a chemical lifetime of about 300 yrs and thus it will tend to be uniformly distributed in the Martian atmosphere. Using the current observational upper limit on atmospheric CH 4 we deduce that its flux, from all sources, into the Martian atmosphere must be at least 10 5 times less than terrestrial value. If there are abiotic sources of CH 4 on Mars then the biological component of the CH 4 must be even less.