Availability of O 2 and H 2O 2 on pre-photosynthetic earth

Jacob Haqq-Misra, James F. Kasting, Sukyoung Lee

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

Old arguments that free O 2 must have been available at Earth's surface prior to the origin of photosynthesis have been revived by a new study that shows that aerobic respiration can occur at dissolved oxygen concentrations much lower than had previously been thought, perhaps as low as 0.05 nM, which corresponds to a partial pressure for O 2 of about 4 ×10 -8 bar. We used numerical models to study whether such O 2 concentrations might have been provided by atmospheric photochemistry. Results show that disproportionation of H 2O 2 near the surface might have yielded enough O 2 to satisfy this constraint. Alternatively, poleward transport of O 2 from the equatorial stratosphere into the polar night region, followed by downward transport in the polar vortex, may have brought O 2 directly to the surface. Thus, our calculations indicate that this "early respiration" hypothesis might be physically reasonable.

Original languageEnglish (US)
Pages (from-to)293-302
Number of pages10
JournalAstrobiology
Volume11
Issue number4
DOIs
StatePublished - May 1 2011

All Science Journal Classification (ASJC) codes

  • Agricultural and Biological Sciences (miscellaneous)
  • Space and Planetary Science

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