DOI: 10.1111/gbi.12116
Scopus记录号: 2-s2.0-84921773510
论文题名: Atmospheric hydrogen peroxide and Eoarchean iron formations
作者: Pecoits E. ; Smith M.L. ; Catling D.C. ; Philippot P. ; Kappler A. ; Konhauser K.O.
刊名: Geobiology
ISSN: 1472-4677
EISSN: 1472-4669
出版年: 2015
卷: 13, 期: 1 起始页码: 1
结束页码: 14
语种: 英语
Scopus关键词: atmospheric modeling
; concentration (composition)
; hydrogen peroxide
; hydrothermal activity
; iron
; photic zone
; photochemistry
; photooxidation
; photosynthesis
; sedimentation rate
; ultraviolet radiation
; Photobacteria
; ferric ion
; ferrous ion
; hydrogen peroxide
; sea water
; astronomy
; atmosphere
; chemistry
; Atmosphere
; Earth (Planet)
; Evolution, Planetary
; Ferric Compounds
; Ferrous Compounds
; Hydrogen Peroxide
; Seawater
Scopus学科分类: Earth and Planetary Sciences: General Earth and Planetary Sciences
; Environmental Science: General Environmental Science
; Agricultural and Biological Sciences: Ecology, Evolution, Behavior and Systematic
英文摘要: It is widely accepted that photosynthetic bacteria played a crucial role in Fe(II) oxidation and the precipitation of iron formations (IF) during the Late Archean-Early Paleoproterozoic (2.7-2.4 Ga). It is less clear whether microbes similarly caused the deposition of the oldest IF at ca. 3.8 Ga, which would imply photosynthesis having already evolved by that time. Abiological alternatives, such as the direct oxidation of dissolved Fe(II) by ultraviolet radiation may have occurred, but its importance has been discounted in environments where the injection of high concentrations of dissolved iron directly into the photic zone led to chemical precipitation reactions that overwhelmed photooxidation rates. However, an outstanding possibility remains with respect to photochemical reactions occurring in the atmosphere that might generate hydrogen peroxide (H2O2), a recognized strong oxidant for ferrous iron. Here, we modeled the amount of H2O2 that could be produced in an Eoarchean atmosphere using updated solar fluxes and plausible CO2, O2, and CH4 mixing ratios. Irrespective of the atmospheric simulations, the upper limit of H2O2 rainout was calculated to be <106 molecules cm-2 s-1. Using conservative Fe(III) sedimentation rates predicted for submarine hydrothermal settings in the Eoarchean, we demonstrate that the flux of H2O2 was insufficient by several orders of magnitude to account for IF deposition (requiring ~1011 H2O2 molecules cm-2 s-1). This finding further constrains the plausible Fe(II) oxidation mechanisms in Eoarchean seawater, leaving, in our opinion, anoxygenic phototrophic Fe(II)-oxidizing micro-organisms the most likely mechanism responsible for Earth's oldest IF. © 2014 John Wiley & Sons Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/85140
Appears in Collections: 影响、适应和脆弱性
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作者单位: Equipe Géobiosphère, Institut de Physique du Globe-Sorbonne Paris Cité, Université Paris Diderot, CNRS, Paris, France; Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada; Department of Earth and Space Sciences and Astrobiology Program, University of Washington, Seattle, WA, United States; Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
Recommended Citation:
Pecoits E.,Smith M.L.,Catling D.C.,et al. Atmospheric hydrogen peroxide and Eoarchean iron formations[J]. Geobiology,2015-01-01,13(1)