skip to main content
Language:
Search Limited to: Search Limited to: Resource type Show Results with: Show Results with: Search type Index

Benthic perspective on Earth’s oldest evidence for oxygenic photosynthesis

Proceedings of the National Academy of Sciences - PNAS, 2015-01, Vol.112 (4), p.995-1000 [Peer Reviewed Journal]

Volumes 1–89 and 106–112, copyright as a collective work only; author(s) retains copyright to individual articles ;Copyright National Academy of Sciences Jan 27, 2015 ;Distributed under a Creative Commons Attribution 4.0 International License ;ISSN: 0027-8424 ;EISSN: 1091-6490 ;DOI: 10.1073/pnas.1415718112 ;PMID: 25583484

Full text available

Citations Cited by
  • Title:
    Benthic perspective on Earth’s oldest evidence for oxygenic photosynthesis
  • Author: Lalonde, Stefan V. ; Konhauser, Kurt O.
  • Subjects: Atmospheric sciences ; Biosphere ; Cyanobacteria ; Earth (Planet) ; Earth Sciences ; Ecosystem studies ; Fossils ; Geochemistry ; Geological time ; Oxidation ; Oxygen ; Paleoecology ; Photosynthesis ; Physical Sciences ; Sciences of the Universe
  • Is Part Of: Proceedings of the National Academy of Sciences - PNAS, 2015-01, Vol.112 (4), p.995-1000
  • Description: The Great Oxidation Event (GOE) is currently viewed as a protracted process during which atmospheric oxygen increased above ∼10 ⁻⁵ times the present atmospheric level (PAL). This threshold represents an estimated upper limit for sulfur isotope mass-independent fractionation (S-MIF), an Archean signature of atmospheric anoxia that begins to disappear from the rock record at 2.45 Ga. However, an increasing number of papers have suggested that the timing for oxidative continental weathering, and by conventional thinking the onset of atmospheric oxygenation, was hundreds of million years earlier than previously thought despite the presence of S-MIF. We suggest that this apparent discrepancy can be resolved by the earliest oxidative-weathering reactions occurring in benthic and soil environments at profound redox disequilibrium with the atmosphere, such as biological soil crusts and freshwater microbial mats covering riverbed, lacustrine, and estuarine sediments. We calculate that oxygenic photosynthesis in these millimeter-thick ecosystems provides sufficient oxidizing equivalents to mobilize sulfate and redox-sensitive trace metals from land to the oceans while the atmosphere itself remained anoxic with its attendant S-MIF signature. As continental freeboard increased significantly between 3.0 and 2.5 Ga, the chemical and isotopic signatures of benthic oxidative weathering would have become more globally significant from a mass-balance perspective. These observations help reconcile evidence for pre-GOE oxidative weathering with the history of atmospheric chemistry, and support the plausible antiquity of a terrestrial biosphere populated by cyanobacteria well before the GOE. Significance The history of oxygen at Earth’s surface is intimately tied to its production by oxygenic photosynthesis, whereby plants, algae, and cyanobacteria release O ₂ as a waste product. Despite this metabolism’s profound importance, its evolutionary timing is poorly understood. Studies have increasingly revealed a temporal disconnect between evidence for the presence of O ₂ during weathering as early as 3.0 billion years ago and its atmospheric accumulation 500 million years later. We review this problem and numerically demonstrate that local O ₂ production and immediate consumption in surface-bound (benthic) microbial ecosystems at profound disequilibrium conditions is the most parsimonious explanation for this delay. Thus, emergence of continental landmass was likely a crucial factor in the earliest oxygenation of Earth’s surface environment.
  • Publisher: United States: National Academy of Sciences
  • Language: English
  • Identifier: ISSN: 0027-8424
    EISSN: 1091-6490
    DOI: 10.1073/pnas.1415718112
    PMID: 25583484
  • Source: Hyper Article en Ligne (HAL) (Open Access)
    GFMER Free Medical Journals
    MEDLINE
    PubMed Central
Back to results list
INSPIRE LIBRARY - TON DUC THANG UNIVERSITY (84-028) 37 755 057 Feedback
19 Nguyen Huu Tho St. Dist.7, HCM thuvien@tdtu.edu.vn

Copyright © 2017 INSPIRE LIBRARY - TON DUC THANG UNIVERSITY

Searching Remote Databases, Please Wait