Anoxygenic photosynthesis and the delayed oxygenation of Earth’s atmosphere

The emergence of oxygenic photosynthesis created a new niche with dramatic potential to transform energy flow through Earth’s biosphere. However, more primitive forms of photosynthesis that fix CO 2 into biomass using electrons from reduced species like Fe(II) and H 2 instead of water would have com...

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Bibliographic Details
Published in:Nature communications 2019-07, Vol.10 (1), p.3026-10, Article 3026
Main Authors: Ozaki, Kazumi, Thompson, Katharine J., Simister, Rachel L., Crowe, Sean A., Reinhard, Christopher T.
Format: Article
Language:English
Subjects:
45
631/158/1144
704/47/4112
Atmospheric models
Biosphere
Carbon dioxide
Earth atmosphere
Energy flow
Essential nutrients
Genomic analysis
Humanities and Social Sciences
Iron
Microbiology
multidisciplinary
Niches
Nutrients
Oxidation
Oxygenation
Photosynthesis
Positive feedback
Science
Science (multidisciplinary)
Substrates
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Summary:The emergence of oxygenic photosynthesis created a new niche with dramatic potential to transform energy flow through Earth’s biosphere. However, more primitive forms of photosynthesis that fix CO 2 into biomass using electrons from reduced species like Fe(II) and H 2 instead of water would have competed with Earth’s early oxygenic biosphere for essential nutrients. Here, we combine experimental microbiology, genomic analyses, and Earth system modeling to demonstrate that competition for light and nutrients in the surface ocean between oxygenic phototrophs and Fe(II)-oxidizing, anoxygenic photosynthesizers (photoferrotrophs) translates into diminished global photosynthetic O 2 release when the ocean interior is Fe(II)-rich. These results provide a simple ecophysiological mechanism for inhibiting atmospheric oxygenation during Earth’s early history. We also find a novel positive feedback within the coupled C-P-O-Fe cycles that can lead to runaway planetary oxygenation as rising atmospheric p O 2 sweeps the deep ocean of the ferrous iron substrate for photoferrotrophy. Competition dynamics between early Earth photosynthetic microorganisms are unclear. Here, the authors demonstrate that competition for light and nutrients between oxygenic phototrophs and Fe-based photosynthesizers in surface oceans provides a novel ecophysiological mechanism for the protracted oxygenation of Earth’s atmosphere.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-019-10872-z