An abiotic source of Archean hydrogen peroxide and oxygen that pre-dates oxygenic photosynthesis.

He, Hongping; Wu, Xiao; Xian, Haiyang; Zhu, Jianxi; Yang, Yiping; Lv, Ying; Li, Yiliang; Konhauser, Kurt O · Nat Commun · 2021

basic_science · Level V

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Abstract

The evolution of oxygenic photosynthesis is a pivotal event in Earth's history because the O<sub>2</sub> released fundamentally changed the planet's redox state and facilitated the emergence of multicellular life. An intriguing hypothesis proposes that hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) once acted as the electron donor prior to the evolution of oxygenic photosynthesis, but its abundance during the Archean would have been limited. Here, we report a previously unrecognized abiotic pathway for Archean H<sub>2</sub>O<sub>2</sub> production that involves the abrasion of quartz surfaces and the subsequent generation of surface-bound radicals that can efficiently oxidize H<sub>2</sub>O to H<sub>2</sub>O<sub>2</sub> and O<sub>2</sub>. We propose that in turbulent subaqueous environments, such as rivers, estuaries and deltas, this process could have provided a sufficient H<sub>2</sub>O<sub>2</sub> source that led to the generation of biogenic O<sub>2</sub>, creating an evolutionary impetus for the origin of oxygenic photosynthesis.

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