资源环境科技发展态势分析平台

Aerobic lifeforms, including humans, thrive because of abundant atmospheric O-2, but for much of Earth history O-2 levels were low. Even after evidence for oxygenic photosynthesis appeared, the atmosphere remained anoxic for hundreds of millions of years until the similar to 2.4 Ga Great Oxidation Event. The delay of atmospheric oxygenation and its timing remain poorly understood. Two recent studies reveal that the mantle gradually oxidized from the Archean onwards, leading to speculation that such oxidation enabled atmospheric oxygenation. But whether this mechanism works has not been quantitatively examined. Here, we show that these data imply that reducing Archean volcanic gases could have prevented atmospheric O-2 from accumulating until similar to 2.5 Ga with >= 95% probability. For two decades, mantle oxidation has been dismissed as a key driver of the evolution of O-2 and aerobic life. Our findings warrant a reconsideration for Earth and Earth-like exoplanets. The early Earth's atmosphere had very low oxygen levels for hundreds of millions of years, until the 2.4Ga Great Oxidation Event, which remains poorly understood. Here, the authors show that reducing Archean volcanic gases could have prevented atmospheric O-2 from accumulating, and therefore mantle oxidation was likely very important in setting the evolution of O-2 and aerobic life.