Peatlands’ O₂ Pulses: Time-resolved Terrestrial Oxygen Production in the Central Congo Basin over the Holocene

Abstract Tropical peatlands represent a critical but poorly constrained component of the global oxygen cycle. Here, we present a 10,600-year record of terrestrial O₂ production from the Congo Basin peatlands, revealing an oxygen surplus of 83 [68–100] Pg. Deep peatlands (>2 m), despite covering 30% of the area, account for over 50% of this flux. Using a novel redox titration method, we show that O₂ release is highly sensitive to hydroclimate, with 80% declines during arid intervals and rapid recovery during wet phases. Globally, peatlands may offset 24–80% of the continental oxidative weathering sinks. However, peatland O2 output occurs in episodic, climate-driven pulses, linking carbon and oxygen cycles across millennial timescales. With precipitation projected to decline by 20–40% by 2100, our findings underscore the dual role of peatlands as vulnerable C sinks and dynamic O₂ sources, while offering rare archives of Earth’s redox evolution.