The Great Oxidation Event (GOE): Biogeochemical Feedback and Tipping Points

TL;DR

This paper proposes that the Great Oxidation Event was driven by intrinsic biogeochemical feedback mechanisms, particularly the coupling of respiration and photosynthesis, leading to a tipping point in Earth's oxygen levels.

Contribution

It introduces a novel feedback mechanism involving aerobic respiration efficiency and cellular coupling as key to the GOE's rapid transition.

Findings

Feedback mechanisms can cause rapid shifts in Earth's oxygen levels.

The coupling of respiration and photosynthesis inside cells amplifies oxygen production.

The GOE represents a critical tipping point in Earth's biogeochemical history.

Abstract

Approximately 1.4 Ga after life first appeared, atmospheric oxygen suddenly jumped by more than an order of magnitude over a 20-50 Ma period. The contrast between these two timescales does not seem to be due to any sudden, large amplitude change in external forcing. However, it could be due to processes intrinsic to the geobiological system itself, namely, positive feedback between atmospheric oxygen and photosynthetic bacteria: More oxygen leads to more photosynthesis, which leads to more oxygen, and so on. Already-published feedbacks include buildup of an ozone shield and nutrient production by oxidative weathering. The feedback proposed here is the 15-fold greater efficiency of aerobic vs anaerobic respiration and the tight coupling of respiration and photosynthesis inside the cell. As in the climate system, feedback leads to tipping points, where a rapid, large amplitude change in the state of the system occurs. For the geobiological system, the GOE is the tipping point, and the long buildup before the GOE is the gradual oxidation of the crust and ocean, due either to burial of organic matter, oxidation of volcanic gases, or escape of hydrogen to space. The feedback hypothesis is a framework for interpreting observations leading to the GOE.