Effect of Geologically Constrained Environmental Parameters on the Atmosphere and Biosphere of Early Earth

Abstract

The Great Oxidation Event (GOE) about 2.3 gigayears ago denotes the first major rise of atmospheric molecular oxygen (O2) in Earth’s history. As a consequence, the planet experienced the emergence of widespread habitability and complex life. Recently, there has been a revolution in improved methods for constraining geological data for atmospheric pressure, composition, and ocean temperature of the early Earth. We investigate the effect of this revised data upon processes which drove the GOE. Results suggest that increasing Archean carbon dioxide (CO2) produces increased O2 with height due to enhanced CO2 photolysis. This is counterbalanced by stronger O2 destruction as a result of enhanced carbon monoxide (CO) (from increased CO2) and nitrogen oxides (NOx) (from decreased hydroxyl via increased CO). Pre-GOE atmospheres with low O2 yet high CO2 could counteract O2 accumulation. For low surface pressures of 0.5 bar, O2 decreases between 0.5 to 0.005 bar. This arose mainly from O2 destruction via hydrogen ox...