The Influence of Atmosphere-Biology-Geology during the Great Oxidation Event

• Applicant: Dr. John Lee Grenfell
• Subject Area: Atmospheric Science
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 276727921

The Great Oxidation Event (GOE) marked a spectacular rise of molecular oxygen (O2) in the history of the Earth. The GOE enabled wide-ranging habitability and allowing complex life to take hold of the planet. Many questions however still remain open. What drove oxygen to flood the atmosphere, the timing and the extent of the event - are all not well-established. Subtle interplays within the atmosphere-biology-geology system are only now starting to be identified. The resulting demise in methanogens and the spiral towards a so-called Snowball Earth state illustrate the alarming extremity of the GOE. A central question we investigate is whether the GOE occurred linearly or in jumps (the so-called yo-yo model) due to a proposed oxygen bistability and examine the effect of the carbon cycle and atmospheric climate upon the nature and timing of the GOE. We also apply our experience in combining one- and three-dimensional modelling expertise to investigate the role of uncertainties in atmospheric climate during the GOE. To achieve this we develop and apply our unique atmospheric model with its detailed oxygen cycle components (e.g. burial, weathering, photochemistry) from the atmosphere, biosphere and geosphere. A central goal is to investigate scenarios constrained with recent marked advances in geological data (e.g. for surface pressure, atmospheric greenhouse gases etc.) to investigate the interplay of key processes which drove the GOE.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1833: Building a Habitable Earth