Oxidation of fossil organic matter as a source of atmospheric CO2

All living organisms contain organic carbon. When an organism dies, organic carbon can become trapped within ancient sedimentary rocks (fossil organic carbon). This is a major carbon reservoir and is a sink for atmospheric carbon dioxide (CO₂) over millennial- and million-year timescales (Hilton and West, 2020).

However, uplift, exhumation and erosion of ancient sedimentary rocks has the potential to oxidize fossil organic carbon and release this CO₂ back into the atmosphere (Hemingway et al., 2019). This may act as a positive climate feedback and increase global temperatures. However, the mechanisms responsible for fossil carbon oxidation remain a major gap in our understanding. Fossil carbon oxidation is likely controlled by a variety of:

1. abiotic factors (e.g., temperature, oxygen availability, erosion rates)
2. biotic factors

Disentangling the relative importance of these different processes is challenging but can be assessed in controlled laboratory and natural field experiments. This project will employ a suite of laboratory and field-based approaches to study the fate of fossil organic carbon in modern environments. The findings of this project will help constrain whether fossil organic carbon oxidation might serve as a large source of atmospheric CO₂ in both past and future climates.

For full project details visit the Inspire project page.