Improving paleoCO2 records through a better understanding of Rubisco carbon fixation
Reconstructing past climate is an important tool for understanding Earth’s climate sensitivity to future CO2 levels. Paleo-CO2 levels are reconstructed from the carbon isotopic signature within organic carbon from sedimentary records. This proxy is currently plagued with uncertainty, largely due to the critical but flawed assumption that Rubisco has a constant preference for the lighter 12-carbon isotope over the heavier 13-carbon isotope. There are few measurements of the kinetic isotope effect (KIE) of Rubisco during carbon fixation, primarily available from terrestrial plants at 25°C. Since half of all photosynthesis occurs in the ocean and a large proportion of paleo-records are of marine origin, this proposal aims to measure Rubisco KIE in dominant marine phytoplankton at relevant environmental temperatures. These new measurements will be used to improve the current paleo-CO2 proxy. This project is funded by the Royalty Research Fund at the University of Washington (RRF AA118648).
Associated Lab Members: