Thursday, March 29, 2018 at 12:20pm to 1:10pm
Abstract: Soils store a large amount of organic carbon (OC), and efforts to increase the amount and persistence of soil OC (SOC) are an important step in mitigating climate change, as well as maintaining the many ecosystem services that SOC supports. The mechanisms of SOC sequestration in soil are complex, but interaction with soil minerals is known to be an important process for formation of persistent SOC. Understanding the processes driving the type and stability of mineral-SOC associations is consequently important for predicting response of mineral-associated SOC to environmental change. In this seminar, I will highlight the role of redox and mineral precipitation processes on mineral-stabilized SOC, from a landscape-scale study of SOC changes with Fe redox state to characterization of SOC-mineral interfaces at the sub-nanometer scale. In particular, I will show applications of cryogenic electron microscopy to reveal sub-nanometer scale differences in C chemistry and mineral structure that inform our understanding of mineral-SOC interaction mechanisms.