Please join us on Wednesday, October 16th, at 2 p.m. for a Geochemistry seminar with Dr. Jianshu Duan, a postdoctoral research associate at Princeton University in the Department of Geosciences. His research focuses on the molecular-scale geochemical processes of nutrients and contaminants (e.g., carbon and trace metals) in the Earth's surface environments. Specifically, he is interested in (geo)chemical reactions at mineral–water, and particle–water interfaces and the application of advanced spectroscopy methods to studying geochemical systems. Before starting his postdoctoral position, he obtained his Ph.D. in geosciences and materials science from Princeton University.
Duality of Minerals in Soil Organic Carbon Storage—Protection and Degradation
Soil organic carbon (SOC) is a major component of soil and constitutes one of the largest active carbon reservoirs. Its dynamics are strongly influenced by the composition and abundance of soil minerals. Through chemical association (adsorption), minerals can retain OC, protecting it from microbial attack and thus controlling carbon cycling in soils. The magnitude of the mineral–organic carbon association varies with the composition and surface chemistry of the minerals. Laboratory and field studies have demonstrated that certain minerals exert a stronger control than others; yet, less is known about the role of minerals in OC breakdown. In this talk, I’ll present results from laboratory studies that show 1) how presentative soil minerals interact with different pools of OC, 2) how water chemistry modifies these interactions, and 3) how they are connected to field observations. Finally, I’ll provide evidence of mineral-catalyzed degradation of organic molecules and discuss potential reaction mechanisms. A summary of how these findings influence the OC cycle in different terrestrial environments will be presented.
