Research
I am fascinated by the relationships between hydrologic processes, geochemical processes, and climate, and I seek to understand the feedback mechanisms that connect these processes in the critical zone. My research focuses on integrating hydrologic and geochemical data to better understand the effect of fluid flow and subsurface heterogeneity on critical zone development. I use data collected in the lab and field and numerical models to investigate critical zone processes at a range of temporal and spatial scales.
carbon fluxes associated with arid agriculture
Pedogenic carbonate formation in arid agricultural settings modifies subsurface structure while releasing abiotic CO2. I am using reactive transport models to quantify the rate of carbonate formation and the flux of CO2 as the irrigation water source changes and climate changes. The goal of this work is to quantify the size of the flux of CO2 to the atmosphere associated with agriculture in arid settings.
Weathering in fractured rock
The heterogeneity associated with fractured rock may be able to explain the difference between laboratory and field dissolution rates. Reactive transport simulations in two and three dimensions indicate a significant rate decrease after 10,000 years, associated with a transition to transport-limited weathering in the domain. If transport-limited weathering is a widespread phenomenon due to heterogeneity in the natural world, there are interesting implications for the weathering-climate feedback.
Lithium isotopes in marine pore fluids
Lithium isotopes in marine carbonates preserve the isotopic composition of the seawater the carbonate precipitated from and can be interpreted as a paleoweathering proxy. However, to be informative, the archive needs to remain undisturbed by diagenetic processes. In a carbonate-rich site in the Eastern Equatorial Pacific, the pore fluid Li isotopic profile with depth is indicative of authigenic clay formation. The Li isotopic composition of the carbonates can only be explained by recrystallization from the clay-impacted fluids, indicating the importance of reverse weathering in carbonate-rich marine settings.