Characterizing the Controls of Subsurface Flow and Reactive Gases on Chemical Weathering Fluxes
IPGP - Îlot Cuvier
Despite its importance for global biogeochemical cycling and climate, the transport and transformation of carbon in the subsurface remains the least characterized aspect of terrestrial carbon cycling. Of particular interest are the controls of subsurface hydrology on biogeochemical reactions, both in terms of water flowpaths and residence times and the regulation of reactive gases (CO2, O2) in the subsurface. In this talk I will present (1) a field study demonstrating direct regulation of the balance of oxidative v. acid-base weathering fluxes by snowmelt hydrology using concentration-discharge relationships in the shale-dominated East River, CO catchment; and (2) a new theoretical framework for assessing the role of CO2 in driving equilibrium solute concentrations and implications for the silicate weathering feedback and the role of productivity in driving chemical weathering fluxes.