Hydrologic constraints on global carbon dioxide emissions from inland waters

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

Inland waters, streams, rivers, lakes, and reservoirs, act as an important component of the global carbon cycle, particularly in their role as sources of carbon dioxide (CO2) to the atmosphere. Despite recent advances in our conceptions of inland water carbon cycling, global CO2 emissions from these waters remain highly uncertain. This research will develop process-based computational models of global CO2 fluxes from streams, rivers, lakes, and reservoirs by combining models of water flow, surface water morphology, and carbon transport and transformation. The models will provide new insights into global CO2 fluxes and the distribution of inland water CO2 sources, and how these fluxes and sources respond to changes in streamflow. The researchers will train a PhD student and mentor a postdoctoral researcher, and enhance STEM education in the Holyoke and Springfield, MA area, by creating educational activities for high school girls through the Eureka! Program in collaboration with Girls, Inc. and the University of Massachusetts Amherst. The primary goal of this project is to provide robust, physically constrained estimates of global CO2 fluxes from inland waters including rivers, streams, lakes, and reservoirs. This will be accomplished through hypothesis-driven research objectives to: (1) couple global state-of-the-art hydraulic and hydrologic routing systems with a recently developed stream network model of CO2 including physical representations of mass transport, inputs (groundwater inflows, hyporheic exchange with CO2-rich pore waters, water column respiration), and outputs (primary productivity, atmospheric exchange); (2) validate the coupled hydrology and stream network model of CO2 against existing datasets of global surface and groundwater geochemical observations, and compare our physics-based model with existing statistical upscaling techniques; and (3) apply the model across a range of flow conditions to characterize average and spatiotemporal variability in CO2 emissions, and explore how changes in streamflow impact stream CO2 emissions. The award will be co-funded by the Hydrologic Sciences and the Geobiology and Low-Temperature Geochemistry programs. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.