James Stegen and Xingyuan Chen Seminar

Title: River Corridor Hydro-biogeochemistry from Molecular to Multi-Basin Scales

ABSTRACT: The Earth system is increasingly impacted by perturbations that directly and indirectly result from human activity. Watershed systems are a foundational unit of Earth’s land surface; how these systems will respond to perturbations over the coming decades is highly uncertain. This uncertainty needs to be reduced to enable effective decisions in support of the Department of Energy’s mission. In the long-term, the River Corridor-Science Focus Area (RC-SFA) will meet this need by delivering predictive understanding of how perturbations impact watershed hydro-biogeochemistry (HBGC) across the hillslope-to-stream continuum. In the next four years, we will reveal how perturbations interact with each other and with climate to influence the movement of water and transformations of organic matter in connected surface and subsurface components of watersheds. We focus on wildfire and drying of streams as two interacting perturbations that are shifting in frequency, duration, and/or severity and that have highly uncertain impacts on watershed HBGC that are relevant across most of Earth’s land surface. Given the global relevance of and shifting impacts of these perturbations, we need clarity on how they jointly impact watershed HBGC. Otherwise, we risk increasingly uncertain predictions for future land surface water and C cycling. The RC-SFA will protect against this risk through a novel focus on interactions between wildfire and variable inundation across environmentally divergent basins of the contiguous United States.

Affiliation: Pacific Northwest National Laboratory