River Corridor Science Focus Area: The Next Evolution
Authors
James Stegen* (james.stegen@pnnl.gov), Xingyuan Chen, Allison Myers-Pigg, Amy Goldman, Timothy Scheibe, RC-SFA Team
Institutions
Pacific Northwest National Laboratory, Richland, WA
URLs
Abstract
The next evolution of Pacific Northwest National Laboratory’s (PNNL) River Corridor Science Focus Area (SFA) will deliver the knowledge, models, and data needed to quantify, understand, and predict how watershed perturbations and biophysical settings combine to drive water and material transport into, perturbations within, and cumulative biogeochemical function of sediment-associated components of stream networks. Researchers take a systems approach to reveal how watershed hydro-biogeochemical processes lead to emergent function. Over the next quadrennial period researchers will reveal how variation in the physical, chemical, and biological attributes of watersheds (i.e., biophysical setting) interacts with watershed perturbations (e.g., wildfire) to drive perturbations occurring directly within stream networks (e.g., loss of surface water), and how that collection of interconnected processes leads to stream-network-scale sediment respiration rates.
Spatiotemporal patterns of sediment respiration (ERsed) is an emergent property of watershed systems that arise from interacting, non-linear processes distributed throughout watershed systems. Researchers focus on ERsed because its contribution to carbon cycling in stream networks range from being the dominant driver to being inconsequential. This variation has not been broadly quantified, understood, or predicted. Further, the ability to understand and predict spatiotemporal patterns of ERsed provides a litmus test for the quality of the predictive understanding of integrated watershed processes. Wildfire and the loss and gain of surface water (i.e., variable inundation) are the focal perturbations external to and within stream networks, respectively. The team focus on these together because they can interactively influence ERsed via physical, chemical, and biological processes. Further, wildfire is becoming more common, higher intensity, and burning larger fractions of watersheds, while variable inundation is, arguably, the most ubiquitous perturbation experienced by Earth’s stream networks. The team will use an integrated research program distributed across basins and founded on a watershed systems approach to test hypotheses and resolve knowledge gaps associated with the impacts of perturbations on emergent properties.