Biogeochemical Asynchrony: Ecosystem Drivers of Concentration-Discharge Dynamics Across Scales
Nandita Basu, University of Waterloo, [email protected]
Kimberly Van Meter, University of Waterloo, [email protected]
Abstract
Watersheds exhibit tremendous heterogeneity in their response to climatic and landscape controls. Understanding this heterogeneity and identifying processes underlying the complexities of watershed response remains a central task of watershed modelers. Accordingly, researchers have become increasingly interested in identifying key hydrologic and biogeochemical signatures of watershed functionality. Such signatures allow us not only to better understand differences between watersheds, but also to identify dominant process controls and improve our ability to predict watershed behavior under changing climate and land use. There has recently been particular interest in characterizing event-scale relationships between solute concentrations and river discharge. These concentration-discharge signatures provide us with means of understanding the export dynamics of nutrients and other stream constituents under varying discharge regimes, and also serve as an indicator of the spatial and temporal availability of these constituents within the landscape. Herein, we characterize concentration-discharge relationships for nitrogen and phosphorus across more than 200 Great Lakes watersheds. Based on this analysis, we are able to demonstrate a diversity of watershed behavior spanning a significant gradient of climate and land use. We also show strong correlations between event-scale nutrient dynamics and seasonal concentration regimes, with these regimes being significantly impacted by agricultural and urban land use.
1. Keyword
nutrients
2. Keyword
watersheds
3. Keyword
phosphorus
4. Additional Keyword
nitrogen
5. Additional Keyword
signatures