Baltimore Ecosystem Study Institute of Ecosystem Studies

2015 BES Annual Meeting Presentation and Poster Abstracts

Closing Watershed Nitrogen Budgets: Integrating Long-Term Data, Sensors, and Models
Duncan, Jon
Co-Authors: Larry Band, Peter Groffman, Neil Bettez

Abstract: The influence of spatial and temporal heterogeneity on nitrogen cycling is profound and catchment scale understanding remains elusive. Losses from denitrification are a major source of uncertainty. At Pond Branch, we developed an approach to scale denitrification flux from seasonal soil cores collected in different landscape positions to the entire watershed using a combination of laboratory core experiments, terrain analysis and in situ soil oxygen and soil moisture content sensors. To examine riverine nitrogen flux, we leveraged long-term water quality data to better account for time, seasonal, and discharge related variability. Taken together improved understanding of denitrification and stream export dynamics improves understanding of watershed nitrogen cycling. Closing watershed nitrogen budgets requires combining long-term data, novel sensors and measurement techniques, and a set of models to scale understanding in the face of environmental heterogeneity.