Baltimore Ecosystem Study Institute of Ecosystem Studies

2011 BES Annual Meeting Presentation and Poster Abstracts

Denitrification Enzyme Activity in Stormwater Control Structures
Bettez, Neil
Co-Authors: Peter Groffman

Abstract: This study focuses on nitrogen (N) cycling in different types of stormwater retention basins with the goal of understanding how these structures, which were engineered to control stormwater runoff influence watershed nitrogen budgets. This is an important aspect of understanding how urbanization affects N cycling and retention in watersheds. In this study, we measured potential denitrification using the denitrification enzyme assay (DEA) in different types of stormwater control structures and in forested and herbaceous riparian zones with different levels of urbanization. We measured DEA in twelve different structures: shallow marsh (2), wet pond (1), detention pond (2), extended detention structure dry (3), extended detention (2), infiltration Basin (1) and sand filter (1). Within each structure samples were taken along moisture gradients at areas that were designed to be perennially wet, regularly wet, periodically wet, and infrequently wet. In riparian areas we measured DEA along transects perpendicular to streams in areas that were estimated to correspond with areas sampled in stormwater structures. We found differences in denitrification potential in different types of stormwater retention structures as well as within each type along soil moisture gradients. Denitrification potential was higher in areas with higher moisture content. These results are an important first step in modeling nitrate losses in stormwater control structures.