Wetland restoration and hydrologic reconnection result in enhanced watershed nitrogen retention and removal

Journal Article (Journal Article)

Restoration of freshwater wetlands presents a potential water quality benefit via removal of nutrients, but complex and unresolved changes in nutrient cycling can occur following restoration. In this study, we evaluated N removal and release in a deltaic wetland under scenarios of hydrologic reconnection and sediment dredging, and we modeled potential downstream impacts of these restoration activities in a Bayesian framework. Denitrification, N2O production, and anammox were measured via the isotope pairing technique in intact sediment cores. Anammox was not detected. Denitrification rates in the control scenario (78.2–87.2 μmol N m−2 h−1) were significantly higher than those under hydrologic reconnection and dredging scenarios (14.7–56.0 μmol N m−2 h−1). N2O production rates were typical of wetland environments. Denitrification and N2O production were stimulated shortly following simulated dredging, indicating a short-term response to sediment disturbance. Under hydrologic reconnection, NH4+ availability was decreased, inhibiting coupled nitrification-denitrification. Despite a decrease in denitrification activity, the wetland has the capacity to remove up to 10% of stream NO3− following hydrologic reconnection. Restoration is predicted to fully mitigate NH4+ delivery to a downstream eutrophic lake, yet permanent N removal may be reduced due to the decoupling of nitrification and denitrification.

Full Text

Duke Authors

Cited Authors

  • Salk, K; Alan D. Steinman, ; Nathaniel E. Ostrom,

Published Date

  • April 2018

Published In

Volume / Issue

  • 38 / 2

Start / End Page

  • 349 - 359

International Standard Serial Number (ISSN)

  • 0277-5212

Digital Object Identifier (DOI)

  • 10.1007/s13157-017-0972-7


  • eng