The Lindbergh Foundation Believes that Innovative Science and Technology Hold the Key to Addressing Humanity’s Environmental and Productivity Challenges

Jennifer L. Morse

Jennifer L. Morse, Duke University, Durham, NC

“Predicting the Fate of Nitrogen and the Impact on Water Quality and Greenhouse Gas Emissions from Sea Level Rise and Wetland Restoration"

Category: Air and Water Conservation: 2009

During the 1960-1980s, many low-lying areas along the Atlantic coastal plain experienced large-scale conversion of forested freshwater wetlands into actively drained agriculture. Currently, many of these farms are being abandoned or restored to wetlands due to economic barriers such as high fuel prices to run drainage pumps, slowly rising sea levels potentially linked to climate change, or through economic incentives to increase wetland habitat. Whatever the motivation, these heavily fertilized soils have a renewed connection to sensitive surface waters, raising questions about the environmental cost-benefit trade-offs. Certainly, restoration of these former wetlands creates wildlife habitats, increased storage of carbon in soil and vegetation, and the potential removal of nitrogen from the soil or surface water through microbial processes. However, under certain conditions, the removal of nitrogen can produce nitrous oxide, a powerful ozone-depleting greenhouse gas.

Using innovative stable isotope tracer methods, Ms. Morse will evaluate the environmental costs and benefits of nitrogen transformations in restored wetlands, with respect to water quality and greenhouse gas emissions. Specifically, she will determine the level of water quality improvement through microbial denitrification, identify which microbial processes are mainly responsible for nitrous oxide emissions, and compare these re-flooded agricultural lands to active farms and forested wetlands. Ultimately, Ms. Morse wants to identify whether and when denitrificaiton benefits water quality at the expense of air quality in re-flooded ecosystems.


From the Final Report

Results from this project suggest that nitrification plays an important and underappreciated role in producing N2O in acid‐organic freshwater wetlands. Experimental results were consistent with field data and help explain patterns of N2O fluxes in different land uses in coastal North Carolina.

Although the ecosystems in our study produced more N2O than expected for freshwater wetlands, in a related study we found no significant trade‐off between denitrification’s water quality benefits and its greenhouse gas costs in the restored wetland. These results suggest that, from a nitrogen perspective, wetland restoration in coastal agricultural lands has a net environmental benefit.

The National Science Foundation has funded an extension of this project that will focus on the effects of saltwater intrusion on carbon, nitrogen, and sulfur cycling in the restored wetland. This new three‐year grant began in July 2010.

Ms. Morse is now a research associate at Duke University, working on a project related to the water quality effects of mountaintop removal coal mining, and will begin a postdoctoral research position at the Cary Institute for Ecosystem Studies in September 2010.

FMI:  Read the Final Report.

Jennifer L. Morse

This grant in air and water conservation is sponsored by Clare Hallward.

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