You are here:
Long-term eutrophication prompts tradeoffs in nitrous oxide and methane emission in a New England salt marsh
Citation:
Martin, R., C. Wigand, I. Valiena, AND E. Elmstrom. Long-term eutrophication prompts tradeoffs in nitrous oxide and methane emission in a New England salt marsh. Society of Wetland Scientists (SWS), San Juan, Puerto Rico, June 04 - 08, 2017.
Impact/Purpose:
This abstract is for an invited presentation at the upcoming (June 2017) Society of Wetland Scientists meeting. The symposium in which this work will be presented is entitled "Global Change Influences on Blue Carbon Pools and Processes".
Description:
Eutrophication is a common problem facing urban estuaries and may stimulate changes in microtopography, plant communities, and microbial processes that drive greenhouse gas (GHG) fluxes. Since coastal wetlands are known to sequester abundant carbon and GHGs relative to terrestrial systems, understanding effects of eutrophication on GHG fluxes in these systems is important. A long-term fertilization experiment (~46 years and counting) and use of laser spectroscopy analyzers at Great Sippewissett Marsh (MA, USA) provides a unique opportunity to study effects of long-term fertilization on GHG fluxes. During one growing season, we measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes from different vegetation cover types in experimental plots receiving high doses of fertilization (1,572 kg N ha−1 year−1) and in control plots (12 kg N ha−1 year−1). Results demonstrated no detectable CO2 flux difference, but potential fertilization-driven tradeoffs in production of the potent greenhouse gases CH4 and N2O. Elevation increases stimulated by fertilization (as changes in vegetation type accelerated peat accumulation) resulted in greater N2O emission, but diminished CH4 emissions. In control plots and at low elevations in fertilized plots, CH4 emissions were substantially greater, likely due to anoxic conditions. These results demonstrate the potential for fertilization to stimulate complex ecosystem-scale changes that significantly alter GHG fluxes and associated carbon sequestration. Furthermore, the study underscores the necessity of long-term experiments to improve understanding of future global change scenarios.