Ye Yuan recently completed her Master’s thesis research titled “Global warming potential driven by nitrogen inflow and hydroperiod in a model of Great Lakes coastal wetlands.” Ms. Yuan worked together with Bill Currie and the rest of the Mondrian model development team to add wetland GHG emissions to the model, including nitrous oxide (N2O), methane (CH4), and net ecosystem exchange (NEE) of CO2. A paper reporting the results of this research is now in press at Journal of Geophysical Research – Biogeosciences.

Key points of this paper, excerpted from Yuan et al. in press, are below:

• “Wetland methane emissions had a far greater effect on net sustained-flux global warming potential (SGWP) than carbon dioxide or nitrous oxide
• While a tradeoff between methane emission and the sequestration of carbon controlled net SGWP, net SGWP was always positive in our simulations
• Nitrogen inflow, water residence time and water level were important drivers of greenhouse gas emissions and interacted in our simulations, illustrating the importance of using a data-based, mechanistic process model to reveal such interactions.”

This research involved thousands of simulations using the Mondrian wetland community-ecosystem model. This approach allowed us to simulate a wide range of environmental conditions present in the Great Lakes region, including ranges of water levels, N inflows, wetland water residence time, and native marsh species versus those invaded by Phragmites australis.

Fig. 6 from Yuan et al. (in press). “Mondrian model results for SGWP (Sustained Global Warming Potential) of each GHG in the 100-year time horizon (SGWP₁₀₀) as functions of N inflow under current regional climate conditions (11.5 °C annual mean temperature), water residence time 10 days and WL (Water Level) scenario D. Error bars represent standard errors among 3 replicate model runs; note that some error bars are within the size of the symbols and thus too small to be visible. NEE = net ecosystem exchange of CO₂; NET = net SGWP from three gases shown.”     

Citation:

Yuan, Y., S. J. Sharp, J. P. Martina, K. J. Elgersma, and W. S. Currie. Sustained-flux global warming potential driven by nitrogen inflow and hydroperiod in a model of Great Lakes coastal wetlands. JGR Biogeosciences in press.