Plant species determine tidal wetland methane response to sea level rise
Peter Mueller, Thomas J. Mozdzer, J. Adam Langley, Lillian R. Aoki, Genevieve L. Noyce, J. Patrick Megonigal
Abstract
Abstract Blue carbon (C) ecosystems are among the most effective C sinks of the biosphere, but methane (CH 4 ) emissions can offset their climate cooling effect. Drivers of CH 4 emissions from blue C ecosystems and effects of global change are poorly understood. Here we test for the effects of sea level rise (SLR) and its interactions with elevated atmospheric CO 2 , eutrophication, and plant community composition on CH 4 emissions from an estuarine tidal wetland. Changes in CH 4 emissions with SLR are primarily mediated by shifts in plant community composition and associated plant traits that determine both the direction and magnitude of SLR effects on CH 4 emissions. We furthermore show strong stimulation of CH 4 emissions by elevated atmospheric CO 2 , whereas effects of eutrophication are not significant. Overall, our findings demonstrate a high sensitivity of CH 4 emissions to global change with important implications for modeling greenhouse-gas dynamics of blue C ecosystems.