Carbon Cycles in Forested Wetlands Face an Uncertain Future under Climate Change
Scientists and collaborators working with the Eastern Threat Center continuously measured the release of carbon dioxide (CO2) from soils in a lower coastal plain forested wetland in North Carolina through two contrasting hydrologic years (a wet year and a dry year). To capture the effects of hydrologic variability, researchers took the measurements along a microtopographic gradient—areas where soil surface variations create different conditions that influence the movement of water and associated biological processes—and developed a model that captured changes in soil carbon release across space and time. Findings indicate that 93% of the annual CO2 emissions were released during non-flooded periods in the wetland, and the decreasing water table during the growing season resulted in a rapid increase in CO2 release. Researchers expect that periods of drought will result in accelerated soil CO2 emissions, but that sea level rise could suppress soil CO2 release and instead increase emissions of methane, a more potent climate-warming greenhouse gas.
Right: Researchers used soil respiration chambers to measure the release of CO2 in a coastal forested wetland. Photo by Guofang Miao, North Carolina State University.
References:
Miao, G.; Noormets, A.; Domec, J.-C.; Trettin, C.C.; McNulty, S.G.; Sun, G.; King, J.S. 2013. The effect of water table fluctuation on soil respiration in a lower coastal plain forested wetland in the southeastern U.S. Journal Of Geophysical Research: Biogeosciences 118:1748-1762.
Forest Service Partners/Collaborators: Southern Research Station Center for Forested Wetlands Research
External Partners/Collaborators: North Carolina State University
Contact: Steve McNulty, Ge Sun, and Asko Noormets
