Gas exchange in wetlands with emergent vegetation: The effects of wind and thermal convection at the air-water interface
Article first published online: 20 SEP 2013
©2013. American Geophysical Union. All Rights Reserved.
Journal of Geophysical Research: Biogeosciences
Volume 118, Issue 3, pages 1297–1306, 3rd Quarter 2013
How to Cite
2013), Gas exchange in wetlands with emergent vegetation: The effects of wind and thermal convection at the air-water interface, J. Geophys. Res. Biogeosci., 118, 1297–1306, doi:10.1002/jgrg.20099., and (
- Issue published online: 10 OCT 2013
- Article first published online: 20 SEP 2013
- Accepted manuscript online: 27 JUL 2013 09:01AM EST
- Manuscript Accepted: 24 JUL 2013
- Manuscript Revised: 23 JUL 2013
- Manuscript Received: 14 SEP 2012
- gas exchange
 Methane, carbon dioxide, and oxygen are exchanged between wetlands and the atmosphere through multiple pathways. One of these pathways, the hydrodynamic transport of dissolved gas through the surface water, is often underestimated in importance. We constructed a model wetland in the laboratory with artificial emergent plants to investigate the mechanisms and magnitude of this transport. We measured gas transfer velocities, which characterize the near-surface stirring driving air-water gas transfer, while varying two stirring processes important to gas exchange in other aquatic environments: wind and thermal convection. To isolate the effects of thermal convection, we identified a semiempirical model for the gas transfer velocity as a function of surface heat loss. The laboratory results indicate that thermal convection will be the dominant mechanism of air-water gas exchange in marshes with emergent vegetation. Thermal convection yielded peak gas transfer velocities of 1 cm h−1. Because of the sheltering of the water surface by emergent vegetation, gas transfer velocities for wind-driven stirring alone are likely to exceed this value only in extreme cases.