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The contribution of an overlooked transport process to a wetland's methane emissions
Author(s) -
Poindexter Cristina M.,
Baldocchi Dennis D.,
Matthes Jaclyn Hatala,
Knox Sara Helen,
Variano Evan A.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl068782
Subject(s) - methane , wetland , environmental science , greenhouse gas , temperate climate , atmosphere (unit) , atmospheric sciences , atmospheric methane , marsh , convection , methanogenesis , hydrology (agriculture) , ecology , geology , meteorology , physics , oceanography , geotechnical engineering , biology
Wetland methane transport processes affect what portion of methane produced in wetlands reaches the atmosphere. We model what has been perceived to be the least important of these transport processes: hydrodynamic transport of methane through wetland surface water and show that its contribution to total methane emissions from a temperate freshwater marsh is surprisingly large. In our 1 year study, hydrodynamic transport comprised more than half of nighttime methane fluxes and was driven primarily by water column thermal convection occurring overnight as the water surface cooled. Overall, hydrodynamic transport was responsible for 32% of annual methane emissions. Many methane models have overlooked this process, but our results show that wetland methane fluxes cannot always be accurately described using only other transport processes (plant‐mediated transport and ebullition). Modifying models to include hydrodynamic transport and the mechanisms that drive it, particularly convection, could help improve predictions of future wetland methane emissions.