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Relationships Between Methane and Carbon Dioxide Fluxes in a Temperate Cattail‐Dominated Freshwater Wetland
Author(s) -
Villa Jorge A.,
Ju Yang,
Vines Chante,
ReySanchez Camilo,
Morin Timothy H.,
Wrighton Kelly C.,
Bohrer Gil
Publication year - 2019
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2019jg005167
Subject(s) - eddy covariance , wetland , environmental science , temperate climate , methane , flux (metallurgy) , carbon dioxide , ecosystem , atmospheric sciences , typha , diel vertical migration , daytime , hydrology (agriculture) , environmental chemistry , ecology , chemistry , biology , geotechnical engineering , organic chemistry , geology , engineering
Wetlands are the most important natural source of methane (CH 4 ) to the atmosphere, and there is still considerable uncertainty of CH 4 flux and net carbon budgets of wetlands. This uncertainty is due in part to the complex role of wetland vegetation in controlling methane production, oxidation and transport, which challenge the modeling and forecast of CH 4 fluxes. We combined CH 4 and carbon dioxide (CO 2 ) fluxes measured by the eddy covariance technique during two consecutive growing seasons with continuous measurements of water levels and water temperature in a Typha angustifolia L patch of a temperate wetland. We seek to evaluate the role of vegetation in CH 4 flux processes. To this end, we determined the relationship between CH 4 and CO 2 fluxes, directly and indirectly linked to plant activity. Our results indicated significant but opposing relationships between CH 4 and CO 2 fluxes during the daytime and nighttime. Consequently, when analyzed on a diel timescale, this relationship was not significant. Both CH 4 and CO 2 fluxes were highly dependent on environmental drivers, and thus, the correlations observed at both the nighttime and daytime were likely the result of a shared response to environmental variables. Focusing on water temperature (the most commonly observed environmental variable in wetlands) and water level (the most commonly controlled one) as operational control variables for wetlands, we identified “hot” condition combinations when CH 4 flux and net ecosystem CO 2 uptake are maximized at half hourly and diel scales.