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Methane Emissions to the Atmosphere Through Aquatic Plants
Author(s) -
Sebacher Daniel I.,
Harriss Robert C.,
Bartlett Karen B.
Publication year - 1985
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1985.00472425001400010008x
Subject(s) - aquatic plant , methane , environmental chemistry , atmosphere (unit) , brackish water , environmental science , sediment , wetland , transpiration , rhizome , aquatic ecosystem , typha , chemistry , botany , macrophyte , salinity , ecology , photosynthesis , biology , paleontology , physics , thermodynamics , organic chemistry
The movement of methane (CH 4 ) from anaerobic sediments through the leaves, stems, and flowers of aquatic plants and into the atmosphere was found to provide a significant pathway for the emission of CH 4 from the aquatic substrates of flooded wetlands. Methane concentrations well above the surrounding ambient air levels were found in the mesophyll of 16 varieties of aquatic plants and are attributed to transpiration, diffusion, and pressure‐induced flow of gaseous CH 4 from the roots when they are embedded in CH 4 ‐saturated anaerobic sediments. Methane emissions from the emergent parts of aquatic plants were measured using floating chamber techniques and by enclosing the plants in polyethylene bags of known volume. Concentration changes were monitored in the trapped air using syringes and gas chromatographic techniques. Vertical profiles of dissolved CH 4 in sediment pore water surrounding the aquatic plants' rhizomes were obtained using an interstitial sampling technique. Methane emissions from the aquatic plants studied varied from 14.8 mg CH 4 d −1 to levels too low to be detectable. Rooted and unrooted freshwater aquatic plants were studied as well as saltwater and brackish water plants. Included in the experiment is a detailed set of measurements on CH 4 emissions from the common cattail ( Typha latifolia ). This paper illustrates that aquatic plants play an important gas exchange role in the C cycle between wetlands and the atmosphere.