The effect of clipping on methane emissions from Carex
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The purpose of this study was to estimate theresistance to methane release of the above-groundportion of Carex, a wetland sedge, and todetermine the locus of methane release from the plant. Measurements conducted on plants clipped to differentheights above the water level revealed that themethane flux from clipped plants was on the order of97% to 111% of control (unclipped) values. Thegreatest increase was observed in the initial fluxmeasurement after the plants had been clipped to aheight of 10 cm. Subsequent measurements on the 10 cmhigh stubble were similar to control values. When theends of plants which had been clipped to 10 cm weresealed, the methane flux was reduced to 65% ofcontrol values. However, sealing had no effect on theflux from plants which were clipped at 15 cm andhigher, indicating that virtually all methane wasreleased on the lower 15 cm of the plants as theyemerged from the water. The results indicate that theabove-ground portions of Carex at our studysite offered only slight resistance to the passage ofmethane, and that the main sites limiting methaneemission are below-ground, at either theporewater-root or root-shoot boundary. We hypothesizethat the transitory increase in flux associated withclipping was due to the episodic release of methaneheld within the plant lacunae. The buildup ofCH4 partial pressure within lacunal spacesovercomes the resistance to gas transport offered byaboveground parts.
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- Chanton JP, Whiting GJ, Showers WI & Crill PM (1992) Methane flux from Peltandra virginica: Stable isotope tracing and chamber effects. Global Biogeochem. Cycles 6: 15–31Google Scholar
- Cicerone RJ & Oremland RS (1988) Bigeochemical aspects of atmospheric methane. Global Biogeochem. Cycles 2: 299–327Google Scholar
- Dacey JWH (1981) How aquatic plants ventilate. Oceanus 24: 43–51Google Scholar
- Happell J, Chanton JP & Showers W (1994) The influence of methane oxidation on the stable isotopic composition of methane emitted from Florida Swamp forests. Geochim. Cosmochim. Acta. 58: 4377–4388Google Scholar
- Harden HS & Chanton JP (1994) Locus of methane release and mass-dependent fractionation from two wetland macrophytes. Limnol. Oceanogr. 39: 148–154Google Scholar
- Knapp AK & Yavitt JB (1992) Evaluation of a closed-chamber method for estimating methane emissions from aquatic plants. Tellus 44: 64–71Google Scholar
- Morrissey LA, Zobel DB & Livingston GP (1993) Significance of stomatal control onmethane release from a Carex dominated wetlands. Chemosphere 26: 339–355Google Scholar
- Nouchi I, Mariko S & Aoki K (1990) Mechanism of methane transport from the rhizosphere to the atmosphere through rice plants. Plant Physiol. 94: 59–66Google Scholar
- Schimel JP (1995) Plant transport and methane production as controls on methane flux from arctic wet meadow tundra. Biogeochemistry 28: 183–200Google Scholar
- Seiler W, Holzapfel-Pschorn A, Conrad R & Scharffe D (1984) Methane emission from rice paddies. J. Atmos. Chem. 1: 241–268Google Scholar
- Whiting GJ & Chanton JP (1996) Control of Diurnal pattern of methane emission from aquatic macrophytes by gas transport mechanisms. Aquatic Botany 54: 237–253Google Scholar