HR: 09:00h
AN: B51F-05 INVITED    [Abstracts]
TI: News about methane emission from plant matter
AU: * Röckmann, T
EM: t.roeckmann@phys.uu.nl
AF: Institute of Marine and Atmospheric Research Utrecht, Utrecht University Princetonplein 5, Utrecht, 3584CC, Netherlands
AU: Vigano, I
EM: i.vigano@phys.uu.nl
AF: Institute of Marine and Atmospheric Research Utrecht, Utrecht University Princetonplein 5, Utrecht, 3584CC, Netherlands
AU: Holzinger, R
EM: r.holzinger@phys.uu.nl
AF: Institute of Marine and Atmospheric Research Utrecht, Utrecht University Princetonplein 5, Utrecht, 3584CC, Netherlands
AU: van Weelden, H
EM: h.vanweelden@umcutrecht.nl
AF: University Medical Center Utrecht, Heidelberglaan 100, Utrecht, 3584CX, Netherlands
AU: Keppler, F
EM: keppler@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Becherweg 27, Mainz, 55128, Germany
AB: Almost two years ago, Keppler et al. [2006] published results from laboratory experiments indicating that living plants, plant litter and the structural plant component pectin emit methane to the atmosphere under aerobic conditions. These findings contradict the accepted view that methane can be formed under oxygen-free conditions only, and in fact we still lack a fundamental understanding of the production process. They also have far-reaching implications since they imply a new and possibly important plant-climate feedback, since the global source strength estimated from those laboratory measurements was large. The scientific debate first concentrated on the up-scaling approach, and several other approaches have been suggested. However, since no up-scaling rule has been identified, also other up-scaling methods lack a solid scientific basis and the fundamental question at this stage is whether aerobic CH4 emissions from the biosphere do actually exist. Several possible experimental artifacts in the experiments of Keppler et al. have been suggested, and in fact one recent study has reported the absence of CH4 emissions from vegetation [Dueck, et al., 2007], but the discrepancy to the measurements of Keppler et al. could not be explained. In our follow up research we have aimed at proving that an aerobic CH4 production mechanism does indeed exist. Our new results – obtained with different analytical techniques – show that dry and fresh plant matter, as well as several structural plant components, emit significant amounts of methane upon irradiation with UV light and heating. Emissions from UV irradiation are almost instantaneous, indicating a direct photochemical process. The size of the methane-forming reservoir exceeds the size of suggested contamination sources by several orders of magnitude. A dry leaf of a pure 13C plant also produces 13CH¬4. References Dueck, T. A., R. de Visser, H. Poorter, S. Persijn, A. Gorissen, W. de Visser, A. Schapendonk, J. Verhagen, J. Snel, F. J. M. Harren, A. K. Y. Ngai, F. Verstappen, H. Bouwmeester, L. A. C. J. Voesenek, and A. van der Werf, No evidence for substantial aerobic methane emission by terrestrial plants: a 13C-labelling approach New Phytologist, doi : 10.1111/j.1469-8137.2007.02103.x, 2007. Keppler, F., J. T. G. Hamilton, M. Brass, and T. Röckmann, Methane emissions from terrestrial plants under aerobic conditions, Nature, 439, 187-191, doi:110.1038/nature04420, 2006.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0365 Troposphere: composition and chemistry
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0454 Isotopic composition and chemistry (1041, 4870)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting