HR: 0800h
AN: B21A-0854    [Abstracts]
TI: Isotopomer Signatures of Nitrous Oxide Emissions From Soils During Nitrification, Denitrification and Chemodenitrification
AU: * Clough, T J
EM: clought@lincoln.ac.nz
AF: Soil Plant & Ecological Sciences Division, Lincoln University, PO Box 84 Lincoln University, Canterbury, PO Box 84 New Zealand
AU: Sherlock, R R
EM: sherlock@lincoln.ac.nz
AF: Soil Plant & Ecological Sciences Division, Lincoln University, PO Box 84 Lincoln University, Canterbury, PO Box 84 New Zealand
AU: Griffith, D W
EM: griffith@uow.edu.au
AF: Atmospheric Chemistry Research Group, Department of Chemistry, University of Wollongong., Department of Chemistry, University of Wollongong, Wollongong, NSW 2522 Australia
AU: Wilson, S R
EM: wilson@uow.edu.au
AF: Atmospheric Chemistry Research Group, Department of Chemistry, University of Wollongong., Department of Chemistry, University of Wollongong, Wollongong, NSW 2522 Australia
AU: Toyoda, S
EM: stoyoda@chemenv.titech.ac.jp
AF: Department of Environmental Chemistry and Engineering, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8502 Japan
AU: Toyoda, S
EM: stoyoda@chemenv.titech.ac.jp
AF: SORST Project, Japan Science and Technology Corporation (JST)., 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012 Japan
AU: Yoshida, N
EM: naoyoshi@depe.titech.ac.jp
AF: SORST Project, Japan Science and Technology Corporation (JST)., 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012 Japan
AU: Yoshida, N
EM: naoyoshi@depe.titech.ac.jp
AF: Frontier Collaborative Research Center, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8502 Japan
AB: New Zealand's greenhouse gas budget is atypical amongst developed nations in that 49.2% of total emissions in 2002 were produced by the agriculture sector. Agricultural soils are the source of most of the N$_{2}$O emissions in New Zealand and have increased by 27.6% since 1990. Emissions of N$_{2}$O arise directly from agriculture soils as a result of fertilizer, predominantly urea, and animal urine deposition onto grazed pastures. Identification of N$_{2}$O source mechanisms in soils would enable better targeting, timing and development of appropriate mitigation strategies. N$_{2}$O isotopomers have shown promise as a means for distinguishing the mechanisms that generate N$_{2}$O emissions due to the differential enrichment in the central N position ($\alpha$) relative to the terminal N position ($\beta$). P\'{e}rez et al. (2001) reported the first isotopomer measurements from agricultural soils with nitrification preferentially enriching the $\alpha$ position. Sutka et al. (2003) reported the first measured N$_{2}$O isotopomer values for isolated microbial processes finding significant differences in site preference following hydroxylamine oxidation by Nitrosomonas and Methylococcus species The results of Yamulki et al. (2001) suggested a possible change from nitrification to denitrification processes following cow urine applications to soil. However, in the urine patch there are three possible mechanisms for N2O formation, nitrification, chemodenitrification, and denitrification. These mechanisms may possibly occur separately or simultaneously. The objective of our work was to measure isotopomer signatures of N$_{2}$O, from the three N$_{2}$O production mechanisms mentioned above, from soils in the laboratory under carefully delineated conditions. Interim results to date are reported on.
DE: 4870 Stable isotopes
DE: 1615 Biogeochemical processes (4805)
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting