HR: 09:45h
AN: B11G-08 INVITED    [Abstracts]
TI: A STXM/NEXAFS Investigation of the Role of Particle Composition in Organic Matter Stablization
AU: * Nico, P S
EM: psnico@lbl.gov
AF: Earth Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Rd. Lawrence Berkeley National Laboratory, Berkeley, ca 94720, United States
AU: Kleber, M
EM: Markus.Kleber@oregonstate.edu
AF: Department of Crop and Soil Science, Oregon State University, Department of Crop and Soil Science, Oregon State University, Corvallis, Or 97331, United States
AU: Sollins, P
EM: phil.sollins@oregonstate.edu
AF: Department of Forestry, Oregon State University, Department of Forestry, Oregon State University, Corvallis, ca 97331, United States
AB: The detailed role of mineral particles in the fractionation and stabilization of soil organic matter remains unclear. We employed STXM (Scanning Transmission X-ray Microscopy) to obtain images of the C, N, and Fe distribution on individual mineral particles from three different soils with varying chemistries and mineral make-up and obtained NEXAFS spectra from specific locations to investigate organic matter chemistry in relation to chemistry of the mineral surface. Specifically we examined the soil density fraction of 2.3-2.6 g cm-3 from A horizons of an Inceptisol, Oxisol, and Alfisol. Preliminary results indicate an average difference between the NEXAFS spectra taken from the particles from the different soils as well as small scale (nm) intra-particle differences in carbon distribution. These intra-particle differences appear to be driven by the particle composition, but the effects are not uniform within each soil. We will present further details of the organic matter heterogeneity along with its implications for carbon stabilization pathways.
DE: 0428 Carbon cycling (4806)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting