HR: 1340h
AN: B13C-0251    [Abstracts]
TI: The Combined Role Of Manganese Oxides And Microbes In The yAbiotic Uptake Of Amino Acid Nitrogen Into Litter And Soil Organic yMatter
AU: * Filley, T R
EM: filley@purdue.edu
AF: Department of Earth and Atmospheric Sciences Purdue University, 550 Stadium Mall Dr, West Lafayette, IN 47907 United States
AU: Dria, K
EM: kdria@purdue.edu
AF: Department of Earth and Atmospheric Sciences Purdue University, 550 Stadium Mall Dr, West Lafayette, IN 47907 United States
AB: Soil organic matter (SOM) is the largest terrestrial C and N store. Microbial yand abiotic processes that control the transformation of protein nitrogen in litter and ysoils into macromolecular humic materials play an important role in organic matter ystorage and soil productivity. There are major gaps, however, in our understanding of ythese processes and behaviors. Abiotic reactions of amines, phenols and sugars derived yfrom forest leachates or present in detrital and litter organic matter are known to be ykey processes in the formation of complex organic nitrogen. We present here the yresults from a study designed to investigate how the inherent chemistry of lignin, leaf ylitter, and progressively advanced brown-rot wood decay impact the chemical reaction yof amino acids with this organic matter. Additionally, experiments in the presence of ybirnessite (MnO2) were also conducted to investigate the role of mineral induced phenol yoxidation on specific amino acid chemical humifcation processes. Solid and liquid state yNMR, 13C-labelled tetramethyl ammonium hydroxide thermochemolysis and stable ycarbon and nitrogen isotope ratio mass spectrometry were used to track the alteration yof litter material and document uptake of 13C and 15N labeled amino acids. yPreliminary results from birnessite-containing experiments suggest that the metal-ypromoted oxidation of the lignin, leaf litter, and, in particular, demethylated brown rot ywood residues, is necessary to convert the phenols to quinones of some type permitting yamine addition. This relationship is particularly true for the production of soluble yfractions after two and six weeks of reaction in the presence of the manganese oxides. yAdditionally, the production of leachable organic matter with incorporated N was ypromoted in the soluble fractions. Ongoing NMR studies will elucidate the nature of ythe chemical binding in these experiments. y
DE: 4805 Biogeochemical cycles (1615)
DE: 4806 Carbon cycling
DE: 1045 Low-temperature geochemistry
DE: 1055 Organic geochemistry
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting