Grantee Research Project Results
Compositional and Molecular Characterization of Soil Organic Matter Under Loblolly Pine Forest Exposed to Elevated CO2EPA Grant Number: U916180
Title: Compositional and Molecular Characterization of Soil Organic Matter Under Loblolly Pine Forest Exposed to Elevated CO2
Investigators: Fimmen, Ryan L.
Institution: Duke University
EPA Project Officer: Graham, Karen
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $157,246
RFA: STAR Graduate Fellowships (2003)
Research Category: Academic Fellowships , Fellowship - Terrestrial Ecology and Ecosystems , Ecological Indicators/Assessment/Restoration
The objective of this research project is to determine if the composition of source dissolved organic carbon (DOC) influences DOC-soil mineral interactions, leads to alterations in mineralogy, and influences carbon-storage potential.Approach:
Chemical composition of DOC from different source material, litter layer, and mineral soils from pine and oak forests and a hayfield was characterized by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy, 13C-nuclear magnetic resonance (NMR), fluorescence spectroscopy, and analysis of carbohydrates. Soil mineralogy was characterized by Brunauer-Emmett-Teller-surface area, total carbon to nitrogen, and Fe/Al-oxide content. Pine litter-DOC contains fulvic acids of smaller molecular size (vs. oak/hayfield litter-DOC). Additionally, pine mineral soil-DOC shows an enrichment of carboxylate functionalities (1,697cm-1) compared to oak and hayfields. These differences in source DOC characteristics possibly explain the low soil-C, surface-area, and Fe-oxide content of the pine mineral soil (0.67 percent, 1.05 m2/g, 1.88 mg-Fe/g) as compared with oak (2.65 percent, 6.62 m2/g, 10.67 mg-Fe/g) and hayfield (2.04 percent, 7.53 m2/g, 17.64 mg-Fe/g).Supplemental Keywords:
fellowship; Attenuated Total Reflection Fourier Transform Infrared Spectroscopy; carbon nuclear magnetic resonance; carbon to nitrogen; Brunauer-Emmett-Teller equation.