Grantee Research Project Results

Compositional and Molecular Characterization of Soil Organic Matter Under Loblolly Pine Forest Exposed to Elevated CO2

EPA 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: Packard, Benjamin H
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $157,246
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Academic Fellowships , Fellowship - Terrestrial Ecology , Ecological Indicators/Assessment/Restoration

Objective:

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.

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.