Date of Award

Summer 8-5-2015

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geography and Geology

Committee Chair

Omar R. Harvey

Committee Chair Department

Geography and Geology

Committee Member 2

Frank Heitmuller

Committee Member 2 Department

Geography and Geology

Committee Member 3

Kevin A. Kuehn

Committee Member 3 Department

Biological Sciences

Abstract

The resistance of plant derived pyrogenic organic carbon (pyC) to abiotic and biotic means of degradation has led to increased interest in the role of pyC as a potential carbon sink, as well as a strategy for sequestering atmospheric CO2 to mitigate excess carbon emissions. Though much research pertaining to the fundamental properties of pyC degradation have been performed in a controlled lab setting, there has been very little work regarding pyC degradation in a field setting where factors such as precipitation and temperature fluctuate seasonally. This work focuses on various degradation characteristics of two different types of plant-derived pyC, placed in both a burned and unburned setting, over a study period of 1-year. We observed that the potential for DOC from outside sources to adsorb itself to the surface of pyC increases in fall and spring due to increases in leaf litter and increases in temperature, respectively. We also observed that the overall recalcitrance of pine-derived pyCs decreases with time and the overall recalcitrance of CG-derived pyCs increases with time, as different portions of the pyCs are utilized by microbes depending on the microbial community present. Finally, we observed that pyCs degrade differently in burnt and unburnt sites. Namely, a more specialized microbial community found in burnt sites is able to utilize pine pyCs faster than the microbial community found in unburned sites. However, this specialization leads to the opposite trend occurring for CG pyCs, in which degradation occurs more quickly in unburnt sites than in burnt sites.

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