Date of Award

8-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Gregory A. Pope

Committee Member

Michael A. Kruge

Committee Member

Matthew L. Gorring

Abstract

Black carbon (BC) is formed by the incomplete combustion of fossil fuels, biofuels, and biomass. It has been suggested due to its ubiquitous nature in soils that BC may act as a significant sink in the global carbon cycle. BC has been widely studied in a variety of soil and sediment types but spodosols (acid forest soils) have been underrepresented in the literature. In the present study, spodosol soil samples were collected along an elevational gradient (~500 to 1,200 m) from three different mountains in the White Mountain National Forest of New Hampshire. Total soil carbon was first measured using the loss on ignition method as a proxy for total organic carbon (TOC) including BC. BC concentrations were then quantified and characterized using both the chemo-thermal oxidation method at 375 degrees Celsius (CTO-375) and Pyrolysis-GC-MS. Using these analyses, it was possible to quantify total BC in the studied soils in addition to the sources. Soil texture was also measured using particle size distributions obtained from the Malvern Particle Size Analyzer to determine if particle size played a role in the sequestration of black carbon in soils. Mineral species and concentrations were measured using x-ray powder diffraction (XRD) to determine relationships between mineral content and BC sequestration due to chemical bonding. The results indicate that the BC/TOC ratio is highest where TOC is lower irrespective of altitude. Only weak trends were observed when comparing BC concentrations to average particle size distributions. Bulk soil mineralogy was also found to be an ineffective means of analyzing mineral concentrations in relation to BC. Pyrolysis-GC-MS analysis detected the presence of PAH compounds confirming the presence of BC in the samples analyzed.

Download

Share

COinS