Defense Date

2014

Document Type

Thesis

Degree Name

Master of Science

Department

Environmental Studies

First Advisor

S. Leigh McCallister

Abstract

Rivers are a significant source of particulate and dissolved organic carbon (POC, DOC) into inland waters and coastal systems and provide a fundamental linkage between the terrestrial, oceanic, and atmospheric carbon reservoirs. Recent studies have examined the relationship between the quantity and form (POC vs. DOC) of carbon delivered to the aquatic system; however, little is known about the age of POC and DOC exported and how the radiocarbon age may vary with latitude, topographic gradient, vegetation, and land use. I provide the first global synthesis of published radiocarbon values of POC and DOC (∆14C). Inclusion of DOC and POC parameters (µM, δ13C, ∆14C) reveal significant driving forces of DOC (µM), latitude, and elevation (m) as capable of explaining 25% of the variability in DO14C in rivers and POC (µM) and latitude accounting for 15% of the variability in PO14C. When δ13C of DOC and POC and latitude were incorporated with ∆14C of DOC observations, 61% of the variability in DOC age was explained revealing the necessity to include dissolved and particulate fractions of organic carbon to yield the most robust predictive models. This study found a global trend of increasing age of DOC and increasing δ13C of DOC and POC with increasing latitude. My study suggests future research should incorporate both particulate and dissolved OC parameters along with elevation, vegetation, land cover, and climate zones to increase understanding of what drives the age of carbon exported in riverine systems.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

5-15-2014

Available for download on Wednesday, May 15, 2019

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