Date of Award

Spring 2012

Project Type

Thesis

Program or Major

Earth Science

Degree Name

Master of Science

First Advisor

Wilfred Wollheim

Second Advisor

Joseph Salisbury

Abstract

The controls on the quantity and chemical composition of dissolved organic carbon (DOC) in freshwater systems are crucial to understanding and managing processes like carbon sequestration, heavy-metal transport, and municipal water sanitization. We analyzed DOC quantity and quality for 17 major North American rivers and the temporal variability of DOC quantity and quality in several thousand small basins. Among large basins, we found positive correlation between wetland-cover and both DOC concentration (R²=0.78; p<0.0001) and specific ultraviolet absorbance at 254nm (SUVA254; R²=0.91; p<0.0001). We found that the role of river networks in altering the annual DOC signal minimal except in systems with long residence times. Among small basins, we found characteristics like runoff, stormflow, and vegetation indices useful in predicting the temporal variability of DOC concentration. Further work should clarify where individual characteristics drive DOC variability and more rigorously define the role of processing in large rivers.

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