Date Awarded

2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Virginia Institute of Marine Science

Advisor

Elizabeth A. Canuel

Committee Member

William G. Reay

Committee Member

Gregory S. Hancock

Committee Member

Carlton H. Hershner

Committee Member

Peter A. Raymond

Abstract

Carbon export from the land to the ocean are an important part of the global carbon cycle, linking terrestrial watersheds and the global carbon cycle. Burial of terrestrial organic carbon represents a long term sink for atmospheric CO2. Approximately 0.4 Pg Cy-1 is delivered to the global ocean from rivers, equally divided between POC and DOC. However, the amount of carbon entering the ocean is a small portion of the total amount entering rivers from the terrestrial environment, suggesting a large amount of processing in inland waters and estuaries. Most monitoring efforts have focused the processing of organic matter on baseflow conditions. However, recent studies have shown that POC and DOC exported during storm events, a small time period during a hydrologic year, can account for the majority of the annual carbon exported from small watersheds.

This dissertation identifies the impact different magnitudes of storm events have on the source, composition and reactivity of organic carbon released to downstream waters from the terrestrial environment at Taskinas Creek, Virginia. The proximity of the Creek to the York River estuary, the changes in water table at the site, along with the small size of the watershed allowing opportunity to examine the connectivity between the watershed processes and delivery of organic matter made the site ideal for identifying how hydrology and environment alter POM and DOM export and reactivity. The sources, composition and flux of DOM and POM were measured during four storm events of different magnitudes to determine how events impacted the sources and fluxes of organic matter and the % reactive DOC exported. Events of different magnitudes with varying sources of DOC and POC had similar % reactive DOC that was not predicted using excitation emission spectroscopy. The events resulted in DOC fluxes 1.5-490 fold higher than baseflow. POC fluxes for storm were 6.7-55 times higher than DOC fluxes. Although the % reactive DOC did not increase during storm event conditions, coupled with the overall flux, storm events represent a considerable pulse of % reactive DOC to downstream waters, well above baseflow levels. When considered with increases in storm intensity due to climate change, storm event fluxes of reactive OM may have broad impacts on estuaries and the global carbon cycle through changes in carbon storage.

DOI

http://doi.org/10.21220/V5HS4G

Rights

© The Author

Readme_Appendices.txt (1 kB)
Appendices to : Cammer, Sarah S. 2015. Storm Event Impact on Organic Matter Flux, Composition and Reactivity in Taskinas Creek, VA. PhD Dissertation, School of Marine Science, College of William and Mary.

EEMS_appendix.zip (47328 kB)
EEMS Appendix: Excitation Emission Spectra collected from 2009-2001 at Taskinas Creek, York River State Park, VA are contained within this folder.

Hydrology_appendix.tgz (943 kB)
Hydrology Appendix: This appendix contains stream level and discharge data for Taskinas Creek, Virginia, from 2009-2011.

Analyte_Appendix.tgz (7 kB)
Analyte_Appendix