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Publication Date

2020

First Advisor

Laura A. Katz

Second Advisor

Paulette Peckol

Third Advisor

Charles A. Schutte

Document Type

Honors Project

Degree Name

Bachelor of Arts

Department

Biological Sciences

Keywords

Coastal wetlands, Salt marsh, Climate change, Biogeochemistry, Greenhouse gas, Fiddler crab, Bioturbation, Oil, CO2, CH4

Abstract

Coastal marsh soils are important sites of carbon burial that can mitigate the intensity of carbon-induced climate change. However, soil microbial processes produce potent greenhouse gases such as carbon dioxide and methane, which can then be released into the atmosphere and offset some of the climate benefits provided by carbon burial. A great deal is known about the influence of seasons, tides, and salinity on salt marsh greenhouse gas emissions, but little effort has been devoted to determining their response to natural and anthropogenic disturbances. In this study, I evaluate how fiddler crab (Uca longisignalis) bioturbation and oil pollution affect the fluxes of carbon dioxide and methane from a Louisiana salt marsh. This study includes three burrow treatments - no burrow, artificial burrow, and crab-made burrow - and four oil treatments with oil concentrations of 0 mg cm-2 , 0.85 mg cm-2, 8.52 mg cm-2, and 25.55 mg cm-2 . Soil mesocosms were incubated for five days after which carbon dioxide and methane fluxes were measured using a field gas analyzer and mesocosms were thereafter extruded to quantify burrow size and depth. A second experiment was created to determine if the presence of the burrow itself along with the excavated soil were driving greenhouse gas fluxes. My study demonstrates the potential for both natural and anthropogenic disturbances to alter salt marsh soil greenhouse gas fluxes allowing for a deeper understanding of salt marshes as carbon sinks and sources, but more work is required to determine their influence on the ecosystem scale.

Rights

©2020 Adrianna K. Grow. Access limited to the Smith College community and other researchers while on campus. Smith College community members also may access from off-campus using a Smith College log-in. Other off-campus researchers may request a copy through Interlibrary Loan for personal use.

Language

English

Comments

42 pages : illustrations (some color) Includes bibliographical references (pages 37-42)

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