First Advisor

Jennifer L. Morse

Date of Award

Spring 6-12-2026

Document Type

Thesis

Degree Name

Bachelor of Science (B.S.) in Environmental Science and University Honors

Department

Environmental Science and Management

Language

English

Subjects

Wetland Restoration, Greenhouse Gas Fluxes, Soil Biogeochemistry, Coastal Wetland, Freshwater Wetland, Climate Change

DOI

10.15760/honors.1928

Abstract

Wetlands provide valuable ecosystem services, one of which is a wetlands ability to sequester carbon. Climate change and human land use threaten a wetlands ability to do so. Globally, 21% of wetlands have been lost since the 1700s. As a result, restoration of wetlands has been increasing. However, wetlands in the process of restoration emit more methane than degraded ones, and as the climate continues to change, these fluxes could respond. Projected sea level rise is expected to cause salt water to infiltrate coastal freshwater systems, increasing the salinity. Past research has found that increased salinity has led to suppressed CH4 and N2O  emissions, but increased CO2 emissions. Additionally, increasing global temperatures are expected to increase N2O  and CH4 emissions. Understanding how salinity and temperature increases impact GHG cycling in restored freshwater wetlands individually and together is important to predicting the ecosystem's response to climate change. This was a lab-based study paired with an ongoing field experiment that investigated how salinity and temperature increases impact the cycles of N2O , CH4, and CO2 in a coastal freshwater wetland that was hydrologically restored in 2017. There were no significant interactions between salinity and temperature impacting GHG cycling, however individually they both had significant effects. Salinity suppressed CH4 emissions and increased N2O  emissions, and temperature was found to suppress N2O emissions. Results from this study were conflicting with past field research, but aligned with some previous lab studies, suggesting the need for more lab and field paired designs.

Persistent Identifier

https://archives.pdx.edu/ds/psu/44890

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