Abstract

Multiple wetland ecosystem services such as carbon sequestration and nutrient removal are influenced by microbial communities and dissolved organic matter (DOM). I examined DOM composition, carbon metabolism, and microbial communities in three created wetlands, which had distinct hydrology, vegetation and antecedent land-use. To study differences between wetlands, porewater and soil were collected from each wetland in spring, summer, and fall of 2018. DOM was analyzed using NMR spectroscopy and fluorescence spectrometry, soil microbial community composition was examined using 16S ribosomal sequencing, and CO2 and CH4 production rates were measured in anaerobic soil incubations. Structural DOM composition varied significantly between the three wetlands but did not vary seasonally. There were distinct differences in the microbial community composition of each wetland, which correlated with soil chemistry factors but did not correlate with CH4 or CO2 production rates. Average CH4/CO2 production ratios were approximately 1:1 for all sites in the spring and summer and approached 3:1 in the fall, with no differences between sites. This suggests that while DOM characteristics and microbial communities in created wetlands are impacted by site characteristics, these differences have less effect on carbon metabolism. I also examined the effects of invasive species removal via herbicide application on microbial communities in one of the wetlands. Soil was collected in the spring and summer before and after the application of glyphosate herbicide and microbial communities were examined using 16S ribosomal sequencing. There were significant and persistent changes in the microbial community following invasive species removal through application of herbicide. Further study is needed to determine direct causal relationships between invasive species control measures and microbial community changes, to determine whether shifts in microbial communities persist past a single growing season and to identify impacts of invasive removal and herbicide application on key wetland functions.

Library of Congress Subject Headings

Constructed wetlands--Ecology; Constructed wetlands--Management; Microbial ecology; Carbon sequestration

Publication Date

8-11-2021

Document Type

Thesis

Student Type

Graduate

Degree Name

Environmental Science (MS)

Department, Program, or Center

Thomas H. Gosnell School of Life Sciences (COS)

Advisor

Carmody McCalley

Advisor/Committee Member

Anna Christina Tyler

Advisor/Committee Member

Nathan Eddingsaas

Campus

RIT – Main Campus

Plan Codes

ENVS-MS

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