Electronic Theses and Dissertations Archive

Date

2026

Document Type

Thesis

Degree Name

Master of Science

Department

Biology

Committee Chair

Shawn Brown

Committee Chair

Leigh Boardman

Committee Member

Jim Adelman

Committee Member

Rachel Diner

Abstract

Many streams in West Tennessee, USA, have been heavily modified for agriculture or flood prevention purposes, which can result in altered stream microbial community dynamics. There is little research comparing biological and physicochemical dynamics between disturbed and natural streams, especially in West Tennessee. There is a need to understand how restoration efforts may impact microbial communities and thus ecosystem processing. Here, we investigate the community and assembly dynamics of microbial communities (prokaryotic and eukaryotic) in a degraded stream slated for restoration by 1) comparing this disturbed site to an undisturbed control stream, 2) examining seasonal variation of biofilms and riparian soil communities in a degraded stream, and 3) using environmental DNA sampling to examine efficacy of eDNA water sampling to quantify stream biodiversity. We established biofilm sampling plots and conducted metabarcoding targeting Bacteria (16S rRNA region) and Eukaryotes (18S rRNA region) using Illumina MiSeq) and separated these into taxonomic or functional groups. Additionally, we collected stream physiochemical data (pH, oxygen reduction potential, dissolved oxygen, total dissolved solids, K+, NO₃⁻, temperature, and electrical conductivity). Using a community assembly analytical framework, we observed significant differences between the degraded and natural streams, with greater diversity and abundance found in the more natural stream, but these patterns are taxonomically context dependent. Community assembly was driven by strong temporal effects on community structure and stream chemistry; however, assembly patterns differed based upon physiochemical variables as well as microbial community patterns. This work highlights that to restore degraded streams in West Tennessee, attention must be directed toward aquatic microbial communities as indicators of ecosystem health and resilience.

Comments

Data is provided by the student.”

Library Comment

Dissertation or thesis originally submitted to ProQuest/Clarivate.

Notes

Open Access

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