Date of Award

Summer 7-6-2017

Degree Type

Thesis

Degree Name

Master of Science in Integrative Biology (MSIB)

Department

Biology

Major Professor

Dr. William Ensign

First Committee Member

Dr. Thomas McElroy

Second Committee Member

Dr. Melanie Griffin

Abstract

Campostoma oligolepis, the Largescale Stoneroller, is a species of minnow native to northwest Georgia. This study investigated the impacts of urbanization on gut length and gut microbiota community composition in C. oligolepis from four small watersheds within the Etowah River drainage basin with different levels of impervious surface coverage (ISC). Individuals were collected from each sample site in the summer of 2016 between late July and early September. A second round of sampling was conducted in the fall between mid-October and mid-November. The gut length to total length ratio was calculated for each individual to allow for an unbiased comparison of gut lengths between individuals of varying sizes. Additionally, gut microbiota communities from summer individuals’ fore- and hindguts were identified using 16S metagenomic sequencing on an Ion Torrent platform. Summer individuals from watersheds with lower ISC had significantly longer gut lengths than individuals from watersheds with higher ISC. However, no significant difference in relative gut length was found between sample sites for the individuals collected in fall. A significant decrease in relative gut length of individuals from sites with lower ISC was observed from summer to fall. Sequence data from the summer individuals revealed the presence of 36 bacterial phyla and 1,008 genera in Campostoma gut contents. Overall, Proteobacteria and Firmicutes accounted for the greatest percentage of the attributable reads. Pseudoalteromonas, Acinetobacter, and Blautia were the three most prevalent genera across sites and between gut regions. Nonmetric multi-dimensional scaling analysis using the 22 bacterial genera that accounted for the highest proportion of sequences across all sites revealed some grouping of samples based on site. However, distinct patterns in bacterial composition according to gut region or ISC by site were not apparent. These findings suggest that Campostoma may not rely on symbiotic bacteria to aid in digestion.

Available for download on Wednesday, July 25, 2018

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