Project Director

Leasi, Francesca

Department Examiner

Alda, Fernando; Schorr, Mark

Department

Dept. of Biological and Environmental Sciences

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

Meiofauna include small-sized animals (< 1mm) distributed in all aquatic ecosystems on Earth, where they play fundamental trophic and ecological roles. The biodiversity of marine meiofauna and its links with anthropogenic activities is routinely investigated, however, freshwater communities are less known. This is particularly true for the Southeastern United States, which is greatly investigated and elected a hotspot of biodiversity for larger species but very little is known about the meiofauna. The purpose of this research is to reveal the biodiversity of meiofauna from the Tennessee River and test for potential correlations with anthropogenic activities. As a proxy for pollution, dissolved and suspended solids were considered in this study. The research hypothesis is that meiofaunal biodiversity would be affected by possible changes of dissolved and suspended solids in the water column. Possible mechanisms causing biodiversity shifts could be ascribed to osmotic stresses of animals to cope with variation in dissolved solids or, more indirectly, because different sunlight penetration caused by suspended solids would affect primary production. To test the hypothesis, water samples were collected from nine stations located along the Tennessee River in Hamilton County. Each station was visited three times, and, during each visit, environmental parameters (including dissolved and suspended solids) were measured. Meiofauna biodiversity (estimated as richness, community composition, and phylogenetic diversity) was revealed using a metagenomic approach. Statistical analyses were applied to test for possible correlations between the biodiversity estimates and the measured environmental parameters. Results show a high biodiversity of meiofauna with more than 200 amplicon-sequence variants distributed across 10 metazoan phyla. Environmental conditions are highly variable among stations and statistical analyses show that while both dissolved solids (TDS) and turbidity (suspended solids, NTU) did not significantly affect meiofauna biodiversity in the collected samples, various other water, and sediment metrics were found to be significant predictors of meiofauna biodiversity. In conclusion, the results of this project not only reveal for the first time the meiofauna biodiversity from the Tennessee River, but also suggest that meiofauna could be used as bioindicators for several anthropogenic activities in freshwater ecosystems.

Acknowledgments

First and foremost, I would like to give my warmest thanks to my mentor and thesis director, Dr. Francesca Leasi, for her knowledge, guidance, and support throughout the entire course of this project. I would also like to thank my committee members, Dr. Fernando Alda and Dr. Mark Schorr, for their support, comments, and advice in making this project the best it could be. Lastly, I wish to thank my fellow students, Noura Elsaeed and Luke Qualey, for helping to process the many samples required for this project. This project was initially funded by Dr. Leasi’s CEACSE 2020 grant ($100,000) which provided for nearly all of the supplies and equipment, and later by a SEARCH grant from UTC’s Undergraduate Research and Creative Endeavor awarded to Jessica Cline in the amount of $1000.

Degree

B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.

Date

5-2022

Subject

Aquatic biodiversity; Meiofauna; Nature--Effect of human beings on

Location

Tennessee River

Keyword

Meiofauna; Freshwater; Tennessee River; Metabarcoding; Anthropogenic

Discipline

Environmental Indicators and Impact Assessment | Terrestrial and Aquatic Ecology

Document Type

Theses

Extent

i, 47 leaves

DCMI Type

Text

Language

English

Rights

http://rightsstatements.org/vocab/InC/1.0/

License

http://creativecommons.org/licenses/by/4.0/

Date Available

4-29-2022

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