Term of Award
Fall 2023
Degree Name
Master of Science in Biology (M.S.)
Document Type and Release Option
Thesis (restricted to Georgia Southern)
Copyright Statement / License for Reuse
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Department of Biology
Committee Chair
Risa A. Cohen
Committee Member 1
Michele Guidone
Committee Member 2
Stephen P. Vives
Committee Member 3
Beth Myers
Abstract
Surface waters receive megatons of plastic waste each year that ultimately accumulate in rivers, lakes, and oceans. Once in the environment, plastics degrade into microplastics in a variety of shapes with microplastic fibers (MFs) being the most common. Existing data suggest MFs decrease zooplankton feeding and survival, which may adversely affect zooplankton abundances, community composition, and potentially higher trophic levels that depend on planktonic food resources. Improving our understanding of MF toxicity will allow us to better predict the effects of plastic contamination and target remediation efforts. Chapter one evaluates the response of the zooplankton Daphnia magna to MFs of different lengths and found that while the proportion of zooplankton ingesting fibers was similar across treatments regardless of length, the accumulation of MFs within daphnids differed. Despite MF ingestion, there were no differences in mortality after 7 days across all treatments. Chapter two describes the use of pond mesocosms containing plankton communities to assesses whether plankton community composition changes in response to MFs over 28 days of exposure. The results suggest that zooplankton may exhibit a stress response to MFs, increasing in abundance and potentially inducing changes in community composition over longer time periods. Although the abundance of phytoplankton in the water column did not differ between treatments, periphyton chl a decreased in response to MFs while mass remained similar, suggesting a change in the algal component of the periphyton community. The final chapter compares the use of bulk water and plankton tow sampling methods to quantify microplastic contamination along the Ogeechee River, GA, USA. Bulk water sampling resulted in concentrations between 1.2 - 6.13 MFs L-1 while estimates from plankton tows were 4 - 5 magnitudes lower (4.6x10-5 - 3.7x10-4 MFs L-1). In general, this study suggests Ogeechee River MP contamination is on the low end of the range for US waterbodies (0.00042 – 103 MPs L-1) and encourages the use of bulk water sampling to estimate MP concentrations.
Recommended Citation
Simon, Conner J., "Plankton Responses to Microplastic Fiber Exposure" (2023). Electronic Theses and Dissertations. 2682.
https://digitalcommons.georgiasouthern.edu/etd/2682
Research Data and Supplementary Material
No
