Date of Award

5-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Paul Bologna

Committee Member

Scott Kight

Committee Member

Meiyin Wu

Abstract

The global impact plastic pollution has on aquatic ecosystems is rapidly increasing and there are numerous studies highlighting the negative impacts from microplastic exposure. While the general effects of microplastics are becoming clearer, less is known about the specific impacts of the various polymers that make up plastic. Moreover, many studies show the effects of exposing organisms to microplastics of the same shape and size, which is an inaccurate representation of what organisms are exposed to in natural environments. I exposed the Eastern Oyster (Crassostrea virginica) to four types of polymers and analyzed their feces, pseduofeces, and internal tissues for microplastics. My results showed plastic particles were present in two main tissue groups: the digestive system and the gills and mantle. Polystyrene was present in nearly all individuals analyzed, suggesting this type of polymer can increase exposure which may be harmful to filter feeders. Despite the use of their rejection mechanism, oysters did not distinguish polystyrene and polyvinyl chloride from food. Polyethylene was absent in tissues, but was detected in the feces, suggesting that C. virginica can reject this polymer. Toward the end of the experimental period, an accumulation of polyethylene and polyvinyl chloride was documented, suggested that longer-term exposure to weathered particles may have a greater impact via biofilm development. Due to their complexity, it is necessary for microplastic studies to expose organisms to polymers of various types as well as irregular shapes and sizes. Understanding the potential impacts from diverse polymers is critical for management of waste and can provide important information on which types of plastic may be most harmful to organisms inhabiting the environment.

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