Plastic debris has been found across the spectrum of freshwater ecosystems, including stormwater retention ponds, tributaries, rivers, and large lakes. The ubiquity of plastic debris in the valuable freshwater ecosystems that we rely on for our water supply and natural resources raises a number of environmental and human health concerns. Little is known about how the composition of plastic-associated microbial biofilms varies across the many types of plastic polymers or how these biofilms vary in microbial composition across freshwater environments. These interactions raise the potential for the selection of unique communities of organisms that shift ecosystem function, or harbor pathogenic or antibiotic-resistant organisms and are further complicated by the inherent differences in the water bodies where plastic polymers are deposited, making it difficult to predict risks. I characterized microbial community structure on four post-consumer polymers incubated for one year in four representative freshwater ecosystems in Western New York. A laboratory experiment was conducted to isolate individual drivers of biofilm community composition. I found that the environmental characteristics of the water body played a key role in community structure, with similarities in the microbial community on polymers incubated in the same site. The community structure was distinct from that in the surrounding water column or sediment, but changed over time to from early colonizers to a community structure that more closely resembles the local environment. Functional analysis indicated the potential for polymer-associated microbes to enhance nutrient and carbon cycling, especially in more nutrient-rich sites. Polymer identity was of secondary importance. The presence of potentially pathogenic organisms in plastic associated biofilms, especially in a stormwater retention pond that conveys water to Lake Ontario, suggests risk to human health. These results help to inform our understanding of the long-term fate and impact of plastic debris in freshwater ecosystems.

Library of Congress Subject Headings

Biofilms--Analysis; Freshwater microbiology; Water--Pollution; Polymers--Biodegradation

Publication Date


Document Type


Student Type


Degree Name

Environmental Science (MS)

Department, Program, or Center

Thomas H. Gosnell School of Life Sciences


College of Science


André Hudson

Advisor/Committee Member

Christy Tyler

Advisor/Committee Member

Nathan Eddingsaas


This thesis has been embargoed. The full-text will be available on or around 5/31/2024.


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