Date of Award

Fall 2023

Document Type


Degree Name

Master of Science (MS)


Ocean & Earth Sciences


Ocean and Earth Sciences

Committee Director

Fred Dobbs

Committee Member

Alexander Bochdansky

Committee Member

Daniel Barshis


As marine plastic pollution increases, it becomes imperative to study the effects of microplastics on marine fauna. Marine plastic debris is a vector for disease to marine invertebrates (Lamb et al., 2018; Rotjan et al., 2019). In this context, studies have shown Astrangia poculata will consume microplastics as they do their normal food (Allen et al, 2017; Rotjan et al., 2019). Further, with temperatures increasing worldwide, there is a concern the virulence of disease-causing bacteria will increase (Vezzulli et al., 2015). In a series of manipulative laboratory experiments, this study quantified changes in respiration rates and visual health of Astrangia poculata when exposed to microplastics alone, microplastics having a biofilm of putative disease-causing bacteria, and warming temperatures. Astrangia fragments were exposed to 4 different temperatures: 22℃, 25℃, 28℃, and 32℃. The initial experiments at 22℃ compared visually determined effects on health exerted by two bacteria known to cause disease in coral, Vibrio alginolyticus and Vibrio coralliilyticus. A significant difference was not found between the bacterial treatments. Within each experiment at higher temperatures, coral fragments were exposed either to “clean” microplastics or microplastics coated with V. coralliilyticus. Although respiration rate and visual health responded significantly to warmer temperatures, significant changes were not observed in response to disease-causing bacteria or microplastics.


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