Date of Award

9-2026

Rights

© 2026 Mikayla Straube

Document Type

Thesis

Degree Name

Master of Science in Marine Sciences

Department

Marine Science

First Advisor

Carrie J. Byron

Second Advisor

Kristin M. Burkholder

Third Advisor

Charles Rolsky

Abstract

Microplastics (< 5 mm) are a pervasive physical pollutant. This study was predominately focused on the development and utilization of fluorescence microscopy to locate and identify microplastics and other particles in the presence of a background autofluorescing biogenic precipitate. Oyster digest samples are visualized with fluorescent microscopy using Nile Red (NR). Photobleaching, or concentrated light exposure, of the filters was tested to determine if it can quench the autofluorescence signal. It was found that photobleaching significantly decreased autofluorescence intensity of the biogenic precipitate in emission wavelengths 518, 580, and 670 nm even with the application of NR, while minimally impacting the fluorescence behavior when bound to plastic particles. In application, fluorescence microscopy still yields some gaps in microplastic identification  when compared to Raman spectral results. This methodology was broadly developed to be able to quantify ambient microplastic quantities in farmed oyster samples. The specific level of aquaculture’s contribution to plastic pollution in global waterways is difficult to estimate. The methodology was applied to a local case study that compared microplastic loading in cultured eastern oysters raised in traditional plastic farm gear and novel plastic-free farm gear. Marginal trends in the gear type treatment and microparticles identified across the harvest season were identified, however effect sizes were too weak, and evidence was too inconsistent to currently suggest that gear type and harvest date affect microplastics and other particle quantities g-1 oyster tissue (d.w.).

Comments

Master's Thesis

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS