Defense Date

4-24-2024

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

David Kerstetter

Second Advisor

Christopher Blanar

Third Advisor

Dorothy-Ellen A. Renegar

Keywords

persistent organic pollutants, feeding ecology, satiation, symbiosis, parasitism, potassium hydroxide, kleptoparasitism, Phalacrocorax auritus, Pelecanus occidentalis, Pandion haliaetus, generalists

Abstract

Microplastics are being studied in a variety of different projects to better understand their impact and threat to wildlife species. Although there is an understanding that microplastics are affecting our wildlife, there are still questions about how coastal seabirds come to ingest them and how the ingestion is altering critical biological processes, such as that for endoparasite communities. This project aims to determine a better understanding of two main objectives: assessment of the presence of secondary ingestion of microplastics in coastal seabirds due to the fish species they prey on and relationship between microplastics and endoparasite communities' structure and state of susceptibility. This project focused on three coastal marine bird species native to Southeastern Florida: Double-Crested Cormorant (Phalacrocorax auratus), Brown Pelican (Pelecanus occidentalis), and Osprey (Pandion haliaetus). Endoparasite and microplastic samples were collected from carcasses from each bird species; Brown Pelican (n=14), Double-crested Cormorant (n=9), and Osprey (n=3). Laboratory analysis included a collection of parasites from the bird's gastrointestinal tract (GI tract) using a dissecting microscope, storing the parasites in 70% ethanol, and staining and mounting them. Analysis also included the digestion of the GI tract, liver, and any liquids collected in 10% potassium hydroxide (KOH) in preparation for filtration powered by a Buchner funnel and vacuum flask. Visual analysis with a dissecting microscope allowed for the identification and quantification of microplastics that remained. The small sample size of the Osprey species limited the information that could be collected; correlation tests were run excluded Osprey samples. Correlation tests showed that microplastic abundance is not affecting endoparasite community structures, nor is it affecting total parasite abundance. There was a correlation between abundance of microplastics in the GI tract and in the liver in Double-crested Cormorants, but not in Brown Pelicans.

Comments

President's Faculty Research & Development Grant

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