Keywords

Oyster; aquaculture; microplastic; Indian River Lagoon; pollution

Abstract

Plastics are widely used in consumer goods and industrial manufacturing, and their degradation into microplastics (MP, size < 5 mm) has created an emergent environmental pollutant. Plastics readily enter aquatic environments, where they accumulate additional contaminants and bioaccumulate in organisms. While MP contamination in marine ecosystems is well documented, less is known about MP presence in aquacultured shellfish. Depuration, the process of purging contaminants from shellfish, is conducted in sterile seawater without food, which may cause oyster starvation and death. To date, MP depuration has not been examined in the aquacultured eastern oyster (Crassostrea virginica) in published studies. This study had 3 goals: 1) evaluate the effects of algal feed on oyster survival during depuration, 2) determine the effect of algal feed on depuration effectiveness, and 3) investigate the effect of a ten-day depuration on MP concentration in aquacultured C. virginica soft tissue. MP were quantified in oyster tissues, biodeposits, and in industrial algal feed. Tissues were digested using alkaline solutions, manually examined via microscopy, and analyzed using Fourier-Transform Infrared Spectroscopy (FTIR) to investigate MP polymer identity. Survival did not differ between fed and unfed oysters. However, oysters given algal feed produced more biodeposits, which corresponded with greater MP abundance in their biodeposits compared to unfed oysters. Fed oysters had a 51.5% MP reduction relative to non-depurated oysters, while unfed oysters had a 36.4% reduction. However, MP abundance per gram of soft tissue did not differ between fed and unfed oysters after the ten-day depuration. These findings highlight the role of algal feed in enhancing MP removal through increased biodeposit production and provide initial evidence that a ten-day depuration period can remove the majority of MP in aquacultured C. virginica. Understanding depuration and feeding can inform consumers, regulators, and mariculturists about the best practices for managing MP in consumed shellfish.

Thesis Completion Year

2026

Thesis Completion Semester

Spring

Thesis Chair

Walters, Linda

College

College of Sciences

Department

Department of Biology

Thesis Discipline

Marine Biology

Language

English

Access Status

Open Access

Length of Campus Access

None

Campus Location

Orlando (Main) Campus

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Rights Statement

In Copyright