Document Type

Honors Paper

Advisor

Maria Rosa

Publication Date

2022

Comments

This paper is restricted to users on the Connecticut College campus until May 17, 2024.

Abstract

Preliminary studies have shown that corals ingest microplastics mistaken as food or co-ingested as food, and that ingestion can have effects on physiology. Coral plastic feeding preferences and egestion times are still not well understood. In a series of experiments, I investigated how exposure to microplastics impacts Astrangia poculata, the Northern Star coral, behavior in response to microplastics (feeding and egestion), and whether microplastic exposure and ingestion has any physiology effects. In the first behavioral experiment, I exposed corals to either brine shrimp eggs, or 500 μm polyethylene spheres, and did not find a significant difference in feeding rates. In a second set of experiments, I investigated feeding preferences of different types of plastics, using hand-feeding trials. Polystyrene fragments were ingested at a significantly higher rate than polyethylene fibers, and ocean seasoned fragments were ingested significantly more than unseasoned fragments. Egestion rates were similar across plastic types. I also investigated physiological effects of microplastic exposure, by measuring respiration and growth rates in two separate experiments. Over a six-week period, I did not find significant differences in growth because of microplastic exposure, however microplastic treatments showed high variation. After a 3-week plastic exposure period, effects on respiration rates were not significant. This work adds to a growing body of literature suggesting that corals ingest a variety of microplastic types, and there is a need for further understanding of the energetic and physiological costs of chronic microplastic exposure, ingestion, and egestion.

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The views expressed in this paper are solely those of the author.