Graduate Thesis Or Dissertation
 

Hold the Plastic, Please: An Investigation of Sea Otter Exposure to Microparticles and Microplastics Using Scat and Diet Analysis

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https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/h128nn712

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  • Sea otters act as valuable indicators of ecosystem health and consume prey items that contain anthropogenic microparticles, including microplastics. Microplastic ingestion can exert a wide range of deleterious effects depending on the organism and plastic type. We investigated the ingestion of microparticles by wild sea otters (Enhydra lutris) in Alaska and those housed at the Seattle Aquarium by assessing the presence and abundance of microparticles in scat samples. We also analyzed diet items of captive otters to evaluate the role trophic transfer has in microparticle exposure for these individuals. Sample processing included digestion of organic material with potassium hydroxide, a density separation using a hypersaline solution, and confirmation of potential plastics with µFTIR spectroscopy. Microparticles were found in 95% and 91% of wild and captive sea otter scats, respectively, and 100% of diet samples. There were no differences between study sites in the particles per gram of wild sea otter scat. Of the total particles confirmed with µFTIR spectroscopy, 98.3% were of anthropogenic origin, and an average of 26.2% ± 6.2% were synthetic. There was also no difference in the proportion of particles identified as synthetic between study sites. This analysis demonstrates that sea otters are ingesting microplastics in wild and captive settings, and that trophic transfer likely contributes to this ingestion. It also provides information on the current level of microplastic exposure to populations of captive and wild sea otters using a non-invasive method, which may be beneficial for understanding sea otter population health. Future studies focusing on additional analysis of wild scats and examination of intestinal tracts of beached sea otters would build on the findings of this work.
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  • Pending Publication
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  • 2023-01-09 to 2024-02-09

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