Defense Date

4-26-2022

Document Type

Capstone

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

Dr. Amy Hirons

Second Advisor

Dr. David Kerstetter

Third Advisor

Dr. Dimitrios Giarikos

Keywords

Marine mammals, persistent organic pollutants, trophic ecology, biomagnification, bioaccumulation

Abstract

Persistent organic pollutants (POPs) are lipophilic semi-volatile organic chemicals that present a range of challenges to marine biota, specifically marine mammals that often occupy a high trophic position in the food web. POPs have become a global problem since they have been shown to cause immunologic, teratogenic, carcinogenic, neurological, and reproductive complications in living organisms due to their resistance to biodegradation and their lipophilic nature. Marine mammals can accumulate these toxic substances through direct ingestion, trophic transfer, adsorption, and maternal offloading. They are susceptible to both bioaccumulation and biomagnification of POPs. Accumulation of POPs is affected by many variables, including habitat, feeding strategy, age, sex, and physiology. This review looks at the trophic transfer and accumulation of persistent organic pollutants in three groups of marine mammals: cetaceans, pinnipeds, and sirenians. These groups are ecologically and physiologically diverse and occupy a large range of trophic positions and habitats; therefore, this diversity is expected to affect how POPs accumulate and magnify in marine mammals. Variations in rates of biomagnification and bioaccumulation of pollutants can help us to understand anthropogenic effects and their impacts on marine mammal trophic ecology. By evaluating data from several different marine mammal organic contaminant studies, we can conclude that POPs are having a direct impact on these animals and their aquatic environments. From the studies evaluated, the mean summed POP concentrations range from undetectable in certain herbivorous species, such as the manatee, to 457,000 ng/g lipid weight in apex predators, such as the California sea lion. There are also substantial differences in contaminant loads between mature male and female mammals, indicating maternal transfer of contaminants to offspring.

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