Microbiome Dynamics and Pathogen-Driven Impacts in Marine Mollusks: Insights from Oysters and White Abalone
Marine ecosystems are facing various threats, from population declines to diseases that impact their overall health. My dissertation investigates the complex interplay between microbiomes, pathogens, and environmental conditions in three distinct marine organisms: Olympia oysters (Ostrea lurida) in...
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| Format: | Thesis |
| Language: | English |
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eScholarship, University of California
2024
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| Online Access: | https://escholarship.org/uc/item/2m195495 https://escholarship.org/content/qt2m195495/qt2m195495.pdf |
| Summary: | Marine ecosystems are facing various threats, from population declines to diseases that impact their overall health. My dissertation investigates the complex interplay between microbiomes, pathogens, and environmental conditions in three distinct marine organisms: Olympia oysters (Ostrea lurida) in the Puget Sound, Pacific oysters (Crassostrea gigas) in San Diego Bay exposed to OsHV-1 SDB µvar, and white abalone (Haliotis sorenseni) afflicted by Abalone Withering Syndrome. The goal of combining and comparing these systems is to elucidate the crucial role of microbiota in understanding ecosystem and host health, including microbes’ response to environmental variables and their interaction with pathogens. The first chapter focuses on the Olympia oyster, a native species in the Puget Sound that has experienced a substantial population crash. To assess the impact of eelgrass habitat and geographical location on oyster microbiomes, Olympia oysters from a single parental family were deployed at multiple sites, both within and outside eelgrass (Zostera marina) beds. Using 16S rRNA gene amplicon sequencing, I demonstrate that gut-associated bacteria differ significantly from the surrounding environment. Regional differences in gut microbiota are associated with the oyster survival rates at different sites after two months of field exposure. However, eelgrass habitat does not influence microbiome diversity significantly. This research highlights the importance of understanding the specific bacterial dynamics associated with oyster physiology and survival rates in the Puget Sound. In the second chapter, I explore the OsHV-1 SDB µvar, a virus threatening oyster aquaculture globally, with a focus on its microvariant in San Diego Bay. The study investigates the influence of temperature on OsHV-1 SDB µvar infectivity. All microvariants of this virus exhibit limited replication and are unable to induce oyster mortality at lower water temperatures. Through experimental infections of hatchery-raised oysters at temperatures ... |
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