Date of Award
2026
Degree Type
Dissertation
Degree Name
Doctor of Philosophy in Biological and Environmental Sciences
Department
Biological Sciences
First Advisor
Jonathan B. Puritz
Abstract
Due to the ever-increasing threats of climate change, disease, and human impacts on coastal ecosystems, there has been an increased awareness of and need to study the species that inhabit them. The continuation and future of populations in these habitats depend upon their ability to acclimate and adapt to changes. Like many marine invertebrates Crassostreavirginica (the eastern oyster) exhibits a complex life cycle encompassing a pelagic larval stage and a benthic, sessile adult, each experiencing divergent, stage-specific pressures. This dissertation focuses on the larval and juvenile stages of eastern oysters and their responses to multiple stressors, disease, and the interactions of sequential stress exposure. The experiments presented here are some of the first to assess the impacts of multiple stressors on early life-stage oysters under realistic diel-cycling regimes, which commonly occur in eutrophic estuaries. These studies employ an integrative approach combining phenotypic, genomic, and transcriptomic analyses to predict both plastic and adaptive trajectories in response to environmental stress. The cultivation of commercial aquaculture lines and larval production in hatchery systems provides a unique framework for exploring how genetic background and environmental history shape early-stage stress responses, while the prevalence of hatchery culture also underscores the increasing importance of understanding disease dynamics such as Vibriosis. Together, these experimental approaches establish a continuum of investigation from larval multi-stressor response to pathogen susceptibility and longer-term juvenile performance under variable conditions. Chapter 1 assessed population-specific responses of larval C. virginica from distinct hatchery lineages to diel-cycled acidification and hypoxia, revealing phenotypic resilience to stress and rapid genomic differentiation influenced by genetic background. Chapter 2 investigated how prior exposure to abiotic stress shaped larval susceptibility to Vibriocoralliilyticus infection, indicating that environmental history can modulate disease outcomes and selective pressures. Chapter 3 examined juvenile responses to diel-cycled multi-stressor conditions, demonstrating substantial phenotypic plasticity in response to stress but limited recovery following exposure, with developmental stage and length of exposure as key determinants of resilience. Together, these studies highlight the interplay between genetic background, environmental variation, and life stage in determining how eastern oysters cope with the combined pressures of dynamic coastal environments. By integrating multi-omic and phenotypic approaches, this work advances our understanding of early life-stage resilience and informs both ecological forecasting and aquaculture practices under future ocean conditions.
Recommended Citation
Delatte-Gurdy, Megan E., "PHENOTYPIC AND GENOMIC RESPONSES OF EARLY LIFE-STAGE CRASSOSTREA VIRGINICA TO MULTIPLE STRESSORS AND DISEASE" (2026). Open Access Dissertations. Paper 4576.
https://digitalcommons.uri.edu/oa_diss/4576