Ocean acidification and disease: How will a changing climate impact Vibrio tubiashii growth and pathogenicity to Pacific oyster larvae?

Ocean acidification and disease: How will a changing climate impact Vibrio tubiashii growth and pathogenicity to Pacific oyster larvae? Elene Marie Dorfmeier Chair of Supervisory Committee: Carolyn S. Friedman, Associate Professor School of Aquatic and Fishery Sciences Vibrio tubiashii (Vt) is a causative agent of vibriosis in molluscan bivalves. Recent re-emergence of vibriosis in economically valuable shellfish, such as the Pacific oyster (Crassostrea gigas) in Washington State, has increased the urgency to understand the ecology of this pathogen. It is currently unknown how predicted environmental changes associated with ocean acidification, such as elevated surface seawater temperature, increased partial pressure of CO2 (pCO2), and Vt abundance, will impact marine organismal health and disease susceptibility. This study investigates how environmental cues predicted with ocean acidification influence physiological changes and pathogenicity in Vt. Using laboratory experiments to manipulate temperature and pCO2, we examined how these environmental factors influenced pathogen growth. Larval susceptibility to vibriosis was determined by exposing C. gigas larvae to a combination of elevated pCO2 and Vt concentrations. These experiments provide insight into the environmental parameters that may drive pathogenicity or influence proliferation of the bacterium. Investigation of single and multivariate parameters such as temperature, pCO2, and pathogen levels will help assess how predicted shifts in ocean conditions can impact shellfish survival and disease resistance.