Influence of ocean acidification on Vibrio tubiashii growth and pathogenicity to Pacific oyster larvae Elene Dorfmeier University of Washington | S A F S Sam White, Carolyn Friedman, Steven Roberts

Aquaculture and Bivalve Larvae Problems in the Pacific Northwest Acidification Temperature Re-emergent Pathogens Photo: Norbert Dankers

Vibrio tubiashii Marine bacterium Pathogen Vibrio tubiashii Marine bacterium Pathogenic to a variety of marine invertebrates Re-emergent vibriosis in the Northwest Photo: Phetsouvanh et al. 2008

Acidification of Northwest Waters SUMMER 2009: Dabob Bay Totten Inlet Map: R. Jacobsen Graphs: Simone Alin et al.

Impact of Acidification on the Oyster Environment Impact of Acidification on the Oyster Affects of OA on calcifying marine organisms: Growth and development Energy allocation Metabolic depression Pathogen – Host interaction? Disease susceptibility?

Project Goals Investigate how ocean acidification will influence Vibrio tubiashii growth and physiology Determine how environmental stressors can influence Pacific oyster larval survival and disease development Environment Pathogen Host

Lab trials with V. tubiashii Environment Host Pathogen Lab trials with V. tubiashii V. tubiashii growth Baseline results and bacterial quantification Acidification and pathogen response V. tubiashii and C. gigas larvae Elevated pCO2

Trial 1: V. tubiashii Growth pCO2: 380 ppm 840 ppm 2000 ppm Seawater Temperature: 12°C 18°C 25°C Establishing at baseline growth curves for V. tubiashii Photo: NOAA NWFSC

Measuring Vt Abundance Host Pathogen Environment Measuring Vt Abundance Viable plate counts Quantitative PCR (qPCR) vtpA gene – (Gharaibeh et al. 2009)

V. tubiashii Baseline Growth ~ 107 CFU

Measuring V. tubiashii Abundance

Lab trials with V. tubiashii Environment Host Pathogen Lab trials with V. tubiashii Acidification and pathogen response V. tubiashii, C. gigas larvae Bacterial abundance Gene expression of V. tubiashii

Trial 2: Larval Challenge pCO2: 380 ppm 900 ppm Seawater Temperature: 23°C V. tubiashii presence Examine how predicted shifts in ocean conditions can influence pathogen physiology Photo: Ghent University

V. Tubiashii Gene Expression VtpR (Hasegawa & Hase 2009) Toxins Metalloprotease Hemolysin Motility Flagellar expression Photo: NOAA NWFSC

Trial 2: Gene Expression Results

Vt Trial 2: Results Growth of Vt alone: ~ 107 CFU/ml Growth of Vt in water column much lower with larvae present: ~ 105 CFU/ml No larval mortality seen Bacterial growth on larvae

Vt Trial Conclusions vtpA qPCR assay accurately measures Vt abundance Environmental stressors may increase Vt virulence expression LD50 needed for future disease to investigate larval susceptibility and OA Photo: L'Ifremer vous révèle les océans

Next Steps… Vt growth curves at elevated pCO2 New disease trials happening this spring Investigate environmental stressors on C. gigas larvae and V. tubiashii Photo: Norbert Dankers

THANK YOU Saltonstall-Kennedy Program (NOAA) UW School of Aquatic & Fishery Sciences Dr. Carolyn Friedman Dr. Steven Roberts Sam White Emma Timmons-Shiffman Joth Davis - Taylor Resources, Inc. Michael O’Donnell (aka “Moose”) and Richard Strathmann, FHL Richard Wilson – Bay Center Mariculture Russell Rogers – WDFW