1. 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

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

3. 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

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

5. 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?

6. 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

7. 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

8. 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

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

10. V. tubiashii Baseline Growth
~ 107 CFU

11. Measuring V. tubiashii Abundance

12. 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

13. 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

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

15. Trial 2: Gene Expression Results

16. 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

17. 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

18. 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

19. 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