Larval Pacific Oyster (Crassostrea gigas)Response to Ocean Acidification

Emma Timmins-Schiffman, Steven Roberts, Paul McElhany, Shallin Busch

University of Washington, School of Aquatic and Fishery Sciences

SICB, January 7, 2011

Objective How do human impacts, such as ocean

acidification, affect oyster larvae?

Outline Background on ocean acidification Oyster development Ocean acidification effects on different stages

of larval development Conclusion

Ocean Acidification

Increased CO2 in atmosphere

Increased oceanic CO2 = lower oceanic pH

1000 ppm

380 ppm

Timeline of C. gigas Larval Development

Developmental Stage

1h

2h

5h

17h

24h

2-cell

4-cell

hatching

veligerTime Post-Fertilization

0h

Fertilization

pre-veliger

Sperm Motility

Photo: A. Bruner

Timing of Development

Pro

port

ion E

gg

s in

Cle

avage

1 hr (2-cell)

2 hrs (>4-cell)

=380 ppm=840 ppm

Timing of DevelopmentPro

port

ion L

arv

ae H

atc

hed

5 17 24

=380 ppm=840 ppm

Timing of Development Developmental lag

under OA conditions Or larvae are not

developing at all

Pro

port

ion E

gg

s in

Cle

avag

e

Resource availability Optimal environmental

conditions

Settlement

Larval Morphology

abnormal

normal

Larval Calcification= calcified

= partially calcified= uncalcified

Larval Morphology/Calcification

Abnormal development at 2000 ppm Evidence of better larval performance at 380

vs. 280 ppm

Larval Gene Expression Environmental shifts cause changes in gene

expression Develop assays to understand organism

response Heat shock protein 70 (Hsp70) – molecular

chaperone, general stress response Serine palmitoyltransferase 1 (Sptlc1) – apoptosis

signaling under environmental stresspH8.1

7.3

OAPerception of environmental change

normal

abnormal

Larval Gene Expression: Hsp70 Stressed

organisms increase Hsp70 expression

Threshold of stress response

Rela

tive E

xpre

ssio

n L

evel

Larval Gene Expression: Sptlc1 OA is

altering phenotype and affecting gene expression

Pathway important in normal development?

Rela

tive E

xpre

ssio

n L

evel

Conclusions Ocean acidification has significant effects on

C. gigas larval development and physiology More abnormal morphology Less calcification Changes in stress-related genes

Conclusions Adaptation to 380 ppm CO2 may not hold true

for projected greater rate of change

250 years, 100 ppm

100 years600 ppm

Acknowledgements University of WA, SAFS

Steven Roberts, PI Carolyn Friedman, co-PI Sam White Elene Dorfmeier Mackenzie Gavery Moose O’Donnell Karen Chan Richard Strathmann

NOAA, NWFSC Paul McElhany Shallin Busch Mike Maher Jason Miller Sarah Norberg Andy Dittman Amanda Bruner

Funding sources SICB student support UW, SAFS student

travel grant Saltonstall-Kennedy

Program (NOAA)