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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)