Characterizing the effects of ocean acidification in larval and juvenile Manila clam, Ruditapes philippinarum, using a transcriptomic approach David Metzger University of Washington School of Aquatic and Fishery Sciences Committee: Dr. Steven Roberts Dr. Carolyn Friedman Dr. Linda Rhodes
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Characterizing the effects of ocean acidification in larval and juvenile Manila clam, Ruditapes philippinarum, using
a transcriptomic approach
David Metzger
University of WashingtonSchool of Aquatic and Fishery Sciences
Calcium carbonate abundance decreases making calcification more difficult.
Genes associated with calcification and calcium ion transport would increase to increase scavenging efforts of calcium ions.
Mean + SE
Week1 Week2 Week30
0.20.40.60.8
11.2
Week1 Week2 Week30.0
0.5
1.0
1.5
2.0
2.5
Protein Translation and Stability
Cathepsin-L Elongation Factor 2
Fold
Cha
nge
Ambient CO2
Elevated CO2
Cathepsin-L consistently lower though differences are not significant.
Organisms respond to stress by changing gene expression and protein synthesis.
Therefore genes involved with protein translation would also increase.
Mean + SE
Stress Response
HSP90
Week1 Week2 Week30
0.2
0.4
0.6
0.8
1
1.2
Fold
Cha
nge
Ambient CO2
Elevated CO2
Transcription molecular chaperones and genes involved in cell stress response increase in response to environmental stress
Mean + SE
Oxidative Stress
Week1 Week2 Week30
0.20.40.60.8
11.2
Glutathione Peroxidase 3
Glutathione peroxidase 3 is lower in elevated pCO2 exposed animals at weeks one and two but difference is not significant
Ambient CO2
Elevated CO2
Fold
Cha
nge
Environmental stress, increases in metabolism, and cell signaling can increase production of ROS.
Genes that catabolize ROS would therefore increase .
Mean + SE
Does this affect the responseto other stressors?
• Juvenile Manila clams do not change transcription levels of candidate genes when exposed to elevated pCO2.
• Do juvenile clams still possess the
physiological potential to cope with multiple stressors when exposed to a high pCO2 environment?
Impact of Multiple Stressors
Temperature
Hypoxia Salinity
Disease
Ocean Acidification
Experimental Design
1 Week
2 Weeks
3 Weeks
GeneExpression
1 hour heat shock1 week recovery
Day1 Day2 Day3 Day4 Day5 Day6 Day70%
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Day1 Day2 Day3 Day4 Day5 Day6 Day70%
20%
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100%39°C38°C
Perc
ent S
urvi
val
Thermal tolerance and OA
1 2 3 4 5 6 7 1 2 3 4 5 6 7Days Post Heat Shock Days Post Heat Shock
Ambient pCO2
Day1 Day2 Day3 Day4 Day5 Day6 Day70%
20%
40%
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Day1 Day2 Day3 Day4 Day5 Day6 Day70%
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100%39°C38°C
Perc
ent S
urvi
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Thermal tolerance and OA
1 2 3 4 5 6 7 1 2 3 4 5 6 7Days Post Heat Shock Days Post Heat Shock
Ambient pCO2
Thermal tolerance and OA
Day1 Day2 Day3 Day4 Day5 Day6 Day70%
20%
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Day1 Day2 Day3 Day4 Day5 Day6 Day70%
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Perc
ent S
urvi
val
1 2 3 4 5 6 7 1 2 3 4 5 6 7
Ambient pCO2
Elevated pCO2
Days Post Heat Shock Days Post Heat Shock
Summary
Hypothesis:Ocean acidification will negatively impact manila clams.
REJECT
Summary1. No affect on larval growth and mortality.
2. Larvae increase expression of genes involved in essential biological processes.
3. Juvenile clams to not respond to elevated pCO2 by increasing gene expression.
4. Elevated CO2 does not impact thermal tolerance.
1 4 7 11 148000
10000
12000
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16000
18000
1 4 7 11 140%
20%40%60%80%
100%120%
Week1 Week2 Week30
0.2
0.4
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0.8
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Day1 Day2 Day3 Day4 Day5 Day6 Day70%
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Day1 Day2 Day3 Day4 Day5 Day6 Day70%
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Impact of Multiple Stressors
Temperature
Hypoxia Salinity
Disease
Ocean Acidification
SummaryHypothesis:
Ocean acidification will negatively impact manila clams.
Constant exposure to changing environmental conditions has conditioned Manila clams to effectively cope with increasing pCO2 levels as a result of ocean acidification
Future Studies• Are other biological processes in juvenile
Manila clams impacted by OA?
• Does ocean acidification impact reproduction and fertilization?
• Is there an effect on calcification?
Acknowledgements
University of WashingtonRoberts Lab:Sam WhiteSteven RobertsEmma Timmins-SchiffmanCaroline StorerMackenzie Gavery