1. Impact of ocean acidification on calcification rate, shell properties, pallial fluid pH, and epigenetics of commercially important mollusks across critical life stages
Justin B. Ries
Carolina Bastidas (co-PI)
Katie Lotterhos (collaborator)
Louise Cameron (graduate student)
Northeastern University

2. OBJECTIVE: To investigate the vulnerability of commercially important calcifying marine mollusks to ocean acidification at various stages of their life history.
PROJECTS:
Impact of OA and warming on calcification rate and shell properties of larval-stage limpets (Crepidula fornicata);
Impact of OA and warming on calcification rate, shell properties, pallial fluid pH, and proteomics of adult sea scallops (Placopecten magellanicus); and
Impact of OA on calcification rate, shell properties, and epigenetics of juvenile- and larval-stage eastern oysters (Crassostrea virginica).

4. Project 1: Impact of OA and warming on limpet calcification

5. Project 1: Impact of OA and warming on limpet calcification

6. Project 1: Impact of OA and warming on limpet calcification
aragonite
Calcification rate (wt-% per day)
2850 ppm
900 ppm
600 ppm
400 ppm
pCO2 = 2850 ppm
pCO2 = 400 ppm
1 mm
1 mm

7. in calcification response to OA?
Role of dissolution
in calcification response to OA?
Gross Calcification (beneath tissue)
– Gross Dissolution (of exposed skeleton)
Net Calcification

8. Ries, 2016, GCA

9. Project 2: Impact of OA on scallop pallial fluid pH and calcification
ΩAragonite

10. Project 2: Impact of OA on scallop pallial fluid pH and calcification
Photo credit: Louise Cameron (graduate student)

12. Project 2: Impact of OA on scallop pallial fluid pH and calcification
Photo credit: Louise Cameron (graduate student)

14. Ωaragonite Ωaragonite Ωaragonite Positive Calcification rate Parabolic
high CO2
ambient CO2
Calcification rate
Ωaragonite
Parabolic
high CO2
ambient CO2
Calcification rate
Ωaragonite
Calcification rate
Negative
high CO2
ambient CO2
Ries, 2011, GCA

16. Project 3: Impact of OA on calcification and epigenetics of oysters
(1) Does OA induce adaptive modifications to gene activity without alterating the underlying DNA sequence (e.g., via DNA methylation)?
(2) Are these modifications heritable and, thus, a mechanism for rapidly evolving in response to OA?
Collaboration with Katie Lotterhos

17. Whole shell Internal view
Low pCO2
Moderate pCO2
High pCO2 A
2 mm
5 mm
500 µm
20 µm
5 µm B C
Whole shell Internal view D E F
Whole shell External view G H I
Shell edge External view J K L
Crystal structure Prismatic layer M N O
Crystal structure Foliated layer

18. Biomechanical Analyses

20. Summary:
Initial results suggest that early-life-stage mollusks exhibit variable degrees of resilience to moderate levels of CO2-induced ocean acidification (700 – 1000 ppm), but converge on a nonlinear (exponential) increase in vulnerability to more extreme acidification (2000 – 3000 ppm)
Ongoing microelectrode studies of pallial fluid pH, coupled with targeted epigenetic and proteomic studies, aim to identify the mechanism(s) behind this non-linearity in mollusks’ response to ocean acidification at various stages of development.