WWW.WAS.ORG • WORLD AQUACULTURE • SEPTEMBER 2019 29 better than oysters under acidification stress and food limitation. To test this, 24-hr old oyster larvae were held in the same standing experiment as previously described and exposed to either ambient or elevated CO2 conditions and given a high-food diet (100 percent of the recommended algal quantity per larvae) or low-food diet (10 percent of the recommended algal quantity per larvae) yielding four different treatments total (Ambient CO2 + High Food, Elevated CO2 + High Food, Ambient CO2 + Low Food and Elevated CO2 + Low Food). Oysters were fed live Tisochrysis lutea cultured in F/2 media in the laboratory. After 24 hours under elevated CO2 concentration, moderate starvation significantly increased the mortality of larval oysters (15.5 percent) compared to those given abundant food resources (7.4 percent) (Fig. 3). Starvation also affected oysters held under ambient conditions with mortality at 8.4 percent under moderate starvation and 0.2 percent under abundant food conditions. Interestingly, moderate starvation under ambient conditions results in similar levels of mortality as elevated CO2 conditions suggesting both are stressors of equal magnitude and that the stress of food limitation and low pH are additive. The results suggest larval oysters are using some energy allocation mechanism that enables diversion of energy to compensate for the stress of acidification. When energy resources are limited, oysters do not have sufficient energy to maintain homeostasis and become more susceptible to acidification stress. Conclusions This study identified some of the challenges early life stage eastern oysters may face and begins to answer questions regarding processes involved in larval resilience to acidification. Energy metabolism is a heritable trait in many species and the evidence of an energy allocation mechanism to cope with acidification stress drives us to further question the molecular features, such as genetic components and molecular pathways orchestrating this mechanism and associated with resilience. More research is needed to identify genes under selection and measure the heritability of potential traits associated with resilience to ocean acidification to determine whether eastern oysters can adapt in the face of climate change. Furthermore, the identification of markers of resistance can be used by the aquaculture industry to identify and promote strains of oysters that are “winners” under ocean acidification and that can overcome the future environmental challenges eastern oysters will certainly face. Acknowledgments This work is supported by funding through NOAA’s Northeast Sea Grant College Consortium in partnership with NOAA Ocean Acidification Program to Bassem Allam and Emmanuelle Pales Espinosa. We also thank the Great Atlantic Shellfish Farm for their invaluable assistance with larval rearing. Notes Michelle Barbosa, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794; Corresponding author: Michelle.Barbosa@stonybrook.edu Caroline Schwaner, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794; Caroline.Schwaner@stonybrook.edu Teresa Schwemmer, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794; Teresa. Schwemmer@stonybrook.edu Emmanuelle Pales Espinosa, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794; Emmanuelle.PalesEspinosa@stonybrook.edu Bassem Allam, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794; Bassem. Allam@stonybrook.edu References Doney, S.C., V.J. Fabry, R.A. Feely and J.A. Kleypas. 2009. Ocean acidification: the other CO2 problem. Marine Science 1:169-192. Intergovernmental Panel on Climate Change (IPCC). 2014. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp. Munroe, R. 2019. Carbon dioxide levels hit record peak in May. The Keeling Curve, Scripps Institution of Oceanography, University of California San Diego, San Diego, CA USA. National Marine Fisheries Service. 2015. Fisheries of the United States, 2014. US Department of Commerce, NOAA Current Fishery Statistics No.2014. US Environmental Protection Agency (USEPA). 2019. Inventory of U.S. Greenhouse Gas Emissions and Sinks. EPA 430-R-19-001. This study identified some of the challenges early life stage eastern oysters may face and begins to answer questions regarding processes involved in larval resilience to acidification. Energy metabolism is a heritable trait in many species and the evidence of an energy allocation mechanism to cope with acidification stress drives us to further question the molecular features, such as genetic components and molecular pathways orchestrating this mechanism and associated with resilience. More research is needed to identify genes under selection and measure the heritability of potential traits associated with resilience to ocean acidification to determine whether eastern oysters can adapt in the face of climate change. Furthermore, the identification of markers of resistance can be used by the aquaculture industry to identify and promote strains of oysters that are “winners” under ocean acidification and that can overcome the future environmental challenges eastern oysters will certainly face.
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