Meeting Abstract

P2.35  Saturday, Jan. 5  Energetic consequences of ocean acidification and warming for coral larvae RIVEST, E.B.*; CHEN, C.-S.; FAN, T.-Y.; LI, H.-H.; EDMUNDS, P.J.; HOFMANN, G.E.; Univ. of California, Santa Barbara (UCSB); National Museum of Marine Biology and Aquarium (NMMBA); NMMBA; NMMBA; California State Univ. Northridge; UCSB emily.rivest@lifesci.ucsb.edu

In a rapidly changing ocean, understanding how larval dispersal and recruitment will be affected is crucial for the management of adult populations. An investigation of the condition of larvae – their physiological tolerances and capacities – may highlight or reveal mechanisms behind the impact of anthropogenic ocean change on larval dispersal. Towards this end, in this study, we assessed the energetics of larvae of tropical scleractinian coral Pocillopora damicornis in response to conditions of ocean acidity and warming during their dispersal, using lipid consumption as an index. Larvae were incubated for 24 hours in seawater containing combinations of CO₂ concentration (450 and 950 µatm) and temperature (27.5 and 30.5°C). An autonomous, modified Honeywell DuraFET® provided a continuous time series of pH on the natal fringing reef throughout the experimental time period. In June/July 2012, pH values averaged 7.968 ± 0.13. Time series of temperature, salinity, and tidal height were also collected. Protein-standardized levels of wax esters changed in response to CO₂ treatments, while those of triacylglycerol were more sensitive to changes in temperature. Changes in additional lipid classes were more variable. Under day-long exposures to seawater with almost twice the acidity of the present fringing reef environment, P. damicornis larvae consume lipids to satisfy additional energy demands; however, these rates vary across the larval release period. As a result, portions of each cohort may deplete their lipid reserves quickly in a future ocean scenario, affecting their dispersal range and their potential for completing settlement and metamorphosis.