Meeting Abstract
As concentrations of CO2 increase in our atmosphere, we have little information on how intensifying ocean acidification (OA) will impact coral recruitment, a process critical to reef persistence and recovery that encompasses three life history stages; larval supply, larval settlement and post-settlement survival. Furthermore, no studies have integrated across these processes to address the potential for trans-generational acclimatization to OA. We manipulated CO2 concentrations in outdoor mesocosms using a pH-stat system (with daily pH fluctuations of 7.8-8.1 [ambient] and 7.5-7.8 [high]) to expose adult Pocillopora damicornis colonies to OA during the brooding period, and then exposed their brooded larvae in a reciprocal contrast after 10 weeks. After 6, 10 and 14 weeks of adult exposure, fecundity was consistently reduced in the corals exposed to OA. Larval survival was greater when adult corals were preconditioned at high pCO2 for 10 weeks. Conversely, larvae exposed to OA conditions for 4 days had lower survival than those in the control treatment regardless of brooding conditions. After one month of post-settlement growth the recruits that originated from adults treated with OA had higher growth rates, but there was no effect of OA on the survival of new recruits. Overall, corals exposed to OA conditions as adults had fewer larvae but those larvae may have better performance. Our data highlight the importance of trans-generational studies for understanding the potential impacts that OA might have on demographic processes that drive reef dynamics.
