Abstract Summary
As climate change decimates coral communities on a global scale, effective outplanting of resilient corals will become an increasingly important management tool. This study examined endangered Caribbean coral Acropora cervicornis with three objectives. 1) Determine if there is significant phenotypic plasticity in thermal tolerance, 2) determine if genotypes differ in their degree of plasticity of thermal tolerance, and 3) Identify if acclimatization to higher temperatures affects survival of outplanted coral depending on the environment they are transferred into. To conduct this study, we partnered with the Coral Restoration Foundation (CRF) to acquire fragments of A. cervicornis for both outplanting and land-based tests. To examine the degree of plasticity, fragments of 20 genotypes were exposed to either ambient or elevated temperatures (32o C) after a short acclimation period at either ambient or elevated temperatures. A comparison of lifespan of fragments exposed to different temperatures shows a significant amount of plasticity exists in A. cervicornis and that genotype is a significant factor in determining the degree of plasticity. To test the survivability of treated coral, 10 coral genotypes were outplanted on two reef sites offshore of Key Largo, FL. These corals are being monitored to determine if heat-treated corals have a higher survivability than corals kept at ambient temperature when planted at different reef depths. Identification of plastic genotypes in regard to thermal stress could be used for stocking programs to contribute easily-acclimatized colonies to exposed locations, such as shallow reef crests. Furthermore, an accurate estimation of the limit of phenotypic plasticity within corals will further the understanding of acclimation capacity of coral communities under the changing climate. Prior heat exposure may increase outplant survivability and aid local managers in reef recovery projects, ultimately bolstering active restoration of decimated reef sites.
