Scleractinian corals are the ‘engineers’ of tropical coral reefs ecosystems. Corals’ three-dimensional structure provides habitat for thousands of fish and invertebrate species. The persistence of corals is however threatened by climate change because corals are extremely sensitive to high temperatures. As oceans warm at a very fast pace, corals might not be able to adapt fast enough. A possible biological mechanism to ‘buy time’ for adaptation to occur is acclimation. Here we studied if corals may be able to increase tolerance to temperatures through developmental acclimation, i.e. we hypothesized that corals which experience warmer temperatures during embryonic and larval development are better able to cope with higher temperatures later in life. To assess the potential for developmental acclimation, larvae of the broadcast spawning coral Montastraea cavernosa were raised at current (29°C) and future predicted ocean warming temperatures (+2°C, 31°C). After larval settlement, coral juveniles from each treatment were split and reared for 2 months at either current or heated conditions (29 and 31°C). The capacity for developmental acclimation was assessed via survival and growth rates of the juveniles.
Results/Conclusions
Larvae reared at heated temperatures had lower survival and displayed a smaller size at the time of settlement. Exposure to heated conditions during the larval stage improved juveniles’ survival at higher temperatures and decreased the survival of juveniles reared in current conditions. This indicates that, in terms of survival, there was developmental acclimation. However, exposure to warmer conditions during the juvenile stage led to faster growth rates. More interestingly, individuals raised during larval and juvenile stages at heated conditions had faster juvenile growth rates than individuals that were only exposed to heat after settlement, thus indicating that developmental acclimation occurred. The lack of latent effects and developmental acclimation in growth suggest these mechanisms may help corals withstand future rises in ocean temperature.