Meeting Abstract
Local adaptation is ubiquitous in marine environments, however populations are increasingly exposed to environmental perturbations under climate change, which could constrain the benefits of being locally adapted. Instead, in rapidly changing environments, it might be beneficial to be plastic to counter environmental change. To understand potential tradeoffs between adaptation and plasticity in corals, we conducted a four year, three way reciprocal transplant experiment of the resilient Caribbean coral Siderastrea siderea across forereef (FR), backreef (BR), and nearshore (NS) environments in Belize. Calcification rates varied by natal reef environment and by transplant location, with corals originating from and living in FR locations calcifying the fastest, suggesting that FR environments are more suitable for growth. Evidence of local adaptation was only observed for FR corals, which exhibited the highest growth rates in their native reef environment. Notably, all corals exhibited high survival in the FR and BR, but corals transplanted to the NS experienced high mortality, suggesting that NS environments present strong environmental selection. Transcriptome profiling 3.5 years post transplantation revealed that both transplanted coral hosts and their algal symbionts exhibited transcriptome profiles more similar to other colonies residing on the same reef, regardless of source location suggesting that transcriptomic plasticity facilitates acclimation to environmental change in S. siderea. Our results suggest that there is the capacity for local adaptation in S. siderea, however, this adaptive competence is limited by strong environmental selection and facilitated by transcriptomic plasticity. Collectively, these findings help explain the recent success of this species on reefs across the greater Caribbean.
