Meeting Abstract
Rising seawater temperatures threaten corals and bleaching events are increasing in extent and frequency. In both 2014 and 2015 corals in Hawai‘i had extensive bleaching in response to high seawater temperatures. We tagged 40 pairs of coral colonies of two species, Montipora capitata and Porites compressa, and tracked their fate for three years. Within each species the tagged corals were selected so that one individual coral colony that bleached was adjacent to one colony that retained its dark color. We collected 23 tissue samples of each coral colony over a three year time period that encompassed two consecutive bleaching events and the recovery period after both bleaching events. Using amplicon sequencing we characterized the Symbiodinium community in each species of coral (ITS-2) and found that different coral species had different communities of Symbiodinium. The microbiome also differed between the coral species and was also different between bleached and unbleached colonies (16S). Using qPCR we quantified the clade and abundance of Symbiodinium in M. capitata over two years and found rapid recovery of symbiont abundance after bleaching but little symbiont shuffling. Using ezRAD we did not detect loci that correlated to bleaching resistance but we did uncover hidden genetic diversity within P. compressa. Overall, there was less than 10% mortality in the tagged coral colonies. By integrating analyses on the same coral colonies we can study the factors that might contribute to how corals resist and recover from thermal stress.
