Abstract
Rapidly warming and steadily acidifying oceans are among the major threats to coral reefs across the globe. Fast-growing but environmentally sensitive Acropora cervicornis, a key reef-building coral in the Caribbean that was once widespread in Florida is now on the IUCN’s red list of critically endangered species, hence calling for its conservation and restoration. It is very well established that high temperatures cause bleaching, but the species’ sensitivity to Ocean Acidification (OA) is still understudied and mostly looked at from a calcification perspective. Moreover, stress tolerance of coral taxa is usually associated with; coral species, their symbiont type, location of origination, life stage, microbiota, and mode of nutrition, whereas little attention, is given to the contribution of the coral host in stress tolerance. The fact that A.cervicornis exclusively hosts Symbiodinium ‘fitti’ on the Florida Reef Tract (FRT), is critical because it helps in factoring out the role of symbiont type and helps in understanding the response of coral animal genotype. Hence, this dissertation aimed to fill the knowledge gaps and find stresstolerant genotypes of ecologically essential A.cervicornis to assist in future genetic interventions, active restoration, and successful conservation. More specifically, this dissertation targeted the questions: 1) Are there any genotypic differences in tolerance to the stressors within A.cervicornis? 2) Does OA increase A.cervicornis susceptibility to mortality? 3) If the stress tolerance is genotypic specific, what are the biochemical or physiological pathways that underly these genotypic differences? 4) Are there any biomarkers that can potentially determine the “fitness” of different genotypes of A.cervicornis? To address these questions, genotypes of A.cervicornis were collected in different seasons, and lab-based studies involving thermal stress as well as chronic OA were conducted over 4 years to answer these questions.