Abstract Summary
Current research has shown strong differences within species between coral colonies in their resistance to bleaching temperatures. Sources of variation range from the symbiont, acclimation by the host, adaptation by the host and microbiome. New efforts in the Pacific show that choosing heat resistant colonies on reefs can lead to more heat resistance in coral nurseries made from fragments of these colonies. Genome and transcriptome and selective breeding experiments in Pacific species of the genus Acropora suggest that many coral genes affect heat resistance. In the Caribbean, Acropora colonies also show strong differences in heat resistance in the field and in lab common garden settings. High genetic diversity still exists even in threatened populations, but new experiments show that multiple stressors such as heat and disease can potentially erode this diversity. Standing genetic diversity can be a source for heat tolerant corals and thus conservation strategies that promote the conservation of coral genetic diversity are recommended.
