Identifying which factors lead to coral bleaching resistance is a priority given the global decline of coral reefs with ocean warming. During the second year of back‐to‐back bleaching events in the Florida Keys in 2014 and 2015, we characterized key environmental and biological factors associated with bleaching resilience in the threatened reef‐building coral
- Award ID(s):
- 1659605
- NSF-PAR ID:
- 10210250
- Date Published:
- Journal Name:
- Coral Reefs
- Volume:
- 39
- Page Range / eLocation ID:
- 1453-1469
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Orbicella faveolata . Ten reefs (five inshore, five offshore, 179 corals total) were sampled during bleaching (September 2015) and recovery (May 2016). Corals were genotyped with 2bRAD and profiled for algal symbiont abundance and type.O. faveolata at the inshore sites, despite higher temperatures, demonstrated significantly higher bleaching resistance and better recovery compared to offshore. The thermotolerantDurusdinium trenchii (formerlySymbiondinium trenchii ) was the dominant endosymbiont type region‐wide during initial (78.0% of corals sampled) and final (77.2%) sampling; >90% of the nonbleached corals were dominated byD. trenchii . 2bRAD host genotyping found no genetic structure among reefs, but inshore sites showed a high level of clonality. While none of the measured environmental parameters were correlated with bleaching, 71% of variation in bleaching resistance and 73% of variation in the proportion ofD. trenchii was attributable to differences between genets, highlighting the leading role of genetics in shaping natural bleaching patterns. Notably,D. trenchii was rarely dominant inO. faveolata from the Florida Keys in previous studies, even during bleaching. The region‐wide high abundance ofD. trenchii was likely driven by repeated bleaching associated with the two warmest years on record for the Florida Keys (2014 and 2015). On inshore reefs in the Upper Florida Keys,O. faveolata was most abundant, had the highest bleaching resistance, and contained the most corals dominated byD. trenchii , illustrating a causal link between heat tolerance and ecosystem resilience with global change. -
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