Ancestral genetic diversity associated with the rapid spread of stress-tolerant coral symbionts in response to Holocene climate change
AuthorsHume, Benjamin C. C.
Voolstra, Christian R.
Burt, John A.
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Environmental Science and Engineering Program
Red Sea Research Center (RSRC)
MetadataShow full item record
AbstractCoral communities in the Persian/Arabian Gulf (PAG) withstand unusually high salinity levels and regular summer temperature maxima of up to ∼35 °C that kill conspecifics elsewhere. Due to the recent formation of the PAG and its subsequent shift to a hot climate, these corals have had only <6, 000 y to adapt to these extreme conditions and can therefore inform on how coral reefs may respond to global warming. One key to coral survival in the world's warmest reefs are symbioses with a newly discovered alga, Symbiodinium thermophilum. Currently, it is unknown whether this symbiont originated elsewhere or emerged from unexpectedly fast evolution catalyzed by the extreme environment. Analyzing genetic diversity of symbiotic algae across >5, 000 km of the PAG, the Gulf of Oman, and the Red Sea coastline, we show that S. thermophilum is a member of a highly diverse, ancient group of symbionts cryptically distributed outside the PAG. We argue that the adjustment to temperature extremes by PAG corals was facilitated by the positive selection of preadapted symbionts. Our findings suggest that maintaining the largest possible pool of potentially stress-tolerant genotypes by protecting existing biodiversity is crucial to promote rapid adaptation to present-day climate change, not only for coral reefs, but for ecosystems in general.
CitationHume BCC, Voolstra CR, Arif C, D’Angelo C, Burt JA, et al. (2016) Ancestral genetic diversity associated with the rapid spread of stress-tolerant coral symbionts in response to Holocene climate change. Proc Natl Acad Sci USA 113: 4416–4421. Available: http://dx.doi.org/10.1073/pnas.1601910113.
SponsorsWe appreciate the help of Cornelia Roder, Sergey Dobretsov, Julia Schnetzer, Todd LaJeunesse, and Drew Wham with sample collection. A. Al-Hemeri (UAE Federal Environment Agency), A. Al-Cibahy (Environment Agency of Abu Dhabi), and the Oman Ministry of Environment & Climate Affairs kindly provided Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) export permits (no. 09FEA555) and collection permits. We acknowledge Tropical Marine Centre (London) and Tropic Marin (Wartenberg) for sponsoring the Coral Reef Laboratory at the University of Southampton. We thank the NYU Abu Dhabi Institute for supporting the 2012/2013 field workshops during which samples for this study were collected and the Interuniversity Institute for Marine Sciences in Eilat for field work support. The study was funded by Natural Environment Research Council Grant NE/K00641X/1 (to J.W.), the European Research Council under the European Union's Seventh Framework Programme Grant FP7/2007-2013/ERC Grant Agreement 311179 (to J.W.), the King Abdullah University of Science and Technology (C.R.V.), and Israel Science Foundation Grant 341/12, United States Agency for International Development/Middle East Regional Co-operation (USAID/MERC) No. M32-037 (to Y.L.).
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