Ancestral genetic diversity associated with the rapid spread of stress-tolerant coral symbionts in response to holocene climate change

Benjamin C.C. Hume, Christian R. Voolstra, Chatchanit Arif, Cecilia D'Angelo, John A. Burt, Gal Eyal, Yossi Loya, Jörg Wiedenmann

Research output: Contribution to journalArticle

Abstract

Coral 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.

Original languageEnglish (US)
Pages (from-to)4416-4421
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume113
Issue number16
DOIs
StatePublished - Apr 19 2016

Keywords

  • Adaptation
  • Climate change
  • Coral
  • Persian/Arabian Gulf
  • Symbiodinium

ASJC Scopus subject areas

  • General

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