Corals use multiple tricks to adapt to hotter seas

Genes and physiological acclimation contribute equally to heat resistance.

Amanda Mascarelli

24 April 2014

The reefs of Ofu Island in American Samoa are a natural laboratory for studies of coral heat resistance.

Coral reefs face a daunting future: climate change, ocean acidification, and overfishing are projected to take a harsh toll in the coming decades. But a study published today suggests that some corals can adjust their physiology to cope with ocean warming.

A population of the table-top coral Acropora hyacinthus living in a back-reef lagoon off Ofu Island in American Samoa can acclimate to hot water temperatures — at least up to a point, researchers report today inScience1. The team teased apart the role of genetic adaptation (natural selection that occurs within a population) and physiological acclimatization (which occurs in individuals), showing that each had roughly equal roles in the corals’ heat resistance.

In the past few decades, reef-building corals have seen global declines owing to bleaching — discoloration that results when corals lose the photosynthetic algae that nourish them — caused by local warming spells.

The study suggests that “corals can buy more time to evolve the necessary adaptations by using acclimatization as a first line of response,” says Christian Voolstra, a coral reef genomicist at King Abdullah University of Science and Technology in Thuwal, Saudi Arabia, who was not involved in the research. But the degree to which the findings apply to other coral species and coral reef ecosystems still needs to be determined, he adds.

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