When Corals Met Algae: Symbiotic Relationship Crucial to Reef Survival Dates to the Triassic

Catherine Zandonella, Office of the Dean for Research ・ Princeton Environmental Institute

The mutually beneficial relationship between algae and modern corals — which provides algae with shelter, gives coral reefs their colors and supplies both organisms with nutrients — began more than 210 million years ago, according to a new study by an international team of scientists including researchers from Princeton University.

That this symbiotic relationship arose during a time of massive worldwide coral-reef expansion suggests that the interconnection of algae and coral is crucial for the health of coral reefs, which provide habitat for roughly one-fourth of all marine life. Reefs are threatened by a trend in ocean warming that has caused corals to expel algae and turn white, a process called coral bleaching.