Scientists found that some reefs in the tropical Pacific Ocean could maintain high coral cover into the second half of this century by shuffling the symbiotic algae they host. The findings offer a ray of hope in an often-dire picture of the future of coral reefs worldwide.Scientists found that some reefs in the tropical Pacific Ocean could maintain high coral cover into the second half of this century by shuffling the symbiotic algae they host. The findings offer a ray of hope in an often-dire picture of the future of coral reefs worldwide.