Healthy surroundings aid coral recovery

SAN DIEGO, July 22 (UPI) -- Bleached corals bounce back to normal growth rates faster when they have clean water and lots of sea life at their side, a U.S. university study indicated.

The study, lead by scientists at Scripps Institution of Oceanography at University of California-San Diego, suggests that better overall ocean health means corals are better able to recover from bleaching events, the university said in a news release.

Bleaching events occur when rising sea temperatures force corals to spew out symbiotic algae. Bleaching is expected to become more frequent as climate change increases ocean temperatures, scientists said.

The study showed Mountainous star coral on reefs in Honduras and Belize was able to recover from a major bleaching event and grow normally within two to three years when the surrounding waters and reef were relatively healthy, scientists said. By contrast, corals living with excessive local impacts, such as pollution, couldn't fully recover after eight years.

"You can imagine that when you are recovering from a sickness, it will take a lot longer if you don't eat well or get enough rest," said Jessica Carilli, Scripps graduate student and lead author on the study. "Similarly, a coral organism that must be constantly trying to clean itself from excess sediment particles will have a more difficult time recovering after a stressful condition like bleaching."

The findings were published in Wednesday's edition of PLoS ONE.