After three deadly years, a massive bleaching event that struck coral reefs across the globe now appears to be ending, scientists announced on Monday, June 19.
Coral bleaching happens when corals are subjected to extreme changes in the environment. During coral bleaching, colorful coral reefs eject symbiotic algae from their tissue, which causes it to turn white or pale. This weakens the coral and makes it susceptible to disease.
In May 2014, rising water temperatures in the Pacific and Atlantic worsened the widespread coral bleaching in the Northern Hemisphere. This trend continued for three years and it was believed that it could lead to the mass deaths of corals.
The End Of The Global Coral Bleaching Event
Now, researchers from the National Oceanic and Atmospheric Administration (NOAA) announced that the global coral bleaching event is easing. In fact, data from satellites and modeling indicate that the unprecedented coral bleaching period has stopped after inflicting damage to coral reefs.
Mark Eakin, coral reef watch coordinator at NOAA, said the three-year bleaching event appears to have killed off nearly 95 percent of a species of tall, cucumber-shaped coral called pillar coral, weakening them enough for disease to kill them off.
"We've had an almost complete loss of pillar coral. It almost looks like the ruins of an old Greek building, said Eakin.
Eakin said the forecast damage does not look widespread in the Indian Ocean, while the Pacific and the Caribbean will still experience coral bleaching, although it will be less severe than recent years.
Places struck by the coral bleaching event have seen catastrophic effects.
For instance, in South Florida, experts witnessed the death of a 300-year-old coral off the coast of Hollywood. Coral reefs located in Australia's Great Barrier Reef have underwent several mass bleaching events and are threatened to become extinct. Guam, northwest Hawaii, and some parts of the Caribbean have also been hit by back-to-back coral bleaching, scientists said.
In recent years, El Niño has been pinpointed as the cause of the bleaching, but Eakin explained that global warming had increased ocean temperatures to the point that El Niño was only a small push that triggered the coral bleaching event.
Researchers say that coral reefs in the Northern Hemisphere are getting some relief from the intense ocean temperatures that caused the bleaching.
"This is really good news," said Julia Baum, a coral reef scientist. "We've been totally focused on coming out of the carnage of the 2015-2016 El Nino."
Too Early To Celebrate
However, experts warn that although conditions are improving, it is still too early to celebrate. Eakin said the world may be at a new normal where coral reefs barely survive even during good conditions.
Another bleaching event may also be looming over reefs located in the United States. As a countermeasure, Eakin said the world must get climate change under control and confront local stressors.
"Neither is going to be sufficient without the other," he added.