Researchers believe the coral bleaching event that began in 2014 could extend well into 2017, thanks in part to El Niño.
Already warming ocean temperatures from climate change combined with the intense El Niño are contributing to a massive bleaching event that NOAA scientists are calling the “longest global coral die-off on record.”
Coral bleaching occurs when waters get too warm for the coral and its zooxanthellae (the little symbiotic organisms that feed coral and give them their color), causing the coral to expel the zooxanthellae, which leaves the coral white and weak. The coral loses its primary source of energy, so it slows in growth and loses its stored energy reserves, making it much more susceptible to diseases and death.
The current bleaching event began in the Pacific Ocean in mid-2014. By October 2015, El Niño was growing and scientists declared the third global bleaching event. It has now been going on for 20 months and shows no sign of slowing down.
“This time we’re in the longest coral bleaching event,” Mark Eakin, a NOAA biological oceanographer explained in a news release. “We’re maybe looking at a 2- to 2-1/2-year-long event. Some areas have already seen bleaching two years in a row.”
The length of this event is bad news because it means some corals don’t have time to recover before another bleaching event begins. Some reefs may never be able to recover.
“The frequency of mass bleaching events are going up because of global warming,” Eakin said. “We are hitting the corals, then we are hitting them again, and then again.”
To learn more:
- Read the AGU news release: El Niño Prolongs Longest Global Coral Bleaching Event
- Check out an abstract from the presentation at the Ocean Sciences Meeting last month: A Crucial Time for Reefs: Climate Change, El Niño, and the 2014-16 Global Bleaching Event
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