El Niño is Causing the Longest Global Coral Die-Off on Record Right Now
Global warming and the intense El Niño currently taking place could be prolonging the longest global coral die-off on record. The loss of corals from disease and heat stress due to record ocean temperatures could stretch well into 2017.
Coral bleaching occurs when corals are stressed by conditions such as high temperatures. The bleaching itself happens when corals expel their zooxanthellae, the symbiotic algae that live within their tissues. Without this algae, the corals lose the ability to properly photosynthesize, which is a significant food source. This causes corals to become more vulnerable to disease and during a severe bleaching event, large swaths of reef-building corals die.
The first mass bleaching event occurred during the 1982-1983 El Niño. A global bleaching event then occurred in 1998 during another strong El Niño that was followed by a very strong La Niña, which brings warmer waters to places like Palau and Micronesia. Then, a second global bleaching event occurred in 2010 during a less powerful El Niño.
Now, it seems as if another bleaching event is underway. Scientists first observed the current global coral bleaching event beginning in mid-2014 when bleaching began in the western Pacific Ocean. In October 2015, as the current El Niño was still strengthening, researchers declared the third global bleaching event on record was underway.
Now, scientists have found that the bleaching event has persisted for 20 months, and could reach into 2017.
We're seeing global bleaching again now," said Mark Eakin, one of the researchers, in a news release. "The frequency of mass bleaching events are going up because of global warming. We are hitting the corals, then we are hitting them again, and then again."
The findings show the importance of taking strides to help reefs. More specifically, conservation efforts are needed as warm temperatures persist and as corals die off.
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