NOAA scientists said that the massive coral bleaching that happens across Hawaii now expands to the Caribbean and may possibly continue into 2016 prompting the agency to declare the third worldwide coral bleaching event in recorded history.

NOAA's Coral Reef Watch coordinator Mark Eakin said that coral bleaching and diseases caused by the warming climate along with events such as El Niño pose the largest threats to coral reefs worldwide.

"We are losing huge areas of coral across the U.S., as well as internationally," said Eakin. " What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it's likely to last well into 2016."

NOAA's estimate is that by the end of this year, nearly 95 percent of the coral reefs in the U.S. will have been exposed to conditions that cause them to bleach. Scientist warned that warm sea temperatures could result in the loss of over 12,000 square miles of coral this year with the event anticipated to have particularly strong impact in U.S. tropical regions.

Many corals tend to be vulnerable to injury and disease when the temperatures of the water stray outside of the ideal temperature range especially for longer periods of time.

Coral bleaching happens when corals are exposed to stressful conditions causing them to expel symbiotic algae that live in their tissues. As a result, the corals turn white or pale. Without the algae, the coral loses its main source of food and become more susceptible to disease.

Although corals can recover from mild bleaching, long term and severe bleaching tend to cause them to die. The phenomenon would mean fewer habitats and less shoreline protection from storms for fish and other marine life.

Jennifer Koss, from NOAA's Coral Reef Conservation Program said that there is a need to do something about these bleaching events. She said that threats to the corals that are produced locally such as unsustainable fishing practices and pollution from land add more stress to the corals and reduce their likelihood to fight bleaching or recover from it.

The first global bleaching event occurred in 1998, when the El Niño event was particularly strong. The second one occurred in 2010. Scientists warned that the current coral bleaching event could be the worst in history.

Photo: NOAA

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