The National Oceanic and Atmospheric Administration (NOAA) has been inundated with reports of coral bleaching since the summer of this year. Professor Ove Hoegh-Goldberg, a coral reef expert from the University of Queensland, recently told the Guardian that the bleaching is on track to be as bad or worse than the record-setting bleaching event that occurred between 1997 and 1998, in which 15 percent of the world’s corals were destroyed.
“Coral bleaching” refers to the process that forces coral, a living organism, to expel the symbiotic algae that sustains it. Algae inhabit the algae and feed off the light of the sun, feeding the coral in the process. Sudden or significant drops in water temperature, however, can distress coral to the point that it forces out the algae. Without it, coral weakens, becomes more susceptible to disease and turns pale in color. If the temperature of the water does not return to normal and the coral does not reclaim its algae, it can die within eight weeks.
In 1998, a severe El Niño event warmed the oceans to the point that a significant portion of the world’s coral population died out. According to NOAA, 2014 will be even hotter – the hottest year on record, in fact. Meanwhile, the ocean is also absorbing about 25 percent of the world’s carbon dioxide, turning the water into carbonic acid, making it more difficult for coral to survive by weakening their limestone skeletons and degrading the shells of crustaceans.
The combined one-two punch of ocean warming and ocean acidification could be devastating to the long-term health of the oceans.
NOAA’s Coral Reef Watch program is reporting “unprecedented levels of thermal stress” among the corals of the Northern Mariana Islands and in the Hawaiian Archipelago. Around the Lisianski atoll, about 1,000 miles northwest of Honolulu, an estimated 35 percent of coral sites observed showed bleaching, with one area exhibiting 90 percent bleaching.
Guam, the Republic of the Marshall Islands, Kiribati and Florida have all reported significant bleaching activity, with major bleaching estimated to have swept through all 34 atolls and islands of the Marshall Islands.
Karl Fellenius, a coral reef manager from the University of Hawaii, told the Guardian that the thermal stress in the Marshall Islands appears “so profound that the corals died within days of getting bleached.”
Unlike in 1997 and 1998, no major El Niño is forecast for the coming year. However, the year has been so warm that corals are being damaged anyway.
According to Dr. Mark Eakin, the coordinator for Coral Reef Watch, “[W]hat’s happening is, as global temperatures increase and especially as the ocean warms through the increase of carbon dioxide and other heat trapping gases in the atmosphere, it’s warming the ocean so that it doesn’t take as big an El Niño to have the same effect on water temperatures.”
As the shift in seasons causes ocean currents to shift, warm water will soon be diverted into the southern Pacific and the Indian Ocean. Coral Reef Watch is predicting that parts of Australia’s Great Barrier Reef may begin to bleach in January.
Major bleaching events can take corals 10 years to recover from, Eakin told the Guardian. But if global temperatures continue to rise, reefs will not be able to recover. Even though coral reefs cover only one percent of the ocean floor, they support one-quarter of all marine life. That makes coral bleaching a significant threat to the future, both above and below the surface.