If scuba diving in the Great Barrier Reef is on your bucket list, you might want to book tickets soon. This week, marine biologists dropped some horribly depressing news: the Great Barrier Reef is dying. The world’s largest reef is in the midst of a widespread coral bleaching event, and scientists aren’t sure whether it will fully recover.
Over the past few days, Terry Hughes of James Cook University has led aerial surveys of more than 500 reefs from Cairns to Papa New Guinea, including the most pristine sections of the Great Barrier Reef. Everywhere Hughes traveled, he was met with a nightmarish scene—the ghostly white remains of a once vibrant ecosystem. All told, Hughes estimates that 95 percent of the northern Great Barrier Reef is “severely bleached,” marking the worst such event on record.
“Almost without exception, every reef we flew across showed consistently high levels of bleaching, from the reef slope right up onto the top of the reef,” Hughes said in a statement. “This has been the saddest research trip of my life.”
Coral reefs are extremely temperature-sensitive, and when the water gets a bit too toasty, they expel their symbiotic algae, called zooxanthellae. When this happens, the coral loses both its vibrant color and its ability to feed itself. Bleaching leaves reefs more susceptible to disease and starvation.
Coral bleaching events used to be infrequent and geographically restricted, but recently, they’ve become much more common, widespread, and devastating. The first global bleaching event occurred during the 1997-1998 El Niño and killed a whopping 18 percent of corals across the planet.
Since 2014, we’ve been witness to a souped-up repeat of that event. Corals are bleaching everywhere, because the planet has been too damn hot for too many months on end. In the fall, the National Oceanic Atmospheric Administration (NOAA) predicted that the current global bleaching epidemic would impact nearly 40 percent of all reefs. In February, NOAA added that this year’s monster El Niño was exacerbating the die-off which might not end until 2017.
Coral bleaching in the Great Barrier Reef is a piece of a much bigger picture, and it shows us that even the most pristine ecosystems on Earth are susceptible to the impacts of climate change. The real concern is that these reefs—which provide habitat to roughly a quarter of all marine species—won’t be able to muster a full recovery. “You have reefs getting hammered time and time again, year after year,” NOAA oceanographer Mark Eakin told Gizmodo last month. “Recovery at this point is very limited.”
Like I said—make sure you get that scuba trip in soon.
[BBC]