In 1998, 2002, and 2016 the Great Barrier Reef in Australia, was put under immense stress due to coral bleaching Coral bleaching occurs when temperatures spike so high that it starts to affect the waters. When the water gets too warm an algae in the coral’s tissues, called zooxanthellae, starts to go into metabolism overdrive releasing toxins that carry out the algae, turning the coral white. Once that algae is gone the coral becomes less defensive against diseases, which is potentially dangerous, especially for as big of a reef as the Great Barrier Reef.
This year during El Nino, temperatures spiked and caused bleaching that has covered about 22 percent of the overall Great Barrier Reef.
These corals are either already dead or still dying. During this bleaching event, the oceans are filling with the corpses of dead fish because of their loss of shelter and the warm waters.
Richard Vevers chief, executive of the Ocean Agency, has been diving for 30 years in his spare time. He said, “It was one of the most disgusting sights I’ve ever seen. The hard corals were dead and covered in algae, looking like they’ve been dead for years.”
The reefs dying is affecting the whole underwater ecosystem around it, killing off other plants and animals. The temperatures however are expected to drop again to a safer level once El Nino is over and the abnormal climate changes that come with it are gone. Then the corals can begin to try and grow back, though it will take a long time due to the extensive damage caused by the heat. These corals may be looking white for a long time.