Time appears to be running out for the treasured corals of the Great Barrier Reef. A 2016 survey of 84 reefs by scientists in Australia found evidence of widespread bleaching at a whopping 93 percent of reefs. They said that 35 percent of corals have already died in the northern and central sectors of the famous reef.
Bleaching is different from actual coral death, and there still may be time for recovery. Bleaching occurs when nutrient-rich algae leaves the coral, causing the colorful animals to turn white. If environmental conditions improve, the coral can come back, but the effects of climate change, which cause abnormally warm ocean water temperatures, are not expected to abate.
A coral reef under siege:
- Bleaching occurs when corals under stress drive out the algae, known as zooxanthellae.
- If normal conditions return to the Great Barrier Reef, the compromised corals can recover -- but it can be a long process that can take decades.
- The southern sector of the reef has been mostly spared, thanks to ocean churning and rainfall in the wake of Tropical Cyclone Winston, which cooled waters in the area in February 2016.