What’s destroying the Great Barrier Reef?

Due to higher-than-normal water temperatures in 2015 and 2016, Australia’s Great Barrier Reef suffered its worst-ever coral bleaching event on record. According to a November report by researchers at ARC Centre of Excellence for Coral Reef Studies in James Cook University, about 67% coral had died in the worst-hit northern part. However, those in the southern part were in good health, while the central part of the Reef witnessed a six % die-off, the report said. Since coral bleaching (or die-off) usually occurred as a result of continuous warm water temperatures, scientists were concerned about the recovery of the corals.

The Great Barrier Reef is made by trillions of tiny invertebrate creatures known as coral polyps, which have built it over the past 600,000 years. The polyps, which excrete calcium carbonate to make reefs, are extraordinarily sensitive to changes in water temperature. When it rises by two to three degrees Celsius above normal levels many species of coral are forced to expel the multicoloured algae that live within its tissues, an effect known as “bleaching”.  The white coral skeletons that remain can regenerate if temperatures fall and water quality conditions are good. But in many instances entire reef systems can be destroyed if water temperatures remain elevated for several months. 

 

Picture Credit : Google