The Great Barrier Reef has lost half of its coral cover in just 27 years, with most of that decline coming as a result of heavy storms, predation by crown-of-thorn starfish, and coral bleaching caused by warming ocean temperatures.
In a comprehensive survey of 214 reefs, researchers at the Australian Institute of Marine Science (AIMS) found that coral cover declined from 28 percent in 1985 to 13.8 percent this year.
Intense tropical storms, particularly in the central and southern parts of the reef, have caused about 48 percent of the coral loss, researchers say. An explosion in populations of starfish along the entire reef caused about 42 percent of the decline; about 10 percent was caused by major bleaching events.
Reefs are typically able to regain their coral cover after such disturbances, said Hugh Sweatman, one of the lead authors of the study, published in the Proceedings of the National Academy of Sciences. “But recovery takes 10-20 years,” Sweatman said.
“At present, the intervals between the disturbances are generally too short for full recovery and that’s causing the long-term losses.” While the scientists say little can be done about the storms, the study found that efforts to reduce starfish populations could help increase coral cover at a rate of 0.89 percent per year.
Article appearing courtesy Yale Environment 360.