SYDNEY, April 19 (Xinhua) -- A new study by Australian researchers on Thursday suggested it's highly unlikely the Great Barrier Reef will ever fully recover from the bleaching event in 2016.
The ecology of one-third of the world's largest reef system permanently changed in 2016, when an extended marine heatwave killed off massive amounts of coral.
"Averaged across the whole Great Barrier Reef, we lost 30 percent of the corals in the nine month period between March and November 2016," lead author and director of the Centre of Excellence for Coral Reef Studies Terry Hughes said.
After the record-breaking temperatures, Hughes and his colleagues mapped the geographical pattern of heat exposure from satellite data spanning a length of 2,300 km.
The scientists were then able to demonstrate that coral deaths were highly related to the amount of bleaching and the level of heat exposure.
They found that the the northern third of the Great Barrier Reef lost the highest amount of corals that year, while the central region suffered the most during another mass bleaching event in 2017.
While some corals died immediately from the heat stress, others died more slowly.
Researchers also noted that 29 percent of the 3,863 reefs lost two-thirds or more of their corals, which has been detrimental to the reef's ecological functions.
"The coral die-off has caused radical changes in the mix of coral species on hundreds of individual reefs, where mature and diverse reef communities are being transformed into more degraded systems, with just a few tough species remaining," co-author Professor Andrew Baird at James Cook University said.
According to the scientists, as many corals are still dying slowly and it will take at least 10 years to replace the dead corals.
As a result, coral reefs throughout the tropics are going to degrade until climate change stabilizes.
"The Great Barrier Reef is certainly threatened by climate change, but it is not doomed if we deal very quickly with greenhouse gas emissions," Hughes said.
"Our study shows that coral reefs are already shifting radically in response to unprecedented heatwaves."