The warmer temperatures are most likely due to climate changes caused by human factors, according to the study.
The sea temperatures around the spectacular coral reef have increased annually since 1960, but were particularly warmer during the latest episodes of mass bleaching of corals.
According to the researchers, the temperatures were relatively stable before 1900, but since 1960 the water has warmed up by an average of 0.12 degrees up to the present day.
Coral bleaching – which occurs as a result of increased temperature in the sea – means that the microorganisms that live in symbiosis with the coral animals remove themselves from the corals, which then become white and die.
This is coral that has lived for 400 years and this is the warmest temperature they are experiencing, says Helen McGregor, one of the authors of the study, and adds that she is "extremely worried" about the reef.
McGregor says that even if the corals could recover, recurring coral bleaching episodes reduce that ability.
