Higher water temperatures this year have caused the worst erosion of corals ever recorded on Australia’s Great Barrier Reef.
Scientists estimate two-thirds of coral coverage has died along a 700km stretch of reef off far north Queensland.
In February, March and April of this year, sea surface temperatures across the Great Barrier Reef were the hottest on record, at least 1°C higher than the monthly average.
These hotter than usual water temperatures cause coral bleaching. When water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white.
When bleaching occurs, in the 6-12-month period afterwards, the corals either survive and regain their colour, or if they don’t regain their colour, they slowly die.
James Cook University researchers have been carrying out underwater surveys since the severe coral bleaching event.
They have confirmed that resulted in the largest die-off of corals ever recorded on the Reef – though some areas showed remarkable improvement.
It could take between 10 and 15 years for new corals to grow.