One third of Great Barrier Reef corals killed in marine heatwave in 2016
Coral bleaching occurs when high water temperatures cause corals to expel the algae, making the coral pale or white
High water temperatures off the east Australian coast in 2016 bleached and “cooked” large sections of the Great Barrier Reef, according to a new scientific study released on Thursday.
The study, published in the journal Nature, showed 29 per cent of the almost 4,000 reefs that make up the Great Barrier Reef lost at least two-thirds of their corals over a nine-month period, affecting their ability to support diverse ecosystems.
“When corals bleach from a heatwave, they can either survive and regain their colour slowly as the temperature drops, or they can die,” Terry Hughes, lead study author and director of the Australian Research Council Centre of Excellence for Coral Reef Studies, said in a statement.
Corals, or coral polyps, are soft-bodied organisms that have a symbiotic relationship with algae living in their tissues. Algae provide food and colour to the corals.
Coral bleaching occurs when high water temperatures cause corals to expel the algae, making the coral pale or white.
The study found corals in the northern third of the reef, where water temperatures were most extreme, were the most severely affected, with half of the coral cover in the most shallow areas dying in an eight-month period.
They cooked because the temperatures were so extreme