Home to 3,000 individual coral reefs stretching across a staggering 1,400 miles (2,300 km), the Great Barrier Reef in Australia is recognised as the biggest living structure on Earth. But the reef is dying and scientists now believe it’s in a “terminal” stage from which it cannot recover.
The reef is home to over 1,500 species of fish, over 100 species of shark and ray, 30 kinds of whales and dolphins and almost 5,000 varieties of molluscs. As well as this, hundreds of non-marine animals—including over 200 species of bird—visit the reef every year. These creatures call the reef their home and without it, many of them cannot survive. But new aerial surveys have revealed that two-thirds of the reef have suffered severe back-to-back bleaching. Events from which it may not be able to recover.
Mass bleaching is a phenomenon caused by global warming-induced rises to sea surface temperatures. The rising temperature causes the coral to lose its endosymbiotic algae, something which provides it with 90% of its energy. After expelling the algae, the coral begins to starve.
The reef has suffered mass bleaching four times in recorded history, and the proximity of the last two events may now mean the reef cannot recover.
After completing aerial surveys, scientists with the Australian Research Council’s Centre of Excellence for Coral Reef Studies discovered 800 individual coral reefs had suffered bleaching. Events in 2016 and 2017 have resulted in two-thirds of the reef being damaged, leaving only the reef’s southern third unscathed.
Professor Terry Hughes, who led the surveys, said the length of time coral needed to recover—about 10 years for fast-growing types—raised serious concerns about the increasing frequency of mass bleaching events. He told The Guardian:
The significance of bleaching this year is that it’s back to back, so there’s been zero time for recovery. It’s too early yet to tell what the full death toll will be from this year’s bleaching, but clearly it will extend 500km south of last year’s bleaching.
Water quality expert Jon Brodie, has devoted much of his life to improving water quality on the reef. But 2017 has proved a disaster year for his team with the compounding effect of back-to-back bleaching and Cyclone Debbie making his job impossible. Speaking to The Guardian, he said:
We’ve given up. It’s been my life managing water quality, we’ve failed. Even though we’ve spent a lot of money, we’ve had no success. Last year was bad enough, this year is a disaster year. The federal government is doing nothing really, and the current programs, the water quality management is having very limited success. It’s unsuccessful.
This news will come as a devastating blow to the scientists, conservationists and groups—like Free the Reef—who’ve worked tirelessly to conserve and protect this incredible wonder. It’ll be incredibly sad to see this beautiful reef perish and the abundance of animals that depend on it.