The Great Barrier Reef Teeters on the Brink of Death

An underwater heatwave has resulted in mass casualties throughout the Great Barrier Reef, bringing one of the Earth’s greatest ecosystems to near collapse.

Miss Rosenby Miss Rosen
Photo: Dead corals still provide habitat to fish but will soon crumble away. Yonge reef (Lizard Island region), October 2016. Photo by Greg Torda

More than 25 million years old, the Great Barrier Reef is the earth’s largest living structure and the only one visible from space—and now, after more than 35 years of dire warnings, it has fallen victim to climate change, resulting in mass casualties throughout much of its spectacular ecosystem.

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At 1,400 miles long, the Great Barrier Reef was a model of biodiversity at its finest, home to 2,900 individual coral reefs and 1,050 islands, harboring some 1,625 species of fish, 3,000 species of mollusk, 450 species of coral, 220 species of bird, and 30 species of whales and dolphins, as well the largest breeding ground of green turtles.

Extensive bleaching of Acropora corals on the reef crest of North Direction Island April 13 2016, Credit Andrew Hoey

Extensive bleaching of Acropora corals on the reef crest of North Direction Island April 13 2016, Credit Andrew Hoey

In Wednesday, October 26, 2016, scientists from the ARC Centre of Excellence for Coral Reef Studies at James Cook University in Queensland have announced that the dramatic underwater heatwave in 2015-16 has resulted in a massive death toll across the Great Barrier Reef.

“Millions of corals in the north of the Great Barrier Reef died quickly from heat stress in March and since then, many more have died slowly,” Dr. Greg Torda reports.

Surviving corals now experience increased pressure from predators like Drupella snails. Yonge reef (Lizard Island region), October 2016. Photo by Greg Torda

Surviving corals now experience increased pressure from predators like Drupella snails. Yonge reef (Lizard Island region), October 2016. Photo by Greg Torda

The heatwave resulted in massive bleaching of the reef, a vision of death and destruction in what was once a vibrant garden of marine life. Under high temperatures, the algae that symbiotically feed the coral upon which it lives, began to produce too much oxygen, which became toxic in high concentrations. In order to survive, the corals were forced to eject the algae from the reef—but without algae to feed on, the corals began to starve to death, turning bone white in the process. If the water temperature returns to normal quickly, the coral can recruit new algae and recover from the loss, but if not, they will perish within months.

In 1981 the UNESCO designated the Great Barrier Reef as a World Heritage Site; this was the first year scientists observed the first mass-bleaching incident. Although it had recovered, mass bleaching continues regularly and it became apparent to scientists that this was the hallmark of climate change.

Map of devastation to Great Barrier Reef (link in article)

Map of devastation to Great Barrier Reef (link in article)

On Wednesday, scientists released unique footage showing the extent of the destruction to the Great Barrier Reef. Dr. Andrew Hoey noted, “In March, we measured a lot of heavily bleached branching corals that were still alive, but we didn’t see many survivors this week. On top of that, snails that eat live coral are congregating on survivors, and the weakened corals are more prone to disease. A lot of the survivors are in poor shape.”

Although the full scale of loss won’t be known until mid-November, Professor Terry Hughes argues that the Great Barrier Reef can and must be saved. Researchers believe that the warming is a result of human events, and therefore can be reversed. Although the trend toward warming continues due to the emissions that already exist, the Paris climate change agreement, which enters into force next month, is an effort to limit the extent of the warming.

This giant clam used to sit in a colourful field of corals before March 2016 – now she is alone on the reef slope. No Name reef (Lizard Island region), October 2016. Photo by Greg Torda

This giant clam used to sit in a colourful field of corals before March 2016 – now she is alone on the reef slope. No Name reef (Lizard Island region), October 2016. Photo by Greg Torda

Dr. Hoey believes it would take 10 to 20 years for the Great Barrier Reef to recover from this heatwave, provided it does not get hit by any other major disturbances in that time.


Miss Rosen is a New York-based writer, curator, and brand strategist. There is nothing she adores so much as photography and books. A small part of her wishes she had a proper library, like in the game of Clue. Then she could blaze and write soliloquies to her in and out of print loves.