Nav: Home

A glimmer of hope for the world's coral reefs

December 10, 2018

The future of the world's coral reefs is uncertain, as the impact of global heating continues to escalate. However, according to a study published today in Nature Climate Change, the response of the Great Barrier Reef to extreme temperatures in 2017 was markedly different to one year earlier, following two back-to-back bouts of coral bleaching. Remarkably, corals that bleached and survived 2016 were more resistant in 2017 to a recurrence of hot conditions.

"Dead corals don't bleach for a second time. The north lost millions of heat-sensitive corals in 2016, and most of the survivors were the tougher species. As a result of bleaching, the mix of species is changing very rapidly," said lead author Prof Terry Hughes, Director of the Australian Research Council Centre of Excellence for Coral Reef Studies (Coral CoE), headquartered at James Cook University.

"We were astonished to find less bleaching in 2017, because the temperatures were even more extreme than the year before," he said.

The new research highlights the extent of damage, or "geographic footprint" of multiple coral bleaching events across the 2,300 km length of the world-heritage listed area.

The back-to-back heatwaves bring the total number of mass bleaching events on the Great Barrier Reef to four over the past two decades (in 1998, 2002, 2016 and 2017). The scientists found that only 7% of the Great Barrier Reef escaped bleaching entirely since 1998, and after the 2017 event, 61% of reefs have now been severely bleached at least once.

"We found, using the National Oceanic and Atmospheric Administration's (NOAA) satellite-based coral bleaching tools, that corals in the north of the Great Barrier Reef were exposed to the most heat stress in 2016. A year later, the central region saw the most prolonged heating," said co-author Dr Mark Eakin, from NOAA's Coral Reef Watch program, in Maryland, USA.

The southern third of the Great Barrier Reef was cooler in both years due to local weather conditions, and escaped with only minor bleaching.

"It's only a matter of time before we see another mass-bleaching event, triggered by the next marine heatwave, driven by global heating," said co-author Dr Andrew Hoey of Coral CoE at James Cook University. "One of the worst possible scenarios is we'll see these southern corals succumb to bleaching in the near future."

"The outcome in 2017 depended on the conditions experienced by the corals one year earlier. We called that 'ecological memory,' and show that these repeating events are now acting together in ways that we didn't expect," said Prof Hughes.

"We've never seen back-to-back mass coral bleaching before on the Great Barrier Reef, in two consecutive summers. The combined footprint has killed close to half of the corals on two-thirds of the world's largest reef system," said Dr Hoey.

"We need urgent global action on greenhouse emissions to save the world's coral reefs. Australia should be - but regrettably isn't - at the forefront of tackling global heating," said Prof Hughes.
-end-


ARC Centre of Excellence in Coral Reef Studies

Related Coral Reefs Articles:

Mysterious glowing coral reefs are fighting to recover
A new study by the University of Southampton has revealed why some corals exhibit a dazzling colorful display, instead of turning white, when they suffer 'coral bleaching' -- a condition which can devastate reefs and is caused by ocean warming.
Can coral reefs 'have it all'?
A new study outlines how strategic placement of no-fishing marine reserves can help coral reef fish communities thrive.
Coral reefs 'weathering' the pressure of globalization
More information about the effects human activities have on Southeast Asian coral reefs has been revealed, with researchers looking at how large-scale global pressures, combined with the El Niño Southern Oscillation (ENSO) climate pattern, can detrimentally impact these delicate marine ecosystems.
Coral reefs: Centuries of human impact
In her AAAS talk, ASU researcher Katie Cramer outlines the evidence of the long-ago human footprints that set the stage for the recent coral reef die-offs we are witnessing today.
Large 'herbivores of the sea' help keep coral reefs healthy
Selective fishing can disrupt the delicate balance maintained between corals and algae in embattled Caribbean coral reefs.
How microbes reflect the health of coral reefs
Microorganisms play important roles in the health and protection of coral reefs, yet exploring these connections can be difficult due to the lack of unspoiled reef systems throughout the global ocean.
3-D printed coral could help endangered reefs
Threats to coral reefs are everywhere--rising water temperatures, ocean acidification, coral bleaching, fishing and other human activities.
Actions to save coral reefs could benefit all ecosystems
Scientists say bolder actions to protect the world's coral reefs will benefit all ecosystems, human livelihoods and improve food security.
Coral reefs shifting away from equator
Coral reefs are retreating from equatorial waters and establishing new reefs in more temperate regions, according to new research in the journal Marine Ecology Progress Series.
Protecting coral reefs in a deteriorating environment
A new report examines novel approaches for saving coral reefs imperiled by climate change, and how local decision-makers can assess the risks and benefits of intervention.
More Coral Reefs News and Coral Reefs Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

TED Radio Wow-er
School's out, but many kids–and their parents–are still stuck at home. Let's keep learning together. Special guest Guy Raz joins Manoush for an hour packed with TED science lessons for everyone.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.