Great Barrier Reef Definitely Not Dead: Experts Announce Significant Signs of Recovery After Mass Bleaching

Experts in Australia have reported that corals affected by mass bleaching events are showing significant signs of recovery in what is a rare piece of good news for the Great Barrier Reef (GBR).

The non-profit Reef & Rainforest Research Centre (RRRC), based in the city of Cairns, Queensland, says that milder summers in 2017 and 2018 have helped the reef to bounce back in several locations.

In 2016 and 2017, many parts of the GBR—and other reefs around the world—experienced severe coral bleaching, which occurs when the organisms are placed under too much stress from high water temperatures, poor water quality, or other triggers.

In stressful conditions, coral expels tiny plant-like organisms called zooxanthellae which live in its tissue, causing it to turn white. If the stressful conditions persist the coral may die, but if conditions return to normal, it can re-absorb the zooxanthellae, regaining health and its distinctive coloring.

Bleaching is a particularly serious threat to reefs across the world, given that climate change is causing the oceans to become warmer and more acidic—a result of increased carbon absorption from the atmosphere.

But according to the RRRC, recent reports and photos taken by tourism operators and tourists themselves show encouraging signs of recovery. Healthy, vibrant coral can be seen at numerous locations which suffered during the back-to-back bleaching events, including Fitzroy Island, Moore Reef, and Saxon Reef.

"It is important to realize that bleaching occurs in multiple stages, ranging from the equivalent of a mild sunburn to coral mortality," Sheriden Morris, Managing Director of the RRRC, said in a statement. "Saxon Reef, for example, suffered some form of bleaching on 47.1 percent of its live coral cover during the 2016 event."

"Fortunately, much of the bleached coral recovered thanks to better conditions experienced in 2018," he said. "It is clearly a misconception that the whole of the GBR suffered from severe coral bleaching and that the reef is dead. This is blatantly untrue".

Doug Baird, a spokesman for reef tourism operator, the Quicksilver Group, said that there had been widespread recovery at the company's regular sites.

"All of our sites that survived the mass bleaching events have shown strong signs of recovery, they look great now. We were fortunate that the effects of bleaching were very patchy," Doug said. "I was in the water a few weeks ago at our pontoon site at Agincourt Reef and it looks stunning, there's staghorn coral that's budding out and re-growing."

According to the RRRC, relatively cool summers in 2017-2018 and restoration techniques employed by scientists, industry and government are thought to have enabled the coral to recover in many places.

The RRRC, for example, established a coral nursery at Fitzroy Island in 2017 to regenerate the damaged reef there. The organization reports that the first crop of corals at this site have exceeded expectation, both increasing in size and multiplying.

However, the GBR is not out of the woods yet, because—like other reefs around the world—it is facing a number of threats which are devastating coral populations. These include climate change, poor water quality, pollution, cyclones, outbreaks of parasites and disease and destructive fishing or tourism practices. As a result, average coral cover in the Great Barrier Reef is estimated to have has dropped by 50% in recent decades.

"This recovery is always going to be contingent on environmental conditions," Morris said. "We all know that the reef may suffer further bleaching events as the climate continues to warm, but we have to do everything we possibly can to help protect our Great Barrier Reef."

This file photo taken on September 22, 2014, shows fish swimming through the coral on Australia's Great Barrier Reef. WILLIAM WEST/AFP/Getty Images

While research has shown that coral reefs have a remarkable ability to bounce back after disturbances, and may even be adapting to rising temperatures, the more stress they are put under, the less likely it is that they will be able to survive in the long-term. In fact, one recent study has suggested that the increased threats that coral reefs are facing are hampering their ability to recover.

The Great Barrier Reef, which stretches for more than 1,400 miles off Australia's east coast, is the one of the seven wonders of the natural world and the largest and most spectacular reef system on the planet. Consisting of 3,000 individual reefs, it is the largest living structure on Earth, featuring an abundance of marine life.