(AU ABC) Promising Signs Of New Life On Australia's Largest Oceanic Reef, Despite Frequent Heat Stress

ABC News - Tyne Logan

Researchers have observed promising signs of new life on Scott Reef, five years after the global mass bleaching event of 2016. (Supplied: AIMS Shannon Duffy)

Key Points Scientists say Scott Reef is slowly recovering after the 2016 mass bleaching event They have concerns about frequent heatwaves impeding the overall recovery of the reef The findings reflect a pattern around the country

A research trip to Australia's largest oceanic reef system has shown promising signs of new life, following the 2016 mass bleaching event, which impacted coral reefs all over the globe.

But unlike mass bleaching events of the past, scientists are concerned Scott Reef is facing a barrier to its recovery.

Coral ecology research scientist James Gilmour, from the Australian Institute of Marine Science, said repeated, smaller marine heatwaves since the 2016 event were compounding bleaching impacts.

"Unfortunately since 2016 we've seen additional heat stress in 2017, 2019 and 2020," he said.

"We're getting this recurrent heating and stress to the reefs which obviously are going to impede its recovery.

"We see this overlying resilience, but the effects of ongoing heat stress impeding that."

Scott Reef is located in the Timor Sea and consists of three separate reef structures. (Supplied: AIMS Luke Thomas)

Located 200 kilometres to the north-west of Broome, the three reefs are incredibly isolated, a trait Dr Gilmour said made them a good case study in pinpointing the impacts of climate change on Australian reefs.

"Because of its isolation, it doesn't have these additional pressures, such as fishing pressure or the pollution pressure that you see on other reefs that can confound our inferences about what is happening from climate change and coral bleaching," he said.

Case study for climate change impacts

The observations at Scott Reef reflect a dire pattern emerging not only in Australia but around the world.

A major global analysis of coral reefs, released in October, found about 14 per cent of the world's coral, the equivalent of more than all living coral in Australia, had been lost in less than a decade.

It found the main cause of the decline was "recurring large scale coral bleaching events" that were "preventing coral from recovering".

But the analysis also found there was hope, with some corals showing strong, and at times surprising resistance to ongoing heat stress.

Dr James Gilmour said some corals were showing impressive signs of recovery, despite recurring heat stress. (Supplied: AIMS)

University of Western Australia and AIMS research associate Luke Thomas said this was observed on Scott Reef too.

"Considering this reef has gone through three serious bleaching events in the last 20 years, it's just been hammered and hammered over and over... the fact that there's any coral left is a remarkable story and a testament of the system," he said.

Making the most of heat-tolerant corals

Dr Thomas said researchers were trying to utilise this surprising resilience.

"One way is if we know this pocket of reef houses heat resistance corals, let's protect them, let's avoid anchor damage or overfishing," he said.

He said a second way was to breed tolerant coral populations for restoration.

"So if we want to restore a degraded section of reef, we don't want to just replace those corals with ones that will bleach and die the next heatwave," he said.

"We want to replace them with much more fit, tougher individuals.

"So we can target this pocket of heat resistance corals as a broodstock, or a supply for those reefs."

Scientists conducted heat tolerance research while at the Scott Reefs. (Supplied: AIMS Luke Thomas)

The science and restoration work on Scott Reef is similar to that happening on the Great Barrier Reef, with the government kicking in half a billion dollars in 2018 to help deal with the problems facing the Great Barrier Reef.

Glasgow climate talks 'discouraging'

The management and restoration work of corals is crucial to saving reef systems in the future, researchers say, but it comes second to the need to cut down carbon emissions.

James Cook University marine biologist Jodie Rummer said Australia left "a lot to be answered for" after the COP26 conference in Glasgow.

"There was a clear message over the past five years of what increased emissions and climate change have been doing to Australia, let alone the entire world, and we weren't able to stand up to do anything about it."

Marine Biologist Dr Jodie Rummer said the recent climate conference in Glasgow left a lot to be answered for in terms of cutting Australia's carbon emissions. (ABC: Travis Mead)

Dr Rummer said the federal government priorities were wrong.

"Clean economic recovery is win win for Australia," she said.

"This is what needs to be the priority for Australia but for some reason Australia is still prioritising coal, gas and oil exploration.

"This goes in complete conflict with Australia's national priority of protecting people, our ecosystems and natural spaces."

Links

• Great Barrier Reef in 'recovery window' after year without major heatwaves, cyclone disturbances
• New study reveals extent of coral bleaching worldwide, with WA reefs suffering at alarming rate
• (Washington Post) Photos Show Vast Coral Spawning Event In Great Barrier Reef, Giving Divers Hope For Climate Change Recovery
• (USA TIME) UNESCO Says Australia's Great Barrier Reef Isn't In Danger Yet. Many Environmentalists And Divers Disagree
• (AU The Conversation) Not Declaring The Great Barrier Reef As ‘In Danger’ Only Postpones The Inevitable
• (AU SBS) Australia Accused Of ‘Censoring Science’ After Great Barrier Reef Avoids World Heritage ‘In Danger’ Listing
• (AU ABC) Coral Reefs Across The World 'In Danger' As Scientists Note Slowing Calcification
• It Might Be The World’s Biggest Ocean, But The Mighty Pacific Is In Peril
• A Race Against Time To Rescue A Reef From Climate Change