Did you know coral skeletons contain a record of every flood event in Queensland since 1648?

We often hear that climate and water pollution conditions on the Great Barrier Reef have changed dramatically since pre-industrial times. But how do we actually know that? After all, weather records only stretch back just over a century, and systematic water quality monitoring only began in the 1980s.

The answer is written in the corals themselves. By extracting a core sample — much like studying tree rings — scientists can read the chemical signatures locked inside the growth layers of coral skeletons, revealing what ocean conditions were like hundreds of years ago.

So what stories are those coral cores telling us? To find out, we’re joined today by Dr Stephen Lewis, Senior Principal Research Officer specialising in water quality at James Cook University in Townsville.

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• Australian Marine Conservation Society: Australia, it's time to lead on Climate Action!
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• Our Islands Our Home: Protect the Torres Strait Islands from Climate Change
• Greenpeace: Save the Great Barrier Reef!
• WWF Australia: Protect Nature
• Rising Tide: ...

For thousands of years, the Great Barrier Reef has had the power to regenerate itself — so until 2017, coral transplantation was illegal. The rule was simple: let nature recover itself. Then mass bleaching events driven by global warming changed everything.

This summer, for the first time, scientists released tens of thousands of genetically selected, heat-tolerant baby corals - attaching them to ceramic stars and dropping them from boats in a bid to boost survival. The ambitious goal of this government-funded project is to plant millions of these devices using robots.

But can engineered human intervention work at the scale of an ecosystem the size of Japan? Is restoration a lifeline - or a distraction from cutting emissions? And what’s riskier: playing God with nature, or doing nothing?

This week, we're joined by Dr Cedric Robillot, Executive Director of the Reef Restoration and Adaptation Program, to explore what the Reef’s future looks like — because one thing is certain: it won’t resemble its past.

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PROTECT THE REEF - Sign these Petitions Now!

• Australian Marine Conservation Society: Australia, it's time to lead on Climate Action!
• Divers for Climate: Sign the 'I'm a Diver for Climate' National Statement
• Australian Conservation Foundation: No New Coal and Gas!
• Queensland Conservation Council: Take Strong Climate Action and Build a Positive Renewable Future!
• Our Islands Our Home: Protect the Torres Strait Islands from Climate Change
• Greenpeace: Save the Great Barrier Reef!
• WWF Australia: Protect Nature
• Rising Tide: ...

Our oceans are 40% more acidic than pre-industrial times, making it harder for corals, molluscs, crustaceans and plankton to build their calcium carbonate skeletons. It's a crucial planetary boundary we've crossed — threatening reefs, fisheries, tourism, food security, and coastal communities. And almost no one is talking about it.

So what’s driving it? What does it mean for the Great Barrier Reef? And what can we do?

This week on Word on the Reef, we’re joined by Dr Katharina Fabricius from the Australian Institute of Marine Science — a global leader in coral reef ecology and ocean acidification research — to unpack the science and the solutions.

Read Dr Fabricius's research: Volcanic bubbles help foretell the fate of coral in more acidic seas

Thumbnail image: CO2 bubbles emerging from volcanic seeps in Papua New Guinea. Dr Katharina Fabricius

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Help Keep Word on the Reef Afloat!
Please take 2 minutes to fill out our Word on the Reef Listener Survey to help us apply for funding for the show!

PROTECT THE REEF - Sign these Petitions Now!

• Australian Marine Conservation Society: Australia, it's time to lead on Climate Action!
• Divers for Climate: Sign the 'I'm a Diver for Climate' National Statement
• Australian Conservation Foundation: No New Coal and Gas!
• Queensland Conservation Council: Take Strong Climate Action and Build a Positive Renewable Future!
• Our Islands Our Home: Protect the Torres Strait Islands from Climate Change
• Greenpeace: Save the Great Barrier Reef!
• WWF Australia: Protect Nature
• Rising Tide: ...

CSIRO scientists have discovered a massive underwater mountain, shaped like a half-eaten flan, rising 3,000 metres from the seafloor off the coast of North Queensland. That's taller than Australia’s highest mainland peak, Mount Kosciuszko. And it’s teeming with life.

To guide us on a deep dive into this 40-million-year-old extinct volcano and its flantastic inhabitants, our guest on Word on the Reef this week is Marine Geophysicist Dr Chris Yuleridge.

Dr Yuleridge also takes us '20 thousands leagues under the sea' to explore lost shipwrecks, follow submerged Aboriginal song lines, meet the faceless cusk eel, and dive inside the recently erupted Hunga Tonga volcano.

If you're a big flan of science, this episode is for you. But be warned - listening may cause cravings for lava pudding, creme brulee and other volcano-shaped desserts.

• RV Investigator Livestream Camera
• Coral Sea Expedition, Including Images of Sea Creatures
• Seafloor Mapping Highlights
• Seabed Data Portal: https://portal.ga.gov.au/

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Help Keep Word on the Reef Afloat!
Please take 2 minutes to fill out our Word on the Reef Listener Survey to help us apply for funding for the show!

PROTECT THE REEF - Sign these Petitions Now!

• Australian Marine Conservation Society: Australia, it's time to lead on Climate Action!
• Divers for Climate: Sign the 'I'm a Diver for Climate' National Statement
• Australian Conservation Foundation: No New Coal and Gas!
• Queensland Conservation Council: Take Strong Climate Action and Build a Positive Renewable Future!
• Our Islands Our Home: Protect the Torres Strait Islands from Climate Change
• Greenpeace: Save the Great Barrier Reef!
• WWF Australia: Protect Nature
• Rising Tide: ...

Have you ever felt confused by conflicting media reports about the health of the Great Barrier Reef? If so, you're not alone. New research shows news coverage has often failed to clearly communicate the risks climate change poses to the reef, sometimes fuelling misinformation and climate denial.

So what's really happening on the Great Barrier Reef? To help unpack this, our guest today is Dr. Gabi Mocatta, Senior Research Fellow in Climate Science Communication at the University of Tasmania.

PLUS it's our last show of the year and we're going out with a bang! Hosts Tanya and Brett celebrate their 40th and final episode of the year and look back at the highlights of 2025.

SOURCES:

The Australian Institute of Marine Science (AIMS) 2022 Media Release as discussed in the episode: https://www.aims.gov.au/information-centre/news-and-stories/highest-coral-cover-central-northern-reef-36-years

Andreotta, M., Mocatta, G., Lubicz-Zaorski, C. et al. Steering Great Barrier Reef climate science narratives through the mediasphere in a time of misinformation. npj Clim. Action 4, 99 (2025). https://doi.org/10.1038/s44168-025-00235-4

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Help Keep Word on the Reef Afloat!
Please take 2 minutes to fill out our Word on the Reef Listener Survey to help us apply for funding for the show!

PROTECT THE REEF - Sign these Petitions Now!

• Australian Marine Conservation Society: Australia, it's time to lead on Climate Action!
• Divers for Climate: Sign the 'I'm a Diver for Climate' National Statement
• Australian Conservation Foundation: No New Coal and Gas!
• Queensland Conservation Council: Take Strong Climate Action and Build a Positive Renewable Future!
• Our Islands Our Home: Protect the Torres Strait Islands from Climate Change
• Greenpeace: Save the Great Barrier Reef!
• WWF Australia: Protect Nature
• Rising Tide: ...

What do the world's largest flying bird, with a wingspan of up to 3.5 metres, and the Australian Sea Lion have in common? Both are endangered due to their high risk of entanglement in fishing nets!

Today's guest, Zoologist Alexia Wellbelove gives us a birds-eye view on how changes to fishing practices can help bring Albatrosses and Sea Lions back from the brink. We'll also unpack recent changes to Australia's nature laws which scientists hope will help slow the alarming rate of extinctions in Australia.

AMCS's Threatened Species Campaign: https://www.marineconservation.org.au/threatened-species/

Support the show

Help Keep Word on the Reef Afloat!
Please take 2 minutes to fill out our Word on the Reef Listener Survey to help us apply for funding for the show!

PROTECT THE REEF - Sign these Petitions Now!

• Australian Marine Conservation Society: Australia, it's time to lead on Climate Action!
• Divers for Climate: Sign the 'I'm a Diver for Climate' National Statement
• Australian Conservation Foundation: No New Coal and Gas!
• Queensland Conservation Council: Take Strong Climate Action and Build a Positive Renewable Future!
• Our Islands Our Home: Protect the Torres Strait Islands from Climate Change
• Greenpeace: Save the Great Barrier Reef!
• WWF Australia: Protect Nature
• Rising Tide: ...

What do the Egyptian Pyramids, the Greek Parthenon, the Notre Dame Cathedral and Melbourne's Parliament House all have in common? They are all built out of fossilised reefs, aka limestone!

Today we’re taking a journey through deep lime - I mean time - to answer some of those burning questions like: How old is the Great Barrier Reef? What ancient forces built this coral colossus? Why are there fossilised reefs hundreds of metres above sea level and kilometres inland? And perhaps most importantly... What do these lessons from the ancient karst - I mean past - mean for our future?

To help us dig up the answers, we’re joined by Russell Kelley - a coral geologist, biologist, and author of the acclaimed Be Your Own Guide coral identification book series - who knows corals both living and extinct like the back of his hand.

Check out Russell's Books at www.BYOGUIDES.com

Support the show

Help Keep Word on the Reef Afloat!
Please take 2 minutes to fill out our Word on the Reef Listener Survey to help us apply for funding for the show!

PROTECT THE REEF - Sign these Petitions Now!

• Australian Marine Conservation Society: Australia, it's time to lead on Climate Action!
• Divers for Climate: Sign the 'I'm a Diver for Climate' National Statement
• Australian Conservation Foundation: No New Coal and Gas!
• Queensland Conservation Council: Take Strong Climate Action and Build a Positive Renewable Future!
• Our Islands Our Home: Protect the Torres Strait Islands from Climate Change
• Greenpeace: Save the Great Barrier Reef!
• WWF Australia: Protect Nature
• Rising Tide: ...

Pigs can't fly, nor can they dive in the ocean. But they are posing a serious threat to endangered sea turtles by pigging out on turtle eggs and hatchlings in Cape York. This is not the good kind of bacon and eggs combo. It's Ham-ageddon for our nesting sea turtles!

Cape York Natural Resource Management representatives Dr Manuela Fischer and Scott Morrison (no relation to the former Australian PM) are working on a solution! Today they join us in the studio to explain how we can deal with this a-pork-alypse and give our sea turtles a chance for the future.

Watch this episode on YouTube: https://youtu.be/Kf1aDsr0p9A

Support the show

Help Keep Word on the Reef Afloat!
Please take 2 minutes to fill out our Word on the Reef Listener Survey to help us apply for funding for the show!

PROTECT THE REEF - Sign these Petitions Now!

• Australian Marine Conservation Society: Australia, it's time to lead on Climate Action!
• Divers for Climate: Sign the 'I'm a Diver for Climate' National Statement
• Australian Conservation Foundation: No New Coal and Gas!
• Queensland Conservation Council: Take Strong Climate Action and Build a Positive Renewable Future!
• Our Islands Our Home: Protect the Torres Strait Islands from Climate Change
• Greenpeace: Save the Great Barrier Reef!
• WWF Australia: Protect Nature
• Rising Tide: ...