Threats To Reef Spawn Alliance Of Marine Guardians

A new breed of aquatic vigilantes aren’t waiting for ‘someone else’ to fight threats to our greatest natural wonder, writes National Geographic staff Samuel Boynton.

Once a year, after a full moon at the start of the Australian summer, the corals of the Great Barrier Reef engage in what’s known as mass spawning – a kind of synchronised group sex in which entire colonies of coral reefs release their sperm and eggs simultaneously.

It's a magnificent spectacle that can be seen from space; an explosion of pink-brown beads floating toward the ocean’s surface – like snow falling upward. These beads produce larvae and coral polyps which (given enough time and the correct conditions) will continue their journey to replicate and build beautiful, thriving coral structures.

Considered one of the greatest examples of synchronised phenomena in nature, coral spawning relies on a variety of factors – time, temperature, currents and tides – which means that very few people in the world have been fortunate enough to encounter it.

Image Credit: Juergen Freund

The notion of an entire reef system giving birth becomes a giant symbol of life, and therein hope for our treasured icon.

But amid back-to-back coral bleaching events, cyclones, and record-breaking warm water, leading scientists fear the climate crisis may be disrupting the ability of corals to synchronise this marine phenomenon, threatening this natural wonder with extinction.

The outlook for the Great Barrier Reef has been downgraded from ‘poor’ to ‘very poor’ by an exhaustive Australian government report.

The report by the Great Barrier Reef Marine Park Authority warns the window of opportunity to safeguard our World Heritage Listed natural wonder “is now”.

In the report, the authority issues an urgent call for effective global and national action on climate change, coupled with local remedies to facilitate reef recovery.

Image Credit: Frank Gazzola

Actions including improving water quality by reducing pollution of inshore water will be imperative over the next 10 years.

“Of the very high-risk threats, most relate to climate change or land-based run-off (water quality) affecting values on a region-wide scale,” the report says.

“Given the current state of the region’s values, actions to reduce the highest risks have never been more time-critical.”

Fortunately, the collaborative effort displayed during this year’s spawning events has been bigger and more intense than ever before.

Image Credit: Juergen Freund

Science and tourism operators join forces

Leading environmental organisation Citizens of the Great Barrier Reef have joined forces with the scientific community and a number of local marine tourism operators to accelerate cutting-edge research that aims to mitigate the impacts of climate change and help safeguard the reef for future generations.

“We hope to make direct partnerships between science and tourism the norm rather than the exception,” says JCU Senior Research Officer Katie Chartrand.

“A collaborative approach is needed to give the reef the best chance of thriving into the future.”

One such project, based on a floating laboratory at the Marine World Pontoon 45km off the coast of Cairns saw researchers led by Southern Cross University Professor Peter Harrison working night and day to complete a radically new approach to coral re-seeding on degraded reefs.

Image Credit: Juergen Freund

The project is a collaboration between researchers and key industry partners including Aroona Boat Charters and Reef Magic Cruises, and is funded by the Queensland and Australian Governments Coral Abundance Challenge.

For the first time the team is trialling its ‘coral-nursery’ rearing pools, designed to turbo-charge the newly-spawned larvae’s one-in-a-million chance of survival through co-culturing with algae (known as symbionts), and tracking their progress using new ultra-sensitive optical sensors in real-time.

“This innovative technique is like giving the baby corals a ‘battery pack’ by allowing the coral larvae to take up symbiotic algae, giving them the potential to acquire more energy, and therefore grow faster and survive better,” says Harrison, who first discovered the mass coral spawning phenomenon with colleagues on the Great Barrier Reef 38 years ago.

UTS Associate Professor David Suggett says this is the first time the ‘turbo charging’ of baby corals’ has been trialled on such a large scale and on the reef itself.

Image Credit: Juergen Freund

Climate action the only long-term solution

He says the team’s ambitious project is already paying off – with millions of healthy coral larvae now swimming around ready to be dispersed and grow into new coral communities

Another promising example of science and tourism working together to protect high-value reefs is taking place at the Coral Nurture Program off the coast of Port Douglas.

An ongoing initiative of UTS’s Suggett and Dr Emma Camp (in partnership with Wavelength Reef Cruises), this unique approach is not about ‘reef restoration’ per se, but enabling long-term stewardship by arming existing tourism operators with simple, low-cost tools to secure coral fragments to the reef and monitor progress.

The project has already delivered more than five thousand coral out-plants at Opal Reef, with the next phase aiming for tens of thousands of corals at five different sites in the next twelve months.

Image Credit: Frank Gazzola

While a key next step will be to monitor just how effectively such initiatives impact coral reef health, the scientists involved are careful to highlight that their approaches cannot by themselves ‘save’ the reef.

"What we're trying to do is buy time for the coral populations that are still present on the Great Barrier Reef and other reefs around the world,” Harrison says. “Climate action is the only way to ensure coral reefs can survive into the future.”

Andy Ridley, CEO of Citizens of the Great Barrier Reef, says the power of these projects is seeing the best of science, conservation and tourism working together to buy time for coral reefs, “while we strive to rapidly bring emissions down over the coming decades”.

Image Credit: Juergen Freund

Now more than ever, we need people to visit the reef, to understand it, and to fall in love with the many areas still supporting beautiful corals and abundant marine life. We need to include a greater number of individuals in the conversation, until the wisdom that emerges accelerates a change that is already well underway.

While millions of healthy coral larvae now continue their quest to create life – and while tourism operators across the reef join the movement to protect, preserve, and spread the word – a message has clearly risen to the surface.

The threats to the reef are real and immediate, but there is hope. The question is not whether a healthy reef is possible, but what we will do together to make it happen.

Image Credit: Christian Miller

Video: Provided by Citizens Of The Great Barrier Reef. Join the movement and become a Citizen of The Great Barrier Reef at


Lead Image Credit: Andrew Watson

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