Last updated May 31, 2017 at 11:42 am
It’s one of the hot environmental issues of our time: the loss of the world’s reefs. Lauren Smith looks into who’s rescuing these iconic habitats and finds a swag of inspiring Aussie researchers hard at work.
I gulped in a lungful of oxygen, kicked my legs and dived down. Out of the inky black beneath me rose a huge spotted blue creature, as long as a school bus. I swam beside it, desperate to reach out and run my fingers along its ridged skin. But I kept a respectful distance, knowing the strength in its huge pectoral fins and sweeping tail was enough to break my arm.
That awesome experience with a whale shark was the first time I’d snorkelled on a reef – in this case, the stunning Ningaloo Reef off Western Australia – and from that moment I was hooked. (Apologies for the fishy pun!) In the years since then, it seems like every new story or study published about reefs – in Australia and elsewhere – warns about their demise. Ningaloo and her massive sister on the other side of the country, the Great Barrier Reef (GBR), as well as fringing reefs along our continent’s north coast and the rocky reefs of the south coast are all under threat.
But this story doesn’t have to end badly. There’s an army of researchers out there working on the frontline to make sure these extraordinary habitats survive. So come and meet some of Australia’s reef warriors and be inspired to join them.
University of Western Australia marine scientist Dr Harriet Paterson is investigating a pollution problem the world is only beginning to get its head around – microplastics. These are particles of plastic smaller than a millimetre, so we hardly notice them, but there’s mounting evidence that they’re particularly harmful to the animals living in marine habitats such as reefs.
Dr Paterson is one of the leaders of a survey trying to determine the extent of microplastic pollution along the south-west WA coastline. It’s a project with a significant citizen science component; enlisting the help of primary school groups from Esperance to Jerramungup, to visit beach sites, take sand samples and identify what microplastics are present.
Plastic pollution generally in marine environments is a growing problem and Dr Paterson has previously spent three years working on how microplastics affect seabirds. “We keep producing [plastic] because our lifestyles rely on it and it keeps getting into the ocean,” she explains. “We are only just beginning to understand the biological consequences.”
Her work is part of the beginning of a shift in the global understanding of plastic pollution. “Dealing with plastics in the environment is going to be an important issue in the future. There will be jobs that we have not yet thought about that will be developed to tackle the effect of plastics,” Dr Paterson says. “Engineers will need to develop new materials that can replace plastic and are environmentally safe. Other engineers will need to figure out how to remove plastics from the environment.
Psychologists will need to facilitate behaviour change in a global population that has a dependence on plastics. And biologists will need to help wildlife and plants get past the harmful effects of plastic.”
TESTING A TELL-TALE ALGAE
The main threat our reefs face is climate change and the associated range of dangers that brings. These include rising water temperature, rising water levels, water acidification and an increased frequency of severe weather, all of which are severe perils for reef ecosystems.
Over on the other side of the country from Ningaloo Dr Emma Kennedy, a postdoctoral research fellow at Griffith University, is working on the GBR to monitor the impact of ocean acidification on a particular type of algae. It’s known as crustose coralline algae, or CCA, and it’s particularly sensitive to acidification, which is a major consequence of increased carbon dioxide in the Earth’s atmosphere: the acidity of marine waters increases as our oceans absorb more and more carbon dioxide from the atmosphere.
Because CCA skeletons dissolve more easily under acidic conditions than coral skeletons, this algae acts as a useful bioindicator of when things are going wrong. Just as miners in underground coal mines once relied on sick or dying canaries to indicate when a mine’s air was becoming poisonous, researchers can rely on this algae to tell them when the surrounding water is becoming acidic enough to affect marine life.
The Griffith Uni project involves measuring CCA skeleton growth rates to first determine a ‘normal’ background level. This then enables the researchers to detect and respond to sudden changes in acidification levels, giving them time to act before it’s too late.
NEVER GIVE UP
Some experts are saying that it may already be too late to save our reefs. But as one of the many scientists and engineers now working to solve the looming issues, Griffith University’s Dr Emma Kennedy is optimistic.
“I do get a bit jealous when I hear stories from the older generations about how huge and colourful the corals were, and how many big and beautiful fish they saw when they were young,” she admits. “Some professors have started saying that there’s no hope, and that we should just enjoy the reefs while we still can, and then use them as an example of the first ecosystem that was lost due to human carelessness and overexploitation.
“But I have to be optimistic otherwise I wouldn’t be able to come to work each day. Humanity is in a very unique position where we understand the risks of climate change and have the technology in our grasp to do something about it.”
ROBOTS AND REEFS
The University of Sydney’s Reef in 3D project is being carried out by a multidisciplinary team that comprises the usual types of scientists you’d expect to see working in an ocean habitat, like marine biologists and coral reef ecologists. But it also includes some more unlikely experts, including researchers in robotics and stereo imaging. Together they are developing complex 3D maps of Australian reefs using robots.
The more complex a coral reef, the more resilient it tends to be as the climate changes. Using robots to map the seafloor in 3D allows changes to be measured over larger areas than traditionally possible, and that means that scientists will be able to react faster to problems as they arise. Professor Maria Byrne, who heads the project, explains: “Reefs have a huge suite of species, all with different functions. It’s like different pieces in a big jigsaw puzzle. If you miss some of the pieces, you actually start reducing resilience. You might be able to lose one species, because the others might be able to fill in the role – they could be herbivores cropping seaweed or damselfishes keeping the corals in good nick, but if you start losing too many… that’s when you start having resiliency being impaired.”
These new 3D maps are being assembled through geolocation. This means that as repeat surveys are undertaken by robots, autonomously operated vehicles and divers, researchers studying phenomena such as coral bleaching will be able to compare current and historical maps. And that will mean researchers will be able to identify and understand what changes came first and how they led to other consequences.
Melbourne University chemical engineer Professor David Solomon is working on an unusual answer to the increasing levels of UV reaching our reefs due to climate change. Prof Solomon, an expert in polymer chemistry, is leading a team investigating the possibility of protecting the coral on reefs with a type of sunscreen. It’s an idea based on a technology already used in dams to minimise evaporation – and would mean that a biodegradable surface film, just one molecule thick, would be positioned on top of the water to protect a reef.
A particularly prickly problem (sorry again for bad puns!) for Australia’s reefs is the crown-of-thorns starfish (COTS). This is a predatory starfish with a voracious appetite for coral polyps. Every so often its numbers boom and decimate reefs. For a long time COTS populations were controlled by divers who searched for the starfish and killed them by injecting them with a toxin. It’s known as the one-shot method and although it’s an effective way of killing the starfish it’s slow and hasn’t kept up with the most recent outbreak, which is presently wreaking havoc on parts of the GBR. Dr Matthew Dunbabin and Dr Feras Dayoub from the Queensland University of Technology have taken what seems like a sci-fi approach to the problem and built an independent starfish-killer that cruises the sea floor, scanning for starfish.
Known as the COTSbot, it’s a submarine-like robot that patrols about a metre off the seafloor. When it recognises a starfish – which it does through a state-of-the-art image recognition system – a target comes up on its screen, an injector arm shoots out and it injects the starfish with toxin.
But this is just one part of a multi-pronged assault on COTS. Dr Peter Thomas-Hall, a chemist and technical officer at the Australian Institute of Marine Science in Queensland, is trying a different approach; enlisting the help of a natural predator of COTS – the triton trumpet shell. “Not only does the triton trumpet shell eat the COTS, the COTS are petrified of the triton,” Dr Thomas-Hall explains. “As soon as the COTS smells a triton, they start running away.”
The triton trumpet shell was heavily fished on the GBR right up until the 1970s and these carnivorous molluscs are now rare. Using the few specimens he’s been able to locate, Dr Thomas-Hall is trying to identify what it is that the triton produces that seems to so effectively repel the starfish. Once he’s worked that out, he’ll then focus on chemically synthesising it in a way that researchers will be able to use it to reduce COTS’ populations.
Part of his work is also focused on increasing production of the triton trumpet shell with the aim of re-building the species’ numbers on reefs where it once flourished.
Written by Lauren Smith – As Australian Geographic’s education editor, Lauren is doing her bit to save the world by writing about it. She spends all her free time in the sea.
- Scuba images supplied by Griffith University
- Matt Dunbabin and Feras Dayoub, COTSbot robot image supplied by QUT Marketing and Communcation/Erika Fish
- Triton Trumpet shell – provided by James St John
Originally published in Ultimate Careers magazine. Read the magazine and find your Ultimate Careers here.