People and ecosystems

Understanding of the links between coral reef ecosystems, the goods and services they provide to people, and the wellbeing of human societies.


Ecosystem dynamics: past, present and future

Examining the multi-scale dynamics of reefs, from population dynamics to macroevolution


Responding to a changing world

Advancing the fundamental understanding of the key processes underpinning reef resilience.

Coral Bleaching

Coral Bleaching

Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au

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An innovative new assessment process shows the iconic Shark Bay World Heritage property in Western Australia is highly vulnerable to the impacts of climate change.

Associate Professor Scott Heron and Jon Day, both from the ARC Centre of Excellence at James Cook University (Coral CoE at JCU) developed the Climate Vulnerability Index (CVI) process to identify the environmental and socioeconomic vulnerability of World Heritage properties.

The CVI assessment indicated that the 23,000-square-kilometre Shark Bay property, on the westernmost point of the Australian continent, is at great risk.

“Shark Bay has High Vulnerability to potential impacts of three key climate stressors – Air Temperature Change, Storm Intensity and Frequency, and Extreme Marine Heat Events – by 2050, with a low capacity for the system to adapt to climate change,” Dr Heron said.

The assessment also considered the economic dependence of key business types on the area, the local population’s connection with the area, and the capacity of the community to adapt to climate change.

Chair of the Shark Bay World Heritage Advisory Committee Phil Scott said around 100,000 tourists visit the area each year to see dolphins, turtles, dugongs and the world’s most extensive population of stromatolites that date back billions of years.

“Commercial and recreational fishing are also extremely important for the local and state economy, so this assessment helps us to better understand just how vulnerable Shark Bay is,” Mr Scott said.

The final report was produced by the Shark Bay World Heritage Advisory Committee and the Western Australian Marine Science Institution (WAMSI) in collaboration with Coral CoE at JCU.

WAMSI Research Director Dr Jenny Shaw said, “The CVI process showed the effects of climate change will have a high degree of impact on the Shark Bay community both socially and economically.”

Shark Bay is one of Australia’s 20 properties on the World Heritage List, along with natural and cultural icons such as Kakadu, the Great Barrier Reef and the Sydney Opera House.

Shark Bay, or Gatharragudu (two-waters), is one of only four marine properties in the world that meets all four natural criteria for World Heritage listing.

Local experts, and representatives from the community, management agencies and academic institutions contributed to two workshops in Western Australia through the CVI process (in Denham, September 2018 and Perth, June 2019).

The CVI has also been applied in international World Heritage properties including a cultural site in the Orkney Islands, Scotland; and the Wadden Sea, a tri-national natural property (Germany, Netherlands and Denmark).

The Shark Bay CVI report is available at: http://www.wamsi.org.au/cvi-shark-bay


Dr Scott Heron – Associate Professor in Physics, James Cook University Townsville 0404 893 420

Phil Scott – Chair, Shark Bay World Heritage Advisory Committee 0418 954 467

Dr Jenny Shaw – Research Director, WAMSI 0401 121 975

Aleta Johnston – Communications Manager, WAMSI 0431 514 677








New research on the Great Barrier Reef associates severe coral loss with substantial increases in the size of large, long-living herbivorous fish. However, the ecosystem is also left vulnerable to crashing.

In research published in the British Ecological Society journal Functional Ecology, an international team of researchers compared reef surveys from 2003-2004 and 2018. They found severe coral loss—up to 83% in some areas—was associated with increases in fish biomass, productivity and consumed biomass. This means the reef currently has more energy stored in the form of fish weight, is able produce more fish weight, and these fish are being consumed by predators.

Lead author Renato Morais, a PhD candidate from the ARC Centre of Excellence for Coral Reef Studies at James Cook University, said “It’s as if the herbivorous fish community has been scaled up, with larger fish growing and providing more food for predators when they die.”

However, he warns this comes at a cost.

Superficially, the presence of bigger fish after a coral reef collapse suggests a stable population. But the researchers warn that reduced turnover, or recycling of biomass, means this feature might not last long.

“The fish have not multiplied,” Mr Morais said. “Instead, there are more bigger fish and less smaller ones.”

“This suggests that many of these long-living herbivorous fishes, such as surgeon fish which can live up to 40 years, could have been there before the corals died, only growing bigger. Eventually, these older fish will die and, if not replaced by young ones, productivity could collapse.”

The increased growth of large fish like surgeonfish, parrotfish and rabbitfish is likely to have been made possible by the accessibility and quality of algal turf, the preferred food of these herbivores. These algal ‘lawns’ grow abundantly over the skeletons of dead coral. A recovery of the coral could result in a reduction in this food source and collapse of these herbivores.

Erosion of dead coral structures and subsequent loss of refuges for fish could also cause a population crash. Although the researchers did observe a decline in coral structure in the reef area studied, it is possible that it had not reached a level where fish biomass would start to decline.

Between 2014 and 2017 the reefs around Lizard Island, where the research took place, were subjected to two back-to-back mass bleaching events and two severe cyclones that decimated the coral populations. Combined, these events led to an 80 percent decline in coral cover throughout the area.

Previous research has mainly taken a static look at the impacts of coral loss on fish. But in this study the researchers looked at the cumulative effects of coral mortality over time using metrics often absent from coral reef studies: fish growth, mortality and energy turnover.

The researchers are now looking to follow any new energetic shifts.

“Will there be a recovery of corals? Or will this degraded state be maintained?” Mr Morais said.

“Then, will these large and old herbivorous fishes be replaced by younger ones?”

“There are many aspects in this story to be investigated.”


Morais R, Depczynski M, Fulton C, Marnane M, Narvaez P, Huertas V, Brandl S, Bellwood D. (2020). Functional Ecology. ‘Severe coral loss shifts energetic dynamics on a coral reef’. DOI: 10.1111/1365-2435.13568


Renato Morais
E: renato.morais@my.jcu.edu.au

Davy Falkner
Media Relations Officer, British Ecological Society
E: Davy@britishecologicalsociety.org

Though coral reefs are in sharp decline across the world, scientists say some reefs can still thrive with plentiful fish stocks, high fish biodiversity, and well-preserved ecosystem functions.

An international team, led by Professor Josh Cinner from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU), assessed around 1,800 tropical reefs from 41 countries across the globe.

“Only five percent of the reefs were simultaneously able to meet the combined goals of providing enough fishing stocks, maintaining biodiversity and a working ecosystem,” Prof Cinner said.

“These are like the Hollywood A-listers of coral reefs. They have it all, but they’re also rare and live in exclusive areas—remote locations with little human pressure. Our study shows how to help other coral reefs get on that A-list.”

The research team assessed if no-fishing marine reserves and other fisheries restrictions helped reefs to meet multiple goals. The study found that implementing such local efforts helped, “but only if the management efforts are in the right locations,” Prof Cinner said.

“It’s all about location, location, location,” he said. “Marine reserves placed in areas with low human pressures had the best results for helping reefs get on the A-list.”

“We also had a B-list of reefs, which met all the goals, but to a lesser degree. Reserves in areas with intermediate human pressure made the biggest difference to getting reefs on our B-list. Quite simply, they occurred in less exclusive locations than our A-listers.”

However, marine reserves made little difference in areas where the environment was so severely degraded that only wider seascape conservation could help.

Co-author Jessica Zamborain-Mason, a Coral CoE and JCU PhD candidate, says coral reefs worldwide are facing intense degradation due to numerous anthropogenic drivers, such as overfishing, pollution, and climate change.

“There is an increasing need to manage coral reefs to meet multiple goals simultaneously,” she said.

“Our findings provide guidance on where to strategically place local management to achieve the greatest benefits.”

Co-author Professor Nick Graham from Lancaster University says the study uses data to show what works.

“Coral reef science and management is often focussed on meeting just a single goal,” Prof Graham said.

“Managing for just one goal at a time is common, but what if you want it all? The multiple goals of biodiversity, fisheries and functioning ecosystems are often required at any given location, yet the science to understand when and how this can be achieved has been lacking.”

“We looked at the fish communities, not the coral communities, and these are affected by different drivers—overfishing really drives the former and climate change the latter.”

“The study not only has important implications for the placement of new marine reserves, but is also relevant to future socioeconomic changes, such as how infrastructure development and population growth may impact the efficacy of reef conservation,” Prof Cinner said.

“We show where managers will be able to maximise multiple goals, and likewise, where they will be wasting their time.”

The study concludes that, while international action on climate change is crucial for ensuring a future for coral-dominated reefs, effective management is also critical to sustaining reefs—and the millions of people whose livelihoods depend on them.


 Cinner J, Zamborain-Mason J, Gurney G, Graham N, MacNeil A, Hoey A, Mora C, Villéger S, Maire E, McClanahan T, Maina J, Kittinger J, Hicks C, D’agata S, Huchery C, Barnes M, Feary D, Williams I, Kulbicki M, Vigliola L, Wantiez L, Edgar G, Stuart-Smith R, Sandin S, Green A, Beger M, Friedlander A, Wilson S, Brokovich E, Brooks A, Cruz-Motta J, Booth D, Chabanet P, Tupper M, Ferse S, Sumaila R, Hardt M, Mouillot D. (2020). Science. ‘Meeting fisheries, ecosystem function, and biodiversity goals in a human-dominated world.’ DOI: 10.1126/science.aax9412


Photos and videos are available for media use here. Please note these are for single-use with this story only, not for any other story. They must be credited as stated and are not to be archived.


Prof Josh Cinner
Phone: + 61 417 714 138
Email: joshua.cinner@jcu.edu.au

Jessica Zamborain-Mason
Email: jessica.zamborainmason@my.jcu.edu.au

Prof Nick Graham
Phone: +44 7479 4389 14
Email: nick.graham@lancaster.ac.uk


Melissa Lyne
Media Manager, ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0) 415 514 328
Email: melissa.lyne@jcu.edu.au

Australia’s iconic Great Barrier Reef is experiencing its third coral bleaching event in just five years. The 2020 bleaching is severe, and more widespread than earlier events.

“We surveyed 1,036 reefs from the air during the last two weeks in March, to measure the extent and severity of coral bleaching throughout the Barrier Reef region,” said Professor Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

“For the first time, severe bleaching has struck all three regions of the Great Barrier Reef – the northern, central and now large parts of the southern sectors,” Prof Hughes said.

Coral bleaching at regional scales is caused by thermal stress due to spikes in sea temperatures during unusually hot summers. The first recorded mass bleaching event along the Great Barrier Reef occurred in 1998, then the hottest year on record. Four more mass bleaching events have occurred since—as more temperature records were broken—in 2002, 2016, 2017, and now in 2020.

This year, February had the highest monthly temperatures ever recorded on the Great Barrier Reef since the Bureau of Meteorology’s sea surface temperature records began in 1900.

“Bleaching isn’t necessarily fatal, and it affects some species more than others,” said Professor Morgan Pratchett, also from Coral CoE at JCU, who led underwater surveys to assess the bleaching.

“A pale or lightly bleached coral typically regains its colour within a few weeks or months and survives,” he said.

However, many corals die when bleaching is severe. In 2016, more than half of the shallow-water corals died on the northern region of the Great Barrier Reef.

“We will go back underwater later this year to assess the losses of corals from this most recent event,” Prof Pratchett said.

“The north was the worst affected region in 2016, followed by the central region in 2017. In 2020, the cumulative footprint of bleaching has expanded further to include the south.”

The distinctive footprint of each bleaching event closely matches the location of hotter and cooler conditions in different years.

“As summers grow hotter and hotter, we no longer need an El Niño event to trigger mass bleaching at the scale of the Great Barrier Reef,” Prof Hughes said.

“Of the five events we have seen so far, only 1998 and 2016 occurred during El Niño conditions.”

The gap between recurrent bleaching events is shrinking, hindering a full recovery.

“We have already seen the first example of back-to-back bleaching—in the consecutive summers of 2016 and 2017,” Prof Hughes said.

After five bleaching events, the number of reefs that have so far escaped severe bleaching continues to dwindle. Those reefs are located offshore, in the far north, and in remote parts of the south.


A selection of photos and videos relating to the surveys are available for media use here. Please note these are for single use only, for this media release, and not for any other story. They must be credited and are not to be archived.

A video summary is available via The Australian Academy of Science here.


Prof Terry Hughes (AEST)
Phone: +61 (0)400 720 164
Email: terry.hughes@jcu.edu.au

Prof Morgan Pratchett (AEST)
Phone: + 61 (0)7 4781 5747
Mobile: +61 (0)488 112 295
Email: morgan.pratchett@jcu.edu.au


Melissa Lyne (AEST)
Media Manager, ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0) 415 514 328
Email: melissa.lyne@jcu.edu.au

Stunning ‘gardens’ of deep-sea corals have been discovered in the Bremer Canyon Marine Park by Australian and international scientists during an oceanographic expedition aboard Schmidt Ocean Institute’s R/V Falkor.

FREMANTLE – Bremer Canyon Marine Park is already known as a biodiversity hotspot for marine species such as whales and dolphins, however, a recent expedition focused on the deep sea has now revealed rich and diverse ecosystems inhabiting the cold waters deep within the canyon. Led by researchers from the University of Western Australia (UWA), including from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE), these discoveries were only made possible by the philanthropic Schmidt Ocean Institute’s (SOI) deep-sea remotely operated vehicle, SuBastian, which is capable of sampling depths to 4,500 meters.

The team strategically collected deep-sea corals, associated fauna, seawater, and geological samples from the abyssal depths (~4,000 meters) to the continental shelf (~200 meters). “We have already made a number of remarkable discoveries from the Bremer Canyon” said Dr Julie Trotter, the Chief Scientist from UWA who led the expedition. “The vertical cliffs and ridges support a stunning array of deep-sea corals that often host a range of organisms and form numerous mini-ecosystems”.

These new discoveries are being integrated into a comprehensive package of biological, geological, and bathymetric data. Such rare records of these deep-sea habitats are a new and very important contribution to the Marine Parks, which will help managers as well as the broader community to better understand and protect these previously unknown ecosystems.

The deeper waters in the three oceans that surround Australia, including the world’s largest barrier reef and submarine canyons, are largely unexplored. The expedition explored the Bremer, Leeuwin and Perth canyons, all of which have extensive fossil coral deposits, with the Leeuwin especially notable for a massive pedestal-like coral graveyard.

“This has global implications given these waters originate from around Antarctica which feed all of the major oceans and regulate our climate system” said Professor Malcolm McCulloch from Coral CoE at UWA.

The country has only one oceanographic vessel available for scientific research and no supporting deep sea underwater robots, which makes this expedition so important and rare.

Facing the Southern Ocean, the Bremer Canyon provides important information on the recent and past histories of climate change and ocean conditions in this region, as well as global scale events. Because the Southern Ocean completely encircles Antarctica, it is the main driver of the global climate engine and regulates the supply of heat and nutrient-rich waters to the major oceans. “A particular species of solitary cup coral was found during the expedition. This is significant because we are working on the same coral in the Ross Sea on the Antarctic shelf, in much colder waters”, said collaborator and co-Chief Scientist Dr Paolo Montagna from the Institute of Polar Sciences in Italy. “This is an important connection between disparate sites across the Southern Ocean, which helps us trace changes in water masses forming around Antarctica and dispersing northward into the Indian and other oceans”.

You can view some of the amazing species discoveries in 4K here Additional high resolution images and Broll can be found here. You can watch the wrap-up video for the expedition here. You can learn more at https://schmidtocean.org/cruise/coralandcanyonadventure/.


Simone Hewett (UWA)
E: simone.hewett@uwa.edu.au

Dr. Carlie Wiener (Schmidt Ocean Institute)
E: cwiener@schmidtocean.org

Scientists using sophisticated genetic analysis techniques have found that some fish are better than others at coping with heatwaves.

A world-first study tracked how wild fish populations responded to a severe marine heatwave, focussing on the 2016 event that killed a third of the Great Barrier Reef corals.

“Our study shows that reef fishes are directly affected by heatwaves, but their responses vary greatly between species,” said co-author Dr Jodie Rummer, Associate Professor from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU).

Dr Rummer was part of an international team that tracked changes in the expression of thousands of different genes in five species of coral reef fishes collected at different time points before, during, and after the 2016 heatwave.

“Changes in gene expression can tell us how an animal responds physiologically to an environmental shock, such as a heatwave,” said one of the co-lead authors, Dr Celia Schunter from the University of Hong Kong.

Regulating gene expression is critical to an organism’s performance and survival.

It is analysed by tracking RNA, which is responsible for converting the genetic information in DNA into a format used to build proteins.

Essentially, RNA controls when proteins are made and in what amount, dictating how cells will function. This can give us clues of how an organism is responding.

The scientists identified species-specific responses to the heightened temperatures, with some fish struggling more than others.

“Spiny damselfish responded to the warmer conditions with changes in the expression of thousands of genes, suggesting it is particularly sensitive to heatwaves,” said co-lead author Dr Moisés Bernal, Assistant Professor at Auburn University. “Other species appear to be more tolerant, with fewer changes in gene expression.”

The results also suggest that fish populations are influenced by both the intensity of a heatwave and how long it lasts.

“Marine heatwaves are becoming more frequent, more severe, and are further exacerbated by climate change,” Dr Rummer said.

“We found the physiological mechanisms the fish used to cope with the warmer waters changed as the heatwave progressed,” she said.

The study provides a possible approach for predicting which fish species are most at risk under repeated heatwave conditions, said co-author Professor Timothy Ravasi, from the Marine Climate Change Unit at the Okinawa Institute of Science and Technology Graduate University (OIST).

“Our results are important because they show that when scientists do experiments, or target commercial species, they cannot generalise based on geography or from one or two species that have been studied in the laboratory,” he said.

“This has ramifications for policy makers and for the fishing industry, because not all species will be equally affected. We need to screen a large number of species to predict which will be sensitive and which will be more tolerant to warming waters and heatwaves.”

“Over time, the fish may adapt to rising temperatures, or even migrate to cooler waters,” Dr Rummer said.

“But these heatwaves are happening now, and it’s necessary to understand and consider the immediate consequences.”

PAPER: Bernal M, Schunter C, Lehmann R, Lightfoot D, Allan B, Veilleux H, Rummer J, Munday P, Ravasi T. (2019). Science Advances. ‘Species-specific molecular responses of wild coral reef fishes during a marine heatwave.’ DOI: 10.1126/sciadv.aay3423

A selection of images for media stories can be used only with credit to the photographer as stated in the image file name.


Associate Prof Jodie Rummer (AEST)
P: + 61 (0)439 166 171
E: jodie.rummer@jcu.edu.au

Prof Timothy Ravasi (JST)
P: +81 8064 950 157
E: timothy.ravasi@oist.jp

Dr Celia Schunter (HKT)
P: +85 297 474 723
E: schunter@hku.hk


Melissa Lyne (AEDT)
Media Manager, Coral CoE
E: melissa.lyne@jcu.edu.au

Researchers have identified key factors that increase the risk of diseases that threaten coral reefs – and their work could one day be used to predict and manage future outbreaks.

“Reducing disease risk during non-outbreak periods is more achievable than trying to stop a disease outbreak once it has begun,” said co-author Scott Heron, Associate Professor at James Cook University (JCU).

“Healthy coral reefs are vital to reef tourism, and disease outbreaks can wreak havoc on coral ecosystems.

“Rather than studying an active outbreak, we focused on understanding the biological, environmental, human-related, and physical drivers of disease.”

The research shows that growth anomalies – ‘coral cancers’ – are more common in reefs with fewer fish, limited water motion, and in areas adjacent to watersheds with high fertiliser and pesticide runoff.  

In contrast, infectious disease that cause coral tissue loss are associated with wave exposu­re, stream exposure, depth, and fewer occurrences of warm ocean temperature. 

Common to both disease types is that larger, older colonies are more susceptible to disease than smaller, younger colonies.

“These results significantly boost our ability to predict future outbreaks based on environmental conditions,” said lead author Dr Jamie Caldwell, a visiting scientist at the ARC Centre of Excellence for Coral Reef Studies at JCU and a postdoctoral fellow at the University of Hawai‘i.

They could also enable us to manage human-related disease drivers to evade outbreaks altogether.

“This information could be used to improve coastal development plans, by considering the downstream effects of different land-use types on corals.”

Because some diseases are rare and hard to observe, it has been difficult in the past to identify which disease drivers were most impactful.

To investigate what drives disease on coral reefs, the researchers used a statistical technique typically used to study human diseases, pairing observations from diseased and healthy corals.

“The methods we used in this study highlight the power of the experimental design common in epidemiology but rarely, if ever, used in ecological studies,” said Megan Donahue, co-author of the study and associate researcher at the University of Hawai‘i.

The team is now using the relationships they identified to forecast coral disease outbreak risk across the Indo-Pacific.

This is part of a NASA-funded project to develop seasonal and near real-time forecasts of coral disease outbreak risk for all US-affiliated Pacific Islands and the Great Barrier Reef. The forecasts will be publicly available through NOAA Coral Reef Watch, one of the project partners.

Caldwell J, Aeby G, Heron S, Donahue M. (2020). Nature. ‘Case-control design identifies ecological drivers of endemic coral diseases’. DOI: https://doi.org/10.1101/662320


Dr Jamie Caldwell
E: jsziklay@hawaii.edu

Dr Scott Heron
P: +61 (0)7 4781 4199
M: +61 (0)404 893 420
E: scott.heron@jcu.edu.au

Prof Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, was awarded with the BBVA Foundation Frontiers of Knowledge Award in Ecology and Conservation Biology overnight.

Prof Hughes was recognised for his efforts to describe and draw attention to the global loss of fragile coral reef ecosystems as a result of widespread warming, acidification, pollution and disease.

He shares the award with two other marine biologists who have made seminal contributions to our understanding of the world’s oceans, whilst applying this knowledge to protect and conserve marine biodiversity and oceanic ecosystem services in a rapidly changing world.

Prof Hughes’ work has led the implementation of measures to conserve and restore the incomparable resources of coral reefs.

“Coral reefs are not just beautiful places where wealthy people can enjoy a holiday,” Prof Hughes said.

“We should not forget that 400 million people depend on them for their livelihoods and their food security.”

Prof Hughes’ research has focused on the coral bleaching caused by climate change. Bleaching occurs when reefs are exposed to stressors such as warming ocean waters and, if it is severe and prolonged enough, many of the corals will die. It will then take at least a decade to replace them.

His studies show that mass coral bleaching was unknown until the 1980s but since then repeated bleaching episodes have become something of a norm as global temperatures continue to rise.

The Great Barrier Reef has suffered four bleaching events since 1998, two in the consecutive years of 2016 and 2017, causing damage on an unmatched scale. Last year, a paper by Prof Hughes showed that coral larvae births on the Great Barrier Reef slumped by 89% with respect to the historical average, due to the unprecedented dying-off of adult corals after the back-to-back bleaching.

“Although overfishing and pollution also cause deterioration, the greatest threat facing reefs today is without doubt climate change,” affirms Hughes. “And this is not a risk that might affect them in future, but something that is harming them right now.”

Prof Hughes works alongside economists, political scientists and other researchers in the social sciences to develop strategies to combat the reef deterioration being driven by climate change.

“It is still not too late. The window of opportunity to save reefs remains open, but it is closing rapidly, so we have to act now to reduce pollutant emissions and stop wasting time.”



Prof Terry Hughes 
Phone: +61 (0)400 720 164
Email: terry.hughes@jcu.edu.au


The BBVA Foundation Frontiers of Knowledge Awards, established in 2008, recognise and reward contributions of singular impact in diverse fields of science, technology, social sciences and the humanities that have demonstrably expanded the frontiers of the known world, opening up new paradigms and knowledge fields. Their eight categories are reflective of the knowledge map of the 21st century, encompassing basic research in Physics, Chemistry and Mathematics, Biology and Biomedicine, Information and Communication Technologies, Humanities and Social Sciences, Economics, Finance and Management, Ecology and Conservation Biology, Climate Change, and, within the arts, the supremely creative realm of music.

A series of papers published by Prof Hughes on coral reefs and the threat of climate change:



Scientists discovered dozens of new coral species on a recent voyage along the length of the Great Barrier Reef.

A team of scientists completed a 21-day trip from the Capricorn Bunkers off Gladstone to Thursday Island in the Torres Strait late last year.

“On almost every dive we were finding species that aren’t in the books,” said Professor Andrew Baird from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU).

Scientists from Queensland Museum (QM), University of Technology Sydney (UTS) and the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia were also part of the expedition.

Prof Baird said the discoveries are timely as recent molecular advances reveal that much of the existing classification of corals is deeply flawed.

“One hard coral species, Acropora hyacinthus, was previously thought to be found on almost every reef crest along the length of the reef,” Prof Baird said.

But the recent molecular advances plus a closer look at the morphology, or shape of the coral, has overturned this assumption.

“What we once thought was a single species is potentially five different species—some with a very limited geographical range,” Prof Baird said.

The team also found a number of species not previously seen on the reef.

“The new species we found means that the biodiversity of some groups is up to three times higher than we had thought,” said Dr Francesca Benzoni, from KAUST.

JCU PhD student Jeremy Horowitz was on the voyage. He said much of what they found was new.

“Despite the economic and ecological importance of black corals this is the first survey of this group on the reef. It’s amazing how much remains unknown and how much more work needs to be done,” Mr Horowitz said.

The end of the voyage is just the beginning of a lot of hard work to formally describe this treasure trove.

“The volume of new material is overwhelming,” Prof Baird said.

“We need more trained taxonomists—biologists who can group organisms into categories—and more funds to reassess the taxonomy of common groups found on the reef, including hard, soft and black corals.”

“Australia is the custodian of the world’s largest coral reef system and as a World Heritage-listed site it is the nation’s obligation to manage it well.”

“Understanding the diversity of species on the reef underpins virtually every area of research and conservation,” Prof Baird said.

“It is vital to ensure we have a robust understanding of species diversity and their distributions, but taxonomy isn’t currently a research priority. This has to change.”

“You can’t manage the Great Barrier Reef if you don’t know how many species you have, how common they are, or where they are found.”

A selection of images for media stories can be used with credit to the photographer named in the file.



Prof Andrew Baird (AEST)
P: +61 (0)7 4781 4857
M: +61 (0)400 289 770
E: andrew.baird@jcu.edu.au

Jeremy Horowitz (AEST)
P: + 61 (0) 473 870 683
E: jeremy.horowitz@my.jcu.edu.au


Melissa Lyne (AEDT)
Media Manager, Coral CoE
M: +61 (0)415 514 328
E: melissa.lyne@jcu.edu.au

Scientists say a type of algae crucial to the survival of coral reefs may be able to resist the impacts of ocean acidification caused by climate change.

In a world-first, the team—including researchers from the ARC Centre of Excellence for Coral Reef Studies at The University of Western Australia (Coral CoE at UWA)—found that coralline algae are able to build tolerance to ocean acidification over multiple generations.

“Coralline algae go through a natural process of calcification, where they build a crustose-like calcium carbonate skeleton,” said lead author Dr Christopher Cornwall.

“Skeletons like this provide structure, allowing them to grow, as well as providing a substrate for other organisms such as corals to grow upon,” he said.

“We show, for the first time, that while growth of these skeletons is initially susceptible to the effects of ocean acidification caused by increased CO2, over multiple generations they develop resistance.”

Coralline algae are vital not only to the survival of coral reefs but many ocean species.

“Crustose coralline algae bind coral reefs together,” said Professor McCulloch, Coral CoE Deputy Director, who led the research group. “Without it, coral reefs as we know them today wouldn’t exist,” he said.

“These species limit erosion in reefs that are often made up of mainly coral fragments, act as a nursery for many marine species, and are the main player in temperate reef formation along the Australian and New Zealand coastlines.”

The experiments took more than 18 months to complete. On average, the algae took six generations of about six to eight weeks each to develop resistance to ocean acidification.

The findings of the study are important in understanding how longer-lived species, such as tropical corals, could respond over multiple generations to ocean acidification.

“Coralline algae are a useful model species to test hypotheses about adaptation or acclimation over time as they grow to maturity in six weeks as opposed to several years for many coral species,” Dr Cornwall said.

The next step is to test a wider range of coralline algae species.

“This research focused on tropical coralline algae species from northern Australia, so the next step is to study temperate species—like those in southern Australian and New Zealand waters—that grow a lot slower and may not acclimatise to climate change as quickly.”

Cornwall C, Comeau S, DeCarlo T, Larcombe E, Moore B, Giltrow K, Puerzer F, D’Alexis Q, McCulloch M. (2020). Nature Climate Change. ‘A coralline alga gains tolerance to ocean acidification over multiple generations of exposure’. DOI: 10.1038/s41558-019-0681-8.


Dr Chris Cornwall (New Zealand)
P: +61 04 463 5720
E: Christopher.cornwall@vuw.ac.nz

Prof Malcolm McCulloch (Perth, WA)
E: Malcolm.McCulloch@uwa.edu.au


Director of the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) Professor Terry Hughes was recently awarded an honorary Doctor in Science from Trinity College in Dublin, Ireland.

Prof Hughes is a Trinity graduate recognised across the globe for his research on coral bleaching. He is founder and Director of Coral CoE, headquartered at James Cook University. The Centre is widely recognised as the world’s foremost authority on coral reef science and a hub for world-leading research.

In addition to his marine ecology and evolution research, Prof Hughes is passionate about social-ecological interactions—in particular, climate change. Prof Hughes is dubbed the “Reef Sentinel” by the prestigious journal Nature.

At the awards ceremony on 6 December 2019, the Public Orator stressed the societal impact of his work:

“His research of a lifetime speaks loud and clear: coral reefs were born after the last glacial period, and in the mere space of a century we have systematically destroyed Nature’s work of ten thousand years. His line of action is resolute. He is not afraid of challenging authorities on their ‘scientific illiteracy’ and irresponsible pursuit of economic interests, and he has braved difficulties and hostility.”

Scientists say coral reefs on a tiny island in the South Pacific have shown incredible resilience and recovery from a recent but very severe disturbance: a volcanic eruption that created a new island.

Hunga Tonga – Hunga Ha’apai was (until October this year) the newest island on Earth. It was a result of a massive 2015 volcanic eruption in the middle of the South Pacific that, over a period of two weeks, created a new island more than 200 metres high.

Lead author Patrick Smallhorn-West is a PhD candidate at the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU) and a National Geographic Explorer. He and a team of scientists surveyed the effects of the eruption on the coral reefs around the island.

“Coral reefs are increasingly compromised by multiple stressors, even in the most remote locations,” Mr Smallhorn-West said.

“While severe disturbances, such as volcanic eruptions, can annihilate entire reef ecosystems, they can also provide unique opportunities to examine ecosystem resilience and recovery.”

“We wanted to see what happens to a coral reef when it experiences the worst of the worst. Not much is as bad as a massive volcanic eruption, short of things such as nuclear testing at places like Bikini Atoll. This event allowed us to document not only how reefs were affected by a massive disturbance, but also how they recovered.”

Co-author Dr Tom Bridge, also from Coral CoE at JCU and the Queensland Museum, says the reefs were surveyed not only to examine the effects of the eruption, but also to understand how new reefs began forming on the new habitat.

The team also included researchers from the NASA Goddard Space Institute who helped piece together the environmental conditions that were present at the time of the eruption.

Dr Jim Garvin, chief scientist from the NASA Goddard Space Flight Centre, explained that large ash clouds from the eruption collapsed into a ground-hugging flow that released massive sediment plumes into the ocean. This was confirmed by scans of rock samples collected from the island and by satellite imagery. The latter showed high sea temperatures around the eruption.

“Some parts of the reef were totally annihilated by the blast,” Dr Bridge said. “They were completely destroyed with huge chunks of reef turned over—you could still see dead coral species in-situ but covered in black sediment, and often upside down.”

“However, one section of the island—shielded by a pre-existing island and prevailing weather conditions—still supported diverse coral reefs.”

“Here we found high cover and diversity of corals, including many large mature coral colonies. This was a well-established reef system that had clearly persisted through the eruption largely unaffected.”

The small area that survived appears to have provided a source of larvae to repopulate reefs around the rest of the island.

“This is evidenced by the large number of juvenile corals that covered the substrate at many locations,” Mr Smallhorn-West said.

“Some of the uplifted land had also made brand new habitat for reef formation, and there was very high recruitment of specific fast-growing species in these areas—all very young and beginning to lay the foundations of a new reef.

“Fish showed a similar pattern, with all the large fish persisting at the one site, and plenty of juveniles now living in the areas that were either annihilated or uplifted by the blast.”

The study suggests that the remote location and lack of additional stressors, such as human activity, have likely contributed to the resilience of these reefs.

“In the absence of chronic man-made stressors such as poor water quality and overfishing, coral reefs can be resilient to one of the largest physical disturbances on Earth,” Mr Smallhorn-West said.

Dr Bridge said natural disasters like these were once the largest catastrophes on Earth, and showed that reefs can recover from severe acute disturbances. However, the key to recovery was the persistence of adult corals and fish in the small area unaffected by the blast.

“Reefs are facing disturbance events at unprecedented spatial scales; for example, the bleaching event on the Great Barrier Reef in 2016 affected huge areas with few refuges available. Therefore, recovery of the hardest hit areas will take decades if it occurs at all,” Dr Bridge said.

“Small and protected populations can be crucial for recovery from severe disturbances in marine as well as terrestrial ecosystems—but recovery is likely to decline as the frequency and severity of man-made disturbances continues to increase.”


Smallhorn-West P, Garvin J, Slayback D, DeCarlo T, Gordon S, Fitzgerald S, Halafihi T, Jones G, Bridge T (2019). Coral Reefs. ‘Coral reef annihilation, persistence and recovery at Earth’s youngest volcanic island’. DOI: 10.1007/s00338-019-01868-8

IMAGES: Images are available for media use with this story only and with credit as marked to the photographer.

Mr Patrick Smallhorn-West (New Zealand)
P: +64 211 329 037
E: patrick.smallhornwest@my.jcu.edu.au

Dr Tom Bridge (Townsville, Australia)
P: +61 414 219 020
E: thomas.bridge@jcu.edu.au

Melissa Lyne (Media Manager, Coral CoE at JCU)
P: +61 415 514 328
E: melissa.lyne@jcu.edu.au

A flotilla of Vietnamese fishing boats with crews suffering in harsh conditions is stripping Pacific coral reefs of seafood as the poaching escalates to become an international human rights and security issue.

Dr Andrew Song, joint ARC Centre of Excellence for Coral Reef Studies and WorldFish research fellow at James Cook University, has produced the first analysis of international attempts to manage Vietnam’s ‘blue boat’ fleet – small fishing vessels, commonly painted blue, that travel thousands of kilometres to fish illegally in Pacific waters.

Dr Song said the reasons are allegedly economic but also geopolitical as the intensified Chinese presence/interference has squeezed them out of their traditional fishing grounds in the South China Sea.

“The boats are between 10–15 metres in length and carry up to 17 people. The crews reportedly have no contract of employment and no insurance and are frequently abandoned after accidents or arrests. They travel more than 7000km around the Pacific and stay up to three months at sea, Dr Song said.

He said their main targets are high-value species of sea cucumber and giant clam found on many Pacific Island coral reefs.

Dr Song estimates the cost of the boats to be around AU$15,000–35,000 each, while processed tropical sea cucumber species can retail at AU$150–300 per kilogram in Hong Kong and Chinese markets. He said there is suspicion that the blue boats were meeting large ‘mother-ships’ in the open ocean to offload their catch and take on supplies. This is yet to be confirmed.

“The collection of sea cucumber in foreign waters is apparently easier and less dangerous, since sea cucumber is still found six to seven metres deep on Pacific island reefs, whereas people have to dive 60 metres, even 80 metres in waters near Vietnam,” Dr Song said.

“The poaching also directly endangers the livelihood security of coastal communities and a significant source of national export revenue in the Pacific. Sea cucumber fisheries are considered to be the second-most valuable export fishery for Pacific Island countries,” he said.

Dr Song said Pacific Island countries face limitations in securing the resources to patrol such a vast area, and the wooden boats are difficult to find, even with radar, and harder to trace administratively than a large ship. He said the problem is intensifying.

“In Australian waters, the latest reported figures show the number of foreign fishing boats caught operating illegally has increased from six in 2014 up to 20 in 2016 with most originating from Vietnam and Indonesia,” he said.

Dr Song said the poachers can be seen as a new kind of security threat—endangering the lives of Vietnamese fishers, endangering food security for Pacific Island nations, and putting Pacific Island economies, coastal communities and the workers on the boats at risk.

“By their dispersed and random nature, blue boats are bolstering the need for closer cooperation not only among governments and agencies but also among coastal communities and individual fishers.

“Given the large unpredictability associated with these boats, it will need a co-ordinated and networked response,” he said.

Song A, Hoang V, Cohen P, Aqorau T, Morrison T. (2019). Asia Pacific Viewpoint. ‘‘Blue boats’ and ‘reef robbers’: A new maritime security threat for the Asia Pacific?’. DOI: 10.1111/apv.12240

Dr Andrew Song (currently based in Sydney).
M: 0481 75 61 41
E: andrew.song@jcu.edu.au

In a study published today, scientists report that the long-term success of clownfish depends more on living in a good neighbourhood than it does on good genes.

The natural home of the clownfish is the anemone, but not all anemones are equal. Study co-author Professor Geoff Jones, from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU), says the reproductive success of the clownfish depends almost entirely on having a high-quality anemone home.

“For a clownfish, it’s not ‘who’ you are, but ‘where’ you are that matters for your future reproductive success,” Prof Jones said.

“In terms of their genes, clownfish are as good as they can be at finding a suitable habitat. The rest comes down to luck—of being in the right place at the right time.”

“The success of big families that extend over many generations is linked to high-quality habitats, not their shared genes.”

The quantitative genetic study comprises ten years of research on the coral reefs of Papua New Guinea. Family trees were established for the entire clownfish population at an island in Kimbe Bay, a well-known biodiversity hot spot. The team of scientists identified each fish individually and sampled its DNA to establish who was related to whom over five successive generations.

After constructing Kimbe Island’s clownfish family tree, the researchers were able to assess the ability of the population to persist and the genetic potential to adapt to increasingly rapid environmental change. Unfortunately, the potential is almost nil.

“There are no particular genetic variants that contribute more offspring to the next generation. The quality of the host anemone contributes most to the ability of the clownfish to renew its population,” Prof Jones said.

The scientists say that if high-quality anemones remain healthy, this will ensure the clownfish population can persist.

However, anemones, and coral reefs in general, are under direct threat from the impacts of climate change.

In increasingly warming waters, corals are more susceptible to bleaching. The process is the same for anemones — their symbiotic algae leave when under stress. If they stay away long enough then the anemone starves to death, killing the fish’s home at the same time.

The study is the first of its kind to evaluate the genetic capacity of a natural marine population to adapt to environmental change. This was otherwise largely the domain of evolutionary studies of species on land.

It is not surprising that intergenerational relationships in a marine population had yet to be sampled, according to co-author Dr Benoit Pujol, an evolutionary biologist from France’s National Centre of Scientific Research (CNRS).

“Working out who is related to whom in the marine environment is extremely challenging,” Dr Pujol said.

“Long-term genetic datasets for individuals within a marine population are incredibly rare. Until now, we just haven’t had the data required to answer this question.”

“But now that we have it, we find that Nemo is at the mercy of a habitat that is degrading more and more every year,” added co-author Dr Serge Planes, a Director of Research at France’s National Centre of Scientific Research (CNRS).

“To expect a clownfish to genetically adapt at a pace which would allow it to persist is unreasonable,” he said.

“Their future depends on our ability to maintain the quality of their habitat,” the authors conclude.

The international team was led by France’s CNRS (CRIOBE USR3278 PSL University Paris : EPHE-UPVD-CNRS) in collaboration with researchers from Australia (Coral CoE at JCU), the United States (WHOI), Saudi Arabia (KAUST) and Chile (Universidad Austral de Chile).


Salles O, Almany G, Berumen M, Jones G, Saenz-Agudelo P, Srinivasan M, Thorrold S, Pujol B, Planes S (2019). Ecology Letters. ‘Strong habitat and weak genetic effects shape the lifetime reproductive success in a wild clownfish population’: https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13428


Images are available for media use with this story only and with credit as marked to the photographer.

Prof Geoff Jones (Townsville, Australia)
E: geoffrey.jones@jcu.edu.au
P: +61 (0)4 35 06 52 96

Dr Benoit PUJOL (Perpignan, France)
E: benoit.pujol@univ-perp.fr
P: +33 (0)4 30 19 23 24

Melissa Lyne (Australia)
Coral CoE Media Manager
E: melissa.lyne@jcu.edu.au
P: +61 (0)4 15 51 43 28

A new study highlights how healthy mangroves can help some coral reef fish navigate the impacts of climate change.

Co-author Professor Peter Mumby, from the ARC Centre of Excellence at the University of Queensland (Coral CoE at UQ), said warming seas cause corals to bleach and reefs to lose their structural complexity—in the process also losing the hiding places that support thousands of fish.

“When a young fish arrives at a degraded reef it has nowhere to hide and is easily targeted by predators,” he said.

“Of course, predators experience the same problem when they’re young. The entire food web becomes unproductive and few fish survive.”

Despite the alarming trend, the team found mangroves provided a partial solution.

“We know some reef fish can use mangroves as an alternative nursery habitat to the reef,” Prof Mumby said.

“Mangroves provide a calm, safe environment with plenty of food and allow fish to grow larger before heading out to the reef as adults.”

The study compared and validated model predictions with field data from Belize.

Lead author Dr Alice Rogers, from the Victoria University of Wellington, said the results should inform reef fisheries management strategies protecting areas now and in the future.

“Mangrove nurseries essentially allow some fish to sidestep the challenges of early life on a degraded reef,” she said.

“Mangrove restoration can be important, but in places where that’s impossible future research might examine adapting structures to offer mangrove-like nursery functions.”

“This would be in environments that either do not support natural mangrove forests, or have too large a tidal range to provide stable nursery functions in coastal fringes.”

The study says while the results offer a glimmer of hope, this does not undermine the importance of healthy coral reef habitats—nor the impacts of their degradation and loss.

Prof Mumby said the protection and restoration of mangrove habitats should remain a priority.

“While we need to take every effort to prevent reef degradation, our study reveals that healthy mangrove forests can help buffer the effects of habitat loss on reef fisheries.”

“It’s critical that they remain a priority as part of the battle to mitigate climate change impacts on coral reefs.”

“Ultimately, we need to protect intact combinations of both mangroves and coral reefs,” Prof Mumby said.


Rogers A, Mumby P (2019). PLOS Biology. ‘Mangroves reduce the vulnerability of coral reef fisheries to habitat degradation’. DOI: 10.1371/journal.pbio.3000510

High-resolution images for this story are available via Dropbox.


Prof Peter Mumby
E: p.j.mumby@uq.edu.au
P: +61 (0)7 3365 1686

Dr Alice Rogers
E: alice.rogers@vuw.ac.nz


Melissa Lyne
Media Manager, Coral CoE
E: melissa.lyne@jcu.edu.au
P: + 61 (0)415 514 328

Scientists say a failure of national management means excessive amounts of harmful chemicals—many now banned in other countries such as the EU, USA and Canada—are damaging the nation’s waterways and the Great Barrier Reef.

The new study was led by Dr Jon Brodie from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU).

Dr Brodie says pesticides found at concentrations exceeding the nation’s own water quality guidelines have the potential to seriously damage aquatic plants and animals. Insecticides affect prawns in freshwater streams, and herbicides affect marine species such as seagrass.

“The notorious insecticide imidacloprid—now banned for its effects on bees across Europe, the USA and soon to be banned in Canada—is found in many freshwater streams and estuaries in the Great Barrier Reef and also Queensland more broadly,” Dr Brodie said.

“This can have a serious effect on aquatic life.”

The regulation and management of pesticides in Australia is a joint responsibility of the Australian and State governments.

“There is no evidence at the moment that imidacloprid may be banned or regulated more closely in Australia,” Dr Brodie said.

“The processes of the Australian Government regulator, the Australian Pesticide and Veterinary Medicine Authority (APVMA), have serious deficiencies and in many cases are seriously flawed,” he said.

However, Dr Brodie notes that the Queensland Government is taking action to reduce pesticide pollution through research, monitoring, risk assessments and application of better pesticide application methods.

Yet, only so much can be done at a local level.

“The APVMA are very slow to act on the copious evidence surrounding, for example, the continued use of a pesticide like imidacloprid.”

The highest concentrations of pesticides, often found above Australian guidelines, are found in freshwater bodies adjacent to, and downstream of, areas of intensive cropping. This is mainly sugarcane cultivation and horticulture.

Dr Brodie says Australia has the expertise and knowledge of pesticide management to take action and regulate.

“Though pesticide regulation and management in the Great Barrier Reef region has been unsuccessful, there is some hope that pesticide levels and risks to species and ecosystems can be reduced,” he said.


Brodie J, Landos M (2019). Estuarine, Coastal and Shelf Science. ‘Pesticides in Queensland and Great Barrier Reef waterways – potential impacts on aquatic ecosystems and the failure of national management’. DOI: 10.1016/j.ecss.2019.106447


Dr Jon Brodie
E: jon.brodie@jcu.edu.au
P: +61 (0)7 4781 6435


Melissa Lyne
Media Manager
E: melissa.lyne@jcu.edu.au
P: + 61 (0)415 514 328

As biodiversity loss continues at an alarming rate across the globe a new study identifies what is needed to tackle the root causes of the problems.

International sustainability policies set clear goals for protecting ecosystems and biodiversity, but how to actually achieve these goals remains elusive in practice.

“We highlight existing gaps and priorities in sustainability research, offering a valuable synthesis of past, present, and future research needs,” says coauthor Prof Graeme Cumming from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU).

This includes more relevant, solutions-focused research to address the social-ecological crisis.

The study also highlights the knowledge gaps for effective governance, institutions, and connections between social and ecological systems. The authors argue these knowledge gaps are an important input for the new global biodiversity targets set to be adopted in 2020 under the United Nations Framework Convention on Biodiversity.

The assessments synthesise current knowledge about the relationship between people and nature, including humans’ role in managing ecosystems to provide human benefits.

The authors compared the knowledge gaps identified in the seven most recent IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) reports to key international sustainability goals set out by the United Nations for both the Aichi Biodiversity Targets, agreed to in 2010 under the Convention on Biological Diversity, and the Sustainable Development Goals, agreed to in 2015.

The reports are a critical tool for both evidence-based policymaking and scientific research agendas. They reflect the need for new ways to value both human well-being and biodiversity protection. The role of indigenous and local knowledge to sustain nature’s benefits to people has also emerged as a key knowledge gap.

Lead author Matias Mastrangelo, from the National University of Mar del Plata in Argentina, says global sustainability goals cannot be achieved without improved knowledge on feedbacks between social and ecological systems, effective governance systems and institutions that can equitably deliver ecosystem services and protect vulnerable people.

“We need to identify management and policy strategies for ecosystems and biodiversity that are effective, just, inclusive, and promote good quality of life.”

To support decisions that ensure both people and nature can thrive, human and natural well-being need to be valued beyond defining a good life based just on gross domestic product.

The importance of human values and institutions puts people at the heart of nature protection, as the future of humanity depends on how we respond to the current social-ecological crisis.


Mastrángelo M, Pérez-Harguindeguy N, Enrico L, Bennett E, Lavorel S, Cumming G, Abeygunawardane D, Amarilla L, Burkhard B, Egoh B, Frishkoff L, Galetto L, Huber S, Karp D, Ke A, Kowaljow E, Kronenburg-García A, Locatelli B, Martín-López B, Meyfroidt P, Mwampamba T, Nel J, Nicholas K, Nicholson C, Oteros-Rozas E, Rahlao S, Raudsepp-Hearne C, Ricketts T, Shrestha U, Torres C, Winkler K, Zoeller K (2019). Nature Sustainability. ‘Key knowledge gaps to achieve global sustainability goals’. DOI: 10.1038/s41893-019-0412-1

Prof Graeme Cumming (Townsville, Australia)
P: (07) 4781 6072
E: graeme.cumming@jcu.edu.au

Melissa Lyne (Media Manager, Coral CoE at JCU)
P: 0415 514 328
E: melissa.lyne@jcu.edu.au

A world-first study is challenging long-held assumptions about the role of sunlight in coral biodiversity.

The research questions a classic theory that predicts coral biodiversity is highest in the shallowest waters where more energy is available in the form of sunlight.

The research, led by Dr Ed Roberts from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU) with colleagues from the Queensland Museum, the UK and Denmark, reveals light—either on its own or in combination with other local factors—doesn’t account for differences in the number of coral species occurring at different depths. The findings test a long-held theory that there is greater species diversity where there is greater available energy.

“Our understanding of how coral diversity varies across depth has been limited by a lack of high-quality data due to the difficulty of deeper surveys,” Dr Roberts said.

“We were able to overcome that in our survey in Kimbe Bay, Papua New Guinea. This allowed us to test the classic Species Energy hypothesis that proposes the greater the energy available, the greater the diversity.”

“Theoretically, more energy allows more individuals to co-exist. This in turn allows more species to maintain large enough populations to avoid local extinction.”

For corals, the highest diversity was expected in the shallows because corals depend on energy from sunlight. To test this idea, the researchers surveyed corals along 98 per cent of the light gradient. Together, they generated an unprecedented dataset of 8,460 coral colonies across six reefs in Kimbe Bay.

“Our results do not agree with this classic explanation of how diversity changes with energy,” Dr Roberts said.

“Instead, the shallowest depths had fewer species, a pattern also poorly explained by alternative explanations such as competition between corals or environmental disturbance.”

The research also revealed that coral diversity was highest at depths between 15 and 20 metres.

The results provide cause to find new theories about diversity distribution.

Co-author Dr Tom Bridge, also from Coral CoE at JCU and the Queensland Museum, said: “Hyper-diverse corals reefs are ideal ecosystems to test theories about how diversity is distributed in nature, so it is really interesting that our results do not support the classic hypotheses.”

“More broadly, our analyses cast doubt on the suitability of these hypotheses more generally across terrestrial, marine and freshwater systems, suggesting that ecologists might need to rethink the underlying causes of these fundamental patterns of diversity.”

Paper: Roberts E, Keith S, Rahbek C, Bridge T, Caley M, Baird A (2019).Biology Letters.‘Testing biodiversity theory using species richness of reef-building corals across a depth gradient’. DOI: 10.1098/rsbl.2019.0493

Images are available for media use with this story only, and with credit to Ed Roberts.


Dr Ed Roberts (currently in the Netherlands)
P: +31 0657 007577
E: edroberts422@gmail.com

Dr Tom Bridge (Townsville, Australia)
P: 0414 219 020
E: Thomas.bridge@jcu.edu.au

Melissa Lyne (Media Manager, Coral CoE at JCU)
P: 0415 514 328
E: melissa.lyne@jcu.edu.au

A long-term study of coral cover on island groups of the Great Barrier Reef has found declines of between 40 and 50 percent of live, hard corals at inshore island groups during the past few decades.

Scientists from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU) say the data was so alarming that they checked and re-checked it.

The study’s lead author Dr Daniela Ceccarelli and a team of researchers surveyed coral cover on fringing reefs of the Palm, Magnetic, Whitsunday and Keppel Island groups along the central and southern Great Barrier Reef, and compared it to historical records.

“Normal cycles of disturbance and recovery are natural, and the reef historically has had good recovery potential,” Dr Ceccarelli said.

“But human impacts are increasing the frequency of disturbances such as coral bleaching, leaving little time between events to allow a full recovery,” she said.

“We were shocked when we calculated the changes.”

JCU researchers have monitored the condition and trends of inshore reefs in the Great Barrier Reef Marine Park (GBRMP) since the late 1990s.

Co-author Dr David Williamson, also from Coral CoE at JCU, said: “The impacts of individual disturbance events were patchy. Some reefs avoided the worst effects—but the cumulative impacts of multiple, frequent events reduced coral cover and diversity.”

Dr Ceccarelli said their latest expedition identified several factors that influenced coral cover on reefs at each island group, but two key drivers consistently stood out for all reefs: temperature stress from marine heatwaves and wave exposure.

“There was a clear threshold of heat stress above which coral cover consistently declined. We were surprised to find that corals on these inshore reefs appear to have a lower heat stress threshold than previously reported,” she said.

Dr Williamson said the effect of wave exposure was more complicated.

“The corals on the exposed, outer sides of the island had an advantage,” he said. “This is because they were well-flushed by currents.”

“This information can test management actions that aim to maintain natural biodiversity and ecological processes.”

“If we can tackle water quality locally and climate change globally, then there is hope,” Dr Ceccarelli said.

Paper: Ceccarelli D, Evans R, Logan M, Mantel P, Puotinen M, Petus C, Russ G, Williamson D. (2019). Ecological Applications. ‘Long‐term dynamics and drivers of coral and macroalgal cover on inshore reefs of the Great Barrier Reef Marine Park’. DOI: https://doi.org/10.1002/eap.2008

Images are available for media use with this story only. Please credit as per the image caption to David Wachenfeld, Triggerfish Images.

Dr Daniela Ceccarelli (Townsville)
P: +61 (0)7 4758 1866
M: +61 (0)488 510 702
E: dmcecca@gmail.com

Dr David Williamson (Currently overseas)
E: david.williamson@jcu.edu.au

Melissa Lyne (Media Manager, Coral CoE at JCU)
P: +61 (0)415 514 328
E: melissa.lyne@jcu.edu.au

Fish that are able to adjust to warming waters may pass heat-tolerant genes not just onto their children, but their grandchildren too.

Dr Jennifer Donelson is an Australian Research Council (ARC) Future Fellow at the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU). She is speaking at the 2019 Coral Reef Futures Symposium in Sydney, today.

Dr Donelson’s research explores the ability of fish to acclimate to future warming. So far, her work has focused on two generations of fish: parents and their offspring. Her next chapter of work digs deeper and brings in a third generation.

“Ocean warming of one to three degrees Celsius has a negative effect on coral reef fish,” Dr Donelson said.

“Traits such as growth, reproduction, aerobic capacity (the ability to deliver energy to the muscles), and sex determination are all affected.”

“So, the projected warming under climate change could have severe effects on coral reef fish populations.”

Dr Donelson says fish that grow in warmer conditions from early life can improve their thermal performance “a little”.

“But the real improvements happen when their parents have experienced warm ocean conditions too.”

Exposing the parents to higher water temperatures appears to signal which genes to switch on, or off. This alteration of genes in the offspring is ‘acclimation’, and acts as a buffer against increasingly warming waters.

Dr Donelson found that both the rate and magnitude of warming can produce different results.

“With only a 1.5C increase, fish were able to fully restore the negative effects of warming on their physiology and reproduction in two generations,” she said.

“With a greater increase in warming, fish really began to struggle. While they were able to restore aerobic capacity, they ceased to reproduce after two generations. Obviously, that’s a terminal impact.”

“When fish experienced only a 1.5C increase in each generation (totalling +3C in two generations), they restored aerobic capacity and partially restored reproductive ability.”

Dr Donelson is now testing if an improved tolerance to warmer waters still holds after the offspring generation go back to cooler conditions.

“This new chapter of work will also focus on the traits and genes of three generations,” she said. “And how their early-life conditions affect their grandkids.”

“In a warming world, there are clear limits to what fish can cope with. My research is getting us closer to identifying the mechanisms that help some acclimatise to modest amounts of heating.”

The ARC Future Fellows are awarded to outstanding mid-career researchers to undertake research in areas of national priority.

Dr Donelson’s work will provide significant benefits to Australian and international communities that rely on fish for nutrition, as well as economic and social values.

Dr Jennifer Donelson presents ‘You can’t escape your past: how thermal experience of previous generations affect current generation performance’ at 11:15 am on Thursday 24 October at the 2019 Coral Reef Futures Symposium at the Australian National Maritime Museum in Sydney.

The symposium also features a free public forum, ‘What Every Australian Should Know About Climate Change’. A panel of four world-renowned experts discuss climate change and renewable energy. They will then answer questions from the audience.

Images are available for media use with this story only. Please credit as per the image caption to Jenni Donelson.


Dr Jennifer Donelson
P: 0402 066 046
E: jennifer.donelson@jcu.edu.au


Melissa Lyne (Media Manager, Coral CoE)
P: 0415 514 328
E: melissa.lyne@jcu.edu.au


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ARC Centre of Excellence for Coral Reef Studies
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Phone: 61 7 4781 4000
Email: info@coralcoe.org.au