1

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.

2

Ecosystem dynamics: past, present and future

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

3

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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Being a fussy eater is a problem for reef fish who seek refuge from climate change on deeper reefs. But, scientists discovered, the coral that these fussy fish eat can support them.

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

Dr MacDonald said it’s increasingly difficult for species to deal with rapidly changing environments across the globe. He says while some species are likely to find refuges in marginal environments, survival may be difficult. Especially if they’re fussy eaters.

“Some animals are likely to be pushed close to the borders of their environmental range, where living will be more difficult,” Dr MacDonald said.

“On coral reefs this could mean deeper waters for fish, where you’d expect them to experience a reduced quantity and quality of their preferred foods,” he said.

“However, we found that fish who are fussy about the corals they feed on can continue to thrive in deeper reef waters if their prey engage in a less ‘precious’ approach to what they themselves eat.”

Although the corals some fish preferred to eat were sparse at depth, the team found the energy content of these corals remained constant, as they adapted their diet to rely less on sunlight and include more plankton.

Coral bleaching, large storms and other destructive events are increasing on tropical reefs.

“Shallow-water coral habitats are rapidly degrading,” co-author Dr Tom Bridge, also from Coral CoE at JCU, said.

“And the deeper coral habitats, which may act as a refuge for some reef fish species, have less light available,” Dr Bridge said.

“Corals mostly depend on light as an energy source to survive, which means there are less corals at depth.”

Fish that eat coral, such as the Triangle and Eight-Band butterflyfish, can live on deeper reefs by either feeding more on their usual resource—or by adapting their diets.

Triangle butterflyfish are fussy eaters (dietary specialists). The Eight-band Butterflyfish are not fussy eaters (dietary generalists). The study compared the diets of the two from shallow to deep depths.

The researchers found that while overall feeding rates did not change with depth, the Triangle Butterflyfish—a dietary specialist—fed more selectively on their preferred corals, which are sparser at greater depths than in shallow waters.

In contrast, the dietary flexibility of the Eight-band Butterflyfish increased with depth as the amount of different coral types changed.

“These observations were compared with lab investigations of light-related changes in the energy content of corals,” Dr MacDonald said.

“Surprisingly, the energy content of the corals that the Triangle butterflyfish preferred to feed on did not decline with depth as expected,” he said.

“However, the pathways through which carbon passed from the corals to the fish did.”

“Our results suggest that the expected declines in the quality of  deeper corals as prey for fish are buffered by increased plankton intake by the corals via their polyps,” co-author Prof Geoff Jones, also from Coral CoE at JCU, said.

“This means the corals adjust to the lack of light at depth, as they usually rely on energy from their internal photosynthetic zooxanthellae,” Prof Jones said.

Dr MacDonald said the increase in plankton uptake was as much as 20 percent.

“This may be why we see healthy members of these fussy fish in both deep and shallow waters,” he said.

“Climate change and other disturbances have increasing impacts on the habitats and compositions of coral reefs.”

“Our study shines a light on the importance of the versatile relationship between species as they seek refuge on the edges of their environmental range—even if one species is fussier than another.”

PAPER

MacDonald C, Bridge T, McMahon K, Jones G (2019). Functional Ecology. ‘Alternative functional strategies and altered carbon pathways facilitate broad depth ranges in coral-obligate reef fishes’. DOI: 10.1111/1365-2435.13400

CONTACTS FOR INTERVIEWS

Dr Chancey MacDonald (AEST)
M: +61 (0)473 210 907
E: chancey.macdonald@jcu.edu.au

Dr Tom Bridge (AEST)
M:  +61 (0)414 219 020
E: thomas.bridge@jcu.edu.au

FOR FURTHER INFORMATION

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

 

Australian scientists have created a world-first tool that can systematically assess climate change risks to all types of World Heritage properties: marine and terrestrial, natural and cultural.

There are nearly 1,100 World Heritage properties, and climate change is their fastest-growing threat.

The Climate Vulnerability Index (CVI) was developed by Mr Jon Day at the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) and Dr Scott Heron at James Cook University (JCU). The pair are presenting their work at the 43rd international meeting of the World Heritage Committee this month.

“While World Heritage areas are ‘the best-of-the best’ globally, many are already experiencing significant negative damage,” Dr Heron said. “They are vulnerable to climate change impacts such as sea level rise, extreme precipitation, rising temperatures, flooding, coastal erosion, drought, worsening wildfires, and human displacement.”

The CVI differs from many other vulnerability assessments as it comprises two distinct stages.

The vulnerability of World Heritage values to physical climate drivers (such as sea level rise) is assessed first.

Then the economic, social and cultural risks for the associated communities—as well as their capacity to adapt—are evaluated.

“The CVI applies a risk-assessment approach that builds upon an existing vulnerability framework used by the Intergovernmental Panel on Climate Change,” Mr Day said.

“But ours is the first tool that can be specifically applied to both a World Heritage property and its associated communities,” he said.

The CVI was first trialled last year in Shark Bay, Western Australia—a World Heritage area known for its outstanding natural features. Extreme marine heat events, increasing storm intensity and air temperature change were identified as the key climate drivers impacting both the World Heritage values and the local community.

The first cultural World Heritage property to apply the CVI was ‘The Heart of Neolithic Orkney’ in Scotland—a late Stone Age settlement and series of monuments. Increasing storm intensity and frequency, sea-level rise and precipitation change were identified as the key climate drivers impacting these cultural values. However, the capacity of the local community to adapt moderated the risk. The full report was released this week.

The CVI method is currently in a pilot phase, but the two trials so far have successfully demonstrated its value as a rapid yet robust assessment tool.

Planning is now underway for further CVI workshops in Scotland, as well as in Germany, Netherlands, Denmark, Norway and Australia.

CONTACT

Mr Jon Day
E: jon.day@my.jcu.edu.au

Dr Scott Heron
E: scott.heron@jcu.edu.au

FOR FURTHER INFORMATION

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

 

An international group of scientists is making major advances in sustaining the world’s environments, untangling the intricate ways in which people and nature depend on each other.

The results are published in today’s Nature Sustainability and includes contributions from a team of scientists based at the ARC Centre of Excellence for Coral Reef Studies (Coral CoE).

With major crises such as extinctions and environmental degradation now upon us, the timing of the study is crucial.

“Environmental problems are messy,” Dr Michele Barnes from Coral CoE said. “They often involve multiple, interconnected resources and a lot of different people—each with their own unique relationship to nature.”

The paper, led by Dr Örjan Bodin from Stockholm University, proposes several advances to a ‘network approach’ that can better analyse and help solve these problems by identifying the key relationships between people and nature that underpin them.

“Research has traditionally only measured and described problems,” Dr Bodin said.

“We are advancing a method that can go beyond this, to find new solutions to environmental challenges,” he said.

Prof Graeme Cumming from Coral CoE said social, economic, and ecological aspects all need consideration to govern and manage sustainable ecosystems.

“These elements often interact in complex ways and are mutually dependent,” Prof Cumming said. “A rapidly changing world means these interdependencies will only increase at all scales—from local to global.”

For example, introducing forest conservation policies in a wealthy country leads to an increase in supply for wood products from a less developed country—leading to de-forestation there.

“Identifying the shortcomings of these human-nature relationships are a relatively easy task. Possible solutions aren’t,” Dr Barnes said.

“This paper paves a path forward for future studies to better address these issues, with research design guidelines to help scholars move beyond single case studies.”

PAPER

Bodin Ö, Alexander S, Baggio J, Barnes M, Berardo R, Cumming G, Dee L, Fischer A, Fischer M, Mancilla-Garcia M, Guerrero A, Hileman J, Ingold K, Matous P, Morrison T, Nohrstedt D, Pittman J, Robins G, and Sayles J (2019). Nature Sustainability. ‘Improving network approaches to the study of complex social–ecological interdependencies’. DOI: 10.1038/s41893-019-0308-0

CONTACT

Dr Michele Barnes (Australia, AEST)
P: +61 (0)7 4781 6328
M: +61 (0)408 677 570
E: michele.barnes@jcu.edu.au

Prof Graeme Cumming (AEST)
P: +61 (0)7 4781 6072
E: graeme.cumming@jcu.edu.au

FOR MORE INFORMATION

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

 

Squid will survive and may even flourish under even the worst-case ocean acidification scenarios, according to a new study published this week.

Dr Blake Spady, from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University (JCU), led the study. He said squid live on the edge of their environmental oxygen limitations due to their energy-taxing swimming technique. They were expected to fare badly with more carbon dioxide (CO2) in the water, which makes it more acidic.

“Their blood is highly sensitive to changes in acidity, so we expected that future ocean acidification would negatively affect their aerobic performance,” said Dr Spady.

Atmospheric COconcentrations have increased from 280 parts per million (ppm) before the industrial revolution to more than 400 ppm today. Scientists project atmospheric CO2—and by extension COin the oceans—may exceed 900 ppm by the end of this century unless current CO2 emissions are curtailed.

But when the team tested two-toned pygmy squid and bigfin reef squid at JCU’s research aquarium, subjecting them to COlevels projected for the end of the century, they received a surprise.

“We found that these two species of tropical squid are unaffected in their aerobic performance and recovery after exhaustive exercise by the highest projected end-of-century COlevels,” said Dr Spady.

He said it may be an even greater boost for the squid as some of their predators and prey have been shown to lose performance under predicted climate change scenarios.

“We think that squid have a high capacity to adapt to environmental changes due to their short lifespans, fast growth rates, large populations, and high rate of population increase,” said Dr Spady.

He said the work is important because it gives a better understanding of how future ecosystems might look under elevated COconditions.

“We are likely to see certain species as being well-suited to succeed in our rapidly changing oceans, and these species of squid may be among them.”

“The thing that is emerging with most certainty is that it’s going to be a very different world,” he said.

The paper is out now: Spady B, Nay T, Rummer J, Munday P, Watson S (2019). Conservation Physiology. ‘Aerobic performance of two tropical cephalopod species unaltered by prolonged exposure to projected future carbon dioxide levels’. DOI: 10.1093/conphys/coz024

IMAGES

Media can find images of Dr Spady here.

CONTACT
Dr Blake Spady (AEST, Australia)
M: 0456 777 883
E: blake.spady@jcu.edu.au

 

Scientists have revealed the torrid, adulterous love lives of the mouth-brooding cardinalfish, with cuckoldry going hand-in-hand with cannibalism of the young.

“This is a small and unassuming coral reef fish,” said Dr Theresa Rueger, who led the study while she was a student at the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

The male fish of this species carries the eggs in his mouth until they are ready to hatch.

“The fish we followed in this study stayed close to each other in pairs for long periods of time, often years,” Dr Rueger said.

On the surface, everything seemed to be as expected, with the pairs of fish apparently monogamous and forming larger social groups.

“Looking at the babies they produced, we saw that most of them do exclusively breed with their own partner,” Dr Rueger said.

But on closer examination the researchers discovered some sneaky behaviour.

“When presented the chance, both males and females take the opportunity to mate with other individuals from outside the group.”

Dr Rueger and her team carefully observed and analysed populations of the mouth-brooding cardinalfish across two years in Papua New Guinea.

Of 105 broods analysed from 64 males, 30% were mothered by a female that was not the partner, about 11% of broods included eggs from two females, and more than 7% of broods were fertilised by two males. These findings are contrary to what the researchers expected to find.

As with most apparently monogamous species who invest time and energy rearing their young, these fish make sacrifices to ensure their babies survive. Paternal care, especially, is associated with a high degree of confidence in paternity.

“Staying faithful and caring for your offspring can be a winning evolutionary strategy,” added co-author Dr Hugo Harrison, also from the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

“By caring for the brood, males increase the survival of their offspring but also allow their partner to allocate more energy into producing the next clutch,” Dr Harrison said.

“However, it seems that having a bit on the side might not hurt your evolutionary fitness.”

“The males can’t feed during that time and their swimming ability is compromised, so brooding is very costly,” explained Dr Rueger.

“This means the females are in an advantageous position, because they can produce eggs quicker than the male can brood them—so they can go and give eggs to another male.”

“But the males can offset that advantage by eating some, or all, of the eggs. They can then accept eggs from another female.”

Dr Rueger said in some cases, males even fertilise the eggs that another male is brooding. This saves them the energy they would need to brood the eggs themselves.

“What this study shows is a complicated mating system, which is something we didn’t expect and could only find out by spending lots of time observing the fish and using genetic analysis to identify parentage,” Dr Rueger said.

“Clearly, social interactions don’t tell the whole story,” added Dr Harrison. “But our parentage tests reveal the complex nature of social groups in fishes and how promiscuity could upturn theories for how monogamy arose.”

The paper is out now: Rueger T, Harrison H, Gardiner N, Berumen M, Jones G (2019). Molecular Ecology. ‘Extra-pair mating in a socially monogamous and paternal mouthbrooding cardinalfish’. DOI: https://doi.org/10.5061/dryad.557br15

* * *

IMAGES

Media may use the photographs here. All use of images must carry the attribution as stated.

CONTACTS

Dr Theresa Rueger 
Phone: 0434 138 905
Email: theresa.rueger@gmail.com

Dr Hugo Harrison
Phone: 0499 523 939
Email: hugo.harrison@jcu.edu.au

FOR FURTHER INFORMATION

Melissa Lyne
Media Manager, ARC Centre of Excellence for Coral Reef Studies
Phone: 0415 514 328
Email: melissa.lyne@jcu.edu.au

 

A new study published today in Nature Climate Change finds coral reefs are under threat from ocean acidification.

The study was led by researchers from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE). Their results suggest some corals and coralline algae—the ‘glue’ that holds reefs together—cannot survive the expected more acidic oceans caused by climate change.

“The results validate previous research on ocean acidification threats to coral reefs,” said lead author Dr Steeve Comeau, who is now based at the Sorbonne Université CNRS Laboratoire d’Océanographie de Villefranche sur Mer in France.

Co-author Prof Malcolm McCulloch, from Coral CoE at the University of Western Australia, said the researchers examined the calcifying fluid of four species of coral and two types of coralline algae under a year-long simulation.

“The effects on the calcifying fluid were rapid and persisted for the whole year,” Prof McCulloch said.

Co-author Dr Chris Cornwall, now at the Victoria University of Wellington in New Zealand, explained coralline algae cements reefs together by acting as a foundation species and breeding ground for many species from the poles to the tropics.

“Declines in coralline algae could lead to the loss of important marine species that use the algae as a nursery,” he explained.

“The results also confirm that ocean acidification could have repercussions on the competition between species. This can affect the ecological function of reefs,” Dr Comeau added.

He said the team did find two coral species were resistant to ocean acidification. However, these are corals that were resistant from the start.

“This indicates they already had an in-built mechanism that made them resistant,” he explained, “whereas sensitive corals were affected from the start and were not actually able to acclimatise.”

The study suggests the composition and function of future reefs—if they can survive climate change—will be very different to what we see today.

PAPER

Comeau S, Cornwall C, DeCarlo T, Doo S, Carpenter R, McCulloch M (2019). ‘Resistance to ocean acidification in coral reef taxa is not gained by acclimatization’. Nature Climate Change. DOI: 10.1038/s41558-019-0486-9

Link to the paper at: https://www.nature.com/articles/s41558-019-0486-9

CONTACTS

Prof Malcolm McCulloch (AWST, Western Australia)
P: (08) 6488 1921
E: malcolm.mcculloch@uwa.edu.au

Dr Steeve Comeau (CEST, France)
E: steeve.comeau@obs-vlfr.fr

Dr Chris Cornwall (NZST, New Zealand)
P: + 64 4463 5720
E: christopher.cornwall@vuw.ac.nz

FOR MORE INFORMATION

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

 

New research has revealed that the short lives and violent deaths of some of coral reefs’ smallest tenants may be vital to the health of reef systems, including the iconic Great Barrier Reef.

Dr Simon Brandl, from Simon Fraser University in Canada, led an international team of researchers searching for answers to the longstanding puzzle of ‘Darwin’s paradox’.

Co-author Prof David Bellwood from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University (JCU) said: “Charles Darwin wondered how fish on coral reefs manage to thrive in isolated areas where there are very low levels of nutrients for them to use. We thought the answer may lie in the tiny fish that live in the gaps in the coral structure.”

“These tiny fish are less than five centimetres long and are known as ‘cryptobenthics’. They include gobies, blennies, cardinalfish, and several other families,” Prof Bellwood said.

The team surveyed reefs around the globe and records of larval abundance. They discovered that cryptobenthics and their larvae make up nearly 60% of all fish flesh eaten on the reef.

“Because of their size and tendency to hide, these little fish are commonly overlooked,” Dr Brandl said, “but their unique demographics make them a cornerstone of the ecosystem.”

“Their populations are completely renewed seven times a year, with individuals in some species living only a few days before they are eaten. The only way they can sustain this is by a spectacular supply of local larvae,” added co-author Renato Morais, a PhD student at JCU.

Prof Bellwood said almost anything capable of eating cryptobenthics does so, including juvenile fish and invertebrates such as mantis shrimps, which then became food for other creatures.

“These factors have made it hard for researchers in the past to realise the importance of cryptobenthics and discover the food supply that the ‘crypto-pump’ supplies.”

He said that the cryptobenthics have finally emerged from the shadows. “Their extraordinary larval dynamics, rapid growth, and extreme mortality underpins their newly discovered role as a critical functional group on coral reefs.”

PAPER

Brandl S, Tornabene L, Goatley C, Casey J, Morais R, Cote I, Baldwin C, Parravicini V, Schiettekatte N, Bellwood D (2019). ‘Demographic dynamics of the smallest marine vertebrates fuel coral-reef ecosystem functioning’. Science. DOI: 10.1126/science.aav3384

Link to paper here.

IMAGES

Link to images here. Please credit as marked.

CONTACTS

Prof. David Bellwood (AEST, Australia)
T: 07 47 81 4447
E: david.bellwood@jcu.edu.au

Renato Morais (AEST, Australia)
M: 0467 479297
E: renato.morais@my.jcu.edu.au

Dr. Simon Brandl (PDT, Canada)
E: simonjbrandl@gmail.com
T: +1-604-348-6423
Skype: sjbrandl

FOR FURTHER INFORMATION

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

 

 

Cooperation is key to most successful endeavours. And, scientists find, when fishermen and women cooperate with other fishers, this can boost fish stocks on coral reefs.

Dr Michele Barnes, a senior research fellow from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University (JCU), is the lead author of a study published today that looks at the relationships between competing fishers, the fish species they hunt, and their local reefs.

“Relationships between people have important consequences for the long-term availability of the natural resources we depend on,” Dr Barnes says.

“Our results suggest that when fishers—specifically those in competition with one another—communicate and cooperate over local environmental problems, they can improve the quality and quantity of fish on coral reefs.”

Co-author Prof Nick Graham, from Lancaster University (previously at JCU), adds: “Coral reefs across the world are severely degraded by climate change, the pervasive impacts of poor water quality, and heavy fishing pressure. Our findings provide important insights on how fish communities can be improved, even on the reefs where they are sought.”

Dr Barnes and her team interviewed 648 fishers and gathered underwater visual data of reef conditions across five coral reef fishing communities in Kenya.

They found that in the places where fishers communicated with their competitors about the fishing gear they use, hunting locations, and fishing rules, there were more fish in the sea—and of higher quality.

Co-author Dr Jack Kittinger, Senior Director at Conservation International’s Center for Oceans, says this is likely because such cooperative relationships among those who compete for a shared resource—such as fish—create opportunities to engage in mutually beneficial activities. These relationships also help build trust, which enables people to develop a shared commitment to managing resources sustainably.

“This is why communication is so critical,” says Dr Kittinger. “Developing sustained commitments, such as agreements on rules, and setting up conflict resolution mechanisms, are key to the local management of reefs.”

“The study demonstrates that the positive effect of communication does not necessarily appear when just anyone in a fishing community communicates – this only applies to fishers competing over the same fish species,” adds co-author Dr Örjan Bodin, from the Stockholm Resilience Centre at Stockholm University.

The study advances a framework that can be applied to other complex environmental problems where environmental conditions depend on the relationships between people and nature.

Co-author Dr Orou Gaoue, from the University of Tennessee Knoxville, emphasises this broad appeal.

“Although this study is on coral reefs, the results are also relevant for terrestrial ecosystems where, in the absence of cooperation, competition for non-timber forest products can quickly lead to depletion even when locals have detailed ecological knowledge of their environment.”

“Environmental problems are messy,” explains Dr Barnes. “They often involve multiple, interconnected resources and a lot of different people—each with their own unique relationship to nature.

“Understanding who should cooperate with whom in different contexts and to address different types of environmental problems is thus becoming increasingly important,” she concludes.

* * *

PAPER

Barnes M, Bodin O, McClanahan T, Kittinger J, Hoey A, Gaoue O, Graham N (2019). ‘Social-ecological alignment and ecological conditions in coral reefs’. Nature Communications. DOI: 10.1038/s41467-019-09994-1

PHOTOS & VIDEO

Images relating to the study are available here for media use with this story only. Any use must carry the credit as stated.

CONTACTS FOR INTERVIEWS

Dr Michele Barnes (Australia, AEST)
Coral CoE at JCU
P: +61 (0)7 4781 6328
M: +61 (0)408 677 570
E: michele.barnes@jcu.edu.au

Prof Nick Graham (London, BST)
Lancaster Environment Centre, Lancaster University
P: +44 (0) 1524 595054
E: nick.graham@lancaster.ac.uk

Dr Jack Kittinger (USA, HST)
Global Oceans and Aquaculture Program, Conservation International
P: +1 808 397-9077
E: jkittinger@conservation.org

FOR FURTHER INFORMATION

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

 

Researchers have discovered some good news for fish populations living on coral reefs hit by climate change.

Renato Morais is a PhD candidate from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University (JCU). He led a study that looked at how fish on a bleached coral reef get their food.

“We already knew that coral reef fish rely on food drifting in from the sea, such as plankton,” Mr Morais said.

“But, we didn’t know exactly how important this was,” he said.

Mr Morais and Professor David Bellwood, also from Coral CoE at JCU, combined high-resolution surveys and individual biomass production estimates to generate the first map of where the energy comes from for all fish on a coral reef.

“We looked at everything from gobies to coral trout and large jacks, assessing more than 18,000 fish from over 300 species,” said Mr Morais.

“We found that various transport mechanisms, such as currents and tides, interact with the reef and bring in vast amounts of plankton.”

The pair found that for every kilogram of fish produced on the reef more than 400 grams of that kilogram relied on food derived from the open ocean, rather than the reef itself. This rises to almost 600 grams on the side of the reef facing the open ocean.

“This means, that for many reefs, food from outside can sustain fish populations, even when the coral is badly damaged,” Prof Bellwood said.

The scientists found that areas of the reef that were more exposed to the open ocean produced the largest quantities of fish – with reef slopes being the most fruitful.

“The discovery that reef fish get so much of their food from off-reef sources was encouraging, especially because many species that feed on oceanic material have a history of disappearing after coral loss,” said Mr Morais.

“This is the first time we have been able to put all species in perspective,” said Prof Bellwood. “Our study offers hope that reefs subject to coral loss can still be productive.”

“The reefs may be damaged but they are still incredibly valuable.”

The study is published today: Morais R and Bellwood D (2019). ‘Pelagic Subsidies Underpin Fish Productivity on a Degraded Coral Reef’. Current Biologyhttps://doi.org/10.1016/j.cub.2019.03.044

 

Contact

Renato Morais
E: Renato.morais@my.jcu.edu.au
M: 0467 479 297

Twitter

@RenatoAMorais
@bellwoodlab

The damage caused to the Great Barrier Reef by global warming has compromised the capacity of its corals to recover, according to new research published today in Nature.

“Dead corals don’t make babies,” said lead author Professor Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University (JCU). “The number of new corals settling on the Great Barrier Reef declined by 89 percent following the unprecedented loss of adult corals from global warming in 2016 and 2017.”

The unique study measured how many adult corals survived along the length of the world’s largest reef system following extreme heat stress, and how many new corals they produced to replenish the Great Barrier Reef in 2018. The loss of adults resulted in a crash in coral replenishment compared to levels measured in previous years before mass coral bleaching.

“The number of coral larvae that are produced each year, and where they travel to before settling on a reef, are vital components of the resilience of the Great Barrier Reef. Our study shows that reef resilience is now severely compromised by global warming,” said co-author Professor Andrew Baird.

“The biggest decline in replenishment, a 93% drop compared to previous years, occurred in the dominant branching and table coral, Acropora. As adults these corals provide most of the three-dimensional coral habitat that support thousands of other species,” he said.

“The mix of baby coral species has shifted, and that in turn will affect the future mix of adults, as a slower than normal recovery unfolds over the next decade or longer.”

“The decline in coral recruitment matches the extent of mortality of the adult brood stock in different parts of the Reef,” added Professor Hughes. “Areas that lost the most corals had the greatest declines in replenishment.”

“We expect coral recruitment will gradually recover over the next five to ten years, as surviving corals grow and more of them reach sexual maturity, assuming of course that we don’t see another mass bleaching event in the coming decade,” he said.

So far, the Great Barrier Reef has experienced four mass bleaching events due to global warming, in 1998, 2002, and back-to-back in 2016 and 2017. Scientists predict that the gap between pairs of coral bleaching events will continue to shrink as global warming intensifies.

“It’s highly unlikely that we could escape a fifth or sixth event in the coming decade,” said co-author Professor Morgan Pratchett.

“We used to think that the Great Barrier Reef was too big to fail – until now,” he said.

“For example, when one part was damaged by a cyclone, the surrounding reefs provided the larvae for recovery. But now, the scale of severe damage from heat extremes in 2016 and 2017 was nearly 1500km—vastly larger than a cyclone track.”

Professor Pratchett added that the southern reefs that escaped the bleaching are still in very good condition, but they are too far away to replenish reefs further north.

“There’s only one way to fix this problem,” says Hughes, “and that’s to tackle the root cause of global heating by reducing net greenhouse gas emissions to zero as quickly as possible.”

 

PAPER

Hughes T, Kerry J, Baird A, Connolly S, Chase T, Dietzel A, Hill T, Hoey A, Hoogenboom M, Jacobson M, Kerswell A, Madin J, Mieog A, Paley A, Pratchett M, Torda G, & Woods R (2019). ‘Global warming impairs stock–recruitment dynamics of corals’. Nature: http://dx.doi.org/10.1038/s41586-019-1081-y

PHOTOS & VIDEO

A selection of photos and videos relating to the study is available here. Please note that any use of this imagery MUST carry the credit given. In addition, permission must be obtained from the ARC Centre of Excellence for Coral Reef Studies for any use beyond this story.

The Australian Academy of Science have produced a video based on the study. The files are available to embed in online stories at the Dropbox hyperlink above, and the YouTube embed link is here. 

CONTACTS FOR INTERVIEWS
 
Prof Terry Hughes (Pacific Coast Time Zone, USA)
Director, ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0)400 720 164
Email: terry.hughes@jcu.edu.au

Prof Andrew Baird (Eastern Australia Time Zone)
ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0)7 4781 4857
Mobile: +61 (0)400 289 770
Email: andrew.baird@jcu.edu.au

Prof Morgan Pratchett (Eastern Australia Time Zone)
ARC Centre of Excellence for Coral Reef Studies
Phone: + 61 (0)7 4781 5747
Mobile: +61 (0)488 112 295
Email: morgan.pratchett@jcu.edu.au

FOR FURTHER INFORMATION

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

A Centre scientist has won a prestigious fellowship that will allow her to examine how environmental management can lead to positive outcomes for people and nature.

Environmental social scientist Dr Georgina Gurney has been awarded a Fulbright Postdoctoral Fellowship that will allow her to spend five months in the United States collaborating with leading researchers and practitioners in sustainability and environmental governance.

Dr Gurney’s research focuses on understanding how communities, government agencies and non-government organisations work together or co-manage environmental resources in the Asia-Pacific region. She is based at the Australian Research Council Centre of Excellence for Coral Reef Studies at James Cook University.

“Achieving global sustainability is one of the most pressing challenges of our time,” Dr Gurney said.

“We need to find ways in which environmental co-management and other forms of environmental governance can deliver outcomes across the three pillars of sustainability: society, the environment, and the economy.”

Dr Gurney’s project involves working with Professor Arun Agrawal at the University of Michigan, where they will investigate the trade-offs and benefits among the multiple social, environmental and economic outcomes of co-management.

“We will be examining the similarities and differences that lead to successful outcomes in managing coral reef fisheries and tropical forests in multiple countries,” Dr Gurney said.

She will also be spending time at Harvard University’s Kennedy School of Government, where she will collaborate with Professor Bill Clark and the international non-profit the Wildlife Conservation Society to develop a decision-support tool to guide co-management for multiple outcomes.

“Although compromises are inevitable in co-management, this project aims to develop ways to mitigate severe trade-offs between outcomes,” Dr Gurney said. 

“In a nutshell, the research seeks to understand what co-management practices work, where to contribute to sustainability and to foster the incorporation of this knowledge in real-world co-management practice.”

In 2018, Dr Gurney was recognised as a Young Tall Poppy Science award winner by the Queensland Government.

Read more about Dr Gurney’s research here.

The Fulbright Program is the flagship foreign exchange scholarship program of the United States of America, aimed at increasing bi-national collaboration, cultural understanding, and the exchange of ideas.

Photo available on Dropbox.
Credit: Australian-American Fulbright Commission

Contact:
Dr. Georgina Gurney
ARC CoE for Coral Reef Studies
P: +61 (0) 415 465 712 (AEST/GMT+10)

JCU Media Contact:
Bethany Keats
JCU Media Liaison
P: +61 (0) 7 4781 4586 (AEST/GMT+10)

Recent north Queensland flooding and the mass outflows of polluted water onto the Great Barrier Reef have focused attention on the impact of water quality on the Reef’s health. 

But new research reveals that even if water quality is improved, it won’t be enough on its own to save the Great Barrier Reef. 

Because of the flooding, rivers have dumped millions of litres of polluted water onto the Reef, but until now the impact of these events on reef corals and marine life has been difficult to assess. 

Using a combination of advanced satellite imaging and over 20 years of coral monitoring across the Reef, a team of researchers from ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE),  Dalhousie University, and the University of Adelaide has found that chronic exposure to poor water quality is limiting the recovery rates of corals across wide swathes of the GBR. 

“We found the Great Barrier Reef is an ecosystem dominated by runoff pollution, which has greatly reduced the resilience of corals to multiple disturbances, particularly among inshore areas,” said lead author Dr. Aaron MacNeil of Dalhousie University. 

“These effects far outweigh other chronic disturbances, such as fishing, and exacerbate the damage done by crown-of-thorns starfish and coral disease. Perhaps most critically, poor water quality reduced the rates at which coral cover recovers after disturbances by up to 25 percent. This shows that, by improving water quality, the rates of reef recovery can be enhanced.”

“Our results provide strong support for government policies aimed at reducing nutrient pollution to help increase the resilience of the Great Barrier Reef, in recovering from damage due to tropical cyclones, crown-of-thorns outbreaks and coral bleaching,” said co-author PhD candidate Sam Matthews of Coral CoE.

Yet the effects of water quality only go so far. Using a series of scenarios modelling future changes in climate and the likelihood of coral bleaching, the team found that no level of water quality improvement was able to maintain current levels of coral cover among the most scenic and valuable outer-shelf reefs that sustain much of the reef tourism industry. 

Dr. Camille Mellin of the University of Adelaide noted that: “Coral reefs, including the Great Barrier Reef, are subject to an increasing frequency of major coral die-off events associated with climate change driven by coral bleaching. With these increasingly common disturbances becoming the new normal, the rate of coral recovery between disturbances has become incredibly important.”

“While the effects of improved water quality on recovery rates of inshore reefs were encouraging, our analysis puts into perspective the limits of how much reducing pollution in river runoff can do to improve the state of the outer Great Barrier Reef. 

“No level of water quality improvement will be sufficient to ensure maintenance of the clear water reefs on the outer shelf, the very reefs that tourists come to Australia to see.”

“What these results emphasise is that there is no silver bullet for addressing the threats facing the Great Barrier Reef,” said Dr MacNeil. 

“Clearly reducing pollution in river runoff can have widespread, beneficial effects on reef corals and should continue to be supported. But for areas of the reef not impacted by water quality, our emphasis must be on mitigating carbon emissions to slow down climate change. 

“We must give our reefs the time and conditions to recover. Without that, the most stunning and iconic parts of the reef will soon decline and be unrecognisable from their current form.”

For interviews please contact:

Sam Matthews
ARC Centre of Excellence in Coral Reef Studies/James Cook University, Townsville Australia
P: c/o Melissa Lyne on +61 (0) 0415 514 328 (AEST/GMT+10)
E: sam.matthews@my.jcu.edu.au

Aaron MacNeil 
Dalhousie University, Halifax Canada
P: +1 902 402 1273 (AST)
E: a.macneil@dal.ca

Camille Mellin
Australian Institute of Marine Science/University of Adelaide, Adelaide Australia
P: +61 4 3635 6396 (ACDT)
E: camille.mellin@adelaide.edu.au

Paper: MacNeil M, Mellin C, Matthews S, Wolff NH, McClanahan TR, Devlin M, Drovandi C, Mengersen K, & Graham NAJ. (2019) Water quality mediates resilience on the Great Barrier Reef. Nature Ecology & Evolution: http://dx.doi.org/10.1038/s41559-019-0832-3

Images available here, please credit as marked.

For further information:

Melissa Lyne (Australia)
Acting Communications Manager
ARC Centre of Excellence for Coral Reef Studies
P: +61 (0) 0415 514 328 (AEST/GMT+10)
E: melissa.lyne@jcu.edu.au 

Niecole Comeau (Canada)
Communications, Faculty of Science, Dalhousie University
P: +1 (902) 494-8443, +1 (902) 223-2446 (ADT/GMT-4)
E: niecole.comeau@dal.ca


Scientists have taken a rare look at the depths of the Great Barrier Reef and have discovered they’re teeming with a kaleidoscope of life.

And they say conservation planners should take into account their findings to better protect the international icon.

ARC Centre of Excellence for Coral Reef Studies at James Cook University PhD candidate Tiffany Sih led the study, which used Baited Remote Underwater Video Stations (BRUVS) and multi-beam sonar to examine the reef down to 260 metres.

“The ecology of deeper habitats along the Great Barrier Reef has rarely been investigated. While we know habitat like coral is important for shallower fish species, there was little understanding of how important reef habitat is to fish in deeper environments,” said Ms Sih.

She said the lack of information was due to the expense of doing research at these depths, which often requires specialist divers, remotely operated submersibles or mini-submarines.

Instead, the team sampled 48 sites between 54 and 260 metres deep in the central GBR using sonar and a relatively simple BRUVS rig, which attracts fish with bait and films them.

“We found the ecology of deeper reef fish communities is fundamentally different from those found at shallower depths. Depth and reef composition was important, but habitat preferences clearly had a role in determining the distribution of fish species.

Both the living components of the habitat – such as algae, soft corals and sponges, as well as big boulders or mud flats – contribute to the structure and complexity of the reef, which has an effect on what kind of fish you find there,” said Ms Sih. 

She said when the rules around fishing in the Great Barrier Reef Marine Park were determined over a decade ago, less environmental data was available for the deeper habitats.

“They took into account what they did not know, and allowed for some uncertainty, by designating some of the deeper areas as no-take zones and zones where certain types of fishing, like bottom-trawling, were banned. But now the technology exists where we can map the deeper areas and fully document the fish community,” said Ms Sih.

She said that in the future it will be important to compare deeper fish communities in the Great Barrier Reef Marine Park and to consider deeper reefs as essential neighbourhoods where communities of fish thrive.

Contact: Tiffany Sih (now located in Ocean Grove, Victoria)
M: 0432 528 008
E: Tiffany.Sih@my.jcu.edu.au

Professor Mike Kingsford (Professor Kingsford works at JCU’s Townsville campus).
M: 0438 731 694
E: Michael.kingsford@jcu.edu.au
T: 07 4781 4312

Paper: Sih TL, Daniell JJ, Bridge TC, Beaman RJ, Cappo M, Kingsford MJ, (2019). Deep-Reef Fish Communities of the Great Barrier Reef Shelf-Break: Trophic Structure and Habitat Associations. Diversity. 11(2):26.

Link to journal here

Video here

New research confirms that drastic changes in ocean salinity from, for example, severe freshwater flooding, as recently experienced off the coast of north-east Queensland from abnormal monsoonal conditions, provoke a similar stress response in corals as extreme heating, resulting in “freshwater bleaching” and if unabated, coral death.Researchers from the ARC Centre of Excellence for Coral Reef Studies at James Cook University  (Coral CoE) and University of Technology Sydney (UTS) report that extreme and sudden changes in salinity, or the ocean salt concentration, cause a biochemical response in corals that is similar to marine heatwaves, but in some ways, more damaging to their cells ability to function.

“Corals are sensitive organisms, known to only tolerate slight changes in their environment. Thriving in clear, sunlit waters – the majority of reef-building corals are found in tropical and subtropical waters with a salinity between 32 to 42 parts per thousand,” said senior author Prof David Miller of Coral CoE.

“During the recent flooding, there are reports that nearshore reefs were exposed to roughly half the normal ocean salinity.”

“Our research shows that this kind of environmental change causes a shock response in corals that prevents normal cell function.”

The researchers used the sequenced genome – a biological blueprint – of the common reef-building coral, Acropora millepora to detect changes in the coral’s biology.

“Using the sophisticated labs at the National Sea Simulator, we put both young and adult corals under a salinity stress test to see how they respond to differing salinity concentrations,” said co-author Dr Jean-Baptiste Raina of UTS.

“We found that there was a common response between both coral life-stages – with the younger corals being more sensitive to low salinity conditions, but faring slightly better with exposure over time.”

“In general, we found that the coral’s cells launch a similar chemical response to reduced salinity as they do for heat stress,” Prof Miller explained.

“However, unlike the heat stress response, corals exposed to reduced salinity experience a complete collapse of their internal cellular protein balance, suggesting that their cells are in deep trouble.”

Although the central Great Barrier Reef may have been spared mass thermal bleaching due to higher-than-normal ocean temperatures this summer, there are many coastal reefs left battling dramatic changes in water conditions from the massive plumes of floodwater.

With the frequency and severity of heavy rainfall and runoff events predicted to increase by 2050, management interventions to increase the resilience of reefs are needed now more than ever.

Paper: Aguilar C, Raina J-B, Fôret S, Hayward DC, Lapeyre B, Bourne DG, Miller DJ (2019). Transcriptomic analysis reveals protein homeostasis breakdown in the coral Acropora millepora during hypo-saline stress. BMC Genomics 20:148

Images are available here.

Contacts for interviews:

Prof David Miller, ARC Centre of Excellence for Coral Reef Studies at James Cook University

E: david.miller@jcu.edu.au

Dr Jean-Baptiste Raina, UTS – Climate Change Cluster

E: Jean-Baptiste.Raina@uts.edu.au

FOR MORE INFORMATION

Catherine Naum

Communications Manager

ARC Centre of Excellence for Coral Reef Studies

P: +61 (0) 0428 785 895, +61 (0)7 4781 6067 (AEST/ GMT +10)

E: Catherine.Naum1@jcu.edu.au

Corals know how to attract good company. New research finds that corals emit an enticing fluorescent green light that attracts the mobile microalgae, known as Symbiodinium, that are critical to the establishment of a healthy partnership.

The study led by researchers at Japan’s National Institute for Basic Biology and the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE) sheds new light on the mechanism that brings corals and Symbiodinium together, for example, following a bleaching episode.

“Most reef corals can not function without Symbiodinium,” said Shunichi Takahashi from the National Institute of Basic Biology.

“Following the back-to-back mass bleaching events, images of bleached white coral contrasted with healthy, vibrantly coloured coral were widespread. The key difference between the two is the abundance of Symbiodinum in the coral’s tissue. Without sufficient Symbiodinum, which provide corals with nutrients via photosynthesis, the coral will starve.”

“Thirty percent of corals receive their Symbiodinium from their parents, the other seventy percent, need a different mechanism” said co-author Professor Andrew Baird of Coral CoE.

But what brings the two organisms together? Corals are stationary creatures, however Symbiodinium can move freely through the water column.

The study reveals that corals have evolved a cunning ability to draw the Symbiodinium to them.

The researchers used the chalice coral, Echinophyllia aspera, to test whether the green fluorescent light emitted by corals under certain conditions can signal the Symbiodinium in the water column to move towards them: a process known as “positive phototaxis.”

“Our research identifies a novel biological signaling tool that underlies the success of a relationship essential for healthy coral reef ecosystems, ” said Prof Baird.

The paper “Green fluorescence from cnidarian hosts attracts symbiotic algae” is published in the journal Proceedings of the National Academy of Sciences.

CITATION
Aihara Y, Maruyama S, Baird AH, Iguchi A, Takahashi S, Minagawa J (2019) Green fluorescence from cnidarian hosts attracts symbiotic algae. Proceedings of the National Academy of Sciences 116 (6): 2118-2123

IMAGES
Link to images here. Please credit as marked.

CONTACT FOR INTERVIEW
Prof Andrew Baird
ARC Centre of Excellence for Coral Reef Studies at James Cook University
Phone: +61 (0) 400 289 770, +61 (0)7 4781 4857 (AEST/UTC +10)
Email: andrew.baird@jcu.edu.au

FOR FURTHER INFORMATION
Catherine Naum, Communications Manager
ARC Centre of Excellence for Coral Reef Studies
Townsville, QLD AUSTRALIA
P: +61 7 4781 5979, +61 (0)428 785 895 (AEST/UTC +10)
E: catherine.naum1@jcu.edu.au

study led by researchers at the ARC Centre of Excellence for Coral Reef Studies at James Cook University found fish become anxious and more cautious when water quality is degraded by sediment, an effect that could stunt their growth and damage their health.

Senior author, Associate Professor Jodie Rummer says there is more sediment in coastal waters than ever before.

“Suspended sediment concentrations in tropical coastal waters have increased substantially over the past few decades as a result of human activities. We wondered if this reduced visibility affected fish performance, especially their ability to escape predators,” she said.

The scientists, led by PhD student Sybille Hess, examined the response of one-month-old cinnamon anemonefish to a simulated predator attack after they had been living in a sediment-filled tank for seven days.

“We found the fish responded faster and were able to dart away from the simulated predator attack more effectively than those living in clear-water, which suggests the fish are on high alert owing to the decrease in visibility,” said Ms Hess.

She said fish in turbid water were also less active when looking for food and avoided open areas.

“But while the faster responses and more cautious foraging may increase survival rates in low-visibility environments where predators are present, there is a price to be paid.”

Dr Rummer said the additional energy spent avoiding predators reduces the energy available for growth, maintenance and reproduction, and may ultimately have equal or greater effects on prey populations than predators themselves.

“It’s particularly bad for juvenile reef fishes, as survivorship is already quite low during this critical life-history stage.”

She said that while juvenile anemone-fish frequently migrate between sea anemones, with which they have a symbiotic relationship, such behaviour could be too risky under turbid conditions.

“More cautious behaviour, such as we observed in elevated suspended sediments, may not only reduce movement within their home range, potentially limiting their access to food, but may also reduce the ability of juveniles to find a suitable anemone to call home.

“Just simply enduring reduced visibility may be enough to affect fish. When fish feel as though they are constantly at risk, this perceived risk takes energy away from other important tasks – side-effects could include impaired growth and a compromised immune system.”

Dr Rummer said predators that depend on clear water conditions to catch their prey may also be affected by turbid conditions, which will be the next question for the team to investigate.

Citation: Hess, S, Allan, BJM, Hoey, AS et al. (2019) Enhanced fast-start performance and anti-predator behaviour in a coral reef fish in response to suspended sediment exposure. Coral Reefs 38(1): 103-108

Contact:

Dr Jodie Rummer
E: jodie.rummer@jcu.edu.au
M: 0439 166 171

Acting Communication Manager:

Melissa Lyne
E: melissa.lyne@gmail.com
M: 0415 514 328

Link to paper here.

Video and images available here. Please credit as marked.

Check out this video produced by the Australian Academy of Science showcasing previous work by the authors.

Queensland’s coastal shark numbers are continuing a 50-year decline, in sharp contradiction of suggestions of ‘exploding’ shark populations, according to an analysis of Queensland Shark Control Program data.

Researchers from the ARC Centre of Excellence for Coral Reef Studies at The University of Queensland (CoralCoE) and Griffith University analysed data from the program, which has used baited drumlines and nets since 1962 to minimise human-shark interactions, and now spans 1760 km of the Queensland coastline.

CoralCoE researcher and lead author of the study Dr George Roff said historical baselines of Queensland shark populations were largely unknown, despite a long history of shark exploitation by recreational and commercial fisheries.

“Explorers in the 19th century once described Australian coastlines as being ‘chock-full of sharks’, yet we don’t have a clear idea of how many sharks there used to be on Queensland beaches,” he said.

“Shark populations around the world have declined substantially in recent decades, with many species being listed as vulnerable and endangered.”

By analysing the Queensland Shark Control Program data, the research team reconstructed historical records of shark catches to explore changes in the number and sizes of sharks over the past half century.

“What we found is that large apex sharks such as hammerheads, tigers and white sharks, have declined by 74 to 92 per cent along Queensland’s coast,” Dr Roff said.

“And the chance of zero catch – catching no sharks at any given beach per year – has increased by as much as seven-fold.”

“The average size of sharks has also declined – tiger sharks and hammerhead sharks are getting smaller.”

“We will never know the exact numbers of sharks in our oceans more than half a century ago, but the data points to radical changes in our coastal ecosystems since the 1960s.”

“The data acts as a window into the past, revealing what was natural off our beaches, and provides important context for how we manage sharks.”

“What may appear to be increases in shark numbers is in reality a fraction of past baselines, and the long-term trend shows ongoing declines.”

“While often perceived as a danger to the public, sharks play important ecological roles in coastal ecosystems.”

“Large apex sharks are able to prey on larger animals such as turtles, dolphins and dugongs, and their widespread movement patterns along the coastline connects coral reefs, seagrass beds and coastal ecosystems.”

“Such losses of apex sharks is likely to have changed the structure of coastal food webs over the past half century.”

The research is published in Communications Biology (DOI: 10.1038/s42003-018-0233-1).

Citation: Roff G, Brown CJ, Priest MA & Mumby PJ. (2018) Decline of coastal apex shark populations over the past half century. Communications Biology 1:223

Media:

Dr George Roff, g.roff@uq.edu.au, +61 432 931 051

Dr Christopher Brown, chris.brown@griffith.edu.au, +61 439 835 343

The future of the world’s coral reefs is uncertain, as the impact of global heating continues to escalate. However, according to a study published today in Nature Climate Change, the response of the Great Barrier Reef to extreme temperatures in 2017 was markedly different to one year earlier, following two back-to-back bouts of coral bleaching. Remarkably, corals that bleached and survived 2016 were more resistant in 2017 to a recurrence of hot conditions.

“Dead corals don’t bleach for a second time. The north lost millions of heat-sensitive corals in 2016, and most of the survivors were the tougher species. As a result of bleaching, the mix of species is changing very rapidly,” said lead author Prof Terry Hughes, Director of the Australian Research Council Centre of Excellence for Coral Reef Studies (Coral CoE), headquartered at James Cook University.
“We were astonished to find less bleaching in 2017, because the temperatures were even more extreme than the year before,” he said.
The new research highlights the extent of damage, or “geographic footprint” of multiple coral bleaching events across the 2,300 km length of the world-heritage listed area.

The back-to-back heatwaves bring the total number of mass bleaching events on the Great Barrier Reef to four over the past two decades (in 1998, 2002, 2016 and 2017). The scientists found that only 7% of the Great Barrier Reef escaped bleaching entirely since 1998, and after the 2017 event, 61% of reefs have now been severely bleached at least once.

“We found, using the National Oceanic and Atmospheric Administration’s (NOAA) satellite-based coral bleaching tools, that corals in the north of the Great Barrier Reef were exposed to the most heat stress in 2016. A year later, the central region saw the most prolonged heating,” said co-author Dr Mark Eakin, from NOAA’s Coral Reef Watch program, in Maryland, USA.

The southern third of the Great Barrier Reef was cooler in both years due to local weather conditions, and escaped with only minor bleaching.

“It’s only a matter of time before we see another mass-bleaching event, triggered by the next marine heatwave, driven by global heating,” said co-author Dr Andrew Hoey of Coral CoE at James Cook University. “One of the worst possible scenarios is we’ll see these southern corals succumb to bleaching in the near future.”

“The outcome in 2017 depended on the conditions experienced by the corals one year earlier. We called that ‘ecological memory,’ and show that these repeating events are now acting together in ways that we didn’t expect,” said Prof Hughes.

“We’ve never seen back-to-back mass coral bleaching before on the Great Barrier Reef, in two consecutive summers. The combined footprint has killed close to half of the corals on two-thirds of the world’s largest reef system,” said Dr Hoey.

“We need urgent global action on greenhouse emissions to save the world’s coral reefs. Australia should be – but regrettably isn’t – at the forefront of tackling global heating,” said Prof Hughes.

Citation: Hughes TP, Kerry JT, Connolly SR, Baird AH,  Eakin CM, Heron SF, Hoey AS, Hoogenboom MO, Jacobson M, Liu G, Pratchett MS, Skirving W & Torda G (2019). Ecological memory modifies the cumulative impact of recurrent climate extremes. Nature Climate Change Vol 9, pp 40–43

IMAGES
Link to video and images here.
Please credit as marked.

CONTACTS FOR INTERVIEWS

Prof Terry Hughes
Director, ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0) 400 720 164, +61 (0)7 4781 4000 (AEST/UTC +10)
Email: terry.hughes@jcu.edu.au

Dr Andrew Hoey
Coral CoE at James Cook University
Townsville, QLD AUSTRALIA
P: +61 7 4781 5979, +61 (0) 0458 174 583 (AEST/UTC +10)
E: andrew.hoey@jcu.edu.au

Dr Mark Eakin
U.S. National Oceanic & Atmospheric Administration
College Park, MD U.S.A.
P: +1 (301) 502 8608 (EST/UTC -5)
E: mark.eakin@noaa.gov

FOR FURTHER INFORMATION

Melissa Lyne, acting Communications Manager
ARC Centre of Excellence for Coral Reef Studies
P: +61 (0) 428 785 895 (AEDT/UTC +11)
E: melissa.lyne@gmail.com

Scientists have solved the mystery of why some closely-related species of an iconic reef fish have vastly different colour patterns, while others look very similar.

Innovative research led by scientists at the ARC Centre of Excellence for Coral Reef Studies based at James Cook University, examined the differences in appearance of 42 species of the butterflyfish.

They found that on reefs where closely related butterflyfish species ranges overlap, the differences in colour patterns between the two were most pronounced.

The team used high-resolution digital colour photographs to quantify colour patterns and explore how they were influenced by evolutionary processes.

“Our results show that, over millions of years, butterflyfishes have evolved the greatest diversity of visual markings when they live in the same area as other, closely related species,” said lead author and PhD student Christopher Hemingson.

“Crucially, we also found that this only happens when both species have ranges that are of similar sizes,” said Mr Hemingson.

“We were surprised to find that when one species’ range is a lot larger than the neighbouring species, the pattern is reversed – with the colour pattern of overlapping species found to be less different,” said co-author Dr Peter Cowman.

Professor David Bellwood, a co-author and senior investigator, noted that this is the first time geographic range dynamics have been shown to be an important predictor of colour differences among marine fish species.

“This research is the first of its kind to quantify colour and pattern differences simultaneously among butterflyfish species. It showed us that colour pattern differences can evolve very quickly among species (within 300,000 years) but then remain stable over millions of years,” said Professor Bellwood.

“Colour is far more complicated than just looking different from other species,” said Mr Hemingson.

“These colour patterns also depend specifically on what other species are also present. It is an interesting piece to the puzzle and may help explain why reef fishes are so colourful.”

The paper “Colour pattern divergence in reef fish species is rapid and driven by both range overlap and symmetry” is published in the journal Ecology Letters.

Citation: Hemingson, RF, Cowman, PF, Hodge, JR &  Bellwood, DR (2018). Colour pattern divergence in reef fish species is rapid and driven by both range overlap and symmetry. Ecology Letters DOI: 10.1111/ele.13180

Images available here. Please attribute as indicated.

Contact

Mr Christopher Hemingson
ARC Centre of Excellence for Coral Reef Studies
James Cook University, Townsville, QLD, 4811, Australia
Email: christopher.hemingson@my.jcu.edu.au

Dr Peter Cowman
ARC Centre of Excellence for Coral Reef Studies
James Cook University, Townsville, QLD, 4811, Australia
Office: +61 7 4781 3194
Email: peter.cowman@jcu.edu.au

Prof. David Bellwood
ARC Centre of Excellence for Coral Reef Studies
James Cook University, Townsville, QLD, 4811, Australia
Office: +61 7 4781 4447
Email: david.bellwood@jcu.edu.au

For More Information

Catherine Naum
Communications Manager
ARC Centre of Excellence for Coral Reef Studies
T: +61 (7) 4781 6067
M: +61 (0) 428 785 895
E: catherine.naum1@jcu.edu.au

Climate change must no longer be viewed as a “tragedy of the commons”, say researchers from the University of Exeter and the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

December marks the 50th anniversary of the paper that popularized the concept of tragedy of the commons: it argued that individuals will always take advantage of a common resource and so degrade it. A new paper argues that the theory limits the way climate change is viewed.

“New findings about how people understand and act suggest that climate change will more likely be solved by appealing to moral arguments rather than purely scientific ones,” said Professor Katrina Brown, one of the paper’s authors.

Professor Brown and Professor Neil Adger, both from the University of Exeter, and Professor Joshua Cinner from the ARC Centre of Excellence for Coral Reef Studies at James Cook University, say that in order to make urgently needed progress in addressing climate change, governments need to promote climate change as a moral issue. And policy needs acknowledge that politicians often make their decisions based on reputation.

“Doing the right thing matters to people, but not everyone agrees what the right thing is. Some people emphasize fairness, others duty and patriotism. We need to appeal to the full range of these values,” said Professor Cinner, co-author of the new paper in the journal Global Environmental Change.

They argue new ways of speaking about climate change that focus on the wide variety values and priorities of people with conservative and liberal views should be harnessed to encourage more concern and action on climate change.

American ecologist and philosopher Garrett Hardin wrote his paper “The tragedy of the commons” in 1968.

Lead author, Professor Brown, said: “Hardin’s theory has been very influential. It has been used to design global co-operation on climate change such as the Paris Agreement. But there is a rapidly closing window to transform the economy and avoid climate catastrophe.

“New social science points the way to political mobilization based on sense of duty, respect for nature and others, and solidarity. These are now more relevant and more likely to win the day.”

“Addressing climate change requires building inclusive moral frames, and fundamental changes in governance systems to better manage the associated risks.”

Their paper is entitled: “Moving climate change beyond the tragedy of the commons.”

Citation: Brown, K, Adger, WN, & Cinner, JE (2019) Moving climate change beyond the tragedy of the commons. Global Environmental Change 54: 61-63. DOI: 10.1016/j.gloenvcha.2018.11.009

For More Information:

University of Exeter, UK
Press Office
P: +44 (0)1392 724828
E: pressoffice@exeter.ac.uk

Catherine Naum, Communications Manager
ARC Centre of Excellence for Coral Reef Studies
Townsville, QLD Australia
P: +61 7 4781 6067
E: catherine.naum1@jcu.edu.au

 

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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