Examining the multi-scale dynamics of reefs, from population dynamics to macroevolution
Advancing the fundamental understanding of the key processes underpinning reef resilience.
James Cook University Townsville
Queensland 4811 Australia
Phone: 61 7 4781 4000
A study has found that coral with high levels of fat or other energy reserves can withstand the impact of annual coral bleaching events, compared to coral with lower levels of fat reserves.
Coral bleaching events occur when sea temperatures rise as the result of climate change. This results in the breakdown of the symbiosis between the coral and their zooxanthellae (which gives coral most of its colour) and threatens the survival of the coral.
The study was carried out by scientists from The University of Western Australia’s Oceans Institute and the ARC Centre of Excellence for Coral Reef Studies, The Ohio State University’s School of Earth Sciences and the University of Delaware’s School of Marine Science and Policy.
Lead author, Dr Verena Schoepf from the ARC Centre of Excellence for Coral Reef Studies at UWA and a Research Associate from the Oceans Institute, says tropical coral is extremely sensitive to heat stress.
“Three global bleaching events have already occurred since the 1980s and will likely occur annually later this century. Therefore, it has become more urgent than ever to know how tropical coral can survive annual bleaching – one of the major threats to coral reefs today,” she said.
“Already bleaching events have resulted in significant amounts of coral dying causing impact to ocean ecosystems, but up until now it was largely unknown whether coral could recover between annual bleaching events.”
Dr Schoepf says the research which simulated annual coral bleaching found some species of coral such as the mustard hill coral (Porites astreoides) were severely affected by repetitive bleaching events, but other coral such as the finger coral (Porites divaricata) and the mountainous star coral (Orbicella faveolata) could recover quickly.
“When coral is bleached, it no longer gets enough food energy and so it starts slowing down in growth and loses its fat and other energy reserves – just like humans do during times of hardship,” she says.
“The coral then becomes increasingly weak and susceptible to disease, and when bleaching is prolonged, it can die.”
Dr Andrea Grottoli from The Ohio State University’s School of Earth Sciences says over the next decades, coral bleaching events were likely to occur more and more frequently and increasingly impact coral reefs around the world, contributing to their worldwide decline.
“Bleaching will significantly change the future of coral reefs with heat sensitive coral unable to recover,” Dr Grottoli says.
“Our research will help with predicting the persistence of coral reefs because knowledge of their capacity to recover from annual bleaching is critical information for these models.”
The research, which was funded by the USA National Science Foundation to Drs. Grottoli and Warner, will be published in the international journal Proceedings of the Royal Society B: Biological Sciences here on Wednesday 18 November.
Dr Verena Schoepf – (+61 8) 6488 3644
Jess Reid (UWA Media) (+61 8) 6488 6876
An international team of scientists, led by the ARC Centre of Excellence for Coral Reef Studies at the University of Western Australia, has analysed coral cores from three reefs in the eastern Indian Ocean to understand how marine heat waves unfold among the unique coral reefs of Western Australia.
The research, which also involved researchers from Australian Institute of Marine Science (AIMS), Curtin University, CSIRO and the University of Santa Barbara California, was published today in the international journal Nature Communications.
Research team leader, Professor Malcolm McCulloch from the ARC Centre of Excellence for Coral Reef Studies at UWA, said the findings provided new insights into how the change in air temperature between the Maritime Continent and the central Pacific affected the wind and ocean circulation leading up to heat waves in the far away south-eastern Indian Ocean.
The Maritime Continent is a term commonly used by scientists to describe the region between the Indian and Pacific Oceans including the archipelagos of Indonesia, Borneo, New Guinea, the Philippine Islands, the Malay Peninsula and the surrounding seas.
“Due to the lack of long-term observations of marine climate we used long coral cores, with annual growth bands similar to tree rings, to provide a record of the past,” Professor McCulloch said.
“By measuring the chemical composition of the coral skeleton from year to year we could see how changing winds and ocean currents in the eastern Indian Ocean were impacted by climate variability in the western tropical Pacific Ocean.”
Dr Jens Zinke, a Senior Research Fellow at Curtin University and lead author of the research paper while at UWA, said the long coral records allowed the scientists to look at the occurrence of marine heat waves as far back as 1795.
When the Maritime Continent is warmer than the central Pacific, a pattern amplified during strong La Niña events in the tropical Pacific, it creates an ocean temperature gradient which reinforces warming in the far western Pacific and south-eastern Indian Ocean.
Dr Zinke said this happened through a series of ocean-atmosphere interactions that resulted in a strengthened Leeuwin Current and unusually warm water temperatures and higher sea levels off south-west Western Australia.
“A prominent example is the 2011 heat wave along WA’s reefs which led to coral bleaching and fish kills,” he said.
The international team found that the temperature gradient in the western Pacific was particularly strong after the late 1990s. The coral cores also reveal that this temperature gradient was intensified in the early and late 1800s, yet against a much lower background ocean temperature off WA.
The authors concluded that strong warming over the past 215 years made it easier for natural climate events, such as La Niña and West Pacific temperature gradient events, to exceed the critical temperature threshold for marine heat waves and mass coral bleaching to occur off Western Australia.
This will likely diminish the future ability of the coral reefs of Western Australia to serve as a climatically stable area for coral growth under future ocean warming.
Dr Janice Lough, AIMS Senior Principal Research Scientist, said it was likely that, given ongoing global climate change, future La Niña events coupled with a strong West Pacific temperature gradient would result in more extreme warming and high sea-level events with potentially significant consequences for the maintenance of WA’s unique marine ecosystems.
The researchers used core samples of massive Porites colonies from the Rowley Shoals, Ningaloo Reef and the Houtman-Abrolhos Islands off the Western Australian coastline which are directly in the path of warm water transport from the Western Pacific to the waters of southern Australia.
The researchers measured the chemical composition of the annual coral growth bands to reconstruct sea surface temperature of the West Australian shelf for 215 years, from 1795 to 2010.
Paper : Coral record of southeast Indian Ocean marine heatwaves with intensified Western Pacific temperature gradient by J. Zinke, A. Hoell, J. M. Lough, M. Feng, A. J. Kuret, H. Clarke, V. Ricca, K. Rankenburg & M. T. McCulloch is published in the journal, Nature Communications http://www.nature.com/ncomms/2015/151023/ncomms9562/full/ncomms9562.html
Professor Malcolm McCulloch – (+61 8) 6488 1921
Dr Jens Zinke (Lead author of the research paper) (+61 4) 0411 529 360
David Stacey (UWA Media and Public Relations Manager) (+61 8) 6488 3229 / (+61 4) 32 637 716
Eleanor Gregory (ARC CoE Communications Manager) – +61 (0) 428 785 895
New research into the impact of climate change has found that warming oceans will cause profound changes in the global distribution of marine biodiversity.
In a study published in the journal Nature Climate Change an international research team modelled the impacts of a changing climate on the distribution of almost 13 thousand marine species, more than twelve times as many species as previously studied.
The study found that a rapidly warming climate would cause many species to expand into new regions, which would impact on native species, while others with restricted ranges, particularly those around the tropics, are more likely to face extinction.
Professor John Pandolfi from the ARC Centre of Excellence for Coral Reef Studies at the University of Queensland says global patterns of species richness will change significantly, with considerable regional variability.
“This study was particularly useful because it not only gave us hope that species have the potential to track and follow changing climates but it also gave us cause for concern, particularly in the tropics, where strong biodiversity losses were predicted,” says Professor Pandolfi.
“This is especially worrying, and highly germane to Australia’s coral reefs, because complementary studies have shown high levels of extinction risk in tropical biotas, where localized human impacts as well as climate change have resulted in substantial degradation.”
To model the projected impact of climate change on marine biodiversity, the researchers used climate-velocity trajectories, a measurement which combines the rate and direction of movement of ocean temperature bands over time, together with information about thermal tolerance and habitat preference.
They say the analysis provides the simplest expectation for the future distribution of marine biodiversity, showing recurring spatial patterns of high rates of species invasions coupled with local extinctions.
Professor Elvira Poloczanska from CSIRO says, “This study shows how climate change will mix up biodiversity patterns in the ocean. Ecological communities which are currently distinct, will become more similar to each other in many regions by the end of the century”
Dr David Schoeman from the University of the Sunshine Coast says the model suggests that there is still time to act to prevent major climate-related extinctions outside of the topics.
“Results under a scenario in which we start actively mitigating climate change over the next few decades indicates substantially fewer extinctions than results from a business-as-usual scenario,” Dr Schoeman says.
“Possibly more worrying, though, is the imminent development of novel biotic assemblages. We have little idea of how these new combinations of species in ocean systems around the world will affect ecosystem services, like fisheries. We should be prioritising ecological research aimed specifically at addressing this question.”
Professor Pandolfi warns the resultant novel combinations of resident and migrant species will present unprecedented challenges for conservation planning.
“Above all, this study shows the broad geographic connections of the effects of climate change – conservation efforts need to be facilitated by cooperation among countries to have any real chance of combating the potentially severe biodiversity losses that a changing climate might impose.”
The paper, Climate velocity and the future of global redistribution of marine biodiversity by Jorge Garcia Molinos, Benjamin S. Halpern, David S. Schoeman, Christopher J. Brown, Wolfgang Kiessling, Pippa J. Moore, John M. Pandolfi, Elvira S. Poloczanska, Anthony J. Richardson and Michael T. Burrows is published in the journal Nature Climate Change http://dx.doi.org/10.1038/nclimate2769
Professor John Pandolfi, firstname.lastname@example.org, +61 (0) 400 982 301
Professor Elvira Poloczanska, Elvira.email@example.com, +61 (0) 428 741 328
Dr David Schoeman, firstname.lastname@example.org, +61 (0) 423 982 898
Eleanor Gregory (media), email@example.com
In a world first study, researchers at the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University have unlocked the genetic mystery of why some species are able to adjust to warming oceans.
In a collaborative project with scientists from the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, the researchers examined how reef fish’s genes responded after several generations living at higher temperatures.
“Some fish have a remarkable capacity to adjust to higher water temperatures over a few generations of exposure,” says Dr Heather Veilleux from the Coral CoE.
“But until now, how they do this has been a mystery.”
Using cutting-edge molecular tools the research team identified 53 key genes that are involved in long-term, multi-generational acclimation to higher temperatures.
“By understanding the function of these genes we can understand how fish cope with higher temperatures,” explains Dr Veilleux.
“We found that shifts in energy production are key to maintaining performance at high temperatures,” says Dr Veilleux.
“Immune and stress responses also helped fish cope with warmer water.”
The project involved rearing coral reef fish at different temperatures for multiple generations in purpose-built facilities at James Cook University.
“We then used state-of-the-art genetic methods to examine gene function in the fish,” says Dr Tim Ravasi from KAUST.
“ By matching gene expression to metabolic performance of the fish we were able to identify which genes make acclimation to higher temperatures possible,” adds Professor Philip Munday from the Coral CoE.
The study is the first to reveal the molecular processes that may help coral reef fishes and other marine species adjust to warmer conditions in the future.
“Understanding which genes are involved in transgenerational acclimation, and how their expression is regulated, will improve our understanding of adaptive responses to rapid environmental change and help identify which species are most at risk from climate change and which species are more tolerant,” Dr Veilleux says.
Molecular processes of transgenerational acclimation to a warming ocean, by Heather D. Veilleux, Taewoo Ryu, Jennifer M. Donelson, Lynne van Herwerden, Loqmane Seridi, Yanal Ghosheh, Michael L. Berumen, William Leggat, Timothy Ravasi and Philip Munday is published in the journal Nature Climate Change.
(Images must carry credits as listed in Dropbox folder)
Dr Heather Veilleux – firstname.lastname@example.org, +61 7 47814850ARC Centre of Excellence for Coral Reef Studies
Professor Philip Munday – Philip.email@example.com, +61 (0) 7 47815341ARC Centre of Excellence for Coral Reef Studies
Professor Timothy Ravasi – firstname.lastname@example.org +966-544700067
KAUST Environmental Epigenetic Program (KEEP) and the Red Sea Research Center
Scientists in Queensland have used historic media to measure the decline in Queensland’s pink snapper fishery, highlighting a drop of almost 90 per cent in catch rates since the 19th Century.
Researchers from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at the University of Queensland and the Department of Agriculture Fisheries and Forestry examined thousands of newspaper articles dating back to1870 to reveal the historic catch rates for the iconic Queensland fishery.
“We found that 19th century recreational fishers would regularly catch hundreds of fish off the coast of Queensland, often in just a few hours of fishing,” says Dr Ruth Thurstan, a Research Fellow from the Coral CoE.
Combining historical data with statistical analyses allowed the researchers to calculate catch rates, which are the number of fish caught per hour fishing per day, for nearly 300 fishing trips between 1871 and 1939.
When the researchers compared the findings to contemporary fishing trips, they found that recent catch rates averaged just one-ninth of historical levels.
The old news articles have given researchers unparalleled insights into the history of the Queensland snapper fishery.
“When we searched through these old newspapers we were amazed by the level of detail they provided,” Dr Thurstan says.
“They give us a much better understanding of just how rich and productive this fishery used to be, as well as providing us with some fascinating insights into the development of offshore recreational fishing in Queensland.”
“Crucially, these newspaper articles place the modern day fishery into a longer-term perspective that isn’t available using only official records. This helps us understand the changes that have occurred in the fishery over time, and provides an additional piece of the puzzle for those managing this fishery today,” Dr Thurstan says.
Study co-author, Professor John Pandolfi, also from Coral CoE agrees.
“This is one of the most comprehensive perspectives on historical trends in catch rates for Australian fisheries ever compiled,” Professor Pandolfi says.
“We expect similar trends to be uncovered for other Australian fisheries.”
‘Nineteenth century narratives reveal historic catch rates for Australian snapper (Pagrus auratus)’ by Ruth H Thurstan, Alexander B Campbell and John M Pandolfi is published in the journal Fish and Fisheries.
Dr Ruth Thurstan: +61 (0) 450 586 263 or email@example.com;
Professor John Pandolfi: + 61 (0)7 3365 3050 or firstname.lastname@example.org
Eleanor Gregory, Communications Manager: +61 (0)7 47816067, +61 (0)428 785 895 or email@example.com
A shark’s habitat can reduce its sensitivity to rising CO2 levels, according to Australian scientists.
Globally, ocean acidification – linked to emissions of greenhouse gases – remains a major concern and scientists say it will harm many marine species over the next century.
Researchers from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University have found that the epaulette shark, a species that shelters within reefs and copes with low oxygen levels, is able to tolerate increased carbon dioxide in the water without any obvious physical impact.
“As part of the study we exposed the sharks to increased CO2 for more than two months, mirroring the levels predicted for the end of the century,” says study co-author Dr Jodie Rummer from Coral CoE.
“We then tested the sharks’ respiratory system, measuring how much oxygen it needed to maintain basic function under the experimental conditions.”
The researchers found the sharks were regulating their systems to counter the higher levels of acid in their bodies. Importantly, Dr Rummer explains, the sharks’ ability to cope with low oxygen levels – similar to that found in its natural habitat – was unaffected by high CO2 levels.
Study co-author, Professor Philip Munday from the Coral CoE says the sharks’ physiological adaptations, which enables it to cope with the conditions within reefs, makes them better able to tolerate ocean acidification.
“Species that live in shallow reef environments, where they can experience naturally high CO2 levels on a regular basis, may have adaptations that make them more tolerant to future rises in CO2 levels than other species.”
Professor Munday says the next critical step is to test the sensitivity of other shark species to ocean acidification.
“Species that live in the open ocean may be more susceptible to future acidification than those that naturally live in shallow reef environments where they already experience a variable environment.”
Dr Rummer adds that by determining which animals are more and less susceptible to high CO2 than others, scientists will be better able to predict the future consequences of ocean acidification on marine ecosystems.
A product of its environment: The epaulette shark (Hemiscyllium) exhibits physiological tolerance to elevated environmental CO2 by Dennis D.U Heinrich, Jodie Rummer, Andrea J. Morash, Sue-Ann Watson, Colin A. Simpfendorfer, Michelle R Heupel and Philip L. Munday is published in the journal Conservation Physiology.
Link to paper: http://conphys.oxfordjournals.org/content/2/1/cou047.full
Epaulette shark sheltering in reef – image credit: M.Heupel.
Dr Jodie Rummer, Coral CoE – +61 7 4781 5300, +61 (0) 439 166 171
Professor Philip Munday, Coral CoE – +61 7 4781 5341
Eleanor Gregory, Coral CoE Media – +61 (0) 428 785 895
One of Australia’s leading coral reef ecologists fears that reef biodiversity may not provide the level of insurance for ecosystem survival that we once thought.
In an international study published today, Professor David Bellwood from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) says we need to identify and protect the most important species within reef ecosystems.
In coral reefs, just as in any modern-day society, there are vital jobs that keep the ecosystem safe and functioning.
Professor Bellwood says, in many cases, a single species of fish carries out a unique and essential role, making the ecosystem vulnerable to loss of that species.
Professor Bellwood and a team of international colleagues, led by Professor David Mouillot from the University of Montpellier, examined the ‘jobs’ of over six thousand coral reef fish species across 169 locations worldwide.
“What we often assume is that if we lose one species on a reef, there are many others that can step in and take over their job,” Professor Bellwood explains.
But he and his colleagues fear that’s not the case. They believe if a reef ecosystem were to lose a species that carried out a ‘specialist’ role, the impact could be profound.
“We could easily lose a type of fish that has no substitute, no replacement,” Professor Bellwood says.
“Unfortunately we have become complacent, we have assumed that biodiversity will buy us some time and give us some insurance, but that’s not necessarily the case.”
“It’s not about numbers of species,” adds Professor David Mouillot. “Biodiversity is important and desirable in an ecosystem, but it is not necessarily the key to being safe and secure”.
Professor Bellwood singles out the parrotfish, explaining that out of thousands of reef fish species, on the Great Barrier Reef only one parrotfish species regularly performs the task of scraping and cleaning inshore coral reefs.
“This parrotfish is a particularly valuable species,” he says, likening this finding to a large city with many inhabitants, but only one doctor.
“To protect ecosystems, we need to ensure that specific jobs are maintained,” Professor Bellwood says. “And that means we must protect the fish that do them.”
‘Functional over-redundancy and high functional vulnerability in global fish faunas on tropical reefs’ by David Mouillot, Sébastien Villéger, Valeriano Parravicini, Michel Kulbicki, Jesus Ernesto Arias-González, Mariana Bender, Pascale Chabanet, Sergio R. Floeter, Alan Friedlander, Laurent Vigliola, and David R. Bellwood appears in Proceedings of the National Academy of Sciences.
The paper is available on request.
Professor David Bellwood, Coral CoE: +44 (0) 7901 236 784, or
+61 (0) 407 175 007, firstname.lastname@example.org
(David Bellwood is travelling in the UK and is contactable on the above number between 1630 – 0600 AEST daily)
Eleanor Gregory, Communications Manager Coral CoE: +61 (0) 7 4781 6067,
0428 785 895 email@example.com
Professor David Mouillot, University of Montpellier: +33 (0) 46 714 3719
James Cook University Townsville
Queensland 4811 Australia
Phone: 61 7 4781 4000