Great Barrier Reef ‘could adapt to avoid climate doom’

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“Great Barrier Reef ‘could adapt to avoid climate doom” (1/11/2008) missed the bigger picture. While I agree that corals have a capacity to adapt to warming waters, it is my firm view that the rate of adaption will be too slow to prevent major loss of biodiversity at current levels and trends in greenhouse gas emissions.

Serious threat to the future of the Reef is not a distant theoretical possibility. The Great Barrier Reef has already had two near misses. Unprecedented, widespread coral death from bleaching occurred in 1998 and 2002. About 50 per cent of the Reef’s corals bleached over a very hot summer with most corals then recovering when peak temperatures eased (only five per cent died).

The Great Barrier Reef’s capacity to survive this mounting pressure is through building the Reef’s health and its ability to repair itself. Poor quality water not only contributes to the risk of bleaching it can also inhibit the corals ability to recover after a bleaching event. Australians are responding to this challenge. We are cleaning up our rivers that now carry excess fertiliser and pesticides; restoring coastal wetlands that not only catch excess silt from floods but provide nursery habitats for many species of fish; preventing pollution from sewage; preventing overfishing of top predators such as sharks and avoiding the accidental loss of iconic species such as dugong and turtle.

The UN report “Confronting Climate Change: Avoiding the Unmanageable and Managing the Unavoidable” captures the  essence of this global problem. The strongest possible action on emissions reduction is needed on a global scale, and local action is needed to help maintain the Reef’s ability to withstand the inevitable and increasing pressure it faces each summer.

R  Reichelt
Chairman, Great Barrier Reef Marine Park Authority

National Geographic photographs southern right whales

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Amongst the winners of the National Geographic “best wild animal photos of 2008” (link) is this incredible photograph of a diver and a southern right whale, taken in New Zealand. Like most whale populations, the souther right whale was extensively hunted from the mid 18th century up until the early 1970’s, severely depleting the southern Pacific populations around the New Zealand coastal waters . Since the ‘official’ worldwide ban on hunting right whales in 1937, southern right whales began to appear off the coast of New Zealand from the early 1960’s onwards. See the full set of photographs by Brian Skerry over at the National Geographic website (Link)

Bush administration considering two massive Pacific marine reserves

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One of the many big political surprises in the US yesterday was news that the Bush administration was considering implementing two or more massive marine reserves in US territories in the Pacific.  The move  would protect some of the regions most remote coral reefs.  What isn’t so surprising is that, according to the Washington Post, über vice president Dick Cheney is trying to scale back or block Bush’s plans (doesn’t the former work for the latter?).

Read the whole story in the Washington Post here.

President Bush’s vision for protecting two vast areas of the Pacific Ocean from fishing and mineral exploitation, a move that would constitute a major expansion of his environmental legacy, is running into dogged resistance both inside and outside the White House and has placed his wife and his vice president on opposite sides of the issue.

In 2006 he designated the nearly 140,000-square-mile Papahanaumokuakea Marine National Monument in the northwestern Hawaiian Islands, creating what at the time was the world’s largest protected marine area. Scientists have advocated designating more such areas to protect them from the effects of overfishing, pollution and global warming, which are degrading oceans worldwide.

“There’s pretty strong evidence that everyone will benefit from the establishment of no-take reserves,” said Jane Lubchenco, a professor of marine biology at Oregon State University, adding that fish populations rebound both within the protected reserves and in nearby fishing grounds. “The administration made a major step forward in designating the Papahanaumokuakea National Monument, but that one alone is not enough to protect the full range of places and habitats and species that need to be protected. It will be part of [Bush’s] legacy, but his ocean and environmental legacy could be much, much more.”

One of the two marine reserves, or “marine conservation management areas”, includes a wide swath of the central Pacific ocean and some of the world’s most remote and pristine coral reefs, such as Kingman Atoll in the Line Islands.

Sadly, the article also highlights how close we came to having some similar reserves implemented closer to the continental US:

Bush initially explored the idea of establishing other protected areas closer to U.S. shores, including one off the southeastern coast near a group of deep-sea corals and another in the Gulf of Mexico. After commercial and recreational fishing interests and oil companies objected, the administration decided to pursue existing resource-management plans in those areas instead.

Political analysts interpret these moves as an attempt by Bush to build some sort of legacy before leaving office in early 2009.  We should know later in the year whether any of his planned reserves are indeed implemented.  And if they aren’t, I suspect the next president will be even more amenable to such logical solutions to some of our major environmental crises.

“Protecting places like this is one of the few things a sitting president can do that will live on in posterity and be remembered long after the other decrees and orders have been forgotten,”  said Joshua Reichert, managing director of the Pew Environmental Group.  “It would signal to the nation and the world that the sea needs to be treated as a threatened resource, and it will open up an era of global ocean conservation.”

Claudia McMurray, the U.S. assistant secretary of state for oceans, environment and science, said the administration will be “working up until the last week” of Bush’s term on the initiatives.  “While it would take a significant amount of work, we haven’t ruled it out,” she said. “We feel fairly confident, scientifically, there are so many unique species in that area, from that standpoint, we think it’s important to wall off as much as we can.”

Avoiding confusion for stabilization targets for climate change and ocean acidification

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Long Cao and Ken Caldeira from the Carnegie Institution at Stanford have a new paper in Geophysical Research Letters on atmospheric carbon dioxide (CO2) stabilization and ocean acidification, a critical topic for current marine science and public policy. Hoegh-Guldberg et al (2007) illustrated the essential chemistry at the heart of this problem as follows:

Essentially, as CO2 dissolves into the oceans it forms an acid leading to decreased coral calcification and growth through the inhibition of aragonite formation (the principal crystalline form of calcium carbonate deposited in coral skeletons). The increased acidity caused by increasing atmospheric CO2 is known as ocean acidification and it is a separate, though inter-related, phenomenon to increased temperatures caused by CO2 acting as a greenhouse gas.

Cao and Caldeira (2008) found “that even at a CO2 stabilization level as low as 450 ppm, parts of the Southern Ocean become undersaturated with respect to aragonite [and] therefore, preservation of existing marine ecosystems could require a CO2 stabilization level that is lower than what might be chosen based on climate considerations alone.”

These results are similar to Hoegh-Gulberg et al (2007), who concluded “… contemplating policies that result in [CO2]atm above 500 ppm appears extremely risky for coral reefs and the tens of millions of people who depend on them directly, even under the most optimistic circumstances.”

Hoegh-Guldberg et al (2007) illustrated the expected the conditions of coral reefs under different levels of atmospheric carbon dioxide and temperature increases as follows:

These findings are very significant for governments around the world and other policy-makers because much of the current policy debate on climate change focuses on stabilizing greenhouse gases, including carbon dioxide, between 450-550 parts per million carbon dioxide equivalents, thereby allowing a rise in mean global temperatures of around 2-3°C (e.g. Stern 2007; Garnaut 2008; Australian Treasury 2008).

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“Great Barrier Reef could adapt to climate change, scientists say” – Facts, fallacies and fanciful thinking.

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The Australian newspaper published an article this weekend entitled “Great Barrier Reef could adapt to climate change, scientists say”.

THE prediction of a prominent marine biologist that climate change could render the Great Barrier Reef extinct within 30 years has been labelled overly pessimistic for failing to account for the adaptive capabilities of coral reefs.

University of Queensland marine biologist Ove Hoegh-Guldberg said yesterday that sea temperatures were likely to rise 2C over the next three decades, which would undoubtedly kill the reef.

But several of Professor Hoegh-Guldberg’s colleagues have taken issue with his prognosis.

Andrew Baird, principal research fellow at the Australian Research Council’s Centre for Excellence for Coral Reef Studies, said there were “serious knowledge gaps” about the impact rising sea temperatures would have on coral.

“Ove is very dismissive of coral’s ability to adapt, to respond in an evolutionary manner to climate change,” Dr Baird said.

“I believe coral has an underappreciated capacity to evolve. It’s one of the biological laws that, wherever you look, organisms have adapted to radical changes.”

Dr Baird acknowledged that, if left unaddressed, climate change would result in major changes to the Great Barrier Reef.

“There will be sweeping changes in the relative abundance of species,” he said. “There’ll be changes in what species occur where.

“But wholesale destruction of reefs? I think that’s overly pessimistic.”

Dr Baird said the adaptive qualities of coral reefs would mitigate the effects of climate change.

I must say I’m a little amazed that Andrew Baird has come out with such poorly supported statements.  In fact, his conclusions seem to depend almost entirely on his personal opinion!  The argument that corals are able to magically “adapt” over one or two decades to climate change (even though their generation times are often longer) has come up many times over the years – always, with a complete dearth of evidence to support it.

I wrote to Andrew Baird yesterday, to try and understand if there was something that he knew that I might have missed in the scientific lecture.  In response, Andrew sent me a recent article published by Jeff Maynard and himself (Maynard et al 2008).

Unfortunately, the article is an opinion piece (a bit like the newspaper article) that is poorly supported by anything but the most scant evidence (if you could actually call it that) from literature.   I have responded to these types of articles before, but frustrated, here we go again:

Maynard et al (2008) state the following as important evidence that corals can adapt to changes in the environment, and therefore that they can adapt to the current very rapid changes in ocean temperature and acidity.

“..geographic variation in bleaching thresholds within species, sometimes over scales <100km, provides circumstantial evidence for ongoing evolution of temperature tolerance between both species and reef”

Let me start by saying that no credible biologist would doubt the role of evolution in the shaping of the physiology and ecology of corals with respect to temperature.  Biological populations evolve in response to stress.  However, the mere observation of geographic variation in thermal tolerance, does not give any hint  about the rates or the length of time that these changes have taken to occur.  Importantly, this statement does not equate to evidence that thermal tolerance can evolve in ecological time.  The only way that Andrew Baird could convince anyone of this particular somewhat fanciful leap of logic is to present data that show that coral populations can rapidly evolved in the period of years.  They can’t, and they haven’t.

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Jacques Piccard, deep sea explorer dies at age 86

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Jacques Piccard, the legendary scientist, explorer (and childhood hero of mine)  passed away yesterday at his home in Lake Geneva.

Jacques Piccard helped his father invent the bathyscaphe, a vessel that allows people to descend to great depths. On Jan. 23, 1960, he and Lt. Don Walsh of the United States Navy took the vessel, named the Trieste, into the Mariana Trench in the Pacific to a depth of 35,800 feet, nearly seven miles below sea level. It remains the deepest human dive ever.

“By far the most interesting find was the fish that came floating by our porthole,” Mr. Piccard said. “We were astounded to find higher marine life forms down there at all.” Solar Impulse said the discovery of living organisms at such a depth played a crucial role in the prohibition of nuclear waste dumping in ocean trenches. (link to NY Times obituary)

“Estate agents told me not to talk: climate expert”

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ABC News, 29th October 2008

A climate change scientist says real estate agents have threatened to make his life difficult if he continues to publish research about how vulnerable particular properties are to rising sea levels and coastal erosion.

Professor Andrew Pitman works at the Climate Change Research Centre at the University of New South Wales.

He says real estate agents do not like potential buyers asking questions about climate change based on his research.

Professor Pitman has told the ABC’s Local Radio that several agents have asked him to stop talking about how vulnerable certain properties are.

“More explicitly [they said] ‘We’re nervous about our particular market niche in a particular suburb’,” he said.

“And, ‘We are going to start making your life difficult if you keep pointing to climate change affecting our particular location’.”

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Origins of sea fan aspergillosis

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Infectious disease outbreaks are a major cause of coral loss and reef degradation.  Evidence from paleontological studies and ecological monitoring indicate that coral disease prevalence, variety, and host range have all increased over the last 30 years.  But what is the origin of coral pathogens?  Even in the few cases where the causal pathogen has been identified, we don’t know where it came from, if it is new or newly introduced or whether it was always present on reefs, but only recently became virulent due to a mutation or environmental change.

Identifying the source of coral pathogens is a key goal of coral disease ecology with obvious importance for disease mitigation and reef management.  Coral pathogens could originate in terrestrial habitats and be introduced to the ocean following deforestation and soil runoff.  They could also be added via sewage outfalls, transported from faraway reefs in the ballast water of cargo ships, and might even be spread within and among regions by human travel.

A pair of exciting new studies clarifies the origins of sea fan aspergillosis, a major Caribbean epizootic caused by the pathenogenic fungus Aspergillus sydowii.  In the first paper, Rypien et al. (2008) used molecular markers to determine patterns of relatedness among strains of Aspergillus sydowii collected from a variety of hosts and environments. Specifically, they tested four hypotheses:

1) The Endemic Marine Hypothesis predicts that corals are infected by fungus that is native to marine habitats and therefore phylogenetically distinct from nearby terrestrial isolates.

2) The Terrestrial Runoff Hypothesis predicts that isolates from diseased corals will be most closely related to terrestrial isolates from nearby landmasses.

3) The single-origin African Dust Hypothesis predicts that isolates will have reduced genetic diversity and allelic richness, with evidence of a recent bottleneck in coral disease-causing isolates. This hypothesis also predicts that isolates will be most closely related to terrestrial isolates from Africa.

4) The multiple origins African Dust Hypothesis predicts no evidence of a recent bottleneck, with disease-causing isolates being most closely related to terrestrial isolates from Africa.

Their results essentially refute all four hypotheses and reveal a pattern of global panmixia and multiple origins, suggesting that a single source of Aspergillus sydowii into reefs is unlikely.  The results illustrate the opportunistic nature of the fungal pathogen and suggest that a diversity of isolates can cause aspergillosis.

Despite coming from very different geographic locations (Japan to North America to Europe) and different sources (diseased corals, diseased humans, dried fish), we found that all strains form a single well-connected global population. – lead author Dr. Krystal Rypien, currently a post doc at Scripps Institution of Oceanography

Aspergillus sydowii fungi in culture

Dr. Rypien added; This has important implications for the management of disease, as it means that any isolate of this fungus has the potential to cause disease in coral, and that we are not dealing with a specialized group of pathogens.  Interestingly, this is similar to a close relative, Aspergillus fumigatus, a common fungal pathogen of immune compromised humans.  Given the global distribution of A. sydowii, and evidence for multiple introductions into marine systems, it seems that this pathogen has always been present in marine systems, and changes in environmental conditions and host immune status are likely to be more important in driving patterns of disease outbreak.

The second study (Rypien 2008) tested the widely-believed hypothesis that African dust plays a role in coral epizootics in general and sea fan aspergillosis in particular.  Each year hundreds of millions of tons of dust is transported from the Sahara desert to the Caribbean.  There are indications that the volume of dust has increased as the Sahara expands and atmospheric conditions and wind patterns change.  The idea is that African dust can cause or exacerbate coral epizootics by depositing nutrients and trace elements that benefit pathogens or by transporting pathogens from terrestrial African habitats to Caribbean coral reefs.  Past studies have indeed found Aspergillus spp. in dust samples collected from the Caribbean, but none have identified the fungi to species, which turns out to be a critical shortcoming.

Dr. Rypien collected dust samples from the Caribbean and Africa, isolated Aspergillus, and identified the isolates to species using standard colony-level and microscopic morphological characteristics.  Despite yielding seven different species of Aspergillus and related taxa, there was no A. sydowii in airborne dust samples from Africa and the Caribbean or in sediment samples from Africa and the Cape Verde Islands.

The lack of A. sydowii in airborne dust and sediment samples suggests that African dust is an unlikely source of the marine pathogen A. sydowii.  Given the high richness of fungi observed, even under selective growth conditions, identification of potential pathogens to the species level is critical.

The study doesn’t entirely refute African dust as a source of Aspergillus sydowii – it is nearly impossible to prove the absence of something – but it does cast doubt on much-heralded theory.

References

Rypien, K. L. 2008. African dust is an unlikely source of Aspergillus sydowii, the causative agent of sea fan disease. Marine Ecology Progress Series 367:125-131.

Rypien, K. L., J. P. Andras, and C. D. Harvell. 2008. Globally panmictic population structure in the opportunistic fungal pathogen Aspergillus sydowii. Molecular Ecology 17:4068-4078.

Will we leave the Great Barrier Reef for our children?

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Amidst the current policy debate in Australia on climate change is a surreal argument that policies that will destroy the Great Barrier Reef (GBR) are acceptable and economically rational. Ross Garnaut was alive to the damage to the GBR when saying Australia should initially aim for a global consensus to stabilise greenhouse gases in the atmosphere at 550 parts per million. Garnaut (2008a: 38) was brutally frank in his supplementary draft report:

“The 550 strategy would be expected to lead to the destruction of the Great Barrier Reef and other coral reefs.”

His final report does not shy away from this conclusion (Garnaut 2008b).

The Australian and Queensland governments have always silently avoided this point when explaining the costs and benefits of their climate policies. Neither has ever stated a stabilisation target for the rise in global temperatures or greenhouse gases. To do so would expose them to the criticism that their policies will not save the GBR or a host of other ecosystems.

Garnaut’s frank admission reflects the findings of research of the impacts of climate change to the GBR since mass coral bleaching occurred globally in 1998 and 2002. Rising sea temperatures and increasing acidity of the oceans due to our use of fossil fuels are now well-recognized as major threats to coral reefs and the marine ecosystem generally in coming decades.

Coral bleaching and partial recovery on Pelorus Island, GBR: (a) 1998; (b) 2002; and (c) 2004. Source: Schuttenberg H and Marshall P, A Reef Manager’s Guide to Coral Bleaching (GBRMPA, Townsville, 2006), p12.

Coral bleaching and partial recovery on Pelorus Island, GBR: (a) 1998; (b) 2002; and (c) 2004. Source: Schuttenberg H and Marshall P, A Reef Manager’s Guide to Coral Bleaching (GBRMPA, Townsville, 2006), p12.

In relation to coral bleaching the IPCC (2007b: 12) found that:

“Corals are vulnerable to thermal stress and have low adaptive capacity. Increases in sea surface temperature of about 1 to 3°C are projected to result in more frequent coral bleaching events and widespread mortality, unless there is thermal adaptation or acclimatisation by corals.”

The findings of the IPCC suggest that a rise of 1°C in mean global temperatures and, correspondingly, sea surface temperatures above pre-industrial levels is the maximum that should be aimed for if the global community wishes to protect coral reefs. The range of 1-3°C is the danger zone and 2°C is not safe. Supporting this conclusion Ove Hoegh-Guldberg and his colleagues concluded in a review of the likely impacts of climate change to the GBR edited by Johnson and Marshall (2007: 295):

“Successive studies of the potential impacts of thermal stress on coral reefs have supported the notion that coral dominated reefs are likely to largely disappear with a 2°C rise in sea temperature over the next 100 years. This, coupled with the additional vulnerability of coral reefs to high levels of acidification once the atmosphere reaches 500 parts per million [CO2], suggests that coral dominated reefs will be rare or non-existent in the near future.”

The IPCC’s (2007a: 826) best estimate of climate sensitivity found that stabilising greenhouse gases and aerosols at 350 parts per million carbon dioxide equivalents (ppm CO2-eq) would be expected to lead to a rise in mean global temperatures of 1°C, stabilising at 450 ppm CO2-eq will lead to a rise of 2°C, and stabilising at 550 ppm CO2-eq will lead to a rise of 3°C.

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