Category Archives: Coral Reefs

“National targets give virtually no chance of protecting coral reefs”

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A study published in Nature Reports Climate Change on 11 June 2009 reports on the consequences of the emission targets being set by countries, including the US and Australia, in the lead-up to the international climate negotiations in Copenhagen in December.

Joeri Rogelj and colleagues conclude, “National targets give virtually no chance of constraining warming to 2 °C and no chance of protecting coral reefs.”

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Citing recent publications of Jacob Silverman and colleagues, they note in relation to ocean acidification and coral reefs:

Acid test
While we have focused on global mean temperature increase here, it is increasingly clear that independent of its effect on temperature, growing CO2 concentrations in the atmosphere will also threaten the world’s oceans owing to acidification. The latest research indicates substantial risk to calcifying organisms at atmospheric CO2 concentrations of 450 ppm, with all coral reefs halting their growth and beginning to dissolve at concentrations of 550 ppm. The best Halfway to Copenhagen emissions pathway would result in CO2 concentrations above this level shortly after 2050.

Unless there is a major improvement in national commitments to reducing greenhouse gases, we see virtually no chance of staying below 2 or 1.5 °C. Coral reefs, in addition, seem to have certainly no chance if the work of Jacob Silverman and colleagues is correct.

Could coral reefs close to seagrass be buffered from ocean acidification?

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coral1Seagrass meadows have long been known to be highly productive habitats, and as a result producing oodles of oxygen in the midday sun. Anyone who’s ever snorkelled over a seagrass meadow on a sunny day will have seen seagrass leaves furiously bubbling away. This photosynthetic productivity can result in an increase in the pH of the water column (becoming less acidic). This is primarily because CO2 and, thus, its form when dissolved in seawater, carbonic acid, are withdrawn from the water as a substrate for photosynthesis. This results in the production of the bubbling O2. But what are the consequences of such a pH change?

Recent research by the Universities of Dar es Salaam, Tel Aviv and Stockholm published in the Marine Ecology Progress Series (volume 382) and conducted in tropical seagrass meadows of East Africa have investigated the impact of such pH changes.  Semasi et al. revealed that this change in pH can cause localised increases in the rates of calcification and growth of calcareous algae such as Hydrolithon sp., Mesophyllum sp., and Halimeda sp., hence seagrass buffers high acidity (low pH).

As has been debated by ClimateShifts previously, there is increasing evidence that oceans have become more acidic since the start of the industrial era. Recent predictions suggest that oceans could become much more acidic over the next 100 years as a result of increasing CO2 emissions. Current predictions suggest that this will result in (amongst other things) declining reef calcification rates.

Although this study by Semesi et al. shows the effects of seagrass upon algae, the questions on the lips of many reef conservationists will be whether such findings are cross transferable to the calcification of corals. These studies in Zanzibar were small scale, carried out in seagrass mesocosms, and currently only reflect small scale patterns. Whether seagrass productivity can result in larger spatial scale changes that could buffer pH changes on nearby reefs remains to be seen. Maybe the World should be looking at seagrass meadows with greater attention?

Reef Relief: Queensland Government enacts new leglisation on the GBR

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In a major step to protecting the inshore reefs of the GBR, the Queensland Government have inacted fairly dramatic legislation on the use of fertilisers and pesticides on farms in the reef catchment. Under the new rules, farmers in the Mackay-Whitsunday, Burdekin Dry Tropics and Far North’s Wet Tropic catchments must keep records on fertiliser usage and apply ‘no more than the optimum amount of fertiliser to their soil’. The use of the pesticides Atrazine, Diuron, Ametryn, Hexazinone or Tebuthiuron are also subject to an array of new rules and regulations.

Although not without controversy, this is great news for the reefs on the GBR. Over 32,000 tonnes of fertiliser (worth $32 million) leaches out into the Great Barrier Reef lagoon every year through overfertilisation on farms. There is strong scientific evidence showing that elevated pesticide and nutrients from the land associated with flood waters induce coral bleaching and mortality during flood years (see here for a great post by Jon Brodie on the subject).

Strict controls on fertilisers and pesticides and close monitoring of large and high-risk farms in north Queensland will help heal the Great Barrier Reef, Climate Change and Sustainability Minister Kate Jones said today.

Ms Jones, introducing the Great Barrier Reef Protection Bill 2009 to State Parliament, said the legislation would reduce the levels of farm chemicals and sediment harming the Reef.

“The Bill will help detox the Great Barrier Reef and give it a fighting chance,” Ms Jones said.

“The Great Barrier Reef is Australia’s most treasured possession and is worth nearly $6 billion to our economy, supporting about 63,000 jobs.

“But its health has been deteriorating from a number of factors, including damaging run-off from sugar cane fields and beef cattle farms in Reef catchments.

“We must do all we can to ensure this natural wonder of the world survives long after us and that means minimising man-made harm. This Bill is good for the Reef and it makes good business sense for farmers.

“While many farmers are doing the right thing and have minimised their impact, we must go further than the voluntary approach to get the results we need faster.

“Our Reef is too precious so we have no option but to act now and act decisively.

“The Bligh Government told Queenslanders last election that we would regulate to reduce the amount of fertiliser and pesticides entering the Reef by 50 per cent in four years.

“The Bill makes good on that commitment. It’s backed by strong scientific evidence and it gives the Reef every chance of recovering from the damage inflicted by over-fertilising, toxic pesticides and soil run-off.”(Link to media release)

Question and answer session on the new Great Barrier Reef Protection Amendment Bill

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I thought this was well worth posting – a comprehensive ‘who, how, what and why’ answer session by the government that neatly answers most common concerns over the new reef protection amendment.

Question – Who and where will the Great Barrier Reef Protection Amendment Bill 2009 affect? When will regulation and Bill commence and come into effect?

Question: Who will the Great Barrier Reef Protection Amendment Bill 2009 affect?

Answer:

•    Around 4,500 farmers are likely to be affected.

•    Around 1,000 farmers will initially be required to prepare Environmental Risk Management Plans (ERMPs).

•    The level of regulatory impact on individual farmers can vary considerably depending on the hazards, problems, and management practices on each property.

•    ERMPs will be required for cattle graziers with a property greater than 2,000 hectares in the Burdekin Dry Tropics and sugarcane farmers with properties greater than 70 hectares in the Wet Tropics catchment.

Question: Where does the Great Barrier Reef Protection Amendment Bill 2009 and regulations apply?

Answer:

•    All cattle grazing of more than 100 ‘standard cattle units’ and all sugarcane farming in the Wet Tropics, Burdekin Dry Tropics, and Mackay Whitsunday catchments.

Question: When will the new regime come into effect?
•    The initially targeted high risk farmers who must prepare and implement an Environmental Risk Management Plan will have nine months in total from 1 January 2010 to submit their ERMP which will be implemented over a number of years depending on their circumstances.
•    If further ‘hot spots’ are identified, farmers and graziers in these areas will be required to submit a Plan within three months of being notified.
•    Farmers will be notified by the Department of Environment and Resource Management either directly, by media advertising or by the Department’s other communications channels.

Question – How will the new regulations improve the health of the Great Barrier Reef?

Answer:
•    The major threats to the health of the Reef are ocean acidification and coral bleaching due to climate change and reduced water quality due to agricultural pollution.
•    The new threat from climate change means it is now even more critical to reduce the existing damage from land runoff of nutrients, sediments, and pesticides to improve the Reef’s water quality and its resilience to the new impacts of climate change.
•    Reducing all of the threats is essential to a healthy Reef, however regulating agricultural runoff is the most immediate and efficient response to halt the decline of the Reef’s health.
•    Therefore, the new regulation focuses on catchment-scale reduction of water pollution from agriculture to increase the health of the Great Barrier Reef by improving the water quality in our waterways generally.

Question – How do we know that agricultural activities are impacting on the Great Barrier Reef?

Answer:
•    There is substantial and credible scientific evidence that indicates the Reef’s health is suffering long-term decline from the nutrient, pesticide and sediment runoff from broad-scale agriculture in adjacent river catchments.

•    In 2008, the Scientific Consensus Statement on Water Quality in the Great Barrier Reef was released by 13 leading scientists after reviewing 500 technical papers.

•    It confirmed the presence of sediment, nutrients and pesticides in the Reef—up to 60 km offshore—in amounts that will cause it harm. In catchment waterways these contaminants were found at levels proportional to the land under agriculture—there were more contaminants where there was more agriculture.

•    Also in 2006 the Great Barrier Reef Marine Park Authority’s annual marine monitoring report found high concentrations of the agricultural pesticide, diuron, at many river mouth sites.

•    Peer reviewed science in 2006 by leading Reef scientists documented the marked decline in the richness of coral for 400 kilometres south of Cooktown—right next to the catchments dominated by these industries.

•    We know that new science, recently or about to be published, reiterates the growing problem of pesticides and herbicides in freshwater and marine environments.  A paper published this year by Robert Packett and others indicates serious atrazine contamination in the Reef catchment.

Question – What do farmers need to do under the new regime?

Answer:

The bill applies to cattle and sugarcane production located in the priority catchments of the Burdekin Dry Tropics, Mackay-Whitsunday and the Wet Tropics.

Cattle grazing and sugarcane growing will now be designated agricultural environmentally relevant activities under the Environmental Protection Act.

What farmers will be required to do under the bill:

•    Record and report as required on such things as use of fertiliser, weed poisons and farming management practices.

•    If applying fertiliser, they must calculate the optimum amount for application using a soil test and other information and not apply more than the optimum amount, so as to prevent over-fertilisation and reduce run-off.

•    Some specified high risk Farmers will need to prepare and implement an ERMP to entrench the adoption of best management practices and continuous improvement.

•    They will need to be aware of the change to the restrictions on the use of key damaging pesticides in the Chemical Usage (Agricultural and Veterinary) Control Regulation 1999.
Great Barrier Reef Protection Amendment Bill 2009

Question – How are you choosing who needs to prepare and keep Environmental Risk Management Plans?

Answer:

1.    Cattle graziers in the Burdekin Dry Tropics catchment with a property greater than 2000 hectares.

Reason:

•    This will capture most large-scale and extensive cattle grazing properties that contribute the majority of sediment runoff to the Reef.

•    This property threshold will also ensure that coastal pasture and dairy operations that are considered lower priority contributors to runoff do not initially fall under the requirement.

2.    Sugarcane farmers in the Wet Tropics catchment with property greater than 70 hectares.

Reason:

•    The average size of sugarcane farms in the Wet Tropics is 60 to 70 hectares which will capture a large proportion of the catchment with proportionately fewer producers, hence allowing the most pollution reduction for the least cost.

•    The Australian Centre for Tropical Freshwater Research report for the State of Queensland’s Great Barrier Reef Protection Package states that: ‘The Wet Tropics generates large amounts of harmful nutrient and pesticide runoff from sugarcane that is directly harming the Great Barrier Reef.  Seventy-eight percent of all nitrogen pollution from human activities comes directly from sugarcane in the Wet Tropics.’

Question – How will you make sure farmers are doing the right thing? How will you know they are not keeping wrong records?

Answer:

•    Farmers’ records, management plans, and chemical and fertiliser use will be audited on risk targeted basis and compliance enforced if necessary.

•    Online advice, tools and forms will be provided free to farmers to help them keep records and improve management practices. This will be supported by ‘how to’ guidance that explains why the information is being collected and what form the records should take.

•    Farmers without access to the internet will be provided with local access to online reporting systems and regional staff.  There will also be training courses available.
•    To save farmers work, the required records will as far as possible align with current automated record keeping systems such as AgDat.  Industry organisations will be invited to help design the tools to ensure the maximum practicality and benefit to farmers and the Reef.

•    There will also be regional reviews where the Department will write to farmers and request their records. This will be risk-based focussing on catchments where poor performance is hindering achievement of Reef Plan targets.

Question – How did the government identify which agricultural chemical to control?

Answer:
•    Key agricultural chemical products to be restricted are: diuron, atrazine, ametryn, hexazinone and tebuthiuron
•    The herbicide residues most commonly found in Reef’s surface waters are diuron, atrazine, ametryn, hexazinone. They come from areas of sugarcane cultivation.
•    Residues of tebuthiuron come from the use of ‘grassland’ on grazing lands for woody weed control.
•    Strong scientific evidence shows the presence of pesticides in the Great Barrier Reef, which have been detected at harmful concentrations up to 60kilometres offshore during the wet season.
•    A recent report noted that river water plumes entering the Reef contain a profile of diuron, atrazine, and hexazinone residues.  Contrary to general belief, these pesticides were not removed by natural physical or biological progress like mixing or dilution with seawater.
•    The study found that exposure to high diuron concentration for four days will hinder the coral’s ability to produce energy, causing bleaching.

Question – Will there be a cost burden on farmers?

Answer:
•    The level of regulatory impact on property owners will vary considerably depending on the level of risk to the Reef of the activity and what current management practices are in place.
•    It is expected that the cost of the regulatory measures are likely, in many instances, to be offset by cost savings from increased productivity and reduced input costs.  Those whose risks are greatest will usually have most to gain by reducing the loss of fertiliser and pesticides, which are increasingly expensive.
•    Many farmers are already doing the right things by keeping a management plan, applying the correct level of fertiliser, using pesticides responsibly and taking measures to minimise Reef run-off.  These farmers will not be greatly affected.
•    For example, a cattle grazing operation implementing a land management agreement under the Delbessie arrangement for leasehold land is likely to be able to satisfy relevant requirements for sediment management on grazing lands without significant additional work.
•    Those who have a plan to implement management practices equivalent to an ERMP will not have to duplicate their effort.
•    The cost of record keeping, preparing plans and reporting under the legislation will vary according to the level of risk of the activity.  Low risk activities will only incur small costs and take very little time.
•    Property owners classified ‘low risk’ will not be required to have an ERMP.
•    For a medium level risk activity an ERMP may cost around $3,500 to prepare.
•    Grazing property owners with an ERMP may need to fence erosion hazard areas, provide off-stream watering points and manage vegetation cover to reduce sediment loss. These measures will vary greatly in cost, but may average around $5,000 a year over three years.  There are major economic benefits in applying these improved management practices.
•    However, ERMPs will be flexible to allow for the spread of investment in new practices over a reasonably long period.
•    There is evidence that optimal application of fertiliser possibly using precision farming equipment (possibly costing about $30,000) might save about $3,000 per year in reduced fertiliser costs for each farmer.  Farmers can use contractors to apply fertiliser or share costs of equipment between a number of farmers.
•    A worst case scenario relates to property owners who perform poorly and:
o    have done no training relating to the use of atrazine, ametryn, hexazinone, diuron, and tebuthiuron handling and application
o    have no property plans relating to environmental management
o    use the atrazine, ametryn, hexazinone, diuron, and tebuthiuron across all areas of their operation
o    do not do any soil testing
o    have not implemented practices that minimise environmental impact
o    do not access any subsidy or grants for training or implementation.
•    The upfront cost to such an operator would be approximately $6,000, consisting of: training ($500); soil testing ($320) and preparation of an ERMP ($5,000 assuming a specialist is employed.  For a simple low risk activity, the farmer should be able to prepare the ERMP without paying for assistance, utilising online and other support provided free by the government).
•    The implementation cost would vary depending on the property and costs would need to be traded off against the benefits in productivity and profits as a result of lower input costs and increased yield.

Question – Will the new laws affect food quality?

Answer:
•    The new laws will not affect food quality.

•    The new laws encourage adoption of better management practices that improve water quality.  It does not require farmers to change practices with respect to production of food that would impact on quality.

•    Food crops will take up the nutrients they need from the soil. Fertiliser that is excess to the crop’s requirements will run off properties to the Reef.

•    The use of atrazine, ametryn, hexazinone, diuron, and tebuthiuron will be restricted in waterways and drainage lines and within certain distances from waterways.  As these are herbicides, there will be no impact on the quality of food.
•     A concern may be around the security of the food generated for local and export markets. The new laws may have some implementation costs for farmers but these costs should be weighed against the benefits in productivity and profits as a result of lower input costs or increased yield. Therefore there should be no impact on security of food supply.

Question – How will we know if Reef run-off has been reduced in four years and the legislation’s objectives have been achieved?

Answer:
•    There will be a comprehensive monitoring and evaluation program to effectively measure the legislation’s progress towards its targets.
•    Program monitoring and evaluation will focus on identifying what effect the regulation has on the level of land practice change and pollution reduction.
•    This data will be modelled to estimate the likely improvement of the quality of water entering the Reef.
•    Monitoring and evaluation will be done collaboratively between Queensland and Australian Government departments, the Great Barrier Reef Marine Park Authority and regional groups.
•    Development and design of the monitoring and evaluation program is underway in conjunction with statistical experts. The program will be thoroughly peer reviewed.

Question – What else are Governments doing to protect the Reef?

Answer:

•    Since the commencement of Reef Plan in 2003, the Queensland Government has invested about $125 million on natural resource management in Reef catchments, including reef water quality related projects.
•    This is an investment in the health of the entire catchment that is ultimately essential to a healthy reef ecosystem.
•    Earlier this year, the Queensland Government introduced a moratorium on the clearing all native re-growth vegetation within 50 metres of identified watercourses in the Wet Tropics, Burdekin and Mackay/Whitsunday.
•    The Delbessie land management agreement between rural leaseholders and the Government commenced in 2008 offering extended leases to landholders in Reef catchments who improve the condition of their land.
•    Water Quality Improvement Plans are being completed by regional natural resource management groups to identify regional targets for water quality improvement and the management actions needed to reach those targets in specified timeframes.
•    Under the Reef Plan, nutrient management zones were identified to focus water quality investments on the critical ‘hot spots’.
•    The Australian Government’s out a $200 million Reef Rescue Plan which is supporting farmers, regional groups and industry groups to help make management practice change to protect the Reef.
How the programs fit together

•    The Australian Government’s Reef Rescue program will deliver an immediate improvement in management practices. This will be locked in for the long term by the Queensland Government’s regulatory package through its extension support services and regulatory measures.

•    The key issue is the need to significantly reduce pollutant loads of up to 90,000 tonnes year of nutrient mainly from cane farming and up to 66 million tonnes of sediment mainly from cattle grazing.

•    The targets announced as part of the Reef Protection Package by the Queensland Government in 2009 aim is to reduce nutrient and pesticides by 50 percent in four years.

•    Achieving Reef Plan targets will require the permanent adoption of management practices, compatible with Reef health, by farmers of about 80 per cent of cane land and over half of cattle grazing land.  It is likely that less than 10 per cent of this land is currently managed at the necessary standard.

•    While it will be impossible to determine the individual contribution to water quality improvement from any program, the outcome will be better, faster and more permanent with both programs operating together in harmony.

•    This is because Reef Rescue grants mainly help farmers to purchase equipment while the regulation ensures equipment is used to achieve the required outcome and continues to be used and replaced when it depreciates. It locks in the benefits of Reef Rescue for the long term and prevents the waste of the Reef Rescue investment.

•    Furthermore, the regulation is performance based so it drives innovation and continuous improvement, further reducing the call on Commonwealth resources for future Reef protection.

‘Reef beef’ – Great Barrier Reef pesticide controls anger farmers

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Conservationists are anticipating a victory in their long running battle with farmers over the effects of runoffs from pesticides and fertilisers on the Great Barrier Reef.

Legislation has been introduced into the Queensland Parliament that would restrict farmers’ use of the chemicals. Failure to comply could trigger a $30,000 fine.

But farmers say there’s no proven links to coral bleaching and infestations of the crown of thorns starfish, and it’s just part of Green preference deals.

(Link to ABC Radio, click below for audio)

[audio:https://climateshifts.org/media/reefbeef.mp3]

Testing the ‘macroalgal dominated coral reefs’ paradigm

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The paradigm of ‘coral vs algae’ has become entrenched in coral reef science over the last few decades. The classic example of this paradigm in the Caribbean was from a paper published byTerry Hughes in a 1994 article in the journal Nature, entitled “Catastrophes, Phase Shifts and Large-Scale Degradation of a Caribbean Coral Reef”. The paper documented a series of disturbances in the late 1970’s and early 1980’s, including two major hurricanes, a disease outbreak and the loss of a seaweed-grazing urchin, after which coral cover declined dramatically from ~70 percent cover to less than 10%, and macroalgal cover to rose to almost complete dominance >90% .

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Temporal trends of coral and algae on Jamaican Reefs (top left, 1975 - 1995, Discovery Bay showing dramatic declines and corals and corresponding dominance of macroalgae, top right 1995 - 2004 from Dairy Bull Reef showing a rapid recovery and reversal of the macroalgal phase shifts)

Since then, reefs throughout the Caribbean have undergone dramatic declines in coral cover, leading to the regionwide collapse of the two dominant reef building corals, Acropora cervicornis and Acropora palmata. One ‘good news’ story did come out from a neighbouring reef in Jamaica called ‘Dairy Bull’ reef, where Joshua Idjadi and a team reported a doubling of live coral cover over the last decade, resetting the balance from a macroalgal dominated reef to a coral reef.

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Photograph of Dairy Bull Reef in 2003 showing the recovery of the branching coral Acropora cervicornis. No macroalgae to be seen!

Since this iconic case study, a considerable quantity of scientific literature has been devoted to management principles, herbivorous grazing pressure and the reversal of macro-algal dominated reefs. However, documented examples of regional ‘phase shifts’ between coral and algae in the literature are surprisingly few and far between (asides from a few notable exceptions). John Bruno & Elizabeth Selig, two coral reef researchers who have developed a considerable dataset on coral reefs throughout the world, decided to test this assumption by randomly samply for regional trends and patterns in algal cover – much the same as an epidimiologist would determine the generality of case reports in the medical literature.

John and his team trawled through an immense number of reef surveys (3,500 to be exact) from over 1,800 reefs across the globe between 1996 and 2006, and developed a ‘phase shift index’ based upon corals and macroalgae. They then tested this index in four geographic regions (Greater Caribbean, Florida Keys, Indo-Pacific and the Great Barrier Reef) to see if the severity of phase shifts altered over the decade between 1996 – 2006. Their findings were  surprising, and might prove to be somewhat controversial…

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A coral reef in the Caribbean dominated by macroalgal cover

Whilst phase shifts were indeed more common in the Caribbean than elsewhere, very few of the worlds reefs fell into either a stable ‘coral reef dominated’ or a ‘macroalgal dominated’ category. Furthermore, the ‘severity’ of phase shifts at a regional level was much less severe than the classic examples of macroalgal dominance, such as the Jamaican coral decline story. The data also suggested that there was no trend (>1995) towards macroalgal dominance in the Florida Keys or Indo-Pacific. Coral cover during this period (1996 – 2006) did decline (primarily due to crown of thorns starfish plagues), but their was no corresponding increase in macroalgal cover at all during this time.

Bruno et al argue that the apparent mismatch between the local scale descriptions of macroalgal dominance and regional scale patterns was caused by a gross generalisation of a relatively small number of ‘atypical’ case studies. This in itself is no small finding, and may go along way to altering the way we manage coral reefs. These findings may be somewhat controversial, it’s hard to disagree with the data. In what’s bound to throw the proverbial cat amongst the pigeons, the authors conclude:

“Since the Jamaica story was an anomaly, it makes a poor foundation for general models of reef ecology (e.g., Knowlton 1992, Bellwood et al. 2004 ). The current paradigm of reef management and ‘‘resilience’’ is based in large part on the perception that most of the world’s reefs are being overrun by seaweed (Szmant 2001, Precht and Aronson 2006, Knowlton 2008). This belief led to the argument that reef managers should focus primarily  on conserving herbivores or water quality (Szmant 2002, Pandolfi et al. 2003, Bellwood et al. 2004 ). While these are clearly important objectives of management, our analysis suggests that the macroalgae problem has been exaggerated.

Overfishing and poor land use practices may trigger widespread coral to macroalgal phase shifts in the future, but to date, the principal form of coral reef degradation has been the loss of reef-building corals, with only limited and localized increases in macroalgae. Therefore, the primary goal for reef managers and policy makers should be the conservation of coral populations, without which the entire system would collapse.”

Disease-hunting scientist: Dr Laurie Richardson and black band disease in coral

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Just finished reading a great excerpt from a book called ‘Disease-hunting scientist’ by a Canadian author called Edward Willett. The scientist in question is Dr Laurie Richardson from Florida International University, who is well known for her work on ‘black band disease’ (see image above) on Caribbean coral reefs. I’ve never read Willett’s work before (and can’t vouch for the book itself), but I’ve long respected Dr Richardson’s research into black band microbial communities, and the ‘interview’ offered a few intriguing insights. More below:

At 287,231 square kilometers, coral reefs are less than a tenth of a percent of the total ocean floor. But they support more than a million species of marine life. They are also dying, from pollution, overfishing—and black-band disease, among others.

Dr. Richardson started her career researching “microbial mats,” communities of microbes that live in the sulfur-rich water of hot springs. She then worked in Wisconsin on a NASA project that used satellite data in the study of aquatic ecosystems. That led to three years at NASA’s Ames Research Centre in California learning remote sensing and image processing, which in turn landed her in Florida with a NASA-funded grant to work on algal pigments and remote sensing.

One day, while she was diving for fun on a coral reef, somebody showed her an example of black-band disease-and she immediately recognized it as similar to the microbial communities she’d studied in hot-spring outflows.

She looked in the scientific literature, and no one else had made that connection. And that was how the research she’s now been doing for more than 15 years began. (Read more)

Why the existence of ‘heat tolerant’ corals does not mean that coral reefs will be able to resist climate change.

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ofuA recent study published by Tom Oliver and Stephen Palumbi from Stanford University in the journal ‘Marine Ecology Progress Series‘ seems to suggest yet another miraculous and novel mechanism by which corals will ‘escape’ the pressures of global warming. In a nutshell, the researchers found that corals from ‘warm pools’ at Ofu Island (American Samoa) hosted ‘heat tolerant’ types of symbiotic algae, whereas corals from cooler lagoons hosted more ‘heat sensitive’ types of algae. When combined with regional data, Oliver & Palumbi suggest that in regions where annual maximum temperatures reached 29 – 31C, coral ‘avoided bleaching’ by hosting higher proportions of ‘heat tolerant’ algal symbionts.  Whilst these findings are interesting, the study is a long way from the suggestion in the paper and accompanying press release that coral reefs are ‘adapting’ and ‘may survive global warming’, and relies mainly on over interpreting their results. There are several issues at hand:

  1. Whilst these results highlight both the diversity of bleaching responses at a community level and the array of algal symbionts, the finding of heat tolerant corals has been shown throughout the Indo-Pacific and Great Barrier Reef on a number of previous occasions. The suggestion that this pattern results from a correlation in local scale heating based upon a limited sampling regime is far from proving causality
  2. The identification of a few remnant tough (‘heat resistant’) corals does not equate to these corals spreading out and maintaining coral reef ecosystems under rapid climate change.  Such coral types are rare, and are likely to have minimal impacts in sustaining reef populations under future climate change scenarios.  In making this argument, the authors are leaping across a myriad of issues that would need to be proven before we could pin our hopes on a few odd-ball corals for building and maintaining functional reef ecosystems into the future.
  3. Although corals have been shown to be able to ‘shuffle’ symbionts (change the proportion of ‘heat sensitive’ to ‘heat tolerant’ types), to date it has never been shown that corals can uptake ‘novel’ symbiont types from external sources. So, corals that are ‘heat sensitive’ can’t acquire ‘heat tolerant’ types from the environment. In light of rapid increases in sea surface temperatures under future climate scenarios, these ‘heat sensitive’ corals will undergo mass mortality, as they are unable to simply ‘adapt’ or switch to more resistant types.
  4. Any successful proliferation of these heat resistant genotypes will depend on a stabilised climate. Continual increases in temperatures means that these genotypes will have a harder time proliferating and stabilising, given that selection pressures will continue to intensify. This is akin to the bar in a high jump competition being placed ever higher.  As time goes on, fewer and fewer ecotypes from the population will be able to pass beyond the barrier.
  5. The authors seem to imply that functional reef ecosystems (and countless ecosystem services) will be ‘saved’, based upon a specific niche of ‘heat resistant’ corals.  The issue here is not the survival of corals species – many of whom will be resistant to extinction under global climate change (albeit as rare organisms) – but the destruction of functional coral reef ecosystems that millions of people depend on. Unfortunately, a few corals in a warm rock pool in Samoa will not save the day or the planet.
  6. These results do not address ocean acidification – the ‘other CO2’ issue along with temperature that threatens all calcifying organisms. To somehow imply that coral reefs are not facing problems from climate change because Oliver and Palumbi found a few tough coral genotypes in a rock pool, verges on the incredible.

These points aside, the study is an interesting one in terms of exploring heat stress in corals. My main issue is that Oliver & Palumbi have massively overextended their conclusions, which is particularly apparent in the associated press release.  Needless to say, these sorts of overblown claims are less than useful in the lead-up to the critically important COP15 negotiations in Copenhagen at the end of year.

Update, 25th May

And here is a classic example of why such media releases are less than useful, courtesy of the detractor Andrew Bolt:

http://blogs.news.com.au/heraldsun/andrewbolt/index.php/heraldsun/comments/shock_news_reef_not_dying#55023

World Ocean Conference (Part I): Key coral reefs ‘could disappear’

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BBC News, 13th May 2009: The world’s most important coral region is in danger of being wiped out by the end of this century unless fast action is taken, says a new report.

The international conservation group WWF warns that 40% of reefs in the Coral Triangle have already been lost. The area is shared between Indonesia and five other south-east Asian nations and is thought to contain 75% of the world’s coral species. It is likened to the Amazon rainforest in terms of its biodiversity.

It’s 2099, and across south-east Asia, a hundred million people are on the march, looking for food. The fish they once relied on is gone. Communities are breaking down; economies destroyed. That is what we can expect, says the new WWF report, if the world’s richest coral reef is destroyed. And that, it says, could happen this century.

It’s billed as a worst-case scenario, but the report’s chief author, Professor Ove Hoegh-Guldberg, says it is not as bad as the future we’re currently headed towards.

“Up until now we haven’t realized how quickly this system is changing,” says Professtor Hoegh-Guldberg.

“In the last 40 years in the Coral Triangle, we’ve lost 40% of coral reefs and mangroves – and that’s probably an underestimate. We’ve fundamentally changed the way the planet works in terms of currents and this is only with a 0.7 degree change in terms of temperature.

“What’s going to happen when we exceed two or four or six?”

Avoiding a worst-case scenario would need significant reductions in greenhouse gas emissions and better controls on fishing and coastal areas, says the report. The Coral Triangle covers 1% of the earth’s surface but contains a third of all the world’s coral, and three-quarters of its coral reef species. If it goes, an entire eco-system goes with it – and that, says Prof Hoegh-Gudberg, has serious consequences for its ability to tackle climate change.

“Pollution, the inappropriate use of coastal areas, these are destroying the productivity of ocean which is plummeting right now. That is the system that traps CO2 – 40% of CO2 goes into the ocean.

“Now if we interrupt that, the problems on planet earth become even greater,” says Prof Hoegh-Gudberg.

Indonesia is hosting the World Ocean Conference this week because, it says, oceans have been neglected so far in global discussions on climate change.

It wants the issue to have a bigger profile at UN climate talks later this year.