Mild summer coral bleaching at Heron Island

One of my students (Chris Doropoulos) noticed the onset of coral bleaching up at Heron Island. Here is Chris’s report (and photographs attached):

We arrived to Heron Island on the 5th of February and did a quick snorkel from the jetty to the shipwreck that afternoon. We noticed that lots of the Acropora aspera colonies (branching corals, see photographs above) were bleached, and that it appeared recent. What was most striking is that, in general, only the east facing sides of the colony branches were bleached and the west facing sides of branches were still intact. The bleaching had only affected the shallowest colonies, and in general it was only the A. aspera. On returning to the area 5 days later, the bleaching appeared to have become more severe and affected a much larger area of the A. aspera beds. Most of the colonies were bleached, some uniformly, but some still only on the east facing side. We didn’t notice any other bleaching on the reef flat or reef slope around the island, so at the moment the bleaching seems very localised to the harbour area.

Diversity of Corals, Algae in Warm Indian Ocean Suggests Resilience to Future Global Warming

Todd LaJeunesse from Penn State has an interesting new paper out about zooxanthellae diversity and coral acclimation to ocean warming.  Also see the great video of Todd talking about this work here.

Penn State researchers and their international collaborators have discovered a diversity of corals harboring unusual species of symbiotic algae in the warm waters of the Andaman Sea in the northeastern Indian Ocean.  “The existence of so many novel coral symbioses thriving in a place that is too warm for most corals gives us hope that coral reefs and the ecosystems they support may persist — at least in some places — in the face of global warming,” said the team’s leader, Penn State Assistant Professor of Biology Todd LaJeunesse.  According to LaJeunesse, the comprehensiveness of the team’s survey, which also included analysis of the corals and symbiotic algae living in the cooler western Indian Ocean and Great Barrier Reef area of Australia, is unparalleled by any other study. The team’s findings will be published during the week ending 20 February 2010 in an early online issue of the Journal of Biogeography.

Corals are colonies of tiny animals that derive nutrients and energy from golden-brown, photosynthetic algae that live inside the corals’ cells.  “This symbiotic relationship is sensitive to changes in the environment,” said LaJeunesse.  “For example, because the algae are photosynthetic, they are very sensitive to changes in light.  They are also sensitive to temperature,” he said.  “An increase in sea-surface temperature of just a few degrees Fahrenheit for a period of several months can cause many of the coral-algal symbioses to break down and the algae to be expelled.  This process is known as bleaching because it leaves behind the clear animal tissue and the white skeleton underneath.  When bleaching is severe, due to either high temperatures or low light availability, corals soon die without their symbiotic partners.”

LaJeunesse said that continued global warming eventually may cause the demise of coral-reef ecosystems, which would have major impacts on the tourism and food-fisheries industries.  According to team member Ove Hoegh-Guldberg, a professor at the University of Queensland in Australia, coral-dominated reefs may become scarce within the next 30 to 50 years, given the increase in the number of bleaching events that recently have taken place.

LaJeunesse2-2010small2.jpg

“The fact that the Andaman Sea and other regions around Southeast Asia are home to such a high diversity of corals is surprising because the water there is so warm and sometimes murky,” said LaJeunesse.  “The inshore locations we surveyed are not the sort of places where you would expect to see thriving coral communities.  Not only is the water warm and murky, but the tidal flux is so great that many of the corals can spend hours out of water, exposed to the harsh sun and dry air.”

The team identified the species of algae that associate with corals, as well as giant clams, sea anemones, zoanthids, and other reef-dwelling animals that form close symbiotic relationships with the single-celled algae that are referred to as zooxanthellae.  In the Andaman Sea, the scientists found a variety of seemingly thermally tolerant algae species, with one species being particularly abundant.  Called Symbiodinium trenchi, the species is a generalist organism — one that is able to associate with a variety of hosts. Corals harboring this symbiont appear to be tolerant of high heat. LaJeunesse found the same species in the Caribbean Ocean during a bleaching event that took place in 2005.  “Symbiodinium trenchi, which normally occurs in very low numbers in the Caribbean, was able to take advantage of the warming event and become more prolific because of its apparent tolerance of high temperatures,” he said. “The species appears to have saved certain colonies of coral from the damaging effects of unusually warm water.”


LaJeunesse2-2010large3.jpg

In contrast, the scientists found very few thermally tolerant algae species in the cooler western Indian Ocean and Great Barrier Reef area.  According to LaJeunesse, the Andaman Sea is on average three or four degrees Fahrenheit warmer than the western Indian Ocean and the Great Barrier Reef area.  “Symbiodinium trenchi and other related symbiont species can tolerate this warm water, but if global warming causes the water to warm further, even these species might not be able to deal with it,” he said.  “However, if the water warms by three or four degrees Fahrenheit in the cooler western Indian Ocean or Great Barrier Reef area, Symbiodinium trenchi easily could persist.  The problem is that Symbiodinium trenchi occurs in very low numbers in these cooler areas and, so far, has not proliferated during bleaching events as it has in the Caribbean.”

LaJeunesse said that some scientists have suggested that reefs suffering from high water temperatures might be “seeded” with the thermally tolerant Symbiodinium trenchi; however, he is not sure the approach will work.  “Symbiodinium trenchi forms symbiotic associations only with corals and other animals that acquire their symbionts from the environment,” he said.  “Other species of coral are born with algae already in their cells.  If Symbiodinium trenchi were introduced into a new environment, it may be able to ‘rescue’ some species that acquire their symbionts from the environment, but it would not be able to ‘rescue’ species that are born with algae already in their cells because these species have evolved special relationships with their algae.”

Not only is LaJeunesse concerned that “seeding” reefs with algae, like Symbiodinium trenchi, will fail to “rescue” animals that are born with algae already in their cells, but he also is concerned about possible negative repercussions.  “You never know what the effects might be of introducing an organism into an ecosystem in which it is not well established,” he said.

LaJeunesse explained that the diversity of species the team found in the Andaman Sea likely is the result of the dramatic changes in the ocean environment that the region has experienced since the beginning of the Pleistocene Epoch.  Typically, during times of environmental change, generalist species of algae that are able to associate with a variety of animal hosts are more successful than specialist species of algae that can associate only with particular hosts because the generalists can spread to many hosts, thus forming new combinations that might be better suited to the new environment.  Once the environmental change has stabilized, some of the generalist species form special associations with new hosts and, as a result, become new specialist species.

LaJeunesse2-2010large4.jpg
In the Andaman Sea off the coast of Thailand, not only is the water warm and murky, but the tidal flux is so great that many of the corals can spend hours out of water, exposed to the harsh sun and dry air.

LaJeunesse said that one of the team’s most important findings is that coral-algal symbioses are much more ecologically and evolutionarily responsive to environmental changes than previously was believed.  “The responsiveness of these symbioses to historical climate change gives us hope that some species may survive in some places in the face of future warming,” he said.  “Yet, even though these symbiotic relationships have persisted through historical climate changes, they never have experienced the rapid rate of warming that we are seeing today.  So, while we shouldn’t underestimate life and its ability to respond to change, we also should do everything in our power not to test its resilience.”

This research was funded by the World Bank, Penn State University, Florida International University, and the U.S. National Science Foundation.

Introducing a new blogger to Climate Shifts

Clare Fieseler is a Master of Environmental Management candidate at the Nicholas School of Environment at Duke University. She received a Bachelor of Science in Foreign Service from Georgetown University with a concentration in Environment. At Georgetown, Clare first began her interest in marine life while working as a research assistant for marine mammalogist Dr. Janet Mann. After a short stint in environmental lobbying, Clare worked for two years at the nexus of science and media in the Natural History Unit for the National Geographic Society. She currently resides at the Duke University Marine Lab where she is furiously writing her thesis work on MPA efficacy along the Belizean Barrier Reef, which is co-advised by Dr. Larry Crowder and Dr. John Bruno. Clare is particularly interested in policy and managerial strategies that respond to changing coastal environments.

New AIMS report on climate change and the tropical marine environment

AIMS has issued an easy to read white paper on its home page, outlining its major findings related to coral reefs and climate change.  This was apparently added on Dec 19, 2009 the same day as Jamie Walker’s “How the reef became blue again” piece in The Australian.  Coincidence?   I’ll excerpt some highlights below:

Climate change and the tropical marine environment

Tropical marine environments such as coral reefs and mangrove forests around the world are under unprecedented pressure due to climate change, changes in water quality from terrestrial runoff and overexploitation. Coral reefs are iconic tropical ecosystems represented by Australia’s irreplaceable Great Barrier Reef (GBR) and the less explored reefs off Western Australia. Corals thrive in locations which also happen to be near their physiological limits, making them sensitive to stresses caused by rising sea surface temperature and an increase in ocean acidity linked to rising carbon dioxide (CO2) in the atmosphere.

What we know

  • The long-term average temperature for the waters of the Great Barrier Reef has increased by about 0.4oC since the 19th century and the Reef system has experienced two mass coral bleaching events (1998 and 2002) caused by long periods of coral exposure to unusually warm seawater.
  • During the 1998 coral bleaching event, 42 per cent of shallow water coral reefs on the GBR bleached and an estimated 2 per cent died that year. This equates to approximately 400km2 of reef area.
  • In 2002, the largest bleaching event on record, an even greater proportion of the Reef bleached (55 per cent) and an estimated 5 per cent died. This equates to approximately 1000km2 of reef area
  • While these percentages may seem small, they can be localised and severe events.
  • Some local extinctions of coral species in several parts of the Great Barrier Reef have been observed and appear to be linked to higher sea surface temperatures causing coral bleaching.
  • Coral bleaching was again observed in the 2006 summer, particularly in the southern GBR, where local water temperatures reached around 1-2oC above the seasonal average.
  • Coral reefs may take 10 to 20 years to recover from serious bleaching events that cause coral death.
  • The amount of CO2 in the atmosphere is known to be increasing and the extra CO2does not stay just in the atmosphere with a significant amount dissolving into the ocean. The pathways it then follow under different conditions and the consequences of its accumulation in different environments is under-researched. Some scientists have proposed that the large portion of CO2 that is entering the ocean from the atmosphere is causing a shift downwards in seawater pH, making it more acidic.
  • A growing body of experimental evidence is showing that seawater acidified to mimic potential future scenarios significantly impacts upon the health of some fish and coral species. There are many millions of species in the ocean and each will have different sensitivities to acidification and respond in different ways. No single species lives in isolation and how the effects seen at an individual species level translate to an ecosystem response is not understood. It has been speculated that acidified seawater may alter the makeup of marine ecosystems and weaken coral reef structures.
  • It is known that heat stress causes corals to expel the symbiotic algae they host in their tissues. What is not sufficiently understood are the numerous mechanisms that may enable corals to adapt to new, warmer and potentially acidic conditions.
  • Based on observations of an increase in hurricane and cyclone events in recent decades, even more severe storms and cyclones have been proposed to occur as our climate changes, though this remains a topic of debate.

The consequences of increasing atmospheric carbon dioxide

The amount of CO2 in the atmosphere has risen to the current level of 383 parts per million (ppm) from about 200 ppm in the days before the Industrial Revolution more than 200 years ago. Measurements of atmospheric CO2 taken from AIMS headquarters outside Townsville show broad agreement with this global figure (see page 1 of this document).

Under current IPCC projections and assuming no measures are adopted to reduce CO2emissions, atmospheric CO2 concentrations are likely to reach 500 ppm in the second half of this century. If that is the case, global temperature averages may increase a further 2oC and possibly more.

Coral reefs provide ecosystem services essential to our national identity and wealth. The GBR contributes more than $5 billion annually to the Australian economy.

While Australia’s coral reefs are well managed, they are not isolated from global atmospheric and ocean changes.

Barrier Reef still vulnerable says AIMS CEO Ian Poiner

The Australian recently published a letter from AIMS CEO Dr. Ian Poiner (only online as far as I can tell) written in response to Jamie Walker’s reef wipeout story.  See our coverage of this debacle here, here and here.

This year the Australian Institute of Marine Science has observed that there is no mass coral bleaching on the southern Great Barrier Reef. Your story (“Report undercuts PM’s reef wipeout”, 3/2) uses these observations to contradict the view that the reef is threatened by climate change. This is not the case. The Great Barrier Reef is one of the healthiest coral reef ecosystems in the world, but climate change is a significant long-term threat. Coral reefs exist in locations that are near their physiological limits, making them especially sensitive to stresses caused by rising sea surface temperature and ocean acidity.

The GBR has already experienced two mass coral bleaching events (1998 and 2002), during which hundreds of square kilometres of reef died. While the reef has shown capacity to recover from mass bleaching, the frequency and scale of such events have a significant bearing on the likelihood of recovery. Frequency and scale are directly related to rising sea surface temperatures and there is ample evidence of warming waters on the Great Barrier Reef.

One or two seasons of no bleaching do not mean that the GBR is not threatened. It is over-generalisation to the point of unreality to extrapolate from one set of observations to what is going to happen to the GBR in the long term.

Dr Ian Poiner, CEO, Australian Institute of Marine Science, Cape Ferguson, Qld

Warming spurs U.S. to consider ESA protection for 82 coral species

Not sure I agree with this strategy or in the science behind it, but I heard this was coming.  The EPA is considering whether to list 82 new coral species in US Waters as threatened or endangered.  Acropora palmata and Acropora cervicornis were listed as vulnerable under the Endangered Species Act in May 2006.

From the Federal Register (Vol. 75, No. 27 / Wednesday, February 10, 2010)

Endangered and Threatened Wildlife; Notice of 90–Day Finding on a Petition to List 83 Species of Corals as Threatened or Endangered Under the Endangered Species Act (ESA)

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Department of Commerce.

ACTION: 90–day petition finding; request for information.

SUMMARY: We (NMFS) announce a 90– day finding on a petition to list 83 species of corals as threatened or endangered under the ESA. We find that the petition presents substantial scientific or commercial information indicating that the petitioned actions may be warranted for 82 species; we find that the petition fails to present substantial scientific or commercial information indicating that the petitioned action may be warranted for Oculina varicosa. Therefore, we initiate status reviews of 82 species of corals to determine if listing under the ESA is warranted. To ensure these status reviews are comprehensive, we solicit scientific and commercial information regarding these coral species.

DATES: Information and comments must be submitted to NMFS by April 12, 2010.

The 83 species included in the petition are: Acanthastrea brevis, Acanthastrea hemprichii, Acanthastrea ishigakiensis, Acanthastrea regularis, Acropora aculeus, Acropora acuminate, Acropora aspera, Acropora dendrum, Acropora donei, Acropora globiceps, Acropora horrida, Acropora jacquelineae, Acropora listeri, Acropora lokani, Acropora microclados, Acropora palmerae, Acropora paniculata, Acropora pharaonis, Acropora polystoma, Acropora retusa, Acropora rudis, Acropora speciosa, Acropora striata, Acropora tenella, Acropora vaughani, Acropora verweyi, Agaricia lamarcki, Alveopora allingi, Alveopora fenestrate, Alveopora verrilliana, Anacropora puertogalerae, Anacropora spinosa, Astreopora cucullata, Barabattoia laddi, Caulastrea echinulata, Cyphastrea agassizi, Cyphastrea ocellina, Dendrogyra cylindrus, Dichocoenia stokesii, Euphyllia cristata, Euphyllia paraancora, Euphyllia paradivisa, Galaxea astreata, Heliopora coerulea, Isopora crateriformis, Isopora cuneata, Leptoseris incrustans, Leptoseris yabei, Millepora foveolata, Millepora tuberosa, Montastraea annularis, Montastraea faveolata, Montastraea franksi, Montipora angulata, Montipora australiensis, Montipora calcarea, Montipora caliculata, Montipora dilatata, Montipora flabellata, Montipora lobulata, Montipora patula, Mycetophyllia ferox, Oculina varicosa, Pachyseris rugosa, Pavona bipartite, Pavona cactus, Pavona decussate, Pavona diffluens, Pavona venosa, Pectinia alcicornis, Physogyra lichtensteini, Pocillopora danae, Pocillopora elegans, Porites horizontalata, Porites napopora, Porites nigrescens, Porites pukoensis, Psammocora stellata, Seriatopora aculeata, Turbinaria mesenterina, Turbinaria peltata, Turbinaria reniformis, and Turbinaria stellula. Eight of the petitioned species are in the Caribbean and belong to the following families: Agaricidae (1); Faviidae (3); Meandrinidae (2); Mussidae (1); Oculinidae (1).

The petition states that all of these species are classified as vulnerable (76 species), endangered (six species: Acropora rudis, Anacropora spinosa, Montipora dilatata, Montastraea annularis, M. faveolata, Millepora tuberosa), or critically endangered (one species: Porites pukoensis) by the World Conservation Union (IUCN). Montipora dilatata and Oculina varicosa are also on our Species of Concern list.

See a summary article on corals as endangered species in the EoE here.

BY Allison Winter, E&E reporter

Published February 11, 2010, link to the original story here

The Obama administration will consider federal protection for 82 coral species threatened by warming water temperatures.

The National Marine Fisheries Service said yesterday that it has found “substantial scientific or commercial information” that Caribbean and Indo-Pacific corals may be threatened or endangered. Environmentalists have predicted the corals — found near Florida, Hawaii and U.S. territories — could be wiped out by midcentury if the government does not take steps to protect them from warming waters, rising ocean acidity and pollution.

The announcement in yesterday’s Federal Register launches a formal status review by federal biologists. The fisheries service will also accept public comment before deciding next year on whether to list the corals under the Endangered Species Act.

“The status review is an important step forward in protecting coral reefs, which scientists have warned may be the first worldwide ecosystem to collapse due to global warming,” said Miyoko Sakashita, oceans director at the nonprofit Center for Biological Diversity. “Endangered Species Act protection can provide a safety net for corals on the brink of extinction.”

The center asked the fisheries service last year to protect corals and threatened to sue the agency last month if it failed to act.

All of the species under consideration have seen population declines of at least 30 percent over 30 years, according to the center.

The group’s petition blamed myriad threats for the corals’ decline: ocean warming and acidification, shipping-channel dredging, coastal development, pollution from agriculture and development, disease, predation, reef fishing, marine debris, invasive species, aquarium trade, and damage from boats and anchors.

In the service’s finding yesterday, biologists agreed that the coral populations are at risk of collapse without recovery, given the population decline that has occurred already and mounting threats.

If the corals are protected as endangered species, it would be illegal to harm or kill the species. That could open commercial fishers, farmers and all the other industries cited in the petition to federal regulation or lawsuits from environmentalists. A “threatened” listing could be less restrictive. The fisheries service would write regulations to protect the corals.

The government now lists two Atlantic coral species, elkhorn and staghorn, as “threatened” due to disease, warming sea temperatures and hurricane damage.

The center had sought a listing for 83 species, but the government left one out of its proposal. The fisheries service said there was not enough evidence to consider a listing for the ivory tree coral, or Oculina varicosa. The ivory tree coral lives in shallow water from Florida to North Carolina and off Bermuda and the West Indies.

Click here to read the Federal Register announcement.

More details from the Register:

The petition states that all of these species are classified as vulnerable (76 species), endangered (six species: Acropora rudis, Anacropora spinosa, Montipora dilatata, Montastraea annularis, M. faveolata, Millepora tuberosa), or critically endangered (one species: Porites pukoensis) by the World Conservation Union (IUCN). Montipora dilatata and Oculina varicosa are also on our Species of Concern list.

Under the ESA, a listing determination may address a ‘‘species,’’ which is defined to also include subspecies and, for any vertebrate species, a distinct population segment which interbreeds when mature (DPS) (16 U.S.C. 1532(16)). Because corals are invertebrate species, we are limited to assessing the status of species or subspecies of corals. A species or subspecies is ‘‘endangered’’ if it is in danger of extinction throughout all or a significant portion of its range, and ‘‘threatened’’ if it is likely to become endangered within the foreseeable future throughout all or a significant portion of its range (ESA sections 3(6) and 3(20), respectively, 16 U.S.C. 1532(6) and (20)).

Of the 83 petitioned species, eight species occur in the U.S. waters of the Caribbean, and 75 occur in the U.S. waters of the Indo-Pacific. The petition includes species accounts (i.e., description of the species’ morphology, life history, habitat, distribution, and loss estimates over 30 years (20 years into the past and 10 years into the future)) of each of the 83 species, threats facing each species, and descriptions of the status of coral reef ecosystems of the wider Caribbean and Indo-Pacific areas. The petition asserts that all of the petitioned species have suffered population reductions of at least 30 percent over a 30–year period, relying on information from the IUCN.

Eight of the petitioned species occur in the Caribbean, and 75 in the Indo-Pacific.

Caribbean species include Agaricia lamarcki, Dendrogyra cylindrus, Dichocoenia stokesii, Montastraea annularis, Montastraea faveolata, and Montastraea franksii.

I agree there is sound evidence that these species have declined substantially (perhaps by 30% in relative terms) across the broader Caribbean over the last several decades.  Yet note a key to this petition passing the smile test is that each species has to have been found to have declined in US waters, which in the Caribbean, isn’t a lot of habitat.  The thing that has always bugged me about this approach, well one thing, is that although a coral species may have declined by 30% or more, there are in some cases literally tens or hundreds of millions of colonies throughout the species’ ranges. Thus it seems a stretch to suggest they are threatened with literal extinction.

Another is that I think this misses the point of coral conservation; which from my perspective is to restore or maximize coral cover.  As I argued in 2001 (Bruno and Bertness 2001) it would be pretty easy to protect populations of foundation species (i.e., habitat-forming species) without actually conserving their ecological function. Which is I think a weakness of the US Endangered Species Act.

The Caribbean, according to the petitioner, has the largest proportion of corals classified as being in one of the high extinction risk categories by the IUCN. The petitioner asserts that the region suffered massive losses of corals in response to climate-related events of 2005 including a record-breaking series of 26 tropical storms and elevated ocean water temperatures.,

This is a dubious argument, not supported by any peer-reviewed science.  IMO the losses caused by warming-bleaching were very isolated and modest in general, despite greater losses on some individual reefs.

Further, the petitioner asserts that the U.S. Virgin Islands lost 51.5 percent of live coral cover,

I very much doubt this and have seen evidence that contradicts this suggestion.  Most of the loss of live coral cover in the USVI appears to have occurred in 1989 and 1999 (Edmunds and Elahi 2007-see the figure below).  I also assume the values are relative coral cover, rather than absolute values, i.e., coral cover could have declined from %4 to 2% and this would be described as a “%50” loss.

Long-term trends in coral community dynamics on a reef at 9-m depth at Yawzi Point, St. John, U.S. Virgin Islands. (A) Percentage of coral cover at each survey period between March 1988 and August 2003.

The petitioner cites Gardner et al. (2003) in asserting that, over the three decades prior to the 2005 events, Caribbean reefs had already suffered an 80 percent decline in hard coral cover, from an average of 50 percent to an average of 10 percent throughout the region.

True, Gardner at al. 2003 does say/find this, but again, note the use of relative %loss values.  Also, we have a paper in press at MEPS (Schutte et al. 2010) that indicates Caribbean mean coral cover is closer to 20% (excluding the very low coral cover FL Keys) and has not noticibly declined since the mid-1980s. But perhaps this is quibbling. There is no doubt coral cover has declined. I just think there could be some exaggeration in the petition. Given what we have seen happening in the media recently, e.g., the IPCC reports, scientists should be really careful about the accuracy of their doom-and-gloom stories.

The abundance and trend information presented by the petitioner for each species is limited to an estimate of the percentage loss of its habitat and/or population over a 30–year period (including 20 years into the past and 10 years into the future), as assessed by the IUCN. However, the petition also asserts that these corals face significant threats. To support this assertion, the petitioner cites Alvarez-Filip et al. (2009) in noting the dramatic decline of the three- dimensional complexity of Caribbean reefs over the past 40 years, resulting in a phase shift from a coral-dominated ecosystem to fleshy macroalgal overgrowth in reef systems across the Caribbean.

We clearly showed this was not true in Bruno et al. 2009.  Very few reefs in the world are truly dominated by macroalgae in any meaningful sense.

Seventy-five percent of the world’s coral reefs can be found in the Indo- Pacific, which stretches from the Indonesian island of Sumatra in the west to French Polynesia in the east (Bruno and Selig (2007), as cited by the petitioner). As recently as 1,000 to 100 years ago, this region averaged about 50 percent coral cover, but 20–50 percent of that total has been lost, according to the petitioner. The petitioner cites Bruno and Selig (2007), stating that regional total coral cover averaged 42.5 percent during the early 1980s, 36.1 percent in 1995, and 22.1 percent in 2003.

Now this, as they say here in Oz, is some dodgy science!

The petition focuses on habitat threats, asserting that the habitat of the petitioned coral species, and indeed all reef-building coral species, is under threat from several processes linked to anthropogenic greenhouse gas emissions, including increasing seawater temperatures, increasing ocean acidification, increasing storm intensities, changes in precipitation, and sea-level rise. The petition also asserts that these global habitat threats are exacerbated by local habitat threats posed by ship traffic, dredging, coastal development, pollution, and agricultural and land use practices that increase sedimentation and nutrient- loading.

References

Bruno J.F. & Bertness M.D. (2001) Habitat modification and facilitation in benthic marine communities. In: Marine Community Ecology (eds. Bertness MD, Gaines SD & Hay ME), pp. 201-218 Sinauer, Sunderland, MA

Bruno J.F., Sweatman H., Precht W.F., Selig E.R. & Schutte V.G.W. (2009) Assessing evidence of phase shifts from coral to macroalgal dominance on coral reefs. Ecology, 90, 1478–1484

Edmunds P.J. & Elahi R. (2007) The demographics of a 15-year decline in cover of the Caribbean reef coral Montastraea annularis. Ecological Monographs, 77, 3-18

Schutte V.G.W., Selig E.R. & Bruno J.F. (2010) Regional spatio-temporal trends in Caribbean coral reef benthic communities. Marine Ecology Progress Series, In Press


Science behind Great Barrier Reef water quality management

Articles from Peter Ridd of James Cook University in newspapers and on blog sites and letters to the editor supporting his position (e.g. Tom Darlington, 9 February 2010 in the Townsville Bulletin) claim there is no scientific evidence agricultural pollution is damaging the Great  Barrier Reef. As well, claims are made that there is a body of research available (specifically from Peter Ridd’s work) that shows that runoff from farming is having no effect (or very little effect) on the Great Barrier Reef (GBR). Neither of these claims is true.

An example of a healthy reef (Princes Charlotte Bay, Far Northern GBR)

An example of a healthy reef (Princes Charlotte Bay, Far Northern GBR)

There is a large body of published results from hundreds of studies  showing that (with just a few of the possible references):

1. Water discharged from rivers to the GBR continues to be of poor quality in many locations. The main source of pollutants is agriculture (cropping and grazing) e.g Packett et al (2009),  Bainbridge et al (2009).

2. Land derived pollutants, including suspended sediments, nutrients and pesticides are present in the GBR at concentrations likely to cause environmental harm e.g. Lewis et al (2009) and  De’ath and Fabricius (in press).

3. Coral cover on the GBR is generally much lower (about 25%) now than 40 years ago (cover about 50%) e.g. Bruno and Selig 2007. Macroalgal cover appears to be greatly increased e.g. De’ath and Fabricius (in press) Wismer et al (2009)

4. This loss in coral cover has been caused by a combination of  factors – poor water quality (see references above), crown of thorns starfish damage also associated with poor water quality (Brodie et al 2005), bleaching associated with climate change, loss of calcification associated with increased carbon dioxide in the surface water (De’ath et al 2008) and some minor damage from fishing activities.

Most of these results up till 2008 are summarised in the following document (click through for a link to the site and pdf download)

On the other hand there are few published results of research showing that agricultural pollution is having no effect on the Great Barrier Reef – none that I can find. What can be found are unsupported (by research results) opinions. Now we all have opinions and I think mine are as good as anybodies but I don’t pass them off as facts when they are not supported by research results.

An example of a degraded macroalgal dominated reef (Russell Island, Wet Tropics, Northern GBR)

I make no statements about the recently introduced Queensland Government legislation or its likely effectiveness, which remain to be tested, but do claim that there is ample well-founded evidence that agricultural pollution of the GBR is occurring, the effects are severe and that management of this pollution is a necessity.

Jon Brodie
Catchment to Reef Research Group
Australian Centre for Tropical Freshwater Research
James Cook University, Townsville.

References:

Bainbridge, Z.T., Brodie, J.E., Faithful, J.W., Sydes, D.A. & *Lewis*, S.E. (2009). Identifying the land-based sources of suspended sediments, nutrients and pesticides discharged to the Great Barrier Reef from the Tully-Murray Basin, Queensland, Australia. Marine and
Freshwater Research, 60, 1081-1090

Brodie, J.E., Fabricius, K., De’ath, G. & Okaji, K. (2005). Are increased nutrient inputs responsible for more outbreaks of crown-of-thorns starfish? An appraisal of the evidence.
Marine Pollution Bulletin, 51:266-278

Bruno JF, Selig ER (2007) Regional Decline of Coral Cover in the Indo-Pacific: Timing, Extent, and Subregional Comparisons. PLoS ONE 2(8): e711

De’ath G. and Fabricius K. in press. Water quality as a regional driver of coral biodiversity
and macroalgae on the Great Barrier Reef. Ecological Applications

De’ath G, Lough JM, Fabricius KE, (2008) Declining Coral Calcification on the Great Barrier Reef, Science, 323, 116-119

Lewis, S.E. Brodie,  J.E. Bainbridge, Z.T. Rohde, K. Davis, A. Masters, B. Maughan, M.
Devlin, M. Mueller, J. Schaffelke, B. ( 2009) Pesticides: A new threat to the Great Barrier Reef. Environmental Pollution 157, 2470-2484

Packett, R. Dougall, C. Rohde, K. Noble, R. 2009. Agricultural lands are hot-spots for annual runoff polluting the southern Great Barrier Reef lagoon. Marine Pollution Bulletin 58, 976-985.

Wismer S, Hoey AS, Bellwood DR (2009) Cross-shelf benthic community structure on the Great Barrier Reef: relationships between macroalgal cover and herbivore biomass. Marine
Ecology Progress Series 376:45-54.

Peter Ridd is not the only reef expert at James Cook University

Although you’d think so given how frequently he is quoted in the Australian media, almost exclusivly in stories arguing that the GBR is in “bloody brilliant shape” and that climate change, sediment pollution, and ocean acidification are not threats to the reef’s future.

For example, in Jamie Walker’s piece last December on “How the reef became blue again” Ridd dismissed a range of threats to coral reefs, stating:

“Ten years ago, I was told that the coral was going to die from sediment, and we have proved that is complete rubbish,” Ridd says. “They are saying that pesticides are a problem, but when you look at the latest data that is a load of rubbish. They are saying that bleaching is the end of the world, but when you look into it, that is a highly dubious proposition.

“So when something comes along like the calcification problem, you are sort of left with this wolf story . . . they are crying wolf all the time . . . and it is very difficult for the public to have confidence in what they are saying.”

I don’t know what he is referring to when he says “we have proved that is complete rubbish” but i’ll email him and ask for a reference.

Also see Peter’s quotes in this recent story:

James Cook University researcher Peter Ridd recently accused Australian scientists of crying wolf over the threat of climate change reef, claiming researchers who predicted corals would be mostly extinct by mid-century had a credibility problem as the natural wonder was in “bloody brilliant shape.”

The Townsville-based Dr Ridd, who is an expert on marine physics, has previously claimed the Great Barrier Reef is as resilient to environmental change as a “cockroach is to a nuclear war”, with threats such as coral bleaching and agricultural run-off not as serious as commonly believed.

With a PhD in Physics and a thesis titled “The Input impedance of a horizontal dipole antenna over a layered halfspace” wouldn’t it be clear he isn’t the best source of information about the GBR at JCU?

JCU has more coral reef experts on one hallway than most countries have.  Certainly more than any other single institution I can think of, e.g., see the ARC Center for Excellence in Coral Reef Studies.  Here is a list of a few of the internationally recognized coral reef experts based at JCU that reporters could be talking to, assuming they actually want to learn something and are not fishing for quotes to back up pre-determined conclusions:

Baird, Andrew
Senior Research Fellow
James Cook University
phone: 61 7 4781 4857
fax: 61 7 4781 6722
Andrew.Baird@jcu.edu.au

Bellwood, David
James Cook University
phone: 07 4781 4447
fax: 61 7 4725 1570
David.Bellwood@jcu.edu.au

Connolly, Sean
James Cook University
Phone: 61 7 4781 4242
Fax: 61 7 4725 1570
Sean.Connolly@jcu.edu.au

Hughes, Terry
James Cook University
Phone: 61 7 4781 4000
Fax: 61 7 4781 6722
Terry.Hughes@jcu.edu.au

Jones, Geoff
James Cook University
Phone: 61 7 4781 4559
Fax: 61 7 4725 1570
Geoffrey.Jones@jcu.edu.au

Kingsford, Michael

James Cook University
Phone: 61 7 4781 4345
Fax: 61 7 4725 1570
Michael.Kingsford@jcu.edu.au

Munday, Philip

Australian Research Fellow

James Cook University
Phone: 61 7 4781 5341
Fax: 61 7 4725 1570
Philip.Munday@jcu.edu.au

Pratchett, Morgan
Australian Postdoctoral Research Fellow
James Cook University
Phone: 07 4781 5747
Fax: 61 7 4781 6722
Morgan.Pratchett@jcu.edu.au

Russ, Garry
James Cook University
Phone: 61 7 4781 4432
Fax: 61 7 4725 1570
Garry.Russ@jcu.edu.au

Willis, Bette
James Cook University
Phone: 61 7 4781 5349 / 61 7 4781 5731
Fax: 61 7 4725 1570
Bette.Willis@jcu.edu.au

And at the nearby Australian Institute of Marine Science, there is:

Lough, Janice
Australian Institute of Marine Science
Phone: 61 7 4753 4248
Fax: 61 7 4753 4386
j.lough@aims.gov.au

McCook, Laurence
Great Barrier Reef Marine Park Authority, Australia
Phone: 61 7 4750 0787
Fax: 61 7 4772 6093
l.mccook@gbrmpa.gov.au

Finally, here at UQ, reporters could talk to:

Anthony, Ken
University of Queensland
phone: 61 7 3365 9154
fax: 61 7 3365 4755
K.Anthony@uq.edu.au

Dove, Sophie
The University of Queensland
Phone: 61 7 3365 7229
Fax: 61 7 3365 4755
sophie@uq.edu.au

Hoegh-Guldberg, Ove
The University of Queensland
Phone: 61 7 3365 1156
Mobile: 040 110 6604
Fax: 61 7 3365 4755
oveh@uq.edu.au

Reducing resilience of the Great Barrier Reef to increased temperature stress

I wanted to add a little to Ove’s continued defence against ‘The Australian’ on going war against science. Whilst most people see the Great Barrier Reef as being one large coral reef, it also contains an array of other habitats including seagrass meadows that are critical to the overall ecosystem. Seagrasses, amongst there many roles in the GBR, are critical in supporting biodiversity and fisheries productivity. These seagrass meadows, like coral reefs, are also under threat from increasing seawater temperatures.

The potential 4°C increase in global temperature by the end of the century, that the leader of the opposition recently described as “not a big moral challenge”, would have an enormous detrimental impact upon seagrass meadows, particularly the abundant intertidal meadows present throughout the GBR. Research published back in 2006 found how seagrasses of the GBR suffer irreparable effects from short-term or episodic changes in seawater temperatures as high as 40–45 °C. Although these temperatures sound high, intertidal pools can commonly approach and exceed these temperatures for short periods throughout the GBR, and seagrasses are observed to ‘burn’. If temperatures were to increase by 4°C, such ranges would be exceeded too regularly to allow for recovery, and seagrass meadows are likely to deteriorate with huge detrimental impacts upon fisheries and coastal productivity.

The Great Barrier Reef described to be “blue again” by ‘The Australian’ is under continued stress. Seagrasses although important in their own right make excellent ‘coastal canaries’ and their tissues are good time integrated indicators of the coastal nutrient environment. Monitoring throughout the GBR continues to find coastal seagrasses containing highly elevated C:N:P ratios, indicating rich and potentially eutrophic environments that are continuing to be enriched. Increasing nutrients onto the reef and into seagrass will continue to promote algae and reduce the resilience of coral and seagrass to future climate change and increasing temperatures.  The combination of elevated nutrients and increased temperatures are of concern as greater temperatures increase metabolic rate, resulting in increased light requirements for seagrass. Such light requirements are not possible when increasing nutrients reduce light availability due to increased epiphytes and phytoplankton, resulting in eventual loss of the seagrass.

As Ove said previously, there exists no evidence to suggest that the GBR is “blue again”, and to the contrary, seagrass biomonitoring suggests nutrient conditions are continuing to deteriorate, with many coastal locations becoming increasingly eutrophic (see Figure 1 taken from the latest Seagrass-Watch magazine). The available evidence suggests that seagrasses and the coastal environment of the GBR are under increasing nutrient stress, reducing future resilience to climate change.

Coral Sea experiences eighth warmest year on record in 2009

Australia’s National Climate Centre (which is housed by the Bureau of Meteorology) undertakes real-time analysis of sea surface temperature around Australia.  This is an important task in terms of assessing the risk faced from climate change by our fisheries and assets such as the Great Barrier Reef.

The latest analysis of the Coral Sea region is of significant interest.  The warming trend is unmistakable and is statistically significant. And it turns out that 2009 was the eighth warmest year on record for this region.  Experts at the National Climate Centre have also suggested that 2010 is likely to be a near-record temperature based on the evolution of the current El Niño event.

With every increase in sea surface temperature, critical organisms such as reef-building corals are pushed closer to the threshold at which they undergo mass coral bleaching and mortality. This is essentially an issue of increasing risk.  With projections of future sea temperatures that are 2 or even 4°C above today, it is incredibly hard to argue that iconic and economically important assets like the Great Barrier Reef are not in the deep trouble.