Rare corals may be smarter than previously thought

Posted on October 27, 2008 by ovehblog

Following on from a previous article at Climate Shifts, a recent article published in PLoS One shows that corals are proving to be even more non-conformist than previously thought. Zoe Richards and co-authors from the ARC Centre of Excellence for Coral Reef Studies found that ‘rare’ species of branching corals are able to cross breed with other branching corals to create hybrids, therefore avoiding probable extinction:

“Coral reefs worldwide face a variety of marine and land-based threats and hundreds of corals are now on the red list of threatened species. It is often assumed that rare coral species face higher risks of extinction than common species because they have very small effective population sizes, which implies that they may have limited genetic diversity and high levels of inbreeding and therefore be unable to adapt to changing conditions.

When we studied some particularly rare species of Acropora (staghorn corals), which you might expect to be highly vulnerable to extinction, we found some of them were actually hybrids – in other words they had cross-bred with other Acropora species. This breaks all the traditional rules about what a species is. By hybridising with other species, these rare corals draw on genetic variation in other species, increasing their own potential to adapt to changing conditions.

When we looked at the genetic history of rare corals, we found that they exhibited unexpected patterns of genetic diversity. This suggests that, rather than being the dying remnants of once-common species, they may actually be coral pioneers pushing into new environments and developing new traits by virtue of the interbreeding that has enabled them to survive there.

This is good news, to the extent that it suggests that corals may have evolved genetic strategies for survival in unusual niches – and may prove tougher to exterminate than many people feared. With such tricks up their sleeve, it is even possible that the rare corals of today could become the common corals of the future.” (Link)

Grazer composition an important factor in controlling macroalgae

Posted on October 20, 2008 by ovehblog

The redband parrotfish was one of the species studied as part of research into the importance of fish diversity for the health of coral reefs.

We know the biomass of macroalgae on coral reefs is largely controlled by herbivory and that one of the most important groups of grazers are parrotfish. A new study published in PNAS (Berkepile and Hay 2008) indicates that the richness and composition of grazer species is also important. In a nutshell, different fish consume different seaweeds because of their differing chemical defenses. Similar work in other benthic marine systems has found that consumer species richness can be an important determinant of ecosystem functioning, yet this is the first such study on a coral reef.

Our study shows that in addition to having enough herbivores, coral ecosystems also need the right mix of species to overcome the different defensive tactics of the seaweeds. explained Mark Hay, the Harry and Linda Teasley Professor of Biology at the Georgia Institute of Technology.

Despite different species of parrotfish in the Caribbean having different feeding behaviors, bioerosion rates, and preferred diets, parrotfishes are often considered as a unified functional group when inferring their effects on community structure. However, we found that redband and princess parrotfish had considerably different effects on communities, suggesting that grouping all parrotfishes may blur important distinctions among species.

Despite their different feeding morphologies, ocean surgeonfish and princess parrotfish generated similar macroalgal communities dominated by upright brown macroalgae (e.g., L. variegata and Sargassum spp.). In contrast, despite their more similar jaw morphology, the communities generated by redband and princess parrotfish differed considerably in the abundance of upright macroalgae. Similar to the work of Bellwood et al., these results show that fishes with different feeding morphologies can have similar effects on community structure, suggesting that relying primarily on jaw functional morphology to construct functional groups or infer a species’ impact may be unreliable.

Working out of the underwater Aquarius laboratory off Key Largo Florida, Hay and co-author Deron Burkpile – who is now at Florida International University in North Miami – constructed 32 cages on the reef. Each cage was about two meters square and one meter tall and was sealed so that larger fish could neither enter nor leave.

The number and type of fish placed into each four-square-meter cage varied. Some cages had two fish that were able to eat hard, calcified plants; some had two fish able to eat soft, but chemically-defended plants; some had one of both types, and some had no fish at all

For the cages in which we mixed the two species of herbivores, the fish were able to remove much more of the upright seaweeds, and the corals in those areas increased in cover by more than 20 percent during ten months, Hay said.

The data we are seeing in Fiji [from similar experiments] suggests that diversity may be even more important there than it was in the Caribbean. There are a lot of different species doing a lot of very different things. These consumers are very important, and in areas where they are over-fished, the reefs are crashing.

Reference

Berkepile, D.E. and M.E. Hay. 2008. Herbivore species richness and feeding complementarity affect community structure and function on a coral reef. PNAS 105: 16201–16206

Diver Todd Barsby secures a cage to the coral reef during a study of the role of diversity among herbivorous fishes.

The missing link in the “solutions” to climate change

Posted on October 9, 2008 by ovehblog

The recent Garnaut report states that “the solutions to the climate change challenge must be found in removing the links between economic activity and greenhouse gas emissions.” In order to successfully mitigate climate change impacts on both the environment and the economy, we need to go a step further and replace those links with avenues for sustainable economic activity. This can effectively begin with innovative designs for improving efficiency in energy production and usage.

Rather than compensating mining companies that are vulnerable to the new emissions trading scheme, the pledged compensation should be used to train employees of these companies with skills that will help them develop innovative designs for efficient energy usage to the commercialisation level. These high emission companies should begin investing in new technologies which could eventually be traded instead of coal to countries like China, in order to spread the improvements in carbon emissions to a global scale. Of course, this is the ten billion ton gorilla in the room that no one quite wants to recognise (at least not publicly!)

Credits to trade-exposed companies and low income households should only be considered to the extent that benefits are not initially received for their investment. Once benefits are realised, this monetary gain must be re-invested into future innovative solutions, thereby replenishing the funding for green solutions. Essentially, we need to amp up the green investment cycle. For example, in the above situation a mining company burdens the cost of training some employees and using their work hours for sustainable development avenues.

Once the company receives return on their investment, re-investment into development of sustainable technologies should occur to the extent of the original “loan” or government credit. Similarly, households given credits, for example, to install solar panels should be encouraged to re-invest the savings on their electricity bills into new innovative technologies. The establishment of this positive feedback loop should be a condition of receiving the credits in order to prevent the misuse of the credits or the undermining of carbon trading.

The missing links in the solutions to climate change are the real ideas that will drive the economy towards sustainable development. Treading softly on this issue is not an option – time is of essence. Another weak link in this much needed cycle is the fact that economic gain is our society’s key motivation and the environment is severely undervalued. The Garnaut Review states that environmental and social costs “are not amenable to conventional measurement”.

In other words, any cost-benefit analysis will not be accurate. Society’s real motivation needs to come from desire to maintain and conserve the environment for future generations. There is no adequate or accurate way to quantify this desire. And there is no way to ensure that that this desire is a top priority of world citizens. It seems that the best way to achieve this goal is to steer people’s actions economically. However, it is unlikely that the outcome will exhibit the same strength when motivated by monetary value.

Australian Government addresses Great Barrier Reef water quality issues

Posted on October 9, 2008 by ovehblog

A report released yesterday by the Queensland Premier Anna Bligh showed that water quality on the Great Barrier Reef is not improving, and that further action is needed to reverse the ongoing decline. As part of the Reef Water Quality Protection Plan initiated by the Australian and Queensland governments, the 2007 Water Quality Report is the first step in a four year process, addressing water quality issues such as catchment pressures, marine ecosystem health and land management practices affecting the Queensland coastline and Great Barrier Reef.

Some of the key findings of the report seem to confirm what scientists have previously observed: that over the last 150 years, the catchments adjacent to inshore reefs have been extensively modified for agriculture (e.g. sugar cane), cattle and sheep grazing, tourism, mining and urban development, leading to significant increased in sediments, nutrients and pesticides impacting upon the inshore Great Barrier Reef. From the report, monitoring of priority catchments has shown that:

6.6 million tonnes of sediment are discharged in the reef lagoon annually (four times higher than estimated pre-European settlement levels)
16,600 tonnes of nitrogen are discharged in the reef lagoon annually (five times higher than estimated pre-European settlement levels)
4,180 tonnes of phosphorous are discharged in the reef lagoon annually (four times higher than estimated pre-European settlement levels)

In response to the report, Premier Bligh called for a summit on reef water-quality issues in the next month:

“Work done to date as part of the Plan includes financial incentives to help farmers improve land management practices and targeting diffuse pollution from broadscale land use,”

“However, since 2003 many external factors have deteriorated including the effects of climate change, coral bleaching and ocean acidification.

“It has increased the urgency for more work to be done.

“I have discussed this matter with the Prime Minister and met with Environment Minister Peter Garrett.

“We agreed that the first step will be a joint Commonwealth-state reef water quality summit at Parliament House at the end of this month,” she said.

“The summit will bring together the best minds from the environmental and scientific fields to study the latest data and discuss what urgent action we need to take to prevent further damage to – or worse – the complete demise of the reef.” (Link to Media Statement)

The Environment Minister Peter Garrett also acknowledges the issue:

“We’ve specifically committed $200 million to reef rescue knowing that we need to provide additional resources, additional investment, and additional effort to safeguard what is one of our most important national and international natural resources and treasures” (Link)

I look forward to the proposed summit and applaud the Queensland government for taking such forward action in addressing water quality issues – it seems for Peter Garrett (pictured above left in typical Midnight Oil attire) there is no excuse!

A threat to coral reefs multiplied? Four species of crown of thorns starfish

Posted on October 6, 2008 by ovehblog

Crown of thorns starfish (COTS – Acanthaster planci) are notorious throughout the Indo-Pacific region. COTS are voracious coralivores, and in outbreak proportions can eat vast areas of reef by exuding their stomachs and digesting coral polyps (read more). Having been diving in oceans around the world over the past few decades, i’ve often pondered the differences in colourations of COTS between reef regions, and whether they represented a single species. A recent paper published in Biology Letters by Catherine Vogler from Göttingen University and colleagues at the Smithsonian and University of California confirms that COTS aren’t a single taxonomic entity, and in fact represent a ‘species complex’ of upto four seperate species.

Different appearances of the Crown of Thorns starfish across locations, clockwise from Top Left: Madagascar (Image credit: Mila Zinkova), Thailand (Image credit: Jon Hanson) Okinawa, Japan (Image credit: Gary Hughes), Fiji (Image credit: Matt Wright)

Using a genetic approach, the researchers analysed DNA from over 237 starfish collected from reefs around the world. Their results strongly suggest that their are in fact four species of COTS, located in the Pacific Ocean, Red Sea, Southern Indian Ocean and Northern Indian Ocean).

Geographical distribution of the different species of crown of thorns (each colour represents a different species where sampled, piecharts indicte the frequency of each species per location)

It’s fascinating to think that the divergence of these species occured between the Pliocene (3.65 million years ago) and early Pliestocene (1.95 million years ago). More importantly though, this discovery may have fairly interesting implications for conservation biology. The researchers point out that whilst outbreaks of COTS are well-researched phenomena on the GBR and Indo-Pacific reefs since the early 1960’s, outbreaks in the Indian Ocean and Red Sea are much less severe. It seems that a better understanding of the genetic structure of COTS populations and identifying species boundaries may go a long way to explaining the intensity and magnitude of COTS outbreaks in different regions.

Reference: Vogler et al (2008) A threat to coral reefs multiplied? Four species of crown of thorns starfish. Biology Letters doi:10.1098/rsbl.2008.0454 (Link)

Reefs in trouble – The real root cause

Posted on September 30, 2008 by ovehblog

Yellow band disease

Dr. Stephen Jameson recently published a provocative essay in the Marine Pollution Bulletin that has stimulated considerable debate among reef scientists and conservationists, especially on the coral list server. His goal was to drill down to the ultimate social/political cause of reef decline, beneath the proximate environmental causes reef scientists study:

The real root cause of coral reef decline is not carbon dioxide emissions, rising sea surface temperatures, ocean acidification, coral disease, over fishing, destructive fishing techniques, eutrophication, sedimentation, sewage, herbicides, pesticides, African dust, increasing human populations or any of the other individual or synergistic combinations of stressors affecting coral reefs locally,regionally or globally – these are only symptoms of much bigger and more profound problem. At its core, the real root cause of coral reef decline, when objectively looking at the evidence, seems to be attributable to innate human species behavior characteristics determined by how we are genetically hard-wired.

Dr. Jameson said, “I wrote it in response to the International Year of the Reef/Science Magazine issue “Reefs in Trouble” (14 Dec 2007) that, in my opinion, missed a golden opportunity to address the “real” root cause of “Reefs in Trouble””. And what he is really trying to get at is whether large groups of humans are capable of cooperatively managing a complex system like a reef. “Do we really have the capability, when operating as a very large group such as a nation or group of nations, to govern ourselves effectively and live sustainably with our environment?” There is lots of evidence that we can do so when in small, communal groups, but why when we organize as nations do things seem to go awry?

Our every day experience in the United States (and in many other countries) informs us that the state of our governance, where wealthy business and special interests use campaign financing, lobbying, and media control to manipulate government policy and public perceptions is not a viable system for conserving coral reefs or for sustainable living because it is predicated on the fact that; ‘‘He who owns the political trump card wins”

It is a great system for creating corporate profit and socializing expense at global cost, but it does not produce clean air and water in natural environments or enhance biodiversity.

Stephen is also asking: can a social, cultural community consciousness evolve into a global consciousness? There are several layers to the answer. As he argues, there may be genetically or socially based behavioral limitations that have and will preclude the development of a new form of global altruism. There are also complex competing forces that have designed a governance system incompatible with the conservation of species and ecosystems half way around the world. But I think a very deep perception gap is another key problem. Even in wealthy nations, where we have the luxury of worrying about such matters, I am struck by how few people recognize that their actions can affect other people in far away nations. Many people I talk to in the US are aware of climate change and the decline of coral reefs, but have a hard time comprehending that their choices and behaviors could actually be causing problems for people and corals in the south Pacific. Making people, especially policy makers, aware of the striking effects we are having on all the world’s oceans, including ocean chemistry and temperature, will be a critical battle in the broader campaign to address the real root cause.

Citation

Jameson SC (2008) Guest editorial: Reefs in trouble the real root cause. Marine Pollution Bulletin 56(9):1513-1514

Scientists urge Prime Minister Kevin Rudd to crack down on climate change issues

Posted on September 29, 2008 by ovehblog

The Age is reporting on an open letter to the Australian Prime Minister Keven Rudd, urging the PM to make strong cuts in Australia’s greenhouse gas emissions by 2020. The letter, written by myself and 15 other Austalian scientists who contributed to the IPCC report, was released on the eve of the final report by the Garnaut review on climate change. In essence, we disagree with the recent advice by Professor Garnaut to make a slower start in cutting emissions (“Targets and Trajectories“ – a 10% reduction by 2020), and strongly advocate the PM to reduce emissions by at least 25% bellow 1990 levels by 2020:

“As a group of Australia’s leading climate change scientists, we urge you to adopt this target as a minimum requirement for Australia’s contribution to an effective global climate agreement,” the letter states.

“Failure of the world to act now will leave Australians with a legacy of economic, environmental, social and health costs that will dwarf the scale of national investment required to address this fundamental problem”.

The scientists who signed the letter are Australia’s world-recognised experts on climate change, including Dr John Church, a leading authority on sea-level rise who recently stepped down as chairman of the joint scientific committee of the World Climate Research Program. Dr Church is also a senior CSIRO researcher, but he and other CSIRO scientists signed the letter as individuals.

Also among the signatories are Dr Roger Jones, from CSIRO, who is currently advising the federal Treasury and Professor Garnaut’s climate change review; Professors Nathan Bindoff and David Karoly, who worked on the most recent IPCC reports; Professor Tony McMichael from the Australian National University, who advised the IPCC on the human health impacts of climate change; Professor Matthew England, joint director of the Climate Change Research Centre at the University of New South Wales; and Professor Ove Hoegh-Guldberg, an expert on climate change and the Great Barrier Reef.

On the back of the report is a recent poll by the Lowy institute, which is quite an intriguing read. Whilst the overall message is a positive one in that Australians want action on climate change, the feeling is that it cannot come at a cost to jobs or at a financial cost. Out of the 1001 people, 19% surveyed said they would be willing to pay >$21 per month ontop of their electricity bill to help solve climate change, and 20% would pay between $11-20. In contrast, 32% would be willing to pay between $1-10 per month, whilst 32% of people surveyed were not prepared to pay anything at all.

Interestingly, 64% of responants believed that the Kyoto Protocol hasn’t solved the issue of climate change but was “a step in the right direction”, yet 26% believed it was “purely symbolic”. On the bright side, if this poll is a genuine reflection of Australian attitudes, 73% would prefer Barack Obama to become the next president of the United States, whilst John McCain recieved only a 16% response.

Never Mind the Mohawk, Here’s the Mary River Turtle

Posted on September 27, 2008 by ovehblog

Sorry for the bad pun… These great images were captured by photographer Chris van Wyk in Queensland, Australia (the green ‘mohawk’ effect, remniscent of the British subculture of the early 1980’s is actually an ephiphytic turf algae growing on the shell and head of the turtle). The Mary River turtle (Elusor macrurus) is considered “endangered” under the Environment Protection and Biodiversity Conservation Act in Queensland, and is geographically limited to shallow slow moving waters in the Mary River and it’s tributaries. Not only is it one of Australia’s largest species of turtles (>50cm), it is the sole species in it’s genus, representing an incredibly old lineage of turtles that has since disappeared from Australia’s evolutionary history. As Queensland has been in one of the longest draughts in over a century, the Queensland government is intending on creating a dam in the Mary River, impacting upon the habitat of the Mary River turtle and a host of other rare and endangered native species such as the Queensland lungfish and the Murray River cod.

Global CO2 emissions exceed IPCC worst case scenario

Posted on September 27, 2008 by ovehblog

A comprehensive report released today by the Global Carbon Project contains the grim news that global CO₂ emissions are exceeding the most pessimistic IPCC emissions scenario. The annual mean growth of atmospheric CO₂ increased from 2.0 ppm (parts per million) during the first half of the decade and from 1.8 ppm in 2006, to 2.2 ppm in 2007. This increase in the growth of emissions makes IPCC stabilization scenarios of 450 ppm – 650 ppm doubtful.

Annual mean growth rates of atmospheric CO2 concentration.

The report “Carbon budget and trends 2007” is a sobering synthetic analysis of the world’s carbon budget, including the sources and sinks of CO₂ parsed by nation, continent, human activity and ecosystem.

Despite the increasing international sense of urgency, the growth rate of emissions continued to speed up, bringing the atmospheric CO₂concentration to 383 parts per million (ppm) in 2007. Anthropogenic CO₂emissions have been growing about four times faster since 2000 than during the previous decade, despite efforts to curb emissions in a number of Kyoto Protocol signatory countries.

Dr. Pep Canadell, executive director of the Global Carbon Project said “This new update of thecarbon budget shows the acceleration of both CO₂ emissions and atmospheric accumulationare unprecedented and most astonishing during a decade of intense international developments to address climate change.”

Fossil Fuel Emissions: Actual vs. IPCC Scenarios

Some of the report highlights are excerpted below:

Atmospheric CO₂ growth: Annual mean growth rate of atmospheric CO₂ was 2.2 ppm per year in 2007 (up from 1.8 ppm in 2006), and above the 2.0 ppm average for the period 2000-2007. The average annual mean growth rate for the previous 20 years was about 1.5 ppm per year. This increase brought the atmospheric CO₂ concentration to 383 ppm in 2007, 37% above the concentration at the start of the industrial revolution (about 280 ppm in 1750). The present concentration is the highest during the last 650,000 years and probably during the last 20 million years. [ppm = parts per million].

Regional fossil fuel emissions
The biggest increase in emissions has taken place in developing countries, largely in China and India, while developed countries have been growing slowly. The largest regional shift was that China passed the U.S. in 2006 to become the largest CO₂ emitter, and India will soon overtake Russia to become the third largest emitter. Currently, more than half of the global emissions come from less developed countries. From a historical perspective, developing countries with 80% of the world’s population still account for only 20% of the cumulative emissions since 1751; the poorest countries in the world, with 800 million people, have contributed less than 1% of these cumulative emissions.

Conclusions: Anthropogenic CO₂ emissions have been growing about four times faster since 2000 than during the previous decade, and despite efforts to curb emissions in a number of countries which are signatories of the Kyoto Protocol. Emissions from the combustion of fossil fuel and land use change reached the mark of 10 billion tones of carbon in 2007. Natural CO₂ sinks are growing, but more slowly than atmospheric CO₂, which has been growing at 2 ppm per year since 2000. This is 33% faster than during the previous 20 years. All of these changes characterize a carbon cycle that is generating stronger climate forcing and sooner than expected.

Citation

Global Carbon Project (2008) Carbon budget and trends 2007, [www.globalcarbonproject.org, 26 September 2008]”

MPAs and climate change II: study finds no-take reserves do not increase reef resilience

Posted on September 23, 2008 by ovehblog

PI Nick Graham surveying a high coral cover reef.

Some coral reefs scientists have argued (and prayed) that marine reserves (no-take MPAs) could limit the impacts of climate change on populations of reef-building corals. The idea is that by maintaining healthy food webs and herbivore populations, reef managers can prevent seaweed blooms that can kill juvenile corals. Restricting fishing would thus increase r eef resilience (which ecologists define as the return rate of an ecological system to its baseline state following a disturbance). Unfortunately, a new study tempers such wishful thinking.

The study (Graham et al. 2008 published on August 27 in the open access journal PloS One) indicates that marine reserves have no effect on coral resilience to ocean warming.

Approximately 45% of coral cover in the Indian Ocean was lost in 1998 due to temperature-related coral bleaching. To compare coral loss within and outside of reserves, the team resurveyed 66 reefs in the Indian Ocean that had originally been surveyed before the 1998 mass bleaching event. The surveyed sites included reefs within nine reserves in four countries.

The results indicated that “A greater proportion of [marine reserves] (71%) than fished (42%) locations showed significant declines in coral cover over the study period. There was no evidence to suggest the percent change in coral cover differed between [marine reserves] and fished areas, and in some cases declines were significantly greater in [marine reserves]”

This is an important study in coral reef ecology. As a believer in Macroecology and a long-time disciple of James Brown (the desert ecologist, not the King of Funk) I think such a regional-scale, carefully implemented approach could be used to answer many other key questions in reef ecology. Having read hundreds of monitoring studies while building a database of >10,000 reef surveys, I can attest that there are few targeted macroecological reef studies of this scope. There are some monitoring programs this large. But few studies of this scale are designed and implemented to answer a specific question. Although the macroecological approach is rarely employed (due to obvious financial and logistical constraints), it certainly isn’t new. Terry Hughes (Hughes 1994 Science) applied it by resurveying nine reefs on the north coast of Jamaica after a variety of disturbances wiped out corals and enabled macroalgae to become the dominant benthic organism. Even earlier, Endean and Stablum surveyed dozens of reefs across the GBR in the late 1960s and early 1970s to assess the impact of and recovery from a regional crown-of-thorns starfish outbreak.

I imagine critics of Graham et al. 2008 and it’s implications could argue that many or most tropical marine reserves are not well-managed and that they might increase resilience if enforced. This would be a fair point, but given the political and socio-economic realities of the region, poaching might be difficult or impossible to eliminate. So to paraphrase Donald Rumsfeld, we might just have to conserve reefs with the marine reserves we have, not the marine reserves we want.

Change in coral cover at sites across the western Indian Ocean. Green and red symbols represent increases and decreases in coral cover respectively. Symbols with solid borders are sites in marine reserves. Data represent 66 sites across the region. Numbers in key (size of bubble) are percent changes between mid 1990s and 2005.