The threats to coral reefs are pervasive, and there are no simple solutions. Saya 2002 is one of many initiatives to find new ways to help protect them. Some detractors see it as marginal and near irrelevant, given the enormous scale of the challenges. But the technique to be employed at Saya de Malha has already shown its worth in the Maldives after the El Nino event of 1998, and elsewhere. What is being attempted here is extraordinarily bold - even visionary - and will contribute new ideas and understanding that may one day make a decisive contribution. The two articles on this page explore the science and technology behind Saya 2002, and put the project in the context of major challenges to the world's reefs.
by Caspar Henderson
Twenty people - including fishermen, the village blacksmith and marine scientists from Indonesia, India, Australia, Israel, the US, Jamaica and elsewhere - stagger under the weight of Ibu Karang or "the mother of all corals", a huge iron frame shaped like a giant tea cosy. Slowly, they carry it down the beach and into the sea. Floats are attached to the 40ft structure and the crew swim with it 100 yards out to sea, release it from the floats and let it settle on the sandy bottom. Later, a small electrical circuit is created in the frame through wires from a solar-powered battery on shore.
This scene, at Permuteran on the island of Bali in Indonesia, is one of the latest in a network of conservation projects using a technique called Biorock. The initiators believe it can make an important contribution to reversing the destruction of the world's coral reefs.
The world's reefs provide about $400bn a year in directly measured benefits in such areas as fisheries and tourism, helping to support the livelihoods of about 500m people. But destruction is both relentless and rapid. Estimates made in 1998, that 11 per cent have been destroyed by human action, were recently revised sharply upwards to more than 27 per cent "effectively" lost by late 2000. The loss is mainly due to exceptionally warm seas, diseases resulting from stress, blast fishing and pollution. Scientists think that at least another 25 per cent will go within 20 years, with global warming taking an even greater toll throughout the rest of the century.
Once a reef is destroyed or severely degraded, recovery may take decades or hundreds of years or never happen at all. Saving the reefs will mean improved systems of management, including no-take zones, and greater community involvement in their preservation. Restoring those that have been damaged or destroyed may be even more difficult, but Biorock, or Mineral Accretion Technology as it is also known, suggests a way forward.
After 20 years of painstaking work on shoestring funds, Wolf Hilbertz and Tom Goreau have shown how to grow a limestone base, and from that entire living reefs, using no more than a few iron bars, electricity and seawater. Biorock uses low-voltage direct currents, usually from tidal or solar energy sources, to grow solid limestone on conductive materials such as iron. The electrolysis causes calcium carbonate and magnesium hydroxide in the seawater to accumulate on the surface of the bars, and greatly accelerates the growth and reproduction of coral attached to the bars.
In natural circumstances, coral polyps feed on food particles in the water and also capture energy from sunlight-trapping microscopic algae called zooxanthellae, which are embedded in their outer surfaces. Electrolysis decreases acidity at the surface of growing Biorock, allowing calcium carbonate crystals to form which the coral uses to create its skeletal structure and so grow more rapidly. Without having to expend their own energy to create these favourable conditions, the corals can put more energy into growth and reproduction and withstanding stress.
Over time, and with just the right voltage and current density, limestone rock, which is the natural base for coral, accumulates. The structure becomes ever stronger and the corals become firmly embedded in the structure as it grows. The technique can also be used to grow breakwaters or construction materials which otherwise have to be imported to atoll nations. Should the structure be damaged, it will 'heal' itself within a few days by renewed deposition of minerals right at the point of impact - a property normally only found in living structures. The mechanical strength of Biorock compares well to lightweight concrete.
"Biorock can be made on any scale, and is viable for even the smallest and most remote communities, as well as the largest," says Hilbertz. "The skills for maintaining and repairing mineral accretion structures are quickly acquired locally. And no expensive foreign experts are needed to maintain them."
Until recently, their work was largely neglected, but in 1998 Goreau and Hilbertz won international recognition with the Society for Ecological Restoration's prestigious Theodore M. Sperry Award. And now, in addition to projects in Bali, Thailand, Papua New Guinea, Mexico and Panama, new schemes are under way in Israel, India and Sulawesi (Indonesia). There is also interest in Hawaii and the Philippines, while a new 150 metre (500ft) artificial reef is planned for Permuteran this month.
Spectacular results achieved at a project in the Maldives have helped to make this surge of activity possible. During the El Niņo event of 1998, more than 90 per cent of branching corals in the Maldives died from high seawater temperatures in a phenomenon known as coral bleaching. As a result, the dead coral framework began to collapse from the destructive activities of internal boring organisms and the heavy grazing of parrotfish, whose populations have exploded.
Prospects for coral reef recovery are severely limited by the massive mortality experienced in all potential Indian Ocean source areas of new coral larvae. Rising temperatures will make bleaching an annual phenomenon in the near future. There is, therefore, a critical need to develop ways to protect coastlines from erosion, restore damaged reef structures, and maintain biodiversity if the Maldivian islands and its people are to survive global climate change.
Commencing in 1998 Goreau and Hilbertz together with local colleagues led by Azeez Hakeem used Biorock to build reefs near the Ihuru Tourist Resort in the Maldives in the North Male Atoll. Prior to the bleaching event in 1998, the limestone accretion had grown to a thickness of 20cm (8in) on the bars in their structures. Coral fragments transplanted on to the structure grew three to five times faster than normal.
One structure, known as the 'Ihuru Necklace', intended as the first part of the reef to encircle the entire island, was 40 metres long, 8 metres wide and 1.5 metres high, and was powered by solar cells and batteries, delivering the equivalent of just one 500 watt bulb. Following the bleaching event, corals on the Biorock structures had much higher survival rates than corals in surrounding reefs, while damaged coral on the structures grew back more than twice as quickly as the few surviving on neighbouring natural reefs.
But coral recovery on the Biorock is far from plain sailing. "After bleaching, there was imbalance in the reef ecosystem" says Hakeem. "Many corals died, but their enemies, such as crown-of-thorn-starfish, did not die". The new baby corals are threatened by these creatures, and require constant vigilance to protect them, he says. And fishermen are continuing to blast near existing structures here and elsewhere.
Some scientists are cautious about coral restoration efforts. "Telling people you can restore damaged reefs [may give] the false impression reefs are expendable, and can be destroyed now to be fixed later," says Robert Richmond, of Marine Biology at the University of Guam. "There is always some mortality associated with transplantation exercises, and the result may be two damaged areas instead of one", he adds.
The best approach, Richmond says, is to restore conditions that support natural recovery, including clean water and clean substrata. Nevertheless, he says, some steps can be taken to "fix" the reefs, and together with colleagues from Australia and Hawaii, Richmond is cultivating coral larvae and inducing them to settle on appropriate surfaces. Goreau agrees, in part: "Our view is that the best reef is a healthy natural one, and even the best Biorock one will be somewhat different. "But sadly, to think that reefs will enjoy [more favourable conditions including] clean water and substrate that allow natural recovery is only a hopeful dream in a world that is moving in just the opposite direction."
This article was first published in the Financial Times on 10 February 2001.
by Caspar Henderson
Shortly before the Climate Conference in the Hague, a panel of the world's most eminent coral reef scientists issued a stark warning that climate change presents an ever bigger threat to these precious ecosystems and that decisive action now is imperative. Speaking in towards the close of the 9th International Coral Reef Symposium, one of the Olympic events of marine science attended by nearly 2,000 top researchers from over fifty countries, the panel painted a picture of almost unremitting gloom.
"We call for an effective reduction in greenhouse gas emissions over the next decade" said Yossi Loya, Professor at the Department of Zoology at the Faculty of Life Sciences at Tel Aviv University in Israel, and the recipient of the Year 2000 Darwin Medal for Lifetime Contribution in Coral Reef Research. The biggest warning sign so far was the massive coral bleaching that occurred in 1997-98. In large areas of the Indian Ocean more than 90% of the corals died.
Coral bleaching occurs when the symbiotic algae that live in corals become stressed and are expelled. This turns corals white, leaving them in an unhealthy state. Research presented at the conference revealed that rising temperatures have been responsible for large scale bleaching and mortality events in 1999 and 2000. The overwhelming majority of scientists at the symposium agreed that climate change is the cause. Such death rates are unprecedented in recent millennia since cataclysmic events long in the earth's past.
Reef building corals have created the richest and most biodiverse habitats on earth. It's estimated they contribute at least US$400 billion a year to the world economy, forming an essential part of the well being and livelihoods of around 500 million people who live near to them. Living reefs also protect vulnerable coastlines from sea surge, an almost priceless service.
"We are not appreciating the true economic value of these resources," said Hugh Kirkman, who directs the United Nations Environment Programme (UNEP) East Asian Seas Regional Coordinating Unit, "and too often our efforts are like sticking band-aids on a great wound." Kirkman made these remarks not long after the Symposium concluded.
The Global Coral Reef Monitoring Network, an international body, presented a new assessment of the status of the world's reefs to the Symposium. It concluded that only two years after a survey of the world's coral reefs found 11% had been destroyed by human action, a more extensive assessment by around 80 countries of their own reefs - most for the first time - had raised the total to 27% "effectively" lost by late 2000. "At least another 25% will be lost within twenty years" said Prof. Clive Wilkinson of the Australian Institute of Marine Science, who edited the report.
"The fact that all major climate models show that the current increases in sea temperature will continue is a source of major concern" said Professor Ove Hoegh-Guldberg of the Centre for Marine Sciences at the University of Queensland, Australia. "We have insufficient evidence that corals are able to acclimatize or adapt fast enough to these sort of changes. This is a clear area for priority research".
"There have been similar rates of climate change in geological history, and we are able to explain these by natural phenomena" said Dr Mark Eaken, Director of Paleoclimatology for the National Ocean and Atmospheric Administration in Washington DC; "but the changes we are currently witnessing can only be explained on the basis of human induced impacts".
The fossil record shows that coral reefs have recovered from such global scale climatic events in the distant past. But this has typically taken between 2 and 100 million years. The scientists agreed that, in the absence of any clear evidence that acclimatisation or adaptation will see coral reefs through such future crises, it was perilous to use this as a reason for little or moderated action.
But increases in sea temperature are far from the only concern. "Newly emergent diseases are raging through the corals of the Caribbean" said Richard Aronson, Senior Marine Scientist at the Dauphin Island Sea Laboratory in Alabama. "Most of these diseases are very difficult indeed to get a handle on, and they are starting to get a hold in the Pacific".
Destructive fishing practices such as the use of dynamite and cyanide are even more immediate threats to reefs than climate change and disease, said Lida Pet-Soede, of WWF Indonesia's Programme Manager for Fisheries. Up to 80% of Indonesia's reefs have been severely degraded in this way, she said.
Involving local communities, who have a direct stake in the continuing well being of their reefs, is the key, said Rili Djohani, an Indonesian national working for The Nature Conservancy, a US based conservation organsation that works in Indonesia. "There are innovative and creative models for us to build on" she said.
But it's a race against time. "The pressures are increasing hugely" said Djohani - especially in regions like South East Asia, which is home to the richest and most diverse coral ecosystems, but also undergoing rapid economic and population growth combined with political turbulence. In most countries, said Djohani, conservation budgets have been cut by 80% since the economic crisis of 1997/98. In Indonesia, exports of fish caught illegally, much of it from reefs in ways that cause severe degradation, are thought to be twice as large as legal exports.
Hoegh-Gulberg agreed that such direct effects from human action were an enormous threat to coral reefs, but added that this was not a good reason for ignoring the danger of climate change. "Just because you have a rhino charging at you and it's only twenty meters away doesn't mean you should completely ignore an angry bull elephant which is fifty meters away".
Jamaican scientist Thomas Goreau was critical of the absence of people from poor countries in the panel issuing the dire warning to the world's press. "We must develop more scientific expertise and management capacity in the developing countries where the people live who are going to be worst affected by this catastrophe" he said. Dr Goreau has helped to develop a method to help local communities restore their reefs at a faster rate and at low cost.
Kirkman said the over-riding challenge is greater co-ordination. Present conservation efforts resemble "a mob of people kicking footballs around a poorly-defined field".
In addition to funding by Western Aid Agencies, the sponsors of the Symposium included Southern Pacific Petroleum/Central Pacific Minerals. The Australian company is exploiting an oil shale reserve estimated to hold 29 billion barrels of oil equivalent and situated only a few yards from the edge of the Great Barrier Reef World Heritage Area. Oil shale is among the most carbon intensive of fossil fuels.
This article was first published in The Ecologist in the February 2001 edition.
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