Electricity revives Bali coral reefs

Joseph Coleman, Associated Press 5 Dec 07;

Just a few years ago, the lush coral reefs off Bali island were dying out, bleached by rising temperatures, blasted by dynamite fishing and poisoned by cyanide. Now they are coming back, thanks to an unlikely remedy: electricity.

The coral is thriving on dozens of metal structures submerged in the bay and fed by cables that send low-voltage electricity, which conservationists say is reviving it and spurring greater growth.

As thousands of delegates, experts and activists debate climate at a conference that opened this week on Bali, the coral restoration project illustrates the creative ways scientists are trying to fight the ill-effects of global warming.

The project — dubbed Bio-Rock — is the brainchild of scientist Thomas Goreau and the late architect Wolf Hilbertz. The two have set up similar structures in some 20 countries, but the Bali experiment is the most extensive.

Goreau said the Pemuteran reefs off Bali's northwestern shore were under serious assault by 1998, victims of rising temperatures and aggressive fishing methods by impoverished islanders, such as stunning fish with cyanide poison and scooping them up with nets.

"Under these conditions, traditional (revival) methods fail," explained Goreau, who is in Bali presenting his research at the U.N.-led conference. "Our method is the only one that speeds coral growth."

Some say the effort is severely limited.

Rod Salm, coral reef specialist with the Nature Conservancy, said while the method may be useful in bringing small areas of damaged coral back to life, it has very limited application in vast areas that need protection.

"The extent of bleaching ... is just too big," Salm said. "The scale is enormous and the cost is prohibitive."

Others note the Bali project is mostly dependent on traditionally generated electricity, a method that itself contributes to global warming. Goreau himself concedes it has yet to attract significant financial backing.

Nonetheless, scientists agree that coral reefs are an especially valuable — and sensitive — global environmental asset. They provide shorelines with protection from tides and waves, and host a stunning diversity of plant and sea life..

Goreau's method for reviving coral is decidedly low-tech, if somewhat unorthodox.

It has long been known that coral that breaks off the reef can be salvaged and restored if it can somehow be reattached.

What Goreau's Bali project has done is to construct metal frames, often in the shape of domes or greenhouses, and submerge them in the bay. When hooked up to a low-voltage energy source on the shore, limestone — a building block of reefs — naturally gathers on the metal. Workers then salvage coral that has broken from damaged reefs and affix it to the structure.

Goreau and his supporters say the electricity spurs the weakened coral to revival and greater growth.

"When they get the juice, they are not as stressed," said Rani Morrow-Wuigk, an Australian-German woman who rents bungalows on the beach and has supported efforts to save the reefs for years.

And indeed, the coral on the structures appear vibrant, and supporters say they have rebounded with impressive vigor. The coral in Pemuteran teems with clownfish, damselfish and other colorful tropical animals.

Funding, however, is a major problem. There are some 40 metal structures growing coral in Pemuteran Bay and about 100 cables laid to feed them with electricity, but only about a third of the wires are working because of maintenance problems and the cost of running them, said Morrow-Wuigk.

The electrification program is part of a wider effort in the bay to save the coral.

Chris Brown, an Australian diving instructor who has lived in Bali for 17 years, said he and other people determined to save the reefs have had a long struggle driving away fishermen who use dynamite and other coral-destroying methods to maintain their livelihoods.

He said a key has been demonstrating to shoreline communities the benefits of coral reef maintenance, such as growing fish stocks and jobs catering to tourists who come to dive in the area.

Brown has participated in Goreau's projects, and won funding from the Australian government to set up a Bio-Rock structure electrified by solar panels fixed on a floating off-shore platform.

Brown has also used seed-money from Canberra to establish the Reef Gardeners of Pemuteran, which trains islanders to dive, maintain the solar-paneled coral structure and clean the reefs of harmful animals.

Kadek Darma, 25, a Balinese who has worked with Brown for two years, said the advantages of the corals to the local economy were obvious.

"They attract the tourists, and more tourists means more jobs," he said. "I hope we can all keep maintaining the reefs for our great-great grandchildren."

Shock treatment for coral restoration
Clark Boyd, BBC News 8 Oct 04

Coral reefs around the world are disappearing. In many places, more than 90% of corals have bleached or died. But an effort is under way to re-grow corals by giving them a bit of electro-shock therapy.

Marine biologist Tom Goreau knows coral. He has been diving among the reefs since before he could walk.

As the director of the Global Coral Reef Alliance, he is passionate about how extraordinary corals are.

"They're very simple animals. They're an animal that's basically a gut with a ring of tentacles around it," he said.

"And with their tentacles they catch zooplankton, little shrimp and animals swimming in the sea. And they eat animals, they don't plants. And they can't move, so that confuses people.

"We're used to thinking of animals as things that run and swim around. These things live in a limestone cup, and they kind of pull into that cup for protection."

Fantastic colour

Corals are the only animals in the ocean that build permanent solid structures. It means that they cannot run away from diseases or pollution.

The problem is that they are especially sensitive to both.

"The reason they're so sensitive is that they're not just animals, they are also plants," said Dr Goreau.

"They're plants because in the cells of the coral they have symbiotic algae living inside and those things photosynthesise.

"Corals have to have clean water and a lot of light to live, because the algae are helping the corals grow their skeleton and grow faster and provide a little bit of their food."

The algae are also what give corals their fantastic colour.

But the algae in the coral tissue will die if the coral encounters stress. The coral then bleaches; it turns white or transparent. The coral itself will die if something is not done.

The news since the 1980s is grim. It seems that warmer ocean temperatures are killing off corals at a record rate. Corals that have survived for 1,000 years are dying.

It is happening just about everywhere, but the corals in the Indian Ocean and the Pacific Ocean are especially hard hit.

"The Maldives and Seychelles and Palau and places I've worked - the mortality in many places was close to 99%," said Dr Goreau.

"In some places it only 90 or 95%, but I've been in reefs where you could find only one live coral afterwards.

"In 2002, there was mass mortality all across the South Pacific, and it never gained the attention of governments. In 1998, most of the corals in the Indian Ocean died. So we're right on the edge."

Low voltage

But Dr Goreau and a German architecture professor named Wolf Hilbertz are working to bring coral populations back.

Professor Hilbertz has developed something he calls sea-creation, which he explains in a video produced by Natural History New Zealand.

"Corals are using calcium carbonate drawn from seawater to build their exo-skeletons. We use these materials for building purposes," said Mr Hilbertz.

The key to the process is electricity.

Professor Hilbertz found he could mimic the natural process that corals use to grow their skeletons.

He did it by putting a low voltage current through seawater. The current draws out the minerals, which essentially constitute limestone. But, you have got to put the limestone somewhere.

So Professor Hilbertz has designed what he calls coral arks. They are made of welded steel bars.

He sinks the arks to the sea floor, and then supplies a current. Within a short period of time, limestone will start to grow on the steel.

Professor Hilbertz says the only special equipment needed is a special titanium mesh that can withstand electric current and sea water.

Safe for divers

The limestone that grows on the steel is stronger than concrete. Live corals can then be grafted on to the structure.

Those corals can survive pollution and high sea temperatures, as long as the electricity stays on. The current takes care of growing a coral's skeleton. That frees the animal up to fight off diseases or other stresses.

"What we found was that we were able to grow corals at three to five times the record rates, in a habitat where all the corals had been killed by pollution," said Tom Goreau.

"And we were able to do that as long as we kept the power on. It's the electricity itself that gives them that growth and that extra resistance to stress."

Tom Goreau and Wolf Hilbertz have about 15 coral ark projects going around the world.

They are all pilot projects as they do not have the money to try it yet on a larger scale.

One of the biggest trials is being carried out in the north of the Indonesian island of Bali. There are currently 21 coral arks in a bay there, powered by a bank of 80 chargers on shore.

The electricity costs are equivalent to running a few beach lights. It is only 12 volts so divers are safe.

It seems to be working, with the corals growing quickly.

The team hope that the Bali project can spur interest in their method. However, both men worry that it may be too late to save the majority of corals worldwide.

Clark Boyd is technology correspondent for The World, a BBC World Service and WGBH-Boston co-production

Are such reef rehabilitation approaches viable?
Extracts from Resolution "Regarding the Need for Scientific and Financial
Evaluation of Coral Reef Rehabilitation Methods" (PDF) submitted at INTERNATIONAL CORAL REEF INITIATIVE (ICRI)General Meeting Seychelles, 25th – 27th April 2005

3. Naturally Governments and the private sector with economic interests in coral reefs will seek ‘quick’ solutions, some based on engineering principles to ‘repair’ the damage and to accelerate natural recovery processes;

4. These agencies, however, may lack the capacity or expertise to evaluate the scientific and costs-to-benefit relationships of proposed coral reef rehabilitation techniques and to apply them in an effective and sustainable way;

5. Most coral reefs have considerable natural recovery capacity, provided that there are supplies of suitable coral, fish and other larvae, and that chronic disturbances such as excess sedimentation, pollution and over-fishing are minimised. Coral reefs can begin to recover immediately, with new coral growth and fish stocks naturally re-colonising the ecosystem within one to two years; complete recovery may take longer depending on the environment;

6. A wide range of ‘engineering’ techniques have been proposed as reef reconstruction or rehabilitation techniques by various commercial and non-commercial organizations. These include:

i. a mechanism using wire frames through which electricity is passed to accrete calcium carbonate and accelerate the growth of transplanted corals;

ii. installation of artificial reefs, including concrete structures; and

iii. mechanisms for re-cementing and re-gluing corals and other organisms to the substratum.

8. [It is} acknowledged that there is often a valid case for rehabilitation of damaged reefs and that some innovative and new approaches to coral reef conservation and management may potentially have applications, however we are concerned that
there have been insufficient peer-reviewed, long-term scientific studies of reef rehabilitation using these and other techniques.

Moreover, there have been few cost-benefit analyses to assess effectiveness of the methods over natural recovery processes.

The available evidence suggests that some techniques may be useful in specialized cases, but all have limited or no application and value for large-scale coral reef rehabilitation.

In addition to effectiveness considerations, construction of any engineered structure on a coral reef must be evaluated against any potential environmental damage caused during construction or later degradation;

The International Coral Reef Initiative (ICRI) is a partnership among governments, international organizations, and non-government organizations. It strives to preserve coral reefs and related ecosystems by implementing Chapter 17 of Agenda 21, and other relevant international conventions and agreements of the Convention on Biological Diversity, December 1994.

Links

Global Coral Reef Alliance website

International Coral Reef Initiative (ICRI) website