Articles about reefs

James M. Cervino cnidaria at
Wed Mar 17 07:39:45 EST 1999

Dear Listers,

This is a Web Site of the Dallas Morning News: they published an article
about the state of the reefs

Below is an artile published in the Sunday Times of London


March 14 1999 - - The Sunday Times of London

Electrically charged frames are being used to create the limestone on which
coral lives.

Sean Hargrave reports

ELECTRICITY is coming to the rescue of coral reefs.

A novel idea of using an electric charge to build new reefs and help dying
coral recover is being tested in the Maldives. But the technology could be
used first 1,000 miles to the west in the Seychelles, where the government
has applied to the World Bank for funds to pay for it.

One in three fish lives on a coral reef, yet global warming and pollution is
killing coral. As much as half of the world's coral may be dead or dying. A
rise of just one degree Celsius above average temperatures is enough to
kill a reef.

The new approach relies on elementary chemistry. First scientists place a
steel frame in the sea and pass an electric charge of one or two volts
through it. The steel then carries a charge and has positive and negative
terminals, just like a battery.

The cathode terminal, which forms the bulk of the construction, makes the
water around it slightly more alkaline. The anode makes the water slightly
acidic but it is placed a couple of metres away from the main steel frame.
Making the water around the frame more alkaline causes calcium carbonate
particles in the sea to settle and form a limestone base.
This is the perfect home for coral, which thrives on clean, fresh limestone.
Tom Goreau of the Global Coral Reef Alliance (324 Bedford Road, Chappaqua,
NY 914-238-8788 Fax: 914-238-8768) says the system brings an extra benefit
to the coral. Usually much of the coral's energy goes into creating a
slightly alkaline stream of water so it can feed. "We are effectively
giving coral exactly what it wants, for free," he says. "We give it a good
clean base to settle on and make sure it doesn't expend its energy turning
the water alkaline. It's a really good environment to create growth, and
it's based on giving a helping hand to a natural principle.

"I cannot see that anybody can come up with a better solution because all
other attempts rely on creating reefs out of rubber tyres or old bricks, but
coral doesn't chose to live there. We are creating exactly the conditions
coral needs."

The limestone that forms the reef can be grown at a rate of between 1cm and
2cm a year. The voltage can be altered to speed up growth but this results
in limestone that is too soft. Scientists using the technique in the
Maldives have found it can promote coral growth of several centimetres a
year once coral settles on the artificially created reef.

The new technolgy is needed, says the GCRA, because there will hardly be
any live coral left if something is not done to redress the damage caused
by pollution and global warming.

"If half the world's trees were disappearing there would be an uproar, but
this is happening under water and so people aren't seeing it," says Goreau.
"We have to act now to give a helping hand. Remember, once the reefs are
gone many islands that are already suffering from erosion are going to be
unprotected against the power of the sea. People forget that apart from
playing home to one in four marine species, coral reefs also hold back the
sea and protect islands. Without them island communities would be

The original idea for the electric process came from a German architect,
Wolf Hilbertz. He developed the idea so that limestone building materials
could be made within steel meshes placed in the sea. This would provide a
free source of materials and stop islanders raiding reefs for stone to build
houses. Now that Goreau's team has proven the principle also works in
creating and sustaining coral reefs, work with solar and turbine power has
begun. These sustainable sources are preferred because they do not add to
the pollution or global warming that are being blamed for the demise of
coral. Goreau is encouraged by the Seychelles government's interest in the
technology. However, the government of the Maldives, where nearly all the
development work has taken place, has no plans to adopt it even though the
island group has been hit more than any other by the death of coral.

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