07 October 2008

Does electricity stimulate coral growth?

A Florida town is spending US$60,000 to try it out. One scientist's response to this was "There are no peer-reviewed papers that I'm aware of that really document that corals grow faster or better on it."

Lauderdale-by-the-sea will try electricity to stimulate coral growth off South Florida coast
Low voltage current to stimulate coral growth off our coast
David Fleshler, South Florida Sun-Sentinel 7 Oct 08;
The thunderclaps and lightning flashes of Victor Frankenstein's laboratory seem far removed from the sunshine, hotels and snorkelers of the South Florida coast.

But the town of Lauderdale-by-the-Sea is pursuing the dream of using electricity to help generate life.

The town plans to install a cluster of electrified artificial reefs off the beach and run a low-voltage current through steel frames to stimulate the growth of corals, creating habitat for fish, crabs and other marine creatures. Shaped like airplane hangars, the six undersea structures each would stretch 6 feet along the ocean floor. Two buoys with solar panels would deliver electricity through insulated cables.

Coral reefs, often called the rain forests of the ocean, have been battered by global warming, pollution, overfishing and ship groundings. Hoping to reinvigorate its reefs, Lauderdale-by-the-Sea has approved a $60,000 contract with Global Coral Reef Alliance of Cambridge, Mass., which has constructed electrified reefs in Mexico, Jamaica, Indonesia, the Maldives and other countries.

The electric current, too weak to harm swimmers or fish, draws dissolved calcium carbonate and other minerals from seawater, helping corals build their skeletons.

But some scientists aren't sure a jolt of electricity is what South Florida's reefs need.

"There are no peer-reviewed papers that I'm aware of that really document that corals grow faster or better on it," said Richard Dodge, executive director of the National Coral Reef Institute at Nova Southeastern University.

John McManus, director of the National Center for Coral Reef Research at the University of Miami, said there's no doubt steel frames will grow coral, if only because they provide a surface off the murky floor of the ocean. But while a mild electric current stimulates coral growth initially, he said it's unclear whether the benefit continues after the coral has thickened enough to block the current. Most important, he said, there have been no studies comparing electrified steel structures with identical structures without electricity.

"There's not much evidence to say it's worth putting the electricity through," he said. "It's probably not going to do any harm. It might do some good."

The town agreed to pursue the idea after being approached by Dan Clark, an environmental activist with the group Cry of the Water; Marc Furth, an underwater photographer and former town commissioner; and Thomas Goreau, head of the Global Coral Reef Alliance.

Goreau, who has a doctorate from Harvard, said in an e-mail that it would be premature to comment until the project obtains necessary permits for construction. He expressed concern that any discussion could generate opposition. He said neither of the two scientists who questioned the technology had seen any of the group's projects, making their comments "uninformed opinion."

Many of the group's reefs, known by the trade name Biorock, have thrived for years, surviving environmental stresses that kill other corals, says the group's Web site. When ocean temperatures rose in the Maldives in 1998, killing 95 percent of the natural reef corals, 80 percent of the Biorock reefs survived, according to the Web site.

Vice Mayor Jerome McIntee, the electrified reef's leading proponent, said the project was worth the $60,000 cost if it could restore the town's reefs, famous among divers for being easily reached from the beach.

"We need to take the initiative and start the rebirth of a natural resource that has been long overlooked," he said.

The town is seeking permits from the Army Corps of Engineers and Florida Department of Environmental Protection.

Once reef structures are installed, divers search the ocean floor for broken pieces of coral that is still living but likely to die, torn off by storms or boat groundings. They attach these corals to the electrified structure. Meanwhile, coral larvae settle on it and grow skeletons.

An electrified reef it would be the latest attempt to rely on technology to fix damage done to the region's natural assets. The Everglades restoration relies on a highly engineered system of diesel-powered pumps, artificial reservoirs and computer-controlled water management. Engineers have attempted to control beach erosion by installing underground sand pipes, and most recently, proposing a 49-foot pit to accumulate sand next to Port Everglades.

Still, scientists don't dismiss the possibility that electrified reefs work.

"I think the jury's probably still out," said Richard Dodge, of Nova's coral reef institute. "Just because it isn't well documented doesn't mean it's not happening."

No comments:

Post a Comment

LinkWithin

Related Posts with Thumbnails