Biorock: Stimulating Coral Growth With Electricity

Can electricity give declining coral reefs a new lease on life? It may seem counter-intuitive, but it apparently has been effective for the last decade, thanks to marine biologist Thomas Goreau and engineer/architect Wolf Hilbertz, who have been experimenting with regenerating coral reefs using electricity in a technology called Biorock.According to the Global Coral Reef Monitoring Network (GCRMN), coral reefs worldwide are fading fast. It's estimated that more than a quarter of the world's reefs are already gone and that another quarter will die within twenty years.

A number of contributing factors to this alarming decline include marine pollution, rising levels of dissolved carbon dioxide and damage from fishing nets. But the greatest menace is rising oceanic temperatures. As the heat is turned up, algae living on the surfaces of coral reefs die off, leaving the calcium carbonate substrate exposed — a process known as coral bleaching — and which eventually leads to coral death.

Efforts to impede coral bleaching have been around since the fifties, usually in the form of artificial reefs made out of concrete blocks or discarded tires — and though they have been marginally successful, most of these reefs are still dismally barren compared to the real thing.

And surprisingly, this is where the Biorock technology shines compared to other artificial stand-ins. While Hilbertz was studying the role of electrical currents in the growth of seashells and reefs in the seventies, he found that sea water would electrolyze, forming a layer of calcium carbonate around the cathode which was as strong as concrete.

Further experiments showed that these electrolyzed coatings grow at a rate of 5 cm per year — as along as the current flows, the coatings will continue to grow and amazingly, will even heal itself when damaged. A meeting with marine biologist Goreau finally turned these discoveries to address the problem of coral bleaching.

The Biorock process works by constructing electrode frames 12 metres across which are electrified. Energy use is minimal, with each dome using around 3 watts per square metre and with most energy sources being solar panels.

It is effective because the calcium carbonate coating that is created mimicks the natural coral reef substrate, with coral actually flourishing 3 to 4 times faster on electrified reef, since they are able to use more energy for reproduction, rather than protection, while also making the coral more resilient to environmental disasters. It is no wonder then that these reef structures have been called "coral arks" in the hope that they will help restore coral populations from the global devastation they are facing now. via ::GreenGeek

See also ::Coral Die-Offs Are Faster and More Widespread than Previously Thought, ::Melting Coral Epidemic Sparked by Warming Oceans, ::Growing Artificial Coral In The Red Sea, ::Corals Engage in Fisticuffs with Global Warming

Image: Biorock Inc.