Electric Cages Offer Small Hope to Coral Reefs

A report on the Guardian website (Sunday, 16 August), suggests that electrified steel cages have had a dramatic effect on coral-reef building off the island of Vabbinfaru, Maldives. However, the researchers involved recognise that this is a local, small-scale solution to declining coral reefs and does little to address the well-documented widespread degradation of reefs.

Researchers have sunk a two-tonne steel cage on to the sea floor in Vabbinfaru. The cage is attached to a cable which supplies an electric current through the structure. The current triggers a chemical reaction which draws calcium carbonate out of the water and leads to deposition on the steel frame. Coral are attracted to the calcium-carbonate coated cage: coral growth on the structure is up to five times faster than on concrete structures implanted into the sea-floor. The coral surrounding the cage and concrete areas is largely dead, due to a mass-bleaching event in 1998.

The cage is not being used for widespread coral reef construction, instead providing a localised area of coral for observation by tourists on Vabbinfaru. It is possible however that this technique could be used to repair degrading reefs, abeit on a small scale.

See original article: Sunken steel cages could save coral reefs, Guardian online, 16 August 2009