The shield is made out of calcium carbonate—the same material found in coral skeletons—and is 50,000 times thinner than a human hair. “It’s designed to sit on the surface of the water above the corals, rather than directly on the corals, to provide an effective barrier against the sun,” Great Barrier Reef Foundation managing director Anna Marsden tells The Daily Mail. “It (the project) created an opportunity to test the idea that by reducing the amount of sunlight from reaching the corals in the first place, we can prevent them from becoming stressed which leads to bleaching.”
The Reef, a World Heritage listed site, has undergone significant bleaching in the last two years because of global warming. While “impractical” to deploy over the entire Reef, the shield could be used to protect high-value or high-risk areas of the reef.