Wednesday, May 20, 2009

How to clean up a lake? Floating islands might be the answer.

Man-made islands can remove ammonia, heavy metals, and other chemicals from the water. They’re constructed of layers of mesh and insulating foam. The mesh feels like the rough side of a sponge: The bigger islands are buoyant enough to hold people.

Most are at least 25 square feet, and the least expensive costs around $600. They’re topped with soil and seeds and then launched in lakes and ponds. The islands act like magnets for microbes, and the seeds sprout into vegetation that pulls nitrogen, phosphorus, and other nutrients that cause slime from the surrounding water, cleaning it and allowing aquatic life to flourish.

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