A powder sprinkled over water, creating a thin film, could reduce evaporation, say scientists who are working on ways to fight water shortages. Evaporation is a problem in Brazil's semi-arid Northeast region, where 75 percent of the water in its reservoirs is lost to this natural phenomenon. The product developed by Lotus Environmental Chemical, a company affiliated with a University of Sao Paulo research center, has the potential to cut evaporation by half, the project's scientific director Marcos Gugliotti told Tierramérica.

In open-air tanks, evaporation rates varied from 16 to 44 percent under different conditions.

Gugliotti hopes to conclude testing in different reservoirs next year, before releasing the product, which is low cost and one kilogram is sufficient to cover a hectare of water surface area. But application must be repeated every 48 hours, which makes its use in large reservoirs difficult.