A red tide washes over Moon Bay in Nan'ao town in Shenzhen's Dapeng New Area, South China's Guangdong province, April 10, 2012. Shenzhen's Marine Environment and Resources Monitoring Center said tests of the water identified the red substance as noctiluca scintillans, or Sea Sparkle, a kind of algae that glows at night and is nontoxic. [Photo/Xinhua]

A worker cleans the sea surface at Moon Bay in Nan'ao town in Shenzhen's Dapeng New Area, South China's Guangdong province, April 10, 2012. [Photo/Xinhua]