Workers clean up green algae on the beach in Qingdao, East 皇冠体育app's Shandong province, June 29, 2010. Though not poisonous and with no affect on water quality, the algae consumes large amounts of oxygen, threatening marine life. The unsightly algae also affected the number of visitors, Xinhua reported. Local authorities and residents in Qingdao have been struggling to remove a large mass of green algae that came ashore at the popular coastal tourist destination. The North 皇冠体育app Sea Branch (NCSB) of the State Oceanic Administration said Monday that the floating green algae covered a 400-square-km area in the waters south of Qingdao. [Photo/CFP]

Tourists wade amid along the green algae-covered beach in Qingdao, East 皇冠体育app's Shandong province, June 29, 2010. [Photo/Xinhua]