A 50-kilometer long strip of sea 100 meters west of Haikou, capital of China's southernmost island province of Hainan, has been turned red by poisonous algae, threatening tourism only days before the May holiday week.

Tourists have been told to avoid lingering or swimming off the beach in Chengmai County of Haikou.

Experts explained that the large amount of algae would exhaust oxygen in water and release sulfureted hydrogen gas which could suffocate sea life and pose danger to human beings. But sample tests of the algae showed that they are not poisonous to seashell life.

Wang Hongxin, director of the Hainan Provincial Marine Monitoring and Forecast Center said that the red tide has been caused by the discharge of pollutants offshore, which have nourished the growth of the algae.

(Xinhua News Agency April 27, 2006)