Jiangsu seaweed farming linked to algae bloom in Qingdao
A rapid expansion of seaweed farming in Jiangsu might be behind the annual "green tide" of algae that engulfs the popular seaside resort city of Qingdao each year, a study suggests.
Qingdao, in Shandong province, has suffered a huge algael bloom every summer since 2008, when a massive clean-up had to be carried out as the city prepared to host sailing events for the Beijing Olympics.
The outbreak in the Yellow Sea reached record levels this year, covering 28,000 square kilometres.
The cause of the bloom has long been mysterious. Research published in the journal Estuarine, Coastal and Shelf Science says the swathes of algae may be a byproduct of seaweed farming in Jiangsu, south of Shandong.
The study by a team from the Yantai Institute of Coastal Zone Research under the Chinese Academy of Sciences suggests that relatively small quantities of the seaweed species Ulva prolifera are cut loose from rafts used in the seaweed industry and swept into the Yellow Sea, where they quickly proliferate due to favourable conditions: abundant sunlight and mild temperatures, and rich nutrients in seawater - a result of wastewater discharged into the sea.
The study has proved controversial, with researchers reluctant to discuss their findings. Scientists fear that until the impasse in finding the cause of the bloom is broken, little will be done to tackle the algae, which has little effect on humans but can damage the marine ecosystem.