"We would only be able to quickly eliminate the algae after knowing where the seaweed comes from and how it flows in the water," a SOA expert told Xinhua.

SOA's North China Sea branch, in charge of water quality monitoring of the sailing event venue, released on Wednesday the statistics of 22 water quality monitoring stations. They showed the nutrient content in the seawater continued to decrease and the water quality was fit for sailing competitions.

Wang Shulian, Qingdao Oceanic and Fishery Department vice director, denied the outbreak had any substantial link to the environmental conditions and water quality off the city.

"The algae is of various sorts, which will prosper if the temperature and salinity of seawater is right."

However, the algae has covered parts of the training area and sometimes blocked sailing routes and affected preparations for the sailing teams for the August Games.

Sailors from at least 30 countries and regions are currently training in Qingdao for the Games that opens on August 8.

The sailing is scheduled for August 9 to 23.