The dawn boat patrols off the coast of this Chinese port on Monday were searching for one very specific threat to Olympic sailing events: Bright green algae. In June-July a vast algae bloom, with names like “The Fairway” and “The Carpet,” clogged about 30 per cent of the 50 sq. km sailing area. Organisers spared no effort in clearing it away, calling out thousands of troops and volunteers to pick it up.

Having won the battle, they are now determined to win the “algae war,” with an armada of 300 fishing trawlers and 1,500 fishermen working off the coast to haul up as much as possible before it reaches the racing venue. Twice a day they send four boats out to check for algae and keep it at bay. “If any algae is spotted in the morning, we will alert command to dispatch boats,” Zhao Jian, a press officer with the Qingdao Olympic Sailing Committee, said. Zhao said the committee guarantees that the nontoxic algae will be cleaned up each day before racing starts. So far, there have been no complaints by sailors.