BEIJING -- To host the Olympic sailing events, the Chinese port city of Qingdao moved a massive boat yard, relocated industries and spent about $850 million on transport links, parks, pollution controls and coastal green belts.
But with little more than a month to go until the Games, a different challenge is cropping up: A forest of blue-green algae is choking the coastal waters, suffocating beaches and lying in thick layers along sailing routes.
Authorities have ordered an all-out drive to clear it and block any more drifting into the area.
"We have stressed ... that the priority should be given to the Olympic venue," Yuan Zhiping, an official with the Qingdao Olympic Sailing Committee, was quoted as saying by the official Xinhua News Agency.
City officials say they'll need at least two weeks to clear coastal waters, mobilizing 10,000 workers aboard 1,000 boats. It wasn't clear how they planned to block other algae from drifting in.
Environmental problems have posed some of the biggest concerns for organizers of the Beijing Olympics, particularly the dust and filthy air in the Chinese capital, compounded by expected torrid heat and humidity.
It isn't clear whether Qingdao's Olympic planners ever allowed for algae-related contingencies. Calls to the city's Ocean and Fishing Bureau, charged with handling the problem, rang unanswered Monday.
Blue-green algae blooms when nutrients, sometimes caused by excessive pollution, build up in water.
China has had a number of similar outbreaks in recent years, mostly on inland lakes, largely as a result of severe pollution from industrial sources, farm chemicals and domestic sewage. Along the coast, red tides of microscopic algae have forced fishing industry shutdowns.
The blooms can be caused by both natural factors and human activity. Wang Shulian, vice director of the Ocean and Fishing Bureau, told reporters Sunday the outbreak had no "substantial link" to environmental conditions or water quality.
"The algae is of various sorts, which will prosper under satisfying temperature and salinity of sea water," Wang said. Calls to the bureau were not answered Monday.
In all, the algae is blooming over an area of 5,000 square miles, Xinhua said -- including 32 percent of the coastal area set aside for the Aug. 9-21 sailing events, with a closing ceremony on Aug. 23.
The algae alert comes as Beijing and other cities hosting Olympic events are making final preparations for the Aug. 8-24 Games. Organizers announced over the weekend that all 37 venues were now fully functional, and sailors from 30 countries and regions have already arrived in Qingdao to begin training, according to Xinhua.
The Games are a huge opportunity for Qingdao to build its brand. German colonizers in the early 20th century left the city with its two best-known features: the European-style buildings of its old town and the brewery that makes China's best-known beer, Tsingtao -- the old-style spelling of the city's name.
The Olympic marina sits at Fushan Bay, up the coastline on the East China Sea beside the high-gloss glass-and-marble new city center. Qingdao created 100 acres of land for dormitories, offices and boat storage by moving out the enormous Beihai boat yard.
The blue-green algae blossomed around June 1 in waters off Qingdao on the coast of Shandong province, about 400 miles southeast of Beijing. Its bright green strands have smothered beaches, forcing swimmers to clear a path with their hands up to several hundred feet from the coast.
Officials say the Qingdao blossom poses no health threat. However, some algae can produce dangerous toxins and if ingested can cause vomiting, respiratory failure and, on rare occasions, death.
The cleanup is expected to be completed by July 15, Xinhua said.