"This is more severe than common algae outbreaks," a microbiology professor surnamed He at Qingdao's Ocean University told Reuters by telephone, adding that ferries to nearby islands had suspended services for several days.

The green tide was brought on by an unfortunate confluence of winds and currents stirred up by storms off the coast of southern China. Reports AP:

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 Qingdao Daily (roughly translated on the official English-language site of Qingdao) described the extreme efforts taken by Chinese officials to clear the 5,000-square-mile swath of algae in Fushon Bay:

In the morning of June 12, the boat found scattered flakelike float-in green alga, and they dispatched a cleaning boat to the site and sweep away the green alga. On June 14, a large amount of float-in green alga entered Qingdao coastal water, Qingdao initiated emergency scheme to handle the green alga crisis. On June 15, 160 cleaning boats were sent to carry out cleaning, on June 18, 350 boats were dispatched; June 21, 520 boats; on June 24, about 900 boats were utilized to clean floating green alga. By June 28, all-front cleaning from the sea to the coast were carried out, thousands of people, more than 1000 boats, scores of large-scale loading machineries were mobilized to carry out the cleaning, and over 100,000 tons green alga were cleaned.

As of yet there are no public contingency plans for alternate sailing venues should the bay still be blighted by algae when the Olympics kick off on Aug 8. Chinese officials maintain that the bloom will be cleared by July 15.