In 2008, millions of tons of algae blanketed the Yellow Sea off the coast of Qingdao, China, threatening to foil sailing events at the summer Olympics. Using satellite images of the sea, researchers at the Chinese Academy of Sciences Key Laboratory of Experimental Marine Biology in Qingdao have helped explain why these blooms flourish.

Their research, which appears in the 15 July issue of Environmental Science & Technology, is the first to combine biological data from algae samples with meteorological and oceanographic analysis. Whether a bloom on the scale of the 2008 disaster forms “completely depends on the waves and the wind,” says the study's lead author, Song Qin. Critical in this process are cyclonic eddies—huge, constantly moving bodies of water— that swirl through the Yellow Sea in spring and summer. In 2008, the eddies made conditions ideal for a bloom of Ulva prolifera.

The group's multidisciplinary approach to tackling algal blooms would be “very useful … for other areas with green tides,” says Jaanika Blomster, an expert on blooms at the University of Helsinki, in an e-mail.  

In the meantime, the blooms that have wreaked so much havoc in the Yellow Sea may carry hidden potential: Qin and colleagues are exploring putting the slime to good use by harvesting it and converting it into biofuel.