Genetic and marine cyclonic eddy analyses on the largest macroalgal bloom in the world.

In 2008, a massive Ulva prolifera bloom, with a 3-million-ton biomass covering an area of 1.29 × 10(4) km(2) at its largest, suddenly appeared from May to July in South Yellow Sea. The mechanism behind the rapid growth of these seaweeds was investigated. Molecular phylogenetic analysis of free-floating algal samples from the Yellow Sea suggested that U. prolifera belong to one population, and that temporary cyclonic eddies in the Yellow Sea in late spring and early summer may help promote the proliferation of this bloom by providing seaweeds with sufficient growth time, abundant nutrition, and favorable habitats. The initial investigation on the relationship between marine cyclonic eddies and the route of free-floating algae extends our knowledge on how the emergence of free-floating macroalgal blooms in coastal areas could yield a large biomass.