Algae blooms occur regularly in the Caribbean, the Gulf of Mexico, and northern South America.
These blooms are driven by the upwelling of phosphorus-rich deep water, which promotes an N-fixing symbiont of the Sargassum algae, giving it a competitive advantage in the tropical Atlantic.
A team led by the Max Planck Institute of Chemistry found that this upwelling of phosphorus-rich deep water is the key factor behind the blooms.
Playa del Carmen, a popular vacation destination on Mexico's Yucatán Peninsula, faces significant Sargassum strandings during summer months, as do other Caribbean coastlines.
To maintain beach access for swimmers, the brown algae must be regularly cleared using machinery.
Researchers at the Max Planck Institute for Chemistry used coral drill cores to uncover the mechanism driving these algal blooms.
Upwelling of phosphorus-rich deep water promotes an N-fixing symbiont of the Sargassum algae giving it a competitive advantage.
Author's summary: Sargassum blooms driven by phosphorus-rich water upwelling.