A University of South Florida researcher thinks he has figured out why there’s so much brown, moss-like algae that causes that rotten egg smell on the Caribbean Sea and Gulf Coast beaches.
Biological oceanographer Frank Muller-Karger is a professor at the USF College of Marine Science.
Muller-Karger and a team of researchers analyzed currents, winds and nutrient levels to determine that vertical currents are behind the massive blooms creating the Great Atlantic Sargassum Belt.
The study, published in Nature Communications, explains that vertical currents are sweeping deep-ocean nutrients up toward the sunlit surface.
"The nutrients are mixed up from deeper water. There's plenty of light and these plants photosynthesize, so they just grow,” Muller-Karger said. “They grow like crazy."
These conditions have occurred annually since 2011.
Muller-Karger said his research could help prevent erroneous information that could lead to an “international incident.” Prior to this study, some researchers had blamed Amazonian deforestation for the sargassum blooms.
When the macroalgae washes onto the beaches, it rots, releasing hydrogen sulfide and a rotten egg smell. While sargassum itself is not toxic to humans, it does carry tiny sea creatures whose sting can create rashes and blisters.
While it may be a nuisance to fishermen and beachgoers, Muller-Karger said the algae supports ocean life.
"We think this is the new normal compared to what it was before,” he said.
