As Florida beaches brace for spring break in the weeks ahead, it should also expect an unpleasant visitor — giant mounds of smelly seaweed.
The massive blob of brown algae, known as “sargassum,” is making its way to South Florida’s shores. It naturally occurs every year, but researchers have noted that there’s been an uptick in overall growth since 2011, except for 2013.
This year’s mass is shaping up to be one of the largest on record, according to marine scientists at the University of South Florida, who have been tracking it. It’s estimated to be 5,000 miles wide (for scale, the U.S. spans about 3,000 miles from coast-to-coast) and can be seen from satellite images.
The sargassum bloom originated in the Atlantic Ocean, and has made its way through the Caribbean Sea and into the Gulf of Mexico. While the seaweed itself is harmless, it can still impact coral reefs, sea turtles and boaters, as well as require a costly beach cleanup.
According to the Florida Health Department, as sargassum washes ashore and decomposes, it releases hydrogen sulfide, leaving behind an unpleasant odor described as akin to rotting eggs. The smell can irritate the eyes, nose and throat, and can cause respiratory issues for those with asthma.
What factors could be contributing to the growth in sargassum? Scientists have pointed out that human activities and climate change are filling rivers that flow into the Atlantic with nitrogen and other nutrients, which then feeds the algae blooms, NBC News has reported.
“You have the Congo, the Amazon, the Orinoco, the Mississippi — the largest rivers on the planet, which have been affected by things like deforestation, increasing fertilizer use and burning biomass,” Brian LaPointe, a research professor at Florida Atlantic University’s Harbor Branch Oceanographic Institute, told the outlet. “All of that is increasing the nitrogen concentrations in these rivers and so we’re now seeing these blooms as kind of a manifestation of the changing nutrient cycles on our planet.”
If you’d like to learn more and stay up-to-date with the bloom in the upcoming months, USF’s Sargassum Watch System (SaWS) provides satellite images and data that track and detect the algae.