5,000-mile algae drop threatens Florida’s tourism industry

(CNN) — A giant mass of seaweed that has formed in the Atlantic Ocean is making its way to the shores of Florida and other coastlines across the Gulf of Mexico, threatening to dump smelly and potentially dangerous piles on beaches and severely disrupt the tourist season.

The seaweed, a species called sargassum, has long been producing large blooms in the Atlantic, and scientists have been tracking massive aggregations since 2011. But this year’s Sargassum mass may be the largest on record, stretching over 5,000 miles from the coast of Africa to the Gulf of Mexico.

The blob is currently moving west and will pass through the Caribbean Sea and into the Gulf of Mexico during the summer, with algae expected to dominate Florida beaches around July, according to Dr. Brian Lapointe, a harbor researcher at Florida Atlantic University. Branch of the Oceanographic Institute.

Lapointe said Sargassum flowers started to form early this year and doubled in size between December and January. Mass “was bigger in January than at any time since this new growth region of sargassum began in 2011,” Lapointe told CNN.

“It’s a brand new oceanographic phenomenon that creates such a problem – a really catastrophic problem – for tourism in the Caribbean where it builds up on beaches up to 5 or 6 feet deep,” Lapointe added.

He noted that in Barbados, locals used “1,600 dump trucks a day to clear the beaches of this algae to make it suitable for tourists and beach recreation.”

What is sargassum

Sargassum is a catch-all term that can be used to refer to over 300 kelp species, although the two species most commonly found in the Atlantic are Sargassum natans and Sargassum fluitans.

Algae has its own benefits when drifting in the sea.

“This floating habitat provides food and protection for fish, mammals, seabirds, crabs and more,” says the Sargassum Information Hub website, which is a collaborative effort between various research institutes. “It serves as an important habitat for endangered sea turtles and a feeding ground for a variety of commercially important fish such as mahi-mahi, jacks and amberjacks.”

Problems arise when sargassum find their way onto beaches, not only accumulating in mounds that are physically difficult to navigate, but also releasing a gas that can smell like rotten eggs. And it can quickly go from an asset to a threat to life in the ocean.

“It comes in in such large quantities that it actually sucks the oxygen out of the water and creates what we call dead zones,” Lapointe said. “Usually these are nurseries for fisheries … and as soon as they are deprived of oxygen, we lose this habitat.”

Sargassum can also be hazardous to human health, Lapointe noted. The gas that rotting algae releases, hydrogen sulfide, is toxic and can cause breathing problems. The seaweed itself also contains arsenic in its flesh, making it dangerous if ingested or used as fertilizer.

“You have to be very careful when cleaning the beaches,” he warned.

Cleaning up heaps of algae washed up on beaches also costs millions of dollars, notes the Sargassum Clearinghouse.

Why sargassum is a problem in 2023

Just like plants and crops on earth, the distribution of seaweed can change from year to year depending on environmental factors that are affected by changes in nutrients, rainfall and winds, the doctor said. Gustavo Jorge Goni, Director of Physical Oceanography, Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.

Similarly, sea currents can affect the annual growth and accumulation of sargassum, Goni added. Phosphorus and nitrogen in the sea can also serve as food for algae.

According to the Environmental Protection Agency, these elements can be released into the ocean from rivers that receive concentrations of phosphorus and nitrogen from human activities such as agriculture and fossil fuel extraction.

For now, researchers are looking at ways to prevent its effects on beaches, perhaps by sinking the algae to the ocean floor or harvesting it for use in commercial products such as soap, Goni said.

Goni also warns that the study of these sargassum aggregations is new, and it is likely that scientists’ understanding of how the algae grow will change over time.

“Whatever we think, we know today, it can change tomorrow,” he said.

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