FGCU professor explains Sargassum algae drop in the Atlantic Ocean

ESTERO, Florida. As we battle the red tide, many are now looking to the future as there are reports of tons of seaweed approaching the coast of Florida. The Great Atlantic Sargassum Belt naturally appears every year, but some argue that seaweed will flood Florida’s beaches this year.

“Everyone thinks the Blob, like in the movies, is about to come in and devour,” said Dr. Barry Rosen of FGCU Aquatic School. “It’s floating algae.”

Dr. Rosen specializes in aquatic biology and harmful algal blooms. He says sargassum may cause minor problems, but it doesn’t create any toxins like other algae blooms like blue green algae or red tide.

“That’s the only time it becomes a nuance — that’s the difference between a harmful algae bloom and a nuance bloom — when it can build up on the beach and start to decompose,” Dr. Rosen said.

And if it builds up along the coast, Sargassum can choke coral reefs, change the pH of the water, and potentially choke the local economy by closing tourist sites, shutting down marinas and limiting fish catches. But the open sea is still an important habitat for many fish and wildlife. It also creates a ton of oxygen through photosynthesis.

“All algae produce oxygen,” said Dr. Rosen. “It’s part of what they do. Without it… 50% of the Earth is where our oxygen comes from algae, including these algae.”

In February, Sargassum was recorded as the second most abundant of the month, but according to the latest NASA satellite data, the bloom has slightly decreased. And the question we all want to know… “Will he come to our shore? We really don’t know that,” Dr. Rosen said.

Dr. Rosen says Southwest Florida residents should be more focused on the current red tide, rather than potential Sargassum being washed onto the beach.

“Now we have a red tide. This is not waiting it’s here. For me, this is a much more important issue. And, of course, it’s real now,” said Dr. Rosen.

“We don’t know what the sargassum will do,” said Dr. Rosen. “We don’t know which way it will go. And he has to drift, he’s planktonic. It will drift – go with the flow.”

Dr. Rosen says it’s possible that the sargassum doesn’t even reach the coast of southwest Florida. And if it does reach this location in the near future, it will compete with the Red Tide for nutrients and release its own set of compounds that the Red Tide will not like. The combination is likely to lessen our current red tide predicament.

The University of South Florida released a forecast for Sargassum earlier this month, giving a glimmer of hope for a 2023 bloom. It may not be as big as before. However, they still predict a major Sargassum year. The USF is forecasting a rise in sargassum in the Caribbean and Gulf of Mexico over the next few months.