Last week’s windy weather washed ashore the first piles of one of Florida’s most notorious summer visitors.
Thick clumps of brown Sargasso seaweed began carpeting Volusia and Flagler counties' beaches last week, and as the tangled piles of seaweed (and the ocean creatures trapped within) decompose in the sun, they’re starting to smell.
So what’s being done about it?
Well, nothing.
"We let Mother Nature take her course," Flagler County spokeswoman Julie Murphy said by email.
The same goes for Volusia County, which has adopted the catchphrase, "Don’t panic. It’s organic."
"The county does not remove the seaweed and, in fact, encourages beachgoers to avoid disturbing the seaweed, because despite its unattractive presence and odor, it plays a vital part to our coastal ecosystem,"Volusia County spokesman Kevin Captain wrote.
Wendy Anderson, professor of environmental science at Stetson University, said that’s precisely the approach that’s needed, even if the seaweed sticks around for months.
"It’s just kind of a shortsighted thing to get out there and clear it all off," she said in an interview Tuesday.
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Sargassum releases nutrients in dunes as it decomposes
Anderson said the annual summer strandings of Sargassum on Florida shores helps maintain the integrity of the dune system, helping the coast remain resilient in the face of storms and rising seas.
"Sand is constantly in motion. Water moves the sand around. Wind moves the sand around, but when you have the architecture of the Sargassum, including the dried-out, crunchy Sargassum that’s been there a couple weeks, it captures the sand," she explained.
"The tide itself kinds of nudges (the Sargassum) up the beach to the base of the dunes. Some of it ends up washing back out. Some of it ends up getting buried. That’s a good thing."
The buried seaweed releases nutrients as it decomposes, fueling the growth of dune plants that form critical habitats and help the dunes stay where they are.
"There’s this sort of internal nutrient cycling that happens in the dunes," Anderson said. "The Sargassum is a really critical link."
The macroalgae also benefits animals like birds and crabs that feed along the wrack line, where organic matter and debris is deposited at high tide.
"It’s just loaded with food," Anderson said.
Shorebirds are often seen pecking at the tangled piles for the crabs and fish trapped within. Ghost crabs tend to burrow around them to capitalize on the abundant resources.
Nesting sea turtles and their babies can run into problems, however. Sea turtle season kicked off May 1, and there are already several marked nests in Volusia and Flagler counties.
"When sea turtles begin to hatch in the fall, they can get caught up in the seaweed and get washed back to shore, where they are aptly coined as washbacks," Captain said, "The county discourages placing washbacks back into the water. Instead, we ask that beachgoers notify the Marine Science Center at 386-304-5545."
For fishermen, the seaweed can be a bit of a nuisance.
"Mostly what it does is gets tangled up in your line," said Zane DeRienzo, who was fishing from the shore in Ormond Beach early Tuesday. "It also makes it super congested out there and the fish can’t really see the bait as well."
Is Sargassum a harmful algal bloom?
A study published Monday in Nature Communications referred to the past decade’s explosion in Sargassum in the Atlantic Ocean as a "harmful algal bloom," likely fueled by excessive nutrients.
A team of researchers led by Florida Atlantic University’s Brian Lapointe compared samples of pelagic Sargassum from the 1980s to samples collected since 2010.
"These findings suggest that increased (Nitrogen) availability is supporting blooms ofSargassumand turning a critical nursery habitat into harmful algal blooms with catastrophic impacts on coastal ecosystems, economies, and human health," the authors wrote.
Sargassum has been observed for decades floatingin the North Atlantic region aptly termed the Sargasso Sea, but that’s not where the seaweed washing ashore in Florida is coming from.
A 2019 study headed up by researchers from the University of South Florida noted a “Great Atlantic Sargassum belt” popped up in the summer of 2011, south of the Sargasso Sea where it had not been previously observed, at times extending from West Africa to the Gulf of Mexico
The bloom has reoccurred nearly every year since, piling seaweed on coasts in the Caribbean, West Africa, the Gulf of Mexico and western Atlantic. The researchers suggested the bloom was driven by upwelling off West Africa and Amazon River discharges, "indicating a possible regime shift and raising the possibility that recurrent blooms in the tropical Atlantic and Caribbean Sea may become the new norm."
Anderson said she’s skeptical to call the blooms of Sargassum "harmful," though the brown seaweed does bring problems, most notably in the form of litter.
Plastics embed in the slimy Sargassum and sharp objects can be hidden within, but she says some strategically carved out paths between walkovers and the ocean can help eliminate the threat to human feet.
"It is a safety hazard. I’m not worried about the smell. I’m not worried about the flies. Flies are part of the ecosystem," she said. "But you don’t want to be stepping on something sharp."
