Caribbean delivers more beach seaweed to snarl Space Coast surf zones

Too much weed on the beach can be a bad thing, especially in surfing meccas such as Cocoa Beach, where Sargassum seaweed snarls boards, snags surf fishing lines, and is a bane to all others who prefer weed-free wading. 

More of the stuff is expected to drift our way in coming weeks, scientists say.

Oceanographers expect Sargassum seaweed and other macroalgae to thicken on our beaches as more washes in from record amounts already in the Caribbean Sea.

Combined, the total amount of the weed increased from 18.8 million tons in May 2022 to 24.2 million tons in June 2022, a new historical record, according to the University of South Florida scientists, alarmed by the new record. 

USF's most recent bulletin on the seaweed, on July 31, forecasts continued "significant beaching events" of Sargassum in the Caribbean Sea. 

While regional decreases in seaweed abundance recently were seen in the tropical Atlantic, USF scientists say there has been no decrease in other waters closer to Florida. 

"This indicates significant beaching events are still ongoing around the CS (Caribbean Sea) nations/islands," USF's bulletin says. "Likewise, some moderate amount of Sargassum was found in the Straits of Florida and along the east coast of Florida, indicating possible beaching events in Florida."

Looking ahead, total Sargassum tonnage will likely decrease in the coming months, however, based on historical seasonality, USF scientists say.

Beyond the usual Sargassum, which the Caribbean Sea delivers seasonally to the Gulf Stream and then Central Florida's beaches, a "filamentous" algae also has at times dominated Brevard's surf zone this summer, scientists at Florida Atlantic University say.

Too much of a good thing?

Overall, the Sargassum and other seaweed it washes in are a benefit to the beach and wildlife.

Shorebirds feed on the small animals that live in the Sargassum and other seaweed "wrack lines" along the beach. Ghost crabs, beetles and other tiny animals feed on the fungus that grows in the clumps of seaweed that line beaches. 

On the beach, the seaweed clumps collect wind-blown sand and plant seeds near the dunes, and nutrients for sprouting plants, promoting formation of small dunes that help prevent erosion.

Offshore, Sargassum provides crucial early meals for hatchling sea turtles that swim out to find the stuff floating in the Gulf Stream.  

Too much, though, can tangle hatchlings on their crucial first journey from nest to the Gulf Stream, but they're taking the weed in stride this nesting season, says Mike McGarry, Brevard's beach renourishment coordinator. Evolution adapted them to such obstacles. 

"Our most recent monthly turtle monitoring reports (for June 2022)  indicated no problem with hatchings reaching the water as a result of Sargassum," McGarry wrote in an email, adding that July nesting reports are pending. 

Female turtles that craw up the beach to nest do so successfully about half the time. "Nesting success is impacted by many things, and often very dry weather causes reduced nesting success (more challenging to dig in dry sand)," McGarry wrote. 

Stringy, smelly algae dominates coastline from Cocoa Beach to Sebastian and beyond

Florida Atlantic University researchers have shown seasonal Sargassum here and in the tropical Atlantic has grown worse in recent years because of increasing nitrogen and phosphorus from discharges from the Congo, Amazon and Mississippi rivers, atmospheric Saharan dust coming down on the water and burning of vegetation in central and South Africa.

USF plans more Sargassum updates by the end of this month.

Jim Waymer is an environment reporter at FLORIDA TODAY. Contact Waymer at 321-261-5903 or jwaymer@floridatoday.com. Or find him on Twitter: @JWayEnviro or on Facebook: www.facebook.com/jim.waymer

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