A rare off-season assault of seaweed has struck South Florida beaches, creating a dinner table for shorebirds and forcing swimmers to pick their way past reeking piles of vegetation.
The seaweed, a bushy brown algae called sargassum, is a common sight along the beach. Carried to South Florida’s beaches by ocean currents from the Caribbean and Gulf of Mexico, the seaweed typically spikes during the summer.
But while there has been some decline during the winter months, the amount of seaweed remained unusually high, with the consequences now washing up.
“This year is extremely severe,” said Chuanmin Hu, professor of optical oceanography at the University of South Florida, whose laboratory tracks seaweed movements and development. “Typically you have a lot of sargassum in summer, but this year the beach events in Florida started early.”
Among the theories for the increase in seaweed in the Caribbean, Hu said, are climate change, nutrients washing off land and from the deep ocean and changing ocean currents. Whatever the cause, the squishy plague has piled up on shorelines across a wide area.
“There is a flood of Sargasso seaweed hitting the Caribbean islands and now Florida,” said Stephen Leatherman, known as Dr. Beach for his ratings of American beaches, who is known more formally as director of the Laboratory for Coastal Research at Florida International University.
Coastal cities have long since established procedures for raking it into the sand or carting it away, but they’re having to work extra hard.
In Fort Lauderdale, work crews typically remove a band of seaweed about six to eight yards wide each day, city spokesman Chaz Adams said.
“On two days last week, we saw a dramatic spike in the amount seaweed coming ashore as crews removed 68 yards on Wednesday, and 44 yards on Thursday,” he said in an email. “On Friday and Saturday, levels returned to normal, however, yesterday crews removed 20 yards of seaweed and today looks to be another heavy day.”
The city hauls the seaweed to Snyder Park for composting, using the resulting soil for planting and landscaping projects and saving more than $180,000 in disposal costs.
In Hollywood, the city has hired a contractor and rented extra equipment to deal with the increase, spokeswoman Joann Hussey said. Although the city typically rakes the seaweed into the sand, work crews now haul off extra thick mats of it to a landfill.
“Because of the increase we decided we needed to step up our efforts,” she said.
Complicating matters, she said, is the need to accommodate sea turtle nesting season and the extra number of beachgoers because of spring break, leaving a small window of time for the work crews to clear away the seaweed.
In Pompano Beach, the area near the surf is “thick with seaweed,” city spokeswoman Sandra King said.
“It’s a good day for the pool,” she said.
dfleshler@sun-sentinel.com, 954-356-4535