As seaweed builds up, so does battle against it
Cities chop, bury or recycle the thick sargassum smothering their sand
Shortly after the sun rises, the war against seaweed begins.
City crews work for hours every morning with large machines to chop up the seaweed and bury it — or use dump trucks to haul it away.
They clear thick mats of brown, squishy stuff that smells like rotten eggs, so beachgoers can enjoy seaweed-free beaches.
But it has been an especially difficult battle lately with a dramatic increase in seaweed floating to South Florida and the Caribbean. From using heavier equipment to more frequent sweeps of the beaches, cities are working harder to clean it up.
Pompano Beach added a tractor to its arsenal two months ago, while Hallandale Beach started clearing its beaches of seaweed daily as of winter.
Fort Lauderdale asked the state, which regulates how cities clean their beaches, if they can use heavier equipment.
Seaweed has affected the region’s beaches and the waters beyond. The mean coverage of the seaweed, also called sargassum, in the Caribbean Sea was about eight times greater last month than June 2017, the University of South Florida’s Optical Oceanography Laboratory found.
The extent of the bloom is the greatest it’s been since 2000, said Mengqiu Wang, a researcher in the lab. In Fort Lauderdale, about three times more seaweed floated onto the city’s four miles of public beaches from May to July this year compared to the same time period last year.
Possible reasons for the abundance of seaweed include:
■ Pollutants from rivers or dust blown from the Sahara into the ocean, which act as nutrients for algae like seaweed.
■ Changes in the ocean current.
■ Warmer sea temperatures.
However, Wang warns that the USF team doesn’t yet know the direct cause of the seaweed increase.
The season for blooms overlaps with sea turtle nesting, which runs from March 1 to Oct. 31.
Broward County, with Nova Southeastern University, runs a program to mark the nests on the beaches every morning before cleaning crews drive their equipment on the sand. Crews must start after the mapping ends but before beachgoers arrive.
Occasionally, Mother Nature can be especially cruel to the crews sent to clear the beaches, said Hollywood spokeswoman Joann Hussey.
“Some days, it’s so bad they clean for three hours and they get to the end and turn around and look and it’s like they haven’t been there,” she said.
Hollywood crews remove trash from the seaweed before using two tractor machines with blades to mix the seaweed with the sand and bury it at the high tide line.
Hussey said the seaweed mixed in helps to stabilize the beach sand and removing the seaweed would take sand with it.
“We don’t want to add to the erosion problem,” she said. “It’s a green option.”
Deerfield Beach, which hauls away the seaweed to a dump, says the sand it removes along with the seaweed is nominal — as much as what is tracked off the beach on the bottom of shoes.
The city uses one tractor to clear its mile-long beach. The tractor drives along the beach and to a dumpster where it deposits the seaweed it collected.
Fort Lauderdale is the only other Broward city that hauls away the seaweed. On heavy days, the city’s crews load more than 70 cubic yards in at least eight dump trucks to cart it off to a facility where they clean off the salt water and compost it into soil — that they use in city parks and on road medians.
Composting saves $180,000 a year for the cost of the soil it replaces, city spokeswoman Angela Sabina said.
Hallandale crews clear the beach by piling the seaweed farther from the water for it to disintegrate, Assistant City Manager Greg Chavarria said.
Like Hollywood, most other Broward cities, including Dania Beach and Pompano Beach, chop up the seaweed and bury it at the high-tide line.
Seaweed is left untouched at beaches in state parks.
Those beaches are covered by decaying seaweed, because it’s an important part of the ecosystem, said Elyssa Finkelstein, a spokeswoman for the Florida Department of Environmental Protection.
Stephen Leatherman, a professor at Florida International University who also is known as “Dr. Beach,” says cities have been clearing their beaches for decades, making sure they look clean for tourists.
The seaweed, although natural and not harmful, is increasing in its abundance. That makes cleanup more crucial to give beachgoers a pleasant, stink-free experience, Leatherman said.
“It’s something you have to do if you want to keep the people coming,” he said.
“Some days, it’s so bad they clean .. and turn around and look and it’s like they haven’t been there.” Joann Hussey, Hollywood spokeswoman