South Florida Sun-Sentinel.com Seaweed invasion creates disposal ...

South Florida Sun-Sentinel.com
Seaweed invasion creates disposal problem
Heavy quantities of floating vegetation hit South Florida, Caribbean
By David Fleshler, Sun Sentinel
5:32 PM EDT, July 29, 2012
A plague of seaweed has struck South Florida's beaches this year, creating a mystery for
biologists and a solid waste disposal problem for cities.
More than 1,000 tons washed up in Fort Lauderdale since January, an increase of more than 300
percent over the same period last year. Boca Raton saw its seaweed double, although the deluge
tapered off in the past few weeks.
In northern Broward County, a controversy has broken out over what to do with the endless piles
of rotting vegetation. The Florida Fish and Wildlife Conservation Commission ordered Beach
Raker, a beach cleaning contractor that serves several Broward cities, to stop burying the
seaweed, saying the practice could harm sea turtle nests.
Robbin Trindell, the commission biologist in charge of sea turtle protection, said the
decomposing vegetation would generate toxic concentrations of bacteria and fungi in the sand,
where clutches of sea turtle eggs lie buried. "The eggs would rot," she said.
Lauderdale-by-the-Sea Commissioner Stuart Dodd, whose city is among those served by Beach
Raker, strongly disagrees. "We've been burying seaweed for 30 years to try to allow sea turtles
the best routes to the ocean," he said. "It's better to get the seaweed buried rather than piled up
and rotting. I can't understand Dr. Trindell's attitude on this one."
Ray Thompson, operating manager of Beach Raker, which cleans beaches from Oakland Park
Boulevard north, including Pompano Beach and Hillsboro Beach, said it's impossible to haul
tons of seaweed off these beaches for disposal because there are few access points for trucks.
The company has begun raking the seaweed into the beach, mixing it with the top layer of sand
rather than burying it in large quantities, in the hope that this will satisfy the state.
"We're going to do the best we can do," he said. "We've been burying seaweed for 30 years plus.
The state would like us leave it on the beach and let it rot, but that's not what beachgoers want."
The invasion of seaweed, primarily species of floating algae called sargassum, reaches far
beyond South Florida. Dense mats of seaweed have washed up on the islands of the eastern
Caribbean over the past year, building up in clumps several feet high and shutting down some
tourist beaches.

"It's a regional phenomenon," said Brian Lapointe, research professor at Florida Atlantic
University's Harbor Branch Oceanographic Institute. "There have been reports of unusually large
amounts of sargassum in Bermuda, in Florida, in the Caribbean, the west coast of Africa. Huge
amounts coming ashore, clogging beaches and shorelines. It creates a solid waste problem. It sits
there and rots and has to be removed."
Asked how unusual this was, Lapointe said, "Based on observations by 'old timers' in the eastern
Caribbean last year, this phenomenon [excessive biomass of Sargassum on beaches, bays, and
coastlines] appears to be unprecedented in recent history."
No one knows the reason for the seaweed increase, but there are several theories. Stephen
Leatherman, director of the Laboratory for Coastal Research at Florida International University,
who is also known as Dr. Beach, said strong winds off the ocean this season may be driving
more seaweed onshore.
Lapointe said there's a strong possibility an increase in plant nutrients, particularly nitrogen and
phosphorus, washed off farms and lawns into rivers and canals, fertilizing the growth of
seaweed. The BP oil spill in the Gulf of Mexico may have contributed, as bacteria broke down
the petroleum, freeing elements such as nitrogen that could further support seaweed growth, he
said.
"We're seeing a regional increase in nutrients that's causing an increase in productivity,"
Lapointe said. "There could also be subtle and significant shifts in ocean currents. We're
carefully watching it right now."
What can be done with all this seaweed? The most effective solution may have been developed
by Fort Lauderdale, which hauls it by truck to a compost pit at Snyder Park, allowing it to
decompose for three months and using the resulting soil for landscaping projects.
"It's good, rich, black dirt," said Mark Almy, the city's beach manager.
Has the city found uses for the 1,008 tons that have washed up so far?
"We definitely have a surplus right now," he said.
Delray Beach uses some seaweed to reconstruct dunes, rakes some into the beach and hands over
any surplus to Waste Management for disposal. Boca Raton holds a permit from the Florida
Department of Environmental Protection to bury it, but does this shoreward of the sea turtle
nests, between the dunes and the lifeguard stands, said assistant city manager Mike Woika.
From the perspective of shorebirds, juvenile fish, crustaceans and many biologists, the preferred
course would be to leave the seaweed on the beach. These piles of rotting vegetation provide
homes for marine creatures, food for a large range of species and foraging grounds for migrating
birds.

"If you live on the beach, what is there to eat?" asked Trindell, of the state wildlife service. "This
material forms the basis for the food chain. Juvenile fish, birds — they're dependent on that
material being present and accessible. I recognize that on a recreational urban beach that's not
likely."
dfleshler@tribune.com, 954-356-4535
What is seaweed?
First, seaweed it's not really a weed, since it doesn't crowd out other plants.
Seaweed includes thousands of species of floating algae and plants, from microscopic plankton
to giant kelp forests.
The most common kinds washing up on South Florida's beaches are various species of
sargassum, brown and greenish seaweeds equipped with air bladders to allow them to float. They
provide homes for juvenile sea turtles, fish, crabs, birds and other marine creatures.
Sources: National Marine Fisheries Service, Florida Department of Environmental Protection