Smelly seaweed piles up on beaches
A group of children from Brandon play in the sand at Turtle Beach on Tuesday among piles of sargassum that have washed ashore over the past few days.
Staff photo by Mike Lang
By Kate Spinner
Herald Tribune
Tuesday, July 31, 2012 at 5:11 p.m.
Beachgoers in Southwest Florida may have to dodge some seaweed to take a dip in the Gulf of Mexico.
Prevailing winds are driving the sticky and smelly algae ashore now, but that is expected to shift this weekend — likely blowing it back out to sea.
Venice Beach appears to be the most hard hit, though seaweed is also washing ashore on Lido, Siesta and Turtle beaches. Seaweed periodically washes ashore, sometime in much larger quantities.
"It's not coming in in catastrophic amounts," said George Tatge, a manager with Sarasota County's Parks and Recreation department, which removes seaweed clumps from the busiest beach areas. "Based on perspective from years past, it's a low to moderate event to date."
A much more extreme seaweed story is playing out on the east coast, where giant rafts of the stuff are washing up. Media in Broward County have reported that 1,000 tons of seaweed had been removed from the shore in Fort Lauderdale since January.
Scientists speculated a link between shifting sea currents or increased nutrient sources.
But even 1,000 tons pales in comparison to the last time the sea spit out massive amounts of seaweed in this region. From October 2006 to March 2007, more than 2,000 tons of seaweed was raked up on Siesta Key alone.
In 2007 it was red drift algae causing the nuisance — a type of seaweed that anchors to rocks or the seafloor and breaks off when ocean currents become rough.
This year's seaweed is sargassum — a floating variety that often forms large mats that provide habitat in the otherwise barren deep sea environment.
On the beach it rots and interferes with some people's ability to enjoy the shoreline.
"I think it's gross honestly. I know it's part of nature," said Mandy Chitwood, who recently moved to the area from Ohio and brought her children to Turtle Beach on Tuesday. "Taking my kids there, I really don't like that it's there.
The seaweed started washing ashore after Tropical Storm Debby and that is probably not a coincidence, said Eric Milbrant, director of the marine laboratory for the Sanibel-Captiva Conservation Foundation.
The drop in salinity from freshwater runoff can cue some types of sargassum to shed their reproductive parts, similar to the way trees release pollen in the spring.
The salinity change and wave action from storm surge likely killed sea grasses as well. Clumps of sea grasses also are washing ashore with the sargassum here.
Although offensive to some people, seaweed plays a very important role in beach ecology: it contains tiny crabs and fish that beach birds love to devour. It also holds nutrients, which act as a natural fertilizer for dune grasses, and it helps beaches build back from erosion by holding back the sand.
Sarasota County removes seaweed from heavily visited beaches on Siesta Key, Lido Key and Venice Beach — about 5 percent of the county's 35 miles of shoreline. Natural areas, such as North Lido, are left alone so that the shorebirds have something to eat.
"We try to leave as much on the beach as we can. It's a buffet table for the birds," Tatge said.
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