Seaweed on our beaches: ‘It looks like this will be the worst ever’
STORY BY SUE COCKING
Gobs of that scratchy, stinky brown algae called sargassum are once again washing up on beaches from here to the Gulf of Mexico and beyond.
Though the seaweed that clutters the island’s shoreline is non-toxic and serves as food and habitat for hundreds of marine creatures on both land and sea, it's becoming too much of a good thing, according to Dr. Brian LaPointe, a research professor at Florida Atlantic University's Harbor Branch Oceanographic Institute who's been studying sargassum since 1983.
"It looks like this will be the worst ever," LaPointe said of the current algae bloom. "It's more widespread now than at this time last year."
On the plus side, the bloom isn't as thick along 32963 beaches as it is from Jupiter south. The seaweeds, which float around on the ocean's surface, are driven inshore by easterly winds where they form bigger piles along the Southeast Florida coast because that's where the peninsula juts out closest to the Gulf Stream carrying the weeds north.
LaPointe says the Caribbean islands are getting the worst of it, with piles 10 feet high in mats the size of tennis courts. When it rots, it releases hydrogen sulfide gas that smells bad enough to drive residents inland and keep tourists away.
Despite the problems it causes people, sargassum floating around in the ocean has been likened to a rainforest – harboring everything from microscopic plankton to fish, crustaceans and baby sea turtles. Large fish such as dolphin (mahi mahi) and wahoo patrol the floating mats, feeding on smaller prey gathered there. The big fish are in turn caught and consumed by people.
The algae is so important to the marine ecosystem that it is protected as essential fish habitat by the U.S. government. It has benefits on the beach, too, where it stabilizes dunes and provides food and shelter for sea birds, crabs and other creatures – though it can interfere with turtle nesting if it is thick enough.
So far, the seaweed coating the 32963 beaches has not disturbed nesting sea turtles, which manage to crawl and dig through it, according to Quintin Bergman, the county's sea turtle coordinator. And because it's nesting season, the city of Vero Beach is prohibited from using mechanical raking tools to clean the beach, said city manager Monte Falls.
"We get calls every year after the raking stops," Falls said. "We explain it's a naturally-occurring phenomenon that provides habitat for animals on the beach."
He said mechanical raking will resume in November after nesting season ends.
The sargassum nuisance was not always as acute as it is now, according to LaPointe.
He says the scientific community first observed excessively large blooms in 2011, and they've occurred every year since then. LaPointe believes they are fed by nitrogen from fertilizer and other human sources that runs off in coastal areas and is carried from inland farmlands by rivers into the oceans. He said nitrogen in the atmosphere generated by fossil fuels and Saharan dust also are contributors.
"It's like a snowball going downhill, getting bigger and bigger as it goes," he explained. "There is no single source feeding this bloom. It's death by 1,000 cuts – many sources that contribute to this."
LaPointe's sargassum studies have shifted dramatically in more than 35 years – from protecting the seaweed to containing it. He says he has received funding from NASA to monitor, track, and study the ecology of sargassum blooms.