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FLORIDA. (CNN) – A giant mass of seaweed twice the size of the continental United States is heading for the shores of Florida and other Gulf Coasts, threatening to dump smelly and possibly harmful heaps on beaches and slow down the tourist season.
Sargassum – the specific variety of algae – has long formed large blooms in the Atlantic Ocean, and scientists have been tracking massive accumulations since 2011. But this year’s bloom could be the biggest ever, if collectively extending over 5,000 miles (8,047 kilometers) from the coasts of Africa to the Gulf of Mexico.
This year’s Sargassum bloom started forming early and doubled in size between December and January, said Dr. Brian Lapointe, a researcher at Florida Atlantic University’s Harbor Branch Oceanographic Institute. The mass “was greater in January than it has ever been since this new sargassum growth region began in 2011,” he told CNN International’s Rosemary Church.
Traveling west, the blob will cross the Caribbean and up into the Gulf of Mexico during the summer. Algae should appear on Florida beaches around July, Lapointe said.
“This is an entirely new oceanographic phenomenon that is creating such a problem – truly a catastrophic problem – for tourism in the Caribbean region, where it is accumulating on beaches up to 5 or 6 feet deep” , said Lapointe.
Here’s what you need to know about why these masses occur and how they affect both humans and ocean life.
What is sargassum?
Sargassum is a catch-all term that can be used to refer to over 300 species of brown algae, although Sargassum natans and Sargassum fluitans are the two most commonly found species in the Atlantic.
When drifting at sea, algae can have benefits for ocean life.
“This floating habitat provides food and protection for fish, mammals, seabirds, crabs, etc.,” according to the Sargassum Information Hub, a joint project between various research institutions. “It serves as critical habitat for endangered loggerhead sea turtles and as a nursery ground for a variety of commercially important fish such as mahi mahi, jacks and amberjacks.”
Is sargassum safe?
Problems with sargassum occur when they reach beaches, collecting in mounds that can be difficult to navigate and emitting a gas that can smell like rotten eggs.
Sargassum can also quickly turn from an asset to a threat to marine life.
It comes in “so large amounts that it basically sucks oxygen out of the water and creates what we call dead zones,” Lapointe said. “These are normally nursery habitats for fisheries…and once they’re starved of oxygen, we’ve lost that habitat.”
Sargassum can also be dangerous to humans, Lapointe added. The gas emitted by decomposing algae – hydrogen sulphide – is toxic and can cause respiratory problems. The seaweed also contains arsenic in its flesh, which makes it dangerous if ingested or used as fertilizer.
“You have to be very careful when cleaning the beaches,” Lapointe said.
Why is there a sargassum problem?
Just like plants and crops on the ground, algal blooms can change from year to year depending on ecological factors, affected by changes in nutrients, rainfall and wind conditions, said Dr Gustavo Jorge Goni , an oceanographer with the National Oceanic and Atmospheric Administration. Atlantic Oceanographic and Meteorological Laboratory.
Sea currents also influence Sargassum growth and accumulation, Goni added. Phosphorus and nitrogen from the sea can serve as food for algae.
According to the U.S. Environmental Protection Agency, these elements can be dumped into the ocean by rivers, which acquire phosphorus and nitrogen concentrations from human activities such as agriculture and fuel production. fossils.
For now, researchers are studying ways to counteract the impact of seaweed on beaches, possibly by sinking it to the ocean floor or harvesting it for use in commercial products such as soap, Goni said. .
Goni warned that research on these sargassum accumulations is new, and it’s likely that scientists’ understanding of algal growth will change over time.
“Everything we think we know today,” he said, “can change tomorrow.”
How does hoarding affect travel?
Before traveling to coastal areas this spring or summer, research whether sargassum is at your destination or could appear there, Lapointe said. Plan ahead so your vacation won’t disappoint.
There are Sargassum Facebook groups, whose members post what they’ve recently seen on beaches, Lapointe said.
“It’s already affected the travel industry,” he said.
Unfortunately, sargassum can build up overnight, so you might not be able to predict its effects while traveling, Lapointe said.
“That’s why we’re trying to work on these early warning systems – high resolution in coastal areas, which requires higher resolution satellite imagery to do a better job of showing what’s actually happening on a beach in the coming 24 or 48 hours,” he added.
Satellite images from the past week show the sargassum is not an amorphous mass moving across the ocean, but rather teardrop-shaped specks trailed by long, thin strands of algae.
Over the past week, patches of Sargassum have been spotted about 215 miles (346 kilometers) from Guadeloupe, between the islands of Saint Vincent and Bequia, 1,000 yards (914 meters) off Martinique and off Key Largo, Florida.
How are sargassum cleaned?
Algae mounds built up on beaches cost millions of dollars to clean up, and removal efforts can also harm marine life, according to the Sargassum Information Hub.
In Barbados, locals were using “1,600 dump trucks a day to clear the beaches of this algae to make it suitable for tourists and beach recreation,” Lapointe said.
In shallow water, Sargassum can be removed using fishing nets towed by light boats or by hand, according to the Dutch Caribbean Nature Alliance.
In the United States, cleanup is often done with tractor-drawn Barber beach rakes, Lapointe said. But once there’s a buildup of more than a foot of sargassum, the rakes don’t work as well, he added. This is when dump trucks can come in handy, but they can be harmful to the health of the beach.
Using dump trucks to remove Sargassum can become problematic.
“A lot of times you have sea turtle nests on beaches that are crushed by the tires of this heavy egg-crushing equipment,” Lapointe said.
What happens if Sargassum is not removed from beaches?
If sargassum isn’t cleaned up from beaches or used as fertilizer, the arsenic in its flesh could leach into groundwater, which could pose a danger to human health, Lapointe said.
Too much rotting sargassum can also promote the growth of fecal bacteria.
And in 2018, a massive bloom that ended on South Florida beaches coincided with the biggest red tide ever seen on that coast, Lapointe said. Red tides occur when blooms of toxin-producing algae get so out of control that they discolor coastal waters. Red tide organisms can live on Sargassum and be transported by it.
Toxins from red tides can harm marine life, and sargassum buildup on beaches can prevent sea turtle hatchlings and adults from setting sail, Lapointe said.
Will this happen every year?
Experts don’t know if a Sargassum bloom of this size will occur every year, Lapointe said.
“It’s hard to project because we don’t know everything we need to know about the drivers (behind it),” he said. “We know it’s variable from year to year and the trajectory is generally up. So based on what we’ve seen in the past, we think we could continue to see that. worse for years to come. What will it be like in 10 years? Will it be double the size it is now?”
More funding to do the research that could answer these questions is needed, he added.
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