Sargassum seaweed, invader of Florida and Caribbean beaches, may be the ‘new norm’
If you’ve been to the Caribbean or Florida this past summer — or anytime the last few years — chances are you’ve encountered sargassum seaweed.
Sargassum is a natural phenomenon first reported by Christopher Columbus in the 15th century, but in recent years it’s flourished due to a host of factors.
“The Caribbean and Florida are both greatly impacted by this, currently the largest macroalgae bloom, with approximately 20 million metric tons of sargassum,” Barry Rosen, eminent scholar and professor at Florida Gulf Coast University told USA TODAY. It’s mainly affecting the Caribbean and Gulf of Mexico, Kathryn Scafidi, a graduate student in the Fish Ecology Lab at California State University, Northridge, told USA TODAY.
But what exactly is sargassum? Is it dangerous to travelers? Is it ever going to go away? We dig into all your burning questions below.
What is sargassum?
Sargassum is a seaweed with small air-filled “berries” that floats in island-like masses on the ocean. It’s naturally occurring and provides an important habitat for migratory organisms such as crabs, shrimps, sea turtles and commercially important fish species such as tuna and marlin.
Why is it appearing on beaches?
Sargassum has flourished in recent years due to the perfect combination of an increase in nutrient runoff from the Amazon River, upwelling off the western coast of Africa and changing water temperatures.
In 2011 the mats grew to form a 5,550-mile-long belt that extended from West Africa to the Caribbean Sea and Gulf of Mexico. Winds and currents then push the seaweed ashore. The floating mats are now affecting tourism, with visitors to some beaches facing stinking mounds of rotting seaweed at the waterline.
When will it go away?
Stephanie Molloy, the city’s natural resources director in Naples, Florida, told the Naples Daily News she expects the conditions to improve around October or November; however, the great Atlantic sargassum belt may be the “new norm,” according to a recent report by the American Association for the Advancement of Science
“Nutrients from deep ocean upwelling as well as African smoke, other atmospheric sources and runoff from South America are fueling its growth,” Rosen says. “Without a reduction in these nutrient sources, it will continue to proliferate.”
What are the health risks?
First off: Sargassum is not toxic. When sargassum washes ashore and starts decaying, it releases hydrogen sulfide, which could negatively affect those with asthma and other respiratory conditions. It could also contain arsenic or other bacteria.
Samples taken from sargassum on some of Mexico’s Caribbean beaches had arsenic levels 60% higher than those permitted in food for humans and animals as well as heavy metal levels as high as 120 parts per million, according to the June 12 online edition of Mexico News Daily.
The kinds and amounts of chemicals in the sargassum you see on the beach depend on where it was before it got there, Ed Phlips, an algae researcher at the University of Florida, told Treasure Coast Newspapers, which are a part of the USA TODAY Network, in July.
“Sargassum is like a floating community,” Phlips says. “It picks up all sorts of bacteria and algae and small plants and animals as it moves around.”
Sargassum is an important habitat for many other organisms that may cause skin reactions via direct contact, according to the Florida Department of Health. Tentacles from jellyfish and jellyfish larvae living in the seaweed are examples of other organisms that can cause rashes and blisters.
It isn’t all bad, however. “Some of it washed ashore is actually good for a healthy sandy beach ecosystem,” Scafidi told USA TODAY. “It provides habitat and food for small organisms living in the sand and for shore birds, as well as helping reduce beach erosion.” In large quantities, though, it could ruin sea turtle nesting sites as well as “smother organisms.”
“As with most things, everything in moderation is important for a balanced system, ” she adds. “What remains unknown are the indirect effects that larger sargassum blooms can have on other regions of the world.”
How are cities dealing with sargassum?
Naples, Florida, staff monitors the beach daily, Dana Souza, director of community services there, told the Naples Daily News, which is a part of the USA TODAY Network. Often the Gulf of Mexico’s tide cycles will pull the seaweed back out to sea. When the tide cycle does not remove the seaweed, city staff will deploy equipment to remove it.
“We have staff on the beach daily and I get reports if we have seaweed accumulating on the beach or if they observe changing conditions (seaweed, debris, fish, patron use, etc.)” Souza says.
In addition to Naples, cities on the east coast of the state, including Miami Beach and Boca Raton, have also been battling the smelly, mucky seaweed, and sargassum began appearing on Fort Myers Beach and Bonita Beach earlier this spring.
And of course, the problem isn’t just in Florida.
“Fighting sargassum is a chore every day,” Cancun Mayor Mara Lezama told the Associated Press in June. “You clean the beaches in the morning, and sometimes you clean them again in the afternoon or at night, and then you have to go back and clean it again.”
Reports estimate that Mexico has spent approximately $17 million as of June to remove more than a half-million tons of sargassum from its beaches, and Jamaica has spent close to $120 million.
Contributing: Tyler Treadway, Treasure Coast Newspapers
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