A blob of sargassum seaweed thousands of miles long is approaching the Southeast United States and Gulf Coast.
It is expected to make landfall over the next several months, bringing with it the stench of rotten eggs and respiratory problems, much to the chagrin of Key West business owners, residents and visitors.
First discovered by Christopher Columbus during his voyage to the Americas, the macroalgae has continued to grow, causing problems for residents in South and Central America, the Caribbean, Florida and the Gulf Coast, according to a 2019 paper written by scientists at the University of South Florida.
This year’s belt is estimated to be more than 5,000 miles long.
The increase in the algae — which serves as a nursery for everything from tiny crabs and shrimp to larval dolphinfish, sailfish, marlin and bluefin tuna — is a boon for offshore anglers throughout the Atlantic Ocean and the Caribbean Sea.
But it is beginning to cause problems for cities like Key West.
When cast ashore by southeasterly and south winds, the seaweed gathers in large mats and decomposes. As that natural process begins, hydrogen sulfide is released. The ensuing rotten-egg stench and associated respiratory problems are an unfortunate consequence.
The bloom has severely impacted businesses along the south side of Key West, including the Southernmost Cafe and South Beach Cafe at the foot of Duval Street. Homeowners along the south side of the island, as well as along the canals of Key Haven, have also complained.
Local attorney and businessman Michael Halpern is in the process of working with the City of Key West to erect barriers to help control and gather the floating algae as it washes onto shore at the base of Duval Street and the Southernmost House.
“We are hoping — at our expense — to install the barriers by April or May,” said Halpern. “Unfortunately, the seaweed has arrived earlier than we anticipated.”
Halpern said that although he hasn’t seen a drop in business, if it gets much worse, it will again be a problem.
At a recent Key West City Commission meeting, employees from the adjacent Southernmost Beach Cafe spoke to commissioners about the impacts caused by the seaweed groundings. Several said they had trouble breathing and suffered lasting effects from inhaling the hydrogen sulfide gas.
Over the past decade, the floating mass has moved further south from its traditional position — the Sargasso Sea — midway between the Mid-Atlantic coast of the United States and West Africa.
As the algae has shifted into warmer water, researchers believe its growth has been fueled by excess nutrients spilling into the Atlantic Ocean from the Amazon River Basin. Scientists also believe nutrients from the Mississippi and Congo rivers contribute to the growth explosion.
Glen Boe and Associates, a structural engineering firm based in Marathon, is designing the barriers.
The city’s Planning Department approved plans for the barriers last year, but Halpern and others interested in building them must seek permitting from applicable state and federal agencies.
Halpern said he is still determining the cost of the barriers but hopes that the cleanup effort, once the floating booms collect seaweed and other marine debris, will be a joint effort between business and the City of Key West.
Mayor Teri Johnston agreed.
“We are looking at ways to increase our beach cleanup efforts regarding sargassum,” said Johnston. “Hopefully, we can prevent this from continuing to be a nuisance for residents, visitors and business owners alike.”
The onslaught of the noxious yellow algae is expected to continue into October. The Florida Department of Health has a few suggestions for those that might be headed to the beach.
Officials suggest always supervising children while at the beach and not touching or swimming near seaweed to avoid stinging organisms that live in it. They recommend wearing gloves when handling the algae, if necessary. Those experiencing breathing issues after inhaling hydrogen sulfide should avoid the area, and those who live near the beach should close windows and doors. They also recommend seeking a physician or calling 911 if experiencing breathing difficulties.
Sargassum isn’t the only respiratory threat residents have to worry about from the ocean.
The DOH has also issued a red tide caution for the area surrounding Sawyer Key on the Gulf side of Cudjoe. A health caution is issued when the level of red tide — caused by microscopic diatomaceous algae called dinoflagellates — is low (more than 10,000 but less than 100,000 cells per liter.)
The particular algae that cause red tide is Karenia brevis (K. brevis.) Typically formed offshore in the Gulf of Mexico, red tide forms commonly appears in late summer or early fall and is carried into coastal waters by winds and currents.
Once inshore, these opportunistic organisms use nearshore nutrient sources to fuel their growth. Blooms typically last into winter or spring but, in some cases, can endure for more than one year.
The DOH also has precautions for residents related to red tide.
They suggest looking for informational signage posted at most beaches and staying away from the water. Those with chronic respiratory problems should be especially cautious and stay away.
If caught live and healthy, finfish are safe to eat as long as they are filleted and the guts are discarded. Rinse fillets with tap or bottled water.
They also recommend avoiding harvesting or eating molluscan shellfish or distressed or dead fish from a red tide location. If you or your pets have come in contact with red tide, they recommend washing your skin, clothing and pets with soap and fresh water as soon as possible.
To report fish kills, contact the Florida Fish and Wildlife Research Institute via the FWC Reporter App, call 1-800-636-0511, or report online at https://myfwc.com/research/saltwater/health/fish-kills-hotline/.
The DOH also recommends people report symptoms from exposure to a harmful algal bloom or any aquatic toxin to the Florida Poison Information Center at 1-800-222-1222.
