TREASURE COAST - Beachgoers along Florida's Treasure Coast have encountered thick mats of brown seaweed blanketing the shoreline in recent weeks — a seasonal phenomenon that looks alarming but is, officials say, entirely natural.
The culprit is sargassum, a free-floating seaweed that drifts through the Atlantic Ocean and periodically washes ashore when winds and tides align just right. Erick Gill, Communications Director for St. Lucie County, says there's no cause for alarm.
"It's a natural occurrence that happens every so often," Gill said. "It is natural in the environment, and it's found in the ocean."
Far from being merely a nuisance, sargassum serves an important ecological role in the open ocean. Gill explains that the floating seaweed provides habitat for sea turtles and offers newly hatched hatchlings a place to hide from predators while they forage for food.
For most people, contact with sargassum poses little risk, though Gill notes that individuals with allergies should exercise caution. "Every person is different, so some people may have allergic reactions to it," he said.
"For the most part, no, it is not harmful." One concern with large accumulations, he added, is that the seaweed can trap debris like bottle caps — though the seaweed itself is not toxic or caustic.
"It's not like poison ivy or anything like that where it can be harmful to folks," he said.
Visitors hoping county workers will clear the beaches may be waiting a long time. St. Lucie County has no plans to remove the seaweed, and Gill says the reasons are both practical and environmental.
Mechanically removing sargassum during sea turtle nesting season risks disturbing nests, and the scale of the task makes manual removal cost-prohibitive.
"You're talking about millions of dollars worth of effort and time to have equipment go up and pull this off the beach," Gill said. "It would be too labor intensive to have staff out there picking it up by hand."
The sargassum is expected to remain until winds and tide patterns shift. Until then, Gill says residents and visitors should try to see it for what it is: part of a healthy coastal ecosystem.
"Some sargassum grass on the beaches is okay for the environment," he said. "The animals will still find refuge in it and a food source."