Summer is practically here, which means we can expect everything from endless pool days to late-afternoon thunderstorms to… well, sargassum, here in Miami. And experts say South Florida is in for a record-breaking year of the brown-colored seaweed.
According to the latest outlook from the University of South Florida, 28.9 million metric tons of sargassum is drifting across the Atlantic, piling up on shores in the U.S. and the Caribbean. While the algae washes ashore every year around spring to summer, its amount is expected to increase for 2026 and potentially set a record.
But the biggest complaint isn’t just how it looks; it’s the smell. When siting on the hot sand for 48 hours, sargassum will decompose and release hydrogen sulfide, which produces an odor similar to rotten eggs. While there is no immediate danger to the public, these gases can irritate the eyes, nose and throat, especially for people with respiratory issues like asthma.
The Florida Department of Health warns against touching these piles of seaweed, as they become breeding grounds for bacteria and biting insects like larvae and sea lice. It can also trap jellyfish, which makes for painful stings and blisters when coming into contact.
What’s being done about this?
Cities up and down the coast are participating in increased cleanup efforts, often deploying special tractors to rake beaches while being careful to avoid disturbing sea turtle nests. In Miami-Dade, sargassum removal accounts for about $9 million of the beach maintenance budget each year to maintain beaches for residents and visitors.
The City of Miami Beach coordinates with Miami-Dade County Parks to use beach-friendly equipment to blend the sargassum across the 7.5 mile beach daily. But before cleanup efforts, the Miami-Dade County Parks Sea Turtle Program surveys beaches for nests and hatchlings.
In Broward County, sargassum removal ranges from composting, burial and disposal inland. Municipal beach maintenance programs include mechanical beach raking, an activity that is regulated through permits by the Florida Department of Environmental Protection (FDEP), aiming to protect sea turtles, shorebirds and nesting habitats.
Why the sudden growth in sargassum?
While sargassum plays an important role in the open ocean, researchers have noticed an uptick in its overall growth since 2011. This is primarily caused by an influx of agricultural nutrients, like nitrogen and phosphorus, being dumped from major rivers (like the Amazon and Orinoco) into warm tropical waters. In this new environment, rising sea temperatures have lengthened the seaweed’s optimal growing season.
This runoff is supercharged by shifting winds and currents that trigger upwellings, bringing deep-sea nutrients to the surface to create a self-sustaining growth loop across the ocean.
If you’re looking to track the current bloom in Florida and beyond, visit NOAA’s Sargassum Inundation Risk tool here.
