A new wave of sargassum seaweed has invaded Miami’s coastline, coating beaches from Key Biscayne to South Beach in thick, brown mats and releasing a strong, sulfur-like odor that’s hard to miss. The scent—often compared to rotting eggs—is the result of the seaweed breaking down in the sun and has left beachgoers holding their noses.
Sargassum is a type of brown algae naturally found in the Atlantic, and its seasonal arrival is nothing new for South Florida. The bloom typically peaks during the warmer months and can persist through October. Scientists say the growth is influenced by ocean currents, rising water temperatures, and nutrient runoff—making large blooms more frequent in recent years.
City crews are already at work clearing the seaweed, but the task isn’t easy. Some areas are seeing repeat build-ups just days after being cleaned. “It’s like mowing a lawn that grows back overnight,” said one worker on the cleanup team.
Local businesses near the shore say they’ve noticed fewer beach visitors since the smell intensified. “People walk in and ask if something died,” said a manager at a beachside café. “We tell them it’s just seaweed, but it doesn’t help their appetite.”
Officials urge residents and tourists to stay informed about water conditions and avoid touching or walking on large seaweed piles. Meanwhile, city departments say they’ll continue working around the clock to manage the smell and keep beaches as clear as possible.
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