Sargassum is piling up on South Florida beaches again. Is it harmful?

South Florida beaches are again inundated by waves of sargassum, a seaweed that attracts attention and concerns coastal authorities. The algae generally poses little harm to people, but it irritates visitors and threatens tourism, fisheries, and coastal economies. The Southeast coast and the Florida Keys remain the hardest hit, with accumulations reaching Cocoa Beach and Miami Beach. A March bulletin from the University of South Florida says 2026 is shaping up as a major sargassum year, likely exceeding 75% of historical values and potentially setting records by summer. The belt across the tropical Atlantic has existed since 2011, affecting ecosystems and coastal management.