When Aaron Isaiah traveled from Chicago to Hollywood Beach, he was expecting the perfect tropical vacation. What he wasn’t expecting was the seaweed.
“It made me not want to get in the water,” he said. “I can’t imagine just floating in it, feeling it brush against your legs and arms.”
Isaiah is one of thousands of beachgoers witnessing a massive sargassum bloom along the coast of South Florida.
This year’s season is one of the largest on record. The University of South Florida’s 2026 sargassum outlook projected that more than 10 million metric tons would wash ashore. Now, at its peak in July, beaches in West Palm Beach, Dania Beach, Fort Lauderdale and Miami are plagued by the pileup. While many factors affect the bloom, student meteorologist Gennylia Dalien said rising ocean temperatures play a significant role.
“We do have record sea surface temperatures in June, and this seaweed floats on the surface,” she said. “It’s too hot for it to live in the ocean, so it dies and washes ashore, and then the heat accelerates its decay.”
The sargassum is more than just unpleasant to look at — it releases gases that can be harmful to health over time.
“When the sargassum rots, it releases both hydrogen sulfide and arsenic, and even if it’s a small amount, it can affect your lungs if you inhale it,” Dalien said. “So you may want to leave that next beach visit until after peak sargassum season.”
