Massive Algae 'Blob' Creeping Toward Florida Can Be Seen From Space

A massive algae bloom visible from space is heading toward Florida's Gulf Coast, which could spell trouble for marine ecosystems and people. Marine scientists warn this 5,000-mile-wide sargassum "blob" could be one of the largest in history.

“It’s incredible,” Brian LaPointe, a research professor at Florida Atlantic University’s Harbor Branch Oceanographic Institute told NBC News. “What we’re seeing in the satellite imagery does not bode well for a clean beach year.”

When these thick mats of this brown algae get closer to shore, they're known to block sunlight to essential coral reefs, deprive other sea life of carbon dioxide, and tank water and air quality when it decomposes. Not only is sargassum gross to look at on beach shores, but it can be dangerous to humans, too.

Rotting sargassum releases hydrogen sulfide, causing respiratory issues to beachgoers, residents, and anyone working on the water. Larger pieces of sargassum can also trap boats and other machinery.

“Even if it’s just out in coastal waters, it can block intake valves for things like power plants or desalination plants, marinas can get completely inundated and boats can’t navigate through,” Brian Barnes, an assistant research professor at the University of South Florida’s College of Marine Science, explained to reporters. “It can really threaten critical infrastructure.”

This news comes as Florida prepares for a busy Spring Break season, which brings thousands of tourists seeking fun at the beach and warm weather. Beaches in nearby Mexico are expecting up to three feet of sargassum along shores, and some mounds have sprung up in the Florida Keys.

Sargassum originally stayed in the titular sea in the Atlantic region, but climate change, rising sea temperatures, and nutrients from fertilizers flowing into the ocean have caused this seaweed's population to explode, according to experts. While blooms are normal, there have been larger ones reported in 2018 and 2022.

“Before 2011, it was there but we couldn’t observe it with satellites because it wasn’t dense enough,” Barnes said. “Since then, it has just exploded and we now see these huge aggregations.”