May 10, 2023 - News

Learn to love the "seaweed blob"

A woman stands in the shallow ocean water while Sargassum seaweed covers the beach and shorebirds  stand in it.

Sargassum seaweed on Miami Beach in 2020. Photo: Pedro Portal/Miami Herald/Tribune News Service via Getty Images

A University of Miami professor wants us to appreciate, not fear, the 5,000-mile mass of seaweed that's floating toward Florida.

Why it matters: Seaweed blooms in the Atlantic Ocean every summer, but a giant mass of it has become so large since 2011 that it's been dubbed the Great Atlantic Sargassum Belt.

  • Researchers believe what's been called a "seaweed blob" has grown due to climate change and fertilizer runoff.
  • If parts of it reach Miami's shores this summer, beachgoers and money-spending tourists could be repelled.

Context: All seaweed is algae. The genus Sargassum encompasses more than 100 species of seaweed.

  • The Sargasso Sea — a patch of the Atlantic Ocean where it grows — was named after the algae.
  • Once on land, the seaweed turns brown, releases hydrogen sulfide and smells like rotten eggs.
  • Small organisms in it can cause skin rashes.

State of play: A University of South Florida tracker found record amounts of Sargassum in the Caribbean Sea in April.

Zoom in: Sargassum typically hits Miami-Dade County beaches from May - October.

  • The parks department removes seaweed from beaches each morning with heavy equipment, checking for turtle nests first.
  • Environmental regulations prohibit proactively removing it from the water.
  • The county spent $2.8 million on seaweed cleanup in 2020 and $3.9 million last year, WUSF reports.

The intrigue: David Die, a marine science professor at UM, acknowledges the problems with seaweed but tells Axios the mass is home to shrimp, crabs, fish and sea turtles.

  • Mahi, marlin, albacore tuna, billfish and eels are all reliant on the food chain sustained by sargassum.

What they're saying: "One of the troubles is that it's called a blob," Die said. "It's really an amazing habitat."

  • Beach managers used to mix seaweed into sand and incorporate it into dunes, which Die says is the most appropriate kind of management because "it mirrors the natural cycle."
  • But they now just haul it away because of the volume, he says.

What we're watching: Inventors are developing fertilizer, cosmetics, leather alternatives and bricks from seaweed.

The bottom line: "The most important thing is to make people understand — and that's both beachgoers and tourists — that this is a natural phenomenon," Die says.

  • Visitors should plan trips with the possibility of seaweed in mind, just as they anticipate storms, Die says. It shouldn't be "an impediment to having a reasonable vacation."

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