Workers clear sargassum seaweed in Tulum, Mexico in August 2022. - Copyright AP

Carib - Is climate change to blame for the 8,000km long seaweed blob floating toward Florida and Mexico?

A massive 8,000km long blob of seaweed is floating towards Florida, Mexico, and the Caribbean.

The Great Atlantic Sargassum Belt - a raft of biomass stretching from West Africa to the Gulf of Mexico - contains scattered patches of seaweed on the open ocean.

It's not a new occurrence, but scientists say that this year’s bloom could be one of the biggest ever recorded.

The thick, brown seaweed is already carpeting some beaches in Florida, releasing a pungent smell as it decays and entangling humans and animals who step into it.

So what is Sargassum - and is climate change to blame for this massive bloom?

What is Sargassum?

Sargassum is a leafy brown seaweed festooned with berry-like air pockets. The seaweed floats on the open ocean and - unlike other marine plants- reproduces on the water's surface. The air-filled structures help to give it buoyancy.

Sargassum originates in a vast stretch of the Atlantic Ocean called the Sargasso Sea, well off the southeast coast of the US.

The matted brown mass of seaweed stretches for kilometres across the ocean and provides breeding grounds, food and habitat for fish, sea turtles and marine birds, according to the National Oceanic and Atmospheric Administration (NOAA).

"It's a dynamic, constantly changing set of pieces of this large mass," said Rick Lumpkin, director of the Physical Oceanography Division at NOAA.

It is vital to the ecosystem but can pose a serious problem for tourism when it washes ashore. The seaweed piles up on beaches where it quickly decomposes under the hot sun, releasing gases that smell like rotten eggs.

Too much of it can also harm coastal marine ecosystems by coating beaches with nearly a metre of seaweed.

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