Clumps of 5,000-mile seaweed blob bring flesh-eating bacteria to Florida

Decomposing pieces of Great Atlantic sargassum belt carry Vibrio bacteria on state's shoreline

It might have been one of Alfred Hitchcock's fanciful tales of the supernatural: a 5,000-mile wide blob of murky seaweed creeping menacingly across the Atlantic before dumping itself along the US shoreline.

But now giant clumps of the 13m-ton morass labeled the Great Atlantic sargassum belt are washing up on Florida's beaches, scientists are warning of a real-life threat from the piles of decomposing algae, namely high levels of the flesh-eating Vibrio bacteria lurking in the vegetation.