A seaweed blob twice the width of the US is heading toward Florida.

Photo: Workers remove sargassum from a beach in Punta Cana, Dominican Republic, in June.

Here’s what you should know.

CNN — A giant blob of seaweed twice the width of the continental United States is headed for the shores of Florida and other coastlines throughout the Gulf of Mexico, threatening to dump smelly and possibly harmful piles across beaches and dampening tourism season.

Sargassum — the specific variety of seaweed — has long formed large blooms in the Atlantic Ocean, and scientists have been tracking massive accumulations since 2011. But this year’s bloom could be the largest ever, collectively spanning more than 5,000 miles (8,047 kilometers) from the shores of Africa to the Gulf of Mexico.

This year’s sargassum bloom began forming early and doubled in size between December and January, said Dr. Brian Lapointe, a researcher at Florida Atlantic University’s Harbor Branch Oceanographic Institute. The mass “was larger in January than it has ever been since this new region of sargassum growth began in 2011,” he told CNN International’s Rosemary Church.

Workers remove sargassum from a beach in Punta Cana, Dominican Republic, in June. Traveling west, the blob will push through the Caribbean and up into the […]

Full article: A seaweed blob twice the width of the US is heading toward Florida. Here’s what you should know