Millions of tons of seaweed currently floating in the tropical Atlantic Ocean could soon make its way toward the U.S., according to researchers following the phenomenon.

Record amounts of sargassum are floating in the Caribbean Sea and ending up on beaches from Puerto Rico to Guyana — but scientists aren't sure why there's so much of it in the first place.

SAN JUAN, Puerto Rico (AP) — A record amount of sargassum piled up across the Caribbean and nearby areas in May, and more is expected this month, according to a new report.