Gamtae is one of South Korea's rarest seaweeds. For centuries, this earthy, sweet seaweed was mainly harvested and eaten raw by locals in the Seosan region.
Millions of tons of sargassum wash up on beaches across North America every year. Exposure can lead to breathing problems, and it costs millions to clean it up.
Alexandre Meneghini/Reuters
A floating blob of seaweed 5,000 miles across, spanning nearly the whole width of the Atlantic Ocean, is headed for Florida’s Atlantic Coast. The sargassum algae, a brown, branching, stringy seaweed that can turn seawater mud-colored when present in large quantities, is likely to cause serious problems for the…