While a toxic red tide algal bloom is invading Florida’s beaches, a vast island of seaweed—spanning twice the width of the United States—is headed for the Sunshine state’s waters. It could seriously impact the tourism industry as Spring Break nears. The mass of floating “Sargassum” seaweed is currently making its way slowly through the Atlantic…

A seaweed blob spanning 5,000 miles, nearly twice the width of the United States, is heading toward the Florida Gulf coast, with officials warning that the thick mat of algae poses environmental and health concerns as it approaches the shore. Known as sargassum, the brown seaweed floats in open oceans, and is considered mostly harmless—while…