TAMPA, Fla. (WFLA) — Giant masses of seaweed are contaminating some of Florida’s most picturesque beaches in the Florida Keys, footage captured on April 14 shows.

According to NASA, whose satellites keep tabs on the massive blooms, more than 13 million tons of sargassum drifted in the Atlantic Ocean in March – a record-breaking amount for the month.

“In smaller amounts, sargassum can be beneficial for marine life and contribute to a healthy ocean, but in large quantities like this, the seaweed can be harmful,” NASA said. “It sinks and smothers coral and makes it hard for species to breathe or move around.”

Video captured by Lori Russo and shared by wire service Storyful, show heaps of seaweed covering Key West’s Higgs Beach. Other footage posted to social media days later, indicated the seaweed had moved away from the shore.

Local media said that popular tourist beaches were removing seaweed each morning as it washed ashore.