Giant masses of yellowish-brown sargassum seaweed gathered on beaches in the Florida Keys, footage captured on April 14 shows.

According to NASA, whose satellites track 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. It sinks and smothers coral and makes it hard for species to breathe or move around,” NASA said.

Footage captured by Lori Russo shows a field of seaweed covering Key West’s Higgs Beach on April 14. Other footage posted to social media on April 19 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.

Credit: Lori Russo via Storyful