'The Coastlines Are Not Built for This'

Swaths of seaweed are blanketing the beaches and coastlines of the Caribbean and Gulf of Mexico, suffocating shorelines and snuffing out marine life while spooking visitors in areas that depend heavily on tourism, per the AP. Some 27 million metric tons of self-sustaining sargassum have been recorded in the Atlantic, Caribbean, and Gulf of Mexico in July, according to a report released Friday by the University of South Florida's Optical Oceanography Lab. The prickly seaweed covers miles of coastline, releasing a foul smell as it rots onshore. Governments in Mexico, Puerto Rico, the Virgin Islands, Caribbean islands such as Martinique, and elsewhere are struggling to cope.

What's known as the Great Atlantic Sargassum Belt has been growing since 2011. Experts have said that agricultural runoff, warming waters, and changes in wind, current, and rain could be factors. The sargassum that began reproducing in the region earlier than usual this year stems from a record 40 million metric tons reported last year. The algae usually reproduces asexually as it travels from Western Africa, said Brian Barnes, a marine scientist and research assistant professor at the University of South Florida. "None of this is normal," he said. "Every year is a little bit of a new story."

Patches of sargassum in open waters provide a healthy breeding ground for wildlife, including turtles, fish, and seabirds, and can be "a bit of an oasis of life in the middle of the ocean," Barnes said. But once it's closer to shore, it reduces oxygen in the water, smothers mangrove roots, and blocks sunlight from reaching coral and sea grass. Once it washes ashore it can prevent newly hatched sea turtles from reaching the ocean, while the heavy machinery used to remove it from beaches risk destroying fragile turtle nests, scientists say. "The coastlines are not built for this," Barnes said.