Seaweed is increasingly blighting beaches along Mexico's Caribbean coast as global warming, marine pollution, and the felling of mangroves and jungles take their toll.
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A brownish seaweed, called sargassum, marred the region's turquoise waters and white sandy beaches as early as January, indicating seaweed season has expanded, said Vivianne Solis-Weiss, an oceanographer from the National Autonomous University of Mexico (UNAM).
Sargassum usually appears from May to October, peaking in August, but satellite images taken by the United States National Aeronautics and Space Administration (NASA) showed the free-floating weed darkening the coastline at the start of the year. Wood debris from construction and urban runoff pollute the water, and as they become compost or nutrients they cause the sargassum to double in volume every 15 to 18 days.
"If there is more global warming, more pollution that reaches the sea, more waste produced by humans, the problem will grow at an accelerated pace. We can only expect a disaster. We have a paradise on the beaches that could turn into hell if they fill with sargassum and there is no comprehensive plan to combat it," Solis-Weiss warned.
Tourism has been hit the hardest by the seaweed's early arrival, because it not only makes the beaches unsightly, but also gives off an unpleasant odor as it rots. Sargassum is harmful to sea turtles, since the weed prevents them from reaching their usual nesting sites and keeps newly hatched turtles from reaching the sea.
Since 2018, when the sargassum covered a record 2,800 square km, at least three strategies have been used to contain it: placing physical barriers to keep the weed out, clearing the weed from the water with specially-equipped boats, and removing it from the beaches, where it collects.
Solis-Weiss believed the best tactic is to take a comprehensive approach that begins with early detection, to find out in advance where the weed will arrive, and prevent the organic material from reaching those beaches.
Mexico's Naval Secretariat has recently warned of "alarming" levels of sargassum reaching Mexico's coast, forecasting up to 32,000 tons, after collecting almost 9,500 tons so far this year. Some of Mexico's top tourism destinations are among the most affected by the seaweed, including the beach resorts of Tulum, Puerto Morelos and Mahahual.