Sargassum Recovery for Clean Coasts

The Riviera Maya: A Reef-Fringed Coastline Dependent on Tourism

Stretching along Mexico’s Caribbean coast south of Cancún, the Riviera Maya is one of the world’s most iconic travel destinations. Home to well-known towns like Playa del Carmen and Tulum, the region draws millions of visitors from around the globe for its turquoise waters, sandy beaches, and world-class scuba diving and snorkeling. 

The coastline is fringed by the Mesoamerican Reef, the second-largest reef system in the world.  The reef’s coral structures shelter hundreds of fish species and form the backbone of the region’s marine biodiversity. The beaches also serve as critical nesting grounds for endangered sea turtles, including green, loggerhead, hawksbill, and leatherback turtles, which return to lay their eggs year after year.

Beneath the surface, the Riviera Maya is shaped by extensive networks of underground caves and waterways, created as rainwater filters through the porous limestone terrain. This subterranean system includes thousands of cenotes—natural freshwater sinkholes revered by the ancient Maya and now crystal-clear pools where visitors can swim and dive.

Tourism is the backbone of the regional economy, accounting for roughly 90% of local GDP. But this dependence also creates vulnerability, particularly given seasonal employment and intensifying environmental pressures. 

What’s Happening: The Sargassum Surge

One of the most visible and disruptive of these environmental pressures is sargassum, a type of brown algae that drifts freely rather than attaching to the seafloor. In the open ocean, sargassum seaweed plays a natural ecological role. Over the past decade, however, sargassum volumes have surged by roughly 600%, with massive blooms turning it into a persistent and escalating challenge. 

Since 2011, these blooms have formed the Great Atlantic Sargassum Belt, a large band of floating sargassum that stretches thousands of miles from West Africa to the Gulf of Mexico. Ocean currents now carry large volumes of this algae into the Caribbean, where it inundates shorelines and accumulates in unprecedented amounts. In Quintana Roo alone, roughly 120,000 tons of sargassum have been removed from beaches this year. Warmer seas, shifting currents, and increased nutrient runoff are all believed to be contributing to this surge.

Strain on Reefs, Wildlife, and Coastal Ecosystems

When sargassum washes ashore in large volumes, marine and coastal ecosystems suffer. As the seaweed decomposes, it releases nutrients that degrade water quality, creating low-oxygen “dead zones” where many marine species cannot survive. Sargassum can introduce heavy metals, microplastics, and invasive species into coastal waters, which may also seep into the groundwater network, threatening wildlife and contaminating food webs. 

Thick mats of sargassum can also smother coral reefs and seagrass beds by blocking the sunlight these ecosystems need. On beaches, dense accumulations form physical obstacles that slow sea turtle hatchlings as they make their way to the ocean, increasing the risk of predation and reducing survival rates. Sargassum buildup on nesting beaches can also change sand temperatures, which may affect the sex of developing hatchlings. 

What It Means for Tourism and Coastal Communities

As sargassum piles up on shorelines, it affects tourism and diminishes the appeal of beach destinations across the Riviera Maya, including Cancún, Playa del Carmen, and Tulum. The rotting seaweed attracts flies and releases hydrogen sulfide—a toxic gas with a strong rotten-egg odor that poses health risks to local communities and visitors. Decaying seaweed can also accelerate beach erosion and clog nearshore waters, making swimming far less inviting. As a result, travelers increasingly seek out ways to avoid sargassum and often think twice before visiting during what has become known as “sargassum season.” 

During severe sargassum events, affected beach areas along the Riviera Maya have experienced an estimated 18% drop in economic activity as the influx of seaweed deters visitors. This downturn can have a lasting “reputation effect” that hurts local people, hotels, and other businesses for up to a year after the seaweed is cleared. 

The economic consequences ripple outward. Fisheries suffer as nets become tangled, fish move away from low-oxygen waters, and nearshore zones become unusable, undermining food security and livelihoods.

A Growing but Overlooked Climate Cost

Beyond its impacts on marine and coastal zones, sargassum also presents a worsening climate challenge. As it decomposes, sargassum releases methane—a greenhouse gas roughly 80 times more potent than carbon dioxide over a 20-year period. A single metric ton of wet sargassum can emit methane equivalent to more than 300 kilograms of CO₂, roughly the same as driving a gasoline-powered car for about 760 miles. Across the Caribbean, where millions of tons wash ashore annually, these emissions add up to a serious and often overlooked climate impact.

Cleanup Challenges

Many resorts collect the sargassum, but cleanup is costly and comes with its own environmental complications. During peak bloom seasons, these efforts place a heavy burden on hotels,  municipalities, and other beachfront businesses. Across the Caribbean, the cost of sargassum cleanup has been estimated at more than $120 million annually. 

Traditionally, much of the collected sargassum has been hauled to landfills, where it continues to decompose, release methane, and contaminate groundwater through heavy-metal leaching and microplastic release. Inland disposal shifts the problem rather than solving it.

Cleanup methods themselves can also cause harm. Conventional sargassum removal often relies on loud, heavy machinery, disrupting the tranquil atmosphere of a beach getaway and causing environmental damage. These machines compact sand and remove healthy sediment, degrading beach ecosystems and accelerating erosion. In the process, sensitive nesting areas and sea turtle nests can be destroyed.