Scientists Say Sargassum Must Be Stopped in the Atlantic, Not on Cancún’s Beaches

Cancún, Quintana Roo — The postcard image of turquoise water and white sand that defines the Mexican Caribbean is under serious threat from the brown tide of sargassum, and a leading reef scientist warns that the containment strategy applied so far at the shoreline will not solve the crisis.

Susana Enríquez Domínguez, a researcher at the Academic Unit of Reef Systems at UNAM’s Institute of Marine Sciences and Limnology in Puerto Morelos, said the real solution must come from science and must attack the problem at its root — in the “ovens,” or aggregation zones, of the Atlantic Ocean, before the algae ever reaches the beaches.

Once sargassum lands on the coast in massive quantities, she said, “the battle is already lost.”

“We have to see that science, and those who generate knowledge, can make the problem manageable in a way that overcomes the frustration of an endless story that invades the beaches every year and seems to have no end,” Enríquez Domínguez said.

Collecting the seaweed after it washes ashore is both insufficient and exhausting, according to the researcher. Sargassum breaks down with exceptional speed, releasing 100 percent of the phosphorus it contains along with nitrogen.

The ecologist said this massive injection of nutrients profoundly alters the water column, triggering an anaerobic process that consumes oxygen, emits toxic gases and produces the characteristic brown tint that ruins the coastal landscape and smothers the reef system.

That ecological damage hits the economic stability of Cancún and the state directly, since the region’s tourism model depends on preserving its white beaches and clear waters. Enríquez Domínguez noted that northern Quintana Roo, already battered by wastewater discharges and rapid urban development, sees its vulnerability sharpened by this constant flow of nutrients.

The technical key, she explained, is to change the operating approach: rather than waiting for the algae to come ashore, authorities should identify and neutralize the aggregation zones in the Atlantic.

Those accumulation zones — influenced by nutrients carried in the plumes of the Orinoco and Amazon rivers — function as incubators where sargassum finds ideal conditions to multiply exponentially.

Scientists still need to pin down the exact location and timing of these accumulations through modeling, but Enríquez Domínguez stressed that intercepting them on the open ocean is the only effective path.

She pointed to biotechnology and engineering alternatives, including one developed in the United Kingdom that involves deploying small, low-cost vessels designed to collect algal populations during the winter months of January and February. Acting in that window, before the spring biological surge, prevents the biomass from swelling to massive volumes and drifting toward Caribbean shores.