Sargassum invasion: Mexico’s Caribbean beaches awash in foul-smelling seawood-like algae as tourism is rebounding

Eduardo Verdugo / AP

Mexican authorities say the problem of foul-smelling, seaweed-like algae washing up on the country’s Caribbean coast tourist-haven beaches has become “alarming.”

The arrival of heaps of brown sargassum on the coast’s normally pristine white sand beaches comes as tourism is recovering to pre-pandemic levels, though jobs in the country’s top tourist destination have been slower to recover.

With more algae floating at sea, experts fear 2022 could be as bad or worse than the catastrophic year of 2018, the biggest sargassum wave to date.

“We can say the current situation is alarming,” said Navy Secretary José Ojeda, who has been entrusted with what could be the hopeless task of trying to gather sargassum at sea, before it hits the beaches.

The Navy has 11 sargassum-collecting boats operating in the area.

But its own figures show the amount those boats have been able to collect before it reaches the beach has been falling. In 2020, the Navy collected 4% of sargassum at sea, while 96% was raked off beaches. That figure fell to 3% in 2021 — and only about 1% so far in 2022.

Allowing the algae to reach beaches creates a problem for tourists and for the environment, according to Rosa Rodríguez Martínez, a biologist in the beachside town of Puerto Morelos who studies reefs and coastal ecosystems for Mexico’s National Autonomous University.

So much algae is reaching beaches that hotels and local authorities are using bulldozers and backhoes because the normal tools — rakes, shovels and wheelbarrows — no longer are enough.

“The heavy machinery, when it picks it [sargassum] up, takes a large amount of sand with it,” Rodriguez Martinez said. “There is so much sargassum that you can’t use small-scale equipment anymore. You have to use the heavy stuff. And, when the excavators come in, they remove more sand.”

Which contributes to erosion.

“In the last few days, there have been amounts washing up and in places that I didn’t see even in 2018,” Rodríguez Martinez said.

Yet the University of South Florida Optical Oceanography Lab has said “2022 is likely going to be another moderate or major sargassum year,” with observable amounts in all waters lower than in 2018 and 2021.

Given the vagaries of ocean currents, it could be it’s just a very bad year for Mexico.

Rodríguez Martinez is feeling the effects herself at her beachside offices.

“I’m about 50 meters from the beach, and the smell is very unpleasant,” she said. “My head is hurting, and another friend said her head hurts, and I said it must be the [hydrogen] sulfide gas from the sargassum, no?”

The problem comes as resorts like Cancun, Playa del Carmen and Tulum are recovering from a two-year drop in tourism brought by the coronavirus pandemic.

Not all beaches have been hit equally. Many in Cancun and Isla Mujeres often are largely free of sargassum. But much of the Riveria Maya has been hit hard.

Carlos Joaquin, governor of the coastal state of Quintana Roo, said the number of tourists arriving by air this year — 3.54 million — is 1.27% above pre-pandemic 2019 levels. But Joaquin said only about 83% of the 98,000 jobs lost during the pandemic have returned.

Sergio León, former head of the state’s employers’ federation, said the seaweed invasion “has definitely affected us. It has affected our image on the domestic and international level obviously not just visually but in term of environmental damage and pain.”

Rodriguez Martinez said, given the limited number of Navy boats and funding, the best solution might be to hang floating offshore barriers to collect sargassum in waters closer to shore.

But there’s another problem, she said: what to do with the thousands of tons of stinking algae collected each year, mainly by hotel owners. Some have been tossing the mounds collected from the beach into disused limestone quarries, where the salt and minerals collected in the ocean can leech into groundwater.

Other toss it into woodlands or mangrove swamps, equally bad.

“The algae has a lot of salt ... so that is not good even for palm trees, which are pretty salt-resistant,” she said.

Initial reports in the 2010s suggested that the masses of seaweed came from an area of the Atlantic Ocean off the northern coast of Brazil near the mouth of the Amazon River. Increased nutrient flows from deforestation or fertilizer runoff could be feeding the algae bloom.

But now experts say other causes might contribute to the problem, including nutrient flows from the Congo River, increased upwelling of nutrient-laden deeper ocean water in the tropical Atlantic and dust that blows in from Africa.