(Santo Domingo) The waters of the Malecon, Santo Domingo’s waterfront, are clouded by brown algae that tractors are busy picking up: the proliferation of sargassum worries the Dominican Republic, which lives largely from tourism.

For the moment, the most affected areas are Santo Domingo and San Pedro de Macoris, on the south coast of the country. The seaweed rotting there on the beaches gives off a fetid smell.

The quantities of Sargassum are lower in the east, in the province of Altagracia where the famous seaside resorts of Punta Cana and La Romana are located.

But reports received at the Ministry of Tourism in April show the presence of Sargassum on 42.5% of the monitored beaches in this tourist area in April. In January only 25% were affected.

Between January and March some 24 million tons of seaweed reached Dominican shores, compared to 14 million during the same period last year. And experts predict that the quantities will increase further.

“Ten years ago you could see the sargassum three months a year, but now they’re there almost all year round from March to November,” says marine biologist Andrea Valcarcel, head of the country’s ocean lab division. .

Hoteliers, concerned about their image and the comfort of tourists, pay brigades to pick up algae in Punta Cana.

“Sargassum is a major economic burden. Most hotels suffer from this and have invested in barriers (to prevent the advance of algae) and the collection of algae at sea and on land, ”explained to AFP David Llivre, president of the hotel association.

“If the volume continues to increase, it could have a negative effect” on tourism, he warns, as the Dominican Republic (10.5 million inhabitants) welcomed 8.5 million visitors in 2022.

For a dozen years, these brown algae have been invading the coasts of the Caribbean, Guyana, Central America, the Gulf of Mexico, but also Côte d’Ivoire, Benin and Togo. They suffocate biodiversity and pose health problems due to the release of gases harmful to health (hydrogen sulphide, ammonia) resulting from their decomposition, but also environmental and economic problems.

The causes of their proliferation continue to be studied. The increase in agricultural activity with the presence of fertilizers in the waters, the supply of nutrient salts linked to the deforestation of the Amazon, the modification of currents, the mists of the Sahara or global warming are the most mentioned.

The government of President Luis Abinader announced a fund of 12 million US dollars three years ago – six from the state and six from the private sector – to fight against Sargassum, but the project was abandoned.

Tenders for a control plan, which included land and water remediation and the construction of offshore barriers, ranged between $25 million and $30 million.

These were “stop-gap measures” that did not offer a “definitive solution”, however, Tourism Minister David Collado told reporters.

Sargassum is also disrupting power generation in the Dominican Republic, where at least 1,200 megawatts are produced in thermal power plants using seawater.

Some power plants are forced to “shut down” or “reduce” production due to the “risk of internal damage from sargassum ingress,” Energy Minister Antonio Almonte said.

Especially since the months of greatest proliferation of these pelagic brown algae which float on the surface of the ocean coincide with peaks in energy demand, during the hot season for air conditioners.

The government has donated a million dollars to universities hoping that scientists will find possible uses for sargassum in the fields of bio-fuels, fertilizers, cosmetics, animal feed, dyes, concrete blocks or thermo panels. -acoustics.

Mr. Llivre, president of the hotel association, hopes that Sargassum will be transformed from a “burden” into something that “has value”.