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How does brown algae damage Caribbean ecosystems and tourism?



Decade of Sargassum: How's Brown Algae Damaging Caribbean Ecosystems and Tourism

Sargassum has been around for centuries. The first report of its existence was written by Christopher Columbus himself in 1492, as he was concerned that his caravels might become stuck in a ‘vegetable blob’, in what is today known as the Sargasso Sea.

All these years, this harmless algae has provided shelter and food to marine species. But not anymore.

Over the past decade, this seaweed has grown uncontrollably, reaching the coasts en masse from West Africa to South Florida, via all countries surrounded by Caribbean waters, including Mexico.

In Quintana Roo alone, authorities have collected more than 200 tons of sargassum in the past four years, according to Huguette Hernández Gómez, Secretary of State for Ecology and Environment. In other words: a total nightmare.

Seaweed on the beach of Cancun

According to experts, sargassum is pose a marine risk never seen before. The worst part is that they don’t really know what exactly causes this phenomenon or how to alleviate it.

Among other things, sargassum forms a barrier that blocks sunlight and prevents marine organisms from performing photosynthesis.

In a 2021 study published by Climate Change Ecology, Sargassum beds were found guilty of reducing access to sunlight by 73% and increasing water temperature by 41°F.

Is climate change responsible for a 5,000-mile-long blob of seaweed drifting toward Florida and Mexico?
Floating Sargassum seaweed above coral reef

Sargassum “It mainly affects species that cannot move or have very little movement, such as starfish, sea urchins, sea grasses and of course corals,” reported biologist María García Rivas, director of Puerto Morelos National Reef Park.

Another study, published by Marine Pollution Bulletin, analyzed the damage caused by algae rot on Mexican Caribbean beaches in 2018. creatures of 78 species died, mainly crustaceans and demersal and neritic fish that live on the seabed.

Yet this is the most affected species the Great Mayan Reefthe second largest in the world, consisting of Mexico, Belize, Guatemala and Honduras, because it is “choked” by enormous amounts of sargassum.

In Colombia there are mountains of sargassum collected from important protected islands prevent naval tortures from reaching the sea before they are stolen.

“We saw that baby turtles had difficulty crossing the sargassum barrier and were vulnerable to predation by ghost crabs, rats and other predators,” informed Briggite Gavio, professor of marine biology at the National University of Colombia.

Academic couples in Antigua, Barbuda and Florida have reported the same problem.

In countries like Belize it is sargassum sweeps up marine litter, suffocates several organisms and makes the environment toxic, says James Foley, director of oceans at the Nature Conservancy.

Finally, Sargassum also appears to be killing Caribbean mangroves, which are saltwater trees that protect coastlines from extreme hurricanes.

These organisms live on the coast, but their roots need oxygen to survive. The problem is that sargassum acts like an oil spill, choking its roots, says Camilo Trench, a Jamaican marine biologist at the University of the West Indies (UWI).

Costs for the tourism sector and governments

The Mexican Navy installs 8,600 meters of barriers to combat Sargassum in the Caribbean
Seaweed barrier in Mexico

Because Mexico is one of the most visited countries in the world, it also pays the highest price. Tourism is declining, but costs are skyrocketing.

In 2023, the Mexican Navy Secretariat spent money $3 million seaweed collecting, purchasing sargasero ships and installing anti-sargassum barriers.

The Federal Maritime Terrestrial Zone has issued $7 million do the same and the government of Quintana Roo has spent money $1.7 million to combat sargasso.

Resort managers, for their part, have spent thousands of dollars hiring cleaning staff to keep the beaches acceptable to beachgoers.

In 2024, expenditures are expected to be similar.

Seaweed video report from Playacar, Mexico: