Sargassum threatens beaches in Mexico, Florida and the West Indies

The Sargasso Sea is an area of ​​the Atlantic Ocean where sea currents bring together a large amount of algae of the same name. Another deposit has recently formed in northern Brazil.

An 8,000 kilometer long belt of algae hidden in the Atlantic Ocean is expected to wash ashore over the next few months on beaches in the Caribbean Sea, South Florida and the North American Peninsula. Yucatan, Mexico.

The Great Atlantic Sargassum Belt – as the biomass known as it stretches from West Africa to the Gulf of Mexico – is consisting of scattered aggregations of seaweed in the open sea rather than a continuous mass of sargassum. This phenomenon is not new, but satellite images taken in February showed that the accumulation of such a quantity of algae in the open sea had begun earlier than at the time. #x27;accustomed.

Once washed up on shore, sargassum is a nuisance: this thick, brown algae coats beaches, emits a pungent odor as it decomposes, and entangles humans and animals that venture there. For hotels and resorts, removing this algae from beaches can be a time-consuming operation.

Beaches in Mexico, like those in Playa del Carmen, were abandoned by tourists in 2018. (File photo)

Here's a look at this year's Sargassum algae bloom.

It's a leafy brown algae scalloped with what looks like berries . The seaweed floats on the high seas and, unlike other algae, it reproduces on the surface of the water, aided by air-filled structures that give it buoyancy.

Sargassum comes from a large stretch of the Atlantic Ocean called the Sargasso Sea, which lies off the southeastern United States.

Seaweed sea ​​turtles stretch for miles across the ocean and are a breeding ground, food source and habitat for fish, sea turtles and seabirds, according to the National Administration of the Oceans and Atmosphere (NOAA) of the United States.

It's a dynamic, ever-changing collection of chunks of that great mass, explained Rick Lumpkin, director of the physical oceanography division at NOAA. It is not one large continuous mass heading directly south from Florida.

Sargassum accumulates on beaches, where they quickly decompose in the scorching sun, releasing gases that smell like rotten eggs.

In recent years, sargassum has covered the beaches of some Caribbean islands and Mexico's Yucatan peninsula in spring and summer. Beach towns and hotels have struggled to cope with the huge amounts of seaweed washing up on the shore.

The beaches of Mexico, Florida and several small Caribbean states are littered with Sargassum seaweed. (File photo)

According to Chuanmin Hu, a professor of oceanography at the University of Southern Florida, some of the sargassum has already reached Key West beaches. However, most Sargassum will arrive during the summer.

What is unusual this year compared to previous years is that it started early, Hu said. Algae usually proliferate in spring and summer, but this year in winter we already have a lot.

South Florida, the Caribbean, and the Yucatan Peninsula typically see sargassum build up during the summer months and it can be expected that x27;it's the same this year, Mr. Hu added.

That's a lot, but it's been worse before.

Scientists estimate that there are over 10 million metric tons of Sargassum in the belt this year. According to Mr. Lumpkin, this is one of the strongest years, but not the strongest, since scientists began to observe biomass closely through satellite imagery, in 2011.

He added that the biomass was more imposing in 2018. The years 2019 and 2021 were also marked by a large amount of Sargassum, he recalled.

Scientists don't know exactly, partly because the phenomenon has only been closely monitored since 2011.

We know that to get lots of algae, you need nutrients and light. Of course, the closer you get to the equator, the more sunshine, explained Mike Parsons, professor of marine science at Florida Gulf Coast University.

Mr. Parsons and other experts believe that agricultural runoff that seeps into the Amazon and Orinoco, and then into the ocean, could explain the increased growth. of the west side belt. Parsons says warmer waters likely help algae grow faster. Changes in wind patterns, ocean currents, precipitation, and drought could also affect blooms.

The entire belt may be fed more in some years than others by dust that contains iron and other nutrients from the Sahara Desert, Lumpkin said, from NOAA.

It is not certain that climate change plays a role. Extreme weather events that are happening more frequently due to global warming — high winds, storms, more rainfall — could contribute to this, Hu said.

Daily strandings of Sargassum seaweed sometimes make beaches in Mexico, the Caribbean and Florida unfrequent. (File photo)

They can be. As it breaks down, Sargassum releases ammonia and hydrogen sulfide, which explains the rotten egg smell it gives off. Brief exposure isn't enough to make people sick, but prolonged exposure — especially for people with respiratory problems — can be dangerous, scientists say.

According to M Hu, this problem could concern hotel workers and others who spend hours removing rotting sargassum from beaches.

Left at the beach abandoned on the beach, Sargassum can harm coastal marine ecosystems and promote the growth of fecal bacteria.