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Riya Anne Polcastro headshot

Giant Seaweed Blobs Are the New Normal

A photo of a boy on a beach in Mexico that is covered in sargassum seaweed.

The record-setting “blob” of seaweed headed for Florida’s coastline is getting a whole lot of attention. But beaches in the Sunshine State and across the Caribbean have seen record-setting amounts of the stuff for at least five years in a row. 

Sargassum seaweed blooms are not new either, though only in recent decades have they grown large enough to study by satellite. Naturally, the phenomenon is linked to human activity. And while the problem may appear small compared to so many others, it doesn’t just threaten spring breakers’ good times. The masses of dead seaweed that wash up on shore threaten marine ecosystems, as well as the local tourism industry, the livelihoods of those working in the industry, and the health of those tasked with cleaning it up.

Too much of a good thing

The Great Atlantic Sargassum Belt stretches 5,000 miles, from the Gulf of Mexico to West Africa. But it’s not one solid stretch of seaweed, Rick Lumpkin, director of the physical oceanography division at the U.S. National Oceanic and Atmospheric Administration (NOAA), told the Associated Press. “It’s a dynamic, constantly changing set of pieces of this large mass. It’s not one big continuous blob heading straight to South Florida.”

Sargassum seaweed starts out in the Sargasso Sea — a gyre in the Atlantic Ocean where four currents meet — and spreads out from there. It supplies marine life with food, habitat and a place to breed. Fish, turtles and seabirds all benefit from the tangled brown algae, making it an important part of the ecosystem. 

But the plant's intrinsic benefits are being lost in the harm done by its proliferation. “It comes in in such large quantities that it basically sucks the oxygen out of the water and creates what we refer to as dead zones,” Dr. Brian Lapointe, a research professor at Florida Atlantic University’s Harbor Branch Oceanographic Institute, told CNN. “These are normally nursery habitats for fisheries … and once they’re devoid of oxygen, we have lost that habitat.”

Seaweed blooms: A stinky, expensive mess

On land, sargassum is a nuisance to beachgoers, a scourge for the tourism industry and a potential health hazard. Though the majority of what is floating along the belt will never wash ashore, what does amounts to piles of stinking, rotting vegetation that releases toxic hydrogen sulfide and often brings sea lice, jellyfish and other pain-inflicting critters with it. Hydrogen sulfide can cause respiratory issues as well as burning in the eyes and nose. It also smells like rotting eggs, a huge turn-off for tourists. The algae contain arsenic too, which limits how it can be repurposed.

And it's difficult and expensive to remove, with Miami-Dade County alone spending millions on cleanup every year. Caribbean nations spent $120 million in 2018 alone, and hotels in the Mexican state of Quintana Roo spent up to $90,000 per month to get the stinky stuff off their beachfronts in 2021. In Barbados, it’s taking “1,600 dump trucks a day to clean the beaches of this seaweed to make it suitable for tourists and recreation on the beaches,” LaPointe said.

Many causes require many fixes

What’s caused this sudden increase in sargassum over recent years? A number of factors are at play, including ocean acidification from increased atmospheric carbon dioxide levels, a 45 percent increase in nitrogen levels since the 1980s, and warming ocean temperatures worldwide. The growth is also cyclical — meaning the worse it gets, the worse it will get.

Much of the increase in ocean nutrient levels is likely due to fertilizer and sewage runoff. Some experts, including Jeff Carbeck, CEO of the consultancy 10EQS, have recommended upgraded fertilizers to help combat the problem. Still, with so much of the issue tied up in CO2 levels and increased temperatures, at least one necessary fix is being held hostage by the lack of real progress on the larger climate crisis. 

A new normal

Experts don’t appear too enthusiastic that the sargassum will be brought back into balance. “This is the new normal, and we’re going to have to adapt to it,” Lapointe told Scientific American.

Like so many other symptoms of our planet in crisis — from sinking islands to worsening turbulence — this new normal should have each and every one of us questioning whether what humanity has built is even worth it. Ultimately, each of these problems will continue to worsen until the assault on our planet by unfettered profit-driven interests is brought to an end. Is allowing it to continue really worth losing so much of what makes the Earth a beautiful, amazing place to live?

Image credit: PNUD México / Flickr

Riya Anne Polcastro headshot

Riya Anne Polcastro is an author, photographer and adventurer based out of Baja California Sur, México. She enjoys writing just about anything, from gritty fiction to business and environmental issues. She is especially interested in how sustainability can be harnessed to encourage economic and environmental equity between the Global South and North. One day she hopes to travel the world with nothing but a backpack and her trusty laptop.

Read more stories by Riya Anne Polcastro