Caribbean Matters: Sargassum seaweed continues to spread

Sargassum seaweed is back, and massive amounts of it continue to create major problems across the Caribbean, impacting people’s health, the environment, and the tourism industry. The situation is not new, yet in spite of efforts by governments and international agencies, the effects are worsening.

“Caribbean Matters” first covered the sargassum story in August 2022, and it is time to revisit. This month, multiple news agencies have tackled this issue.

Caribbean Matters is a weekly series from Daily Kos. If you are unfamiliar with the region, check out Caribbean Matters: Getting to know the countries of the Caribbean.

As the National Ocean Service explains, the Sargasso Sea is “defined only by ocean currents” and has no land boundaries—it’s the only sea on the planet with that distinction. Notably, it’s named for the destructive algae  at the center of this story, which is unique in that it’s rootless, while “[o]ther seaweeds reproduce and begin life on the floor of the ocean.”

Even as sargassum terrorizes coastlines, it provides benefits for many species, National Geographic notes, with one oceanographer calling it “a golden rainforest.” Clumps of sargassum provide “a kind of canopy”—an edible one.

Its tangled tresses support an astonishing diversity of organisms that hide in and feed off the weed—the larvae and juveniles, according to one study, of 122 different species of fish, as well as hatchling sea turtles, nudibranchs, seahorses, crabs, shrimps, and snails. The seaweed in turn is nourished by the excrement of these organisms.

Larger creatures such as fish and turtles find plenty to eat amid the sargassum, and they attract bigger predators—triggerfish, tripletails, filefish, mahi-mahis, and jacks, on up the chain of life to sharks, tuna, wahoos, and billfish. Tropic birds, shearwaters, petrels, terns, boobies, and other birds of the open ocean roost and forage on sargassum mats.

Unfortunately, sargassum doesn’t stay in the waters of its namesake sea. Several major publications recently raised the alarm about sargassum in multiple stories, including this group effort:

Caribbean People at Risk from Sargassum Invasion

Project of The BVI Beacon, The Virgin Islands Daily News, América Futura - El País América, Television Jamaica and the RCI Guadeloupe  in collaboration with Centro de Periodismo Investigativo

The growing invasion of sargassum in the Caribbean has impacted the quality of life of the islands' residents. But local governments and some of their metropolises have so far failed to coordinate an international response to address the problem, which scientists believe is triggered by global pollution, the climate crisis, and a shortage of funds to mitigate it.

In another story from Centro de Periodismo Investigativo, Olivia Losbar writes:

From Poisoning to Skin Diseases: Multiple Effects of Sargassum on Health

In the quiet seaside village of Capesterre on Marie-Galante island in Guadeloupe on April 18, 2023, the air-quality monitoring institute Gwad’Air issued a “red alert” to warn people away from coastal areas. The culprit was sargassum. After washing ashore for days, the floating seaweed was emitting a dangerous level of hydrogen sulfide gas as it rotted on the beach.

[...]

“You know, I love wearing costume jewelry, but now I can’t keep it on my skin for more than a quarter of an hour. They oxidize and make my skin itch. When you see what it does to electrical equipment and metal, you wonder what it does inside your body, to your lungs,” [Guadeloupe business owner Marie-Louise Bade] said.

Thanks to recent research carried out in the French Caribbean — much of which has struggled with similar problems as Marie-Galante — scientists can now better answer that question. They paint a bleak picture. Their studies suggest that the hydrogen sulfide and ammonia gasses released by rotting sargassum can endanger pregnant women, exacerbate respiratory issues like asthma, and cause headaches and memory loss, among other serious health problems. But this knowledge has not been enough to protect Bade and many other Guadeloupe residents.

Even as the French Caribbean has emerged as a regional leader in the fight against sargassum, researchers such as Martinique-based doctor Dabor Resiere have said response efforts there have fallen far short. As a result, many residents regularly face dangerous health risks — and the French government has turned to the world stage to call for an international response to address sargassum as a global problem.

Freeman Rogers at The BVI Beacon tackles the stink of sargassum.

Infrastructure in Decay and Tap-Water Tasting Like Bad Eggs in the British Virgin Islands

Virgin Gorda is known for laidback luxury. It is the second-most populated of the British Virgin Islands (BVI). It boasts swanky seaside villas, a five-star beach resort built by Laurance Rockefeller in the 1960’s, and the billionaires’ yachting playground of North Sound. But in mid-August 2023,Virgin Gorda residents started complaining about the fetid odour of their tap water.

“When you take a shower, you come out smelling like sulphur dioxide — like bad eggs,” construction contractor Christina Yates said at the time.    

The problem was widespread across The Valley, which is home to most of the island’s approximately 4,000 residents. Some said the water burned or gave them a rash when they showered. Others said it killed their house plants when they watered them. And soon, many residents had no tap water at all for hours or days at a time.

As the complaints grew louder, the government offered an explanation that many residents had suspected: Sargassum had entered the intake pipe at the desalination plant that produces most of the island’s public water. This problem had exacerbated longstanding issues with the water distribution system, leading to rationing that cut the supply nearly in half.

María Mónica Monsalve and Krista Campbell at El País explain how the helpful smaller patches of “canopy” sargassum provide in the Sargasso Sea can become a death trap elsewhere. 

A decade of sargassum damage is suffocating Caribbean ecosystems

From Colombia’s north coast to Mexico, corals, mangroves and turtle nests are threatened by the massive influx of floating seaweed

While small amounts of sargassum benefit marine life, the large blooms since 2011 have disrupted the ecological balance in potentially irreversible ways. The algae further stresses Caribbean reefs already threatened by mass coral bleaching due to climate change. Sargassum patches cover up sea turtle nesting sites and overwhelm mangroves, important nurseries for aquatic species. In some areas, beaches have eroded due to algae removal using heavy machinery, with fishermen noting a significant decline in daily catches.

[...]

While floating sargassum can offer a healthy habitat, large amounts onshore can suffocate specific organisms, says James Foley, oceans manager at The Nature Conservancy. “In places like coastal Belize, the issue gets worse because floating sargassum traps a bunch of marine litter — trash from rivers flowing into the Caribbean from Central America. So, it turns into quite a toxic situation.”

Foley explains that floating sargassum acts as a barrier, blocking light and hindering organisms below from photosynthesizing. A 2021 study in Climate Change Ecology examined three bays in Quintana Roo and found that light filtration drops by up to 73% under floating sargassum patches, and water temperatures can rise by up to 5°C (9°F).

Moving into more familiar outlets, Freeman Rogers, Olivia Losbar, Maria Mónica Monsalve, Krista Campbell and Suzanne Carlson took a big-picture look at the sargassum crisis for The Guardian.

Toxic gas, livelihoods under threat and power outages: how a seaweed causes chaos in Caribbean

Leaders have failed to tackle invasion of sargassum, which may have a bumper year in 2024

Schools evacuated due to toxic gas. Smelly tap water at home. Tourist operators and fishers struggling to stay in business. Job losses. Power outages affecting tens of thousands of people at a time. Dangerous health problems. Even lives lost.

Such crises were some of the consequences of sargassum seaweed in the islands of the Caribbean in 2023, which have become common in the region since 2011, when massive blooms began inundating the shorelines in the spring and summer months.

On 18 April 2023 in Guadeloupe, the air-quality monitoring agency Gwad’Air advised vulnerable people to leave some areas because of toxic levels of gas produced by sargassum. Six weeks later, about 600 miles to the north-west, it blocked an intake pipe at an electricity plant at Punta Catalina in the Dominican Republic. One of the facility’s units was forced to temporarily shut down, and a 20-year-old diver named Elías Poling later drowned while trying to fix the problem.

Tom Bayles, of NPR station WGCU, reported on sargassum’s impact on the mainland U.S., providing some interesting data on how large the problem has become.

Sound at sea, sargassum buries beaches and threatens tourism Millions of tons of yellow-brown algae that have been swirling about in a region of the tropical Atlantic known as the Sargasso Sea are now breaking loose and landing on Florida shores

The Great Atlantic Sargassum Belt was coined by scientists about the same time that oceanographer Ajit Subramaniam, who has run scientific research expeditions in the South Atlantic for 25 years, is credited for first coming across the endless blotches of sargassum in 2018 during one of his expeditions.

It has been growing at such a rate as to alarm scientists. Two years ago, the Great Atlantic Sargassum Belt grew to a combined 24.2 million tons — about four times the weight of the Great Pyramid of Giza — and it was recognized as the largest macroalgae bloom in the world.

After the sargassum died back that winter, it regrew in 2023 to a swath that stretched some 5,000 miles long and 300 miles wide, extending from West Africa to the Gulf of Mexico and weighed in at some 13 million tons.

Tourism, of course, is a major source of revenue across the Caribbean and Florida, and sargassum-covered beaches understandably aren’t appealing to visitors.

In another collaboration, Suzanne Carlson of The Virgin Islands Daily News and Rafael Díaz from the Center for Investigative Journalism explain how the costs of containment and removal too often fall on the local resorts.

Caribbean resorts, tourism operators pay high price for sargassum

The 2023 sargassum season started early at the Bolongo Bay Beach Resort on St. Thomas in the United States Virgin Islands. Around the end of March, staff launched the response system they have devised over the years in the absence of any official guidance from the government: hand-raking the beaches and spreading the seaweed to dry on the grounds of the 65-room property, which is nestled in a cove on the southern side of the island of about 50,000 people.

As usual, the family-owned resort had to foot the full bill for the response.

It is not alone. Without a national sargassum management strategy or a dedicated pool of funding from the V.I. government, the financial burden for cleaning the shorelines in the territory has often fallen squarely on resorts, yacht charterers and other tourism operators.

“We’re in the millions of dollars being spent on mitigation over the last decade,” said Lisa Hamilton, President of the V.I. Hotel and Tourism Association. Often these costs come on top of lost revenue as tourists increasingly select their vacation destinations to avoid affected beaches.

There are groups attempting to find uses for the seaweed.

As the Caribbean News Service reports:

Field trials on the horizon for Sargassum-derived fertilizer

The Sargassum-derived plant growth enhancer will be tested on crops such as tomatoes, watermelons, and sweet potatoes

A multi-country mission to monitor progress with the regional Sargassum Products for Climate Resilience Project, funded by the New Zealand Ministry of Foreign Affairs and Trade, has recently concluded. Representatives from the Caribbean Regional Fisheries Mechanism (CRFM) and the New Zealand Institute for Plant and Food Research Limited (PFR) met with key partners in Barbados, Trinidad and Tobago, and Jamaica in February and March 2024, to review progress and plan future activities.

Based on the successful outcome of recent scientific studies and greenhouse trials for a Sargassum-derived liquid fertilizer, the partners will commence field trials within the next few weeks. These efforts, which will be advanced in collaboration with the Caribbean Agricultural Research and Development Institute (CARDI) and regional private sector partners, signal promising progress towards valorization of Sargassum and strengthening the Caribbean’s food security and climate resilience.

“Since the COVID-19 pandemic, the cost of fertilizers has skyrocketed, and farmers across the region need more affordable, high-quality fertilizers to improve their yields, especially in the stressful environment brought about by warmer temperatures and drought conditions. Anything that we can do to improve the supply and reduce costs and dependence on imports will be impactful,” Milton Haughton, Executive Director, CRFM Secretariat, stated.

Here’s hoping that this initiative comes to fruition, and that governments—including our own—will increase efforts to mitigate the damages of the spread of sargassum.

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