In the summer of 2018, a large (and fascinating) band of brown algae popped up in the Atlantic – it stretched from coast to coast, from West Africa to the Gulf of Mexico.
At 8,850 kilometers, the seaweed bloom known as the “great seaweed belt (Sargassum) of the Atlantic” was the largest ever recorded.
Researchers analyzing satellite imagery estimated their mass to be more than 20 million tons – heavier than 200 fully loaded aircraft carriers.
Although the 2018 event was a record, the spread of seaweed in the Atlantic has been a nuisance for several years as it affects coastal biodiversity, fishing and the tourism industries in the Caribbean and Mexico. For example, Barbados declared a state of emergency in June 2018 after its coast was taken over by the Sargasso.
And it’s a problem that seems to be getting worse in the Atlantic. After analyzing 19 years of satellite data, researchers from the University of South Florida, USA, found that Sargasso flowers have been taking place and increasing in size every year since 2011.
“2011 was a turning point. We didn’t see much seaweed before. After that, we see huge and recurring algal blooms in the central Atlantic,” says Mengqiu Wang of the University of South Florida, one of the team members who discovered the spread of algae in the Atlantic Year 2018. According to her, the flowering is greatest in June and July.
Other researchers like Elizabeth Johns of the US National Oceanic and Atmospheric Administration agree that 2011 was a tipping point for seaweed in the Atlantic, suggesting future blooms are likely to be even larger.
In fact, a research vessel in the Caribbean recorded sargasso concentrations ten times higher in the fall of 2014 than in the 2011 episode – and 300 times more than any other fall in the past 20 years, according to research by marine scientist Amy Siuda and her colleagues at the Sea Education Association ( SEA) of the Woods Hole Oceanographic Institution in Massachusetts, USA.
Although the exact causes of the proliferation have not yet been discovered, Wang’s team believes a number of environmental factors contributed to the Sargasso explosion. Including ocean currents and abnormal wind patterns related to climate change.
The destruction of the Amazon rainforest is also believed to have fueled the growth of Sargasso. When large parts of the rainforest are cleared, they are replaced by heavily fertilized agricultural land.
The fertilizer ends up in the Amazon and eventually the Atlantic, where it floods the ocean with nutrients like nitrogen. Records show that during the major 2018 bloom in the central Atlantic area where Sargasso is growing, there was higher nutrient levels compared to 2010, Wang adds.
Distributed in open water, the seagrass – sometimes referred to as the “floating golden tropical forest” – serves as an important nursery for baby turtles and as a refuge for hundreds of species of fish.
The problem arises when the kelp reaches the beaches and begins to rot, releasing hydrogen sulfide – a gas that smells like rotten eggs.
“There is good vegetation in the sea, but it becomes bad on the beach,” explains Wang.
The strong smell and unpleasant appearance drive tourists away from beach resorts in the Caribbean and on the Mexican Yucatan peninsula – a severe blow to the region’s economy, which is heavily dependent on tourism.
In 2018, Laura Beristain Navarrete, mayor of the coastal city of Playa del Carmen, Mexico, told a local newspaper that the number of tourists in the area had decreased by up to 35% because of Sargasso.
Removing algae from beaches is an expensive and time-consuming process. In 2019, Mexican President Andrés Manuel López Obrador estimated the cost of cleaning the entire Sargasso this year to be $ 2.7 million – and urged the country’s Navy to help.
In addition to having a disastrous impact on tourism, Sargasso is also a public health issue, according to Wang. When it collapses, it attracts insects that can cause skin irritation. Exposure to hydrogen sulfide has been linked to neurological, digestive, and respiratory symptoms.
Stranded algae also pose a serious threat to marine wildlife. Huge piles of algae prevent turtles from building nests and from catching dolphins and fish on coral reefs.
“Sargasso can suffocate coral reefs by covering them and decimating turtle pools,” says Mike Allen, a marine researcher at the University of Exeter in the UK who has developed an inexpensive way to convert sarcasm into sustainable biofuels and fertilizers.
Allen and a team of researchers at the Universities of Exeter and Bath, also in the UK, developed a process called hydrothermal liquefaction (HTL), which breaks the moist biomass into four components under high pressure and temperature.
They are: a bio-oil that can be converted into biodiesel; water-soluble organic compounds for making fertilizers; Carbon dioxide (which the researchers say they want to capture instead of releasing it into the atmosphere); and coal, a solid material that contains all of the metals present in the algae that the team intends to reclaim in the future.
“I compare that to geology in a can,” says Allen.
“Since the pressures and temperatures are very high, we can put almost anything there. We can convert plastic together with biomass [de sargaço] in the same process, “he adds. That is, the nylon fishing nets entangled in the coral reefs are also converted into fertilizers.
There are some drawbacks, however. The process uses a lot of energy and works on fossil fuels, says Allen, although the heat from the process can be recovered and reused to improve efficiency.
The project is still at the research stage and researchers have converted 100kg of Sargasso so far – but Allen hopes to expand it and work with businesses and governments to resolve the problem. The aim is to find a solution to the Sargasso problem that is economical and supports the local community.
“We try to make cleaning contaminated areas profitable so that there is an incentive to do so, improve the quality of life and protect the environment,” explains Allen.
In parts of Mexico and the Caribbean, local residents are taking matters into their own hands and looking for innovative ways to turn the environmental disaster on their shores into a sustainable economic opportunity.
Some turn the algae into paper, others into building material. In Playa del Carmen, one of Mexico’s most popular travel destinations, a community group is fighting the Sargasso invasion by turning it into soap.
The Biomaya Initiative, an organization created to deal with excess seaweed, hires residents to collect the smelly algae from the beaches and then clean them up to remove metals and plastics.
Next, women who live in nearby Mayan-era villages mix the processed seaweed with glycerin and honey to make soap – and sell the bar to hotels, hospitals, and stores in the area for $ 2.
“As a community, we have decided to protect the planet and take care of our beaches,” says Gonzalo Balderas, founder of the Biomaya initiative.
According to him, over the past three years the number of tourists has decreased due to the Sargasso in Playa del Carmen.
“It should be a dream beach.”
In St. Catherine’s, a coastal community in southeast Jamaica, Daveian Morrison uses seaweed to make animal feed. Morrison founded Awganic Inputs in 2018 after hearing reports of Sargasso piled 4 feet high on the beaches.
“It affects local tourism, recreational activities, and suffocates fish and baby turtles,” says Morrison.
“I thought it was time to act.”
Morrison wanted to solve two main problems in Jamaica: Sargasso and the lack of affordable feed for goats, a local delicacy. The country currently imports $ 15 million worth of mutton and goat meat each year.
“Our goats look very thin because they don’t use enough minerals. Sargasso has a lot of nutrients, minerals and salt,” he explains.
Awganic Inputs buys seaweed from local scavengers and dries, cleans, and grinds the seaweed while it is still fresh before mixing it with harvest by-products to make goat feed. The lazy Sargasso, on the other hand, is converted into charcoal and sold for use in cosmetics. She recently ran a pilot project converting 544 kg of seaweed into goat feed and selling it to farmers for $ 0.26 per kilo. According to Morrison, the response was very positive.
Although the coronavirus pandemic has crippled production for the time being, he hopes to ramp up his production and sell cheap sargasso forage across Jamaica next year.
“A lot of people see Sargasso as annoying,” he says. “And they are glad that something is being done with it.”
These overgrowth control efforts are undoubtedly small compared to the gigantic crumbling hills on the Atlantic beaches.
Goat feed, soap, and biofuels won’t make much of a difference in these heaps anytime soon, but they are a sign of the resilience of the coast – and the adjustment of the local economy to turn a putrefaction scenario into something useful, no matter what the Throwing oceans on the beaches.