Author: Jhayrise Coppin — Staff Writer
Date: July 29th, 2025
Since 2011, sargassum seaweed, due to shifting ocean currents and an increase in coastal pollution, has been experiencing episodic "blooms" in the Atlantic Ocean. Sargassum, as its own organism, has ecological importance in its original ecosystem. It contains a slew of nutrients, minerals, and microorganisms that can foster and even accelerate plant growth, such as iron, magnesium, potassium, calcium, and more. Unfortunately, due to the overproduction of these blooms, sargassum now threatens already struggling coastal environments such as coral reefs, mangroves, and seagrass beds. The seaweed physically covers coral reefs and limits the amount of oxygen in the water. These ecological changes also affect local fish and their living patterns.
When sargassum emerges from the sea, it has a light color, but it oxidizes once exposed to air and takes on its more familiar brown algae appearance that has plagued beaches throughout the Caribbean. While not aesthetically pleasing, decomposing sargassum produces toxic gases including ammonia and hydrogen sulphide. Ammonia gas is responsible for the rotten egg smell associated with sargassum. Beyond the unpleasant odor, the gases released by the algae are hazardous to human health, resulting in respiratory illnesses.
Sargassum seaweed has now become a yearly problem for Barbados, especially during the hot summer months, causing significant issues for the island's tourism and fishing industries as well as its coastal environment. With most of the coasts of Barbados—East Coast (Consett Bay), North Coast (River Bay), South Coast (Oistins, Skeete’s Bay)—being affected, it is not an exaggeration to say that the overproduction of sargassum blooms is an island-wide concern. Sargassum's unappealing color deters tourists from visiting Barbados' famous white sand beaches, further impacting businesses that rely on tourism revenue.
Barbados has implemented many management efforts to curb the sargassum blooms. An official Sargassum Seaweed Removal Programme was launched, deploying teams to clean up the seaweed from beaches. Overall, while sargassum poses a challenge, Barbados is actively working to address the issue through various strategies and innovations—such as composting sargassum or using it as biogas for vehicles. However, while some methods might prove innovative, others may become problematic if the wrong method is chosen hastily. One such method is using sargassum as fertilizer—a seemingly simple solution: collect the sargassum from the beach and turn it into fertilizer for local Barbadian crops. A win-win, as the beach gets cleaned up and a new organic source of fertilizer is discovered. But considering the fertilizer is related to consumables, we should err on the side of caution and conduct rigorous tests.
One study found that while sargassum seaweed contributed to an increase in soil nutrient content—specifically nitrate nitrogen and phosphorus levels—certain parameters associated with plant growth performance, including plant height, leaf count, and bud count, appeared to be adversely affected. Another study showed that sargassum fertilizer increased arsenic levels in plants.
The health implications stemming from these results remain ambiguous. In its 2010 report, the EFSA Panel on Contaminants in the Food Chain (CONTAM) asserted that no "safe" levels of arsenic are defined, highlighting that prolonged ingestion of inorganic arsenic has been linked to a range of health issues, such as skin problems, cancer, cardiovascular diseases, and diabetes. Further research is required to fully comprehend the implications of elevated heavy metal levels and the potential long-term effects associated with their consumption.
As the occurrence of sargassum influxes becomes more frequent, both nations and individuals will likely explore innovative methods for utilizing and disposing of this material. Until we have a better understanding of the health concerns, it would be prudent to restrict the use of sargassum to non-consumable applications. This means using sargassum as a construction material, biofuel, or—if used as fertilizer—only for ornamental plants.