Sargassum - Transforming a Coastal Menace into an Industrial Wonder
Sargassum, a genus of brown macroalgae, has become an increasingly significant challenge for coastal ecosystems in the Caribbean, Mexico and Central America due to its rapid and often overwhelming blooms. While floating at sea, Sargassum provides a habitat for marine life and absorbs carbon dioxide, helping to mitigate climate change. However, when it washes ashore (referred to as Sargassum brown-tide—when water close to shore becomes inundated with rotting Sargassum), it decomposes, releasing hydrogen sulphide and ammonia, creating a foul smell reminiscent of rotten eggs. This can drive away tourists, harming the crucial tourism industry that many economies in the region depend upon.
Our Lead Scientist Dr Franziska Elmer, Barbados, 2024
The annual Sargassum cleanup cost across the Caribbean was calculated at US$120 million by Milledge and Harvey (2016) and US$210 million by Davis et al. (2021). Sargassum-filled beaches become anoxic zones, deprived of both oxygen and light, killing off seagrass meadows that normally provide coastal stability during storms. The absence of seagrass has been directly correlated to coastal erosion, which can affect entire villages. Once Sargassum is removed from beaches, it is usually transported inland to landfill sites, where it is left to decompose out of sight. While this may provide a short-term solution, the decomposing biomass releases fluids containing heavy metals, which leach into underground aquifer systems, contaminating limited fresh water supplies. The overall toll across local communities, tourism, politics, and public health is overwhelming and requires a drastic solution.
However, innovative industries are beginning to recognise that Sargassum can be more than just a nuisance. It is now being transformed into a valuable resource for sectors such as construction, agriculture, and energy (through biofuel production). This blog explores the various applications of Sargassum, turning it from a coastal menace into an industrial asset.
Applications in Sustainable Construction
One of the most promising applications for Sargassum lies in sustainable construction materials, particularly eco-friendly cement and building components. Due to its fibrous structure and high mineral content, Sargassum offers a sustainable alternative to traditional building materials.
Sargablock, a project in Mexico, has pioneered methods to create Sargassum-based bricks and other construction materials. By incorporating 40% Sargassum with other organic materials, the project tackles the excessive influx of seaweed while promoting low-cost, sustainable building solutions for local communities. Their process can produce 1,000 blocks per day, which dry and are ready for use after just four hours in the sun. Another initiative, Sargacreto, also based in Mexico, is developing similar materials. These innovative approaches are proving that Sargassum can play a role in addressing local housing shortages while mitigating environmental damage.
Sargassum as a Natural Biostimulant in Agriculture
Sargassum is also gaining recognition in agriculture as a natural biostimulant. Rich in trace minerals, growth hormones, and bioactive compounds, liquid Sargassum extracts can enhance plant growth, improve soil health, and increase crop yields without synthetic chemicals. This is especially valuable for organic and regenerative farming practices.
Sarga Agriscience, powered by one of our partners, Carbonwave, is leading the development of Sargassum-based biostimulants. By processing the seaweed into liquid fertiliser, they have developed a product that significantly improves plant health and resilience. Sarga Agriscience biostimulant has proven effective for crops such as maize, tomatoes, and grapes, contributing to increased yields and healthier soils. Carbonwave’s products are increasingly popular with farmers seeking sustainable alternatives to chemical inputs. In trials, farmers reported crop yield increases of up to 15% when using Sargassum-based fertilisers, showing its potential to improve agricultural productivity.
Sargassum for Biofuel Production
Sargassum is also emerging as a promising feedstock for biofuel production. Its high carbohydrate and lipid content makes it suitable for conversion into bioethanol and biodiesel, contributing to renewable energy goals. This transformation turns a waste problem into an energy solution, particularly in regions heavily affected by Sargassum blooms.
Macrocarbon, one of our partners, offers an efficient approach to cultivating and processing seaweed for industrial use, and ultimately establish sustainable biomass value chains worldwide. Additionally, MacroFuels, a European research project, has explored the use of macroalgae, including Sargassum, for biofuel production. Their research shows that macroalgae can be converted into bioethanol and other fuels, presenting a viable alternative to fossil fuels. By transforming Sargassum into biofuel, regions facing the environmental burden of the blooms can turn this challenge into a valuable energy resource.
Industrial Potential of Sargassum
Expanding Sargassum's Industrial Applications
Beyond construction, agriculture, and biofuels, Sargassum is being explored for numerous other applications, including:
Cosmetics: Carbonwave has launched SeaBalance, a Sargassum-based oil-in-water emulsifier with applications in high-end cosmetics, replacing harmful synthetic ingredients.
Pharmaceuticals: Research is ongoing into Sargassum's bioactive compounds, which show promise for antiviral and antimicrobial agents.
Bioplastics: Carbonwave and Macrocarbon are working on biodegradable plastics made from Sargassum, offering a sustainable alternative to petroleum-based plastics. There are also some fantastic companies creating plastics from various strains of Seaweed, such as ZeroCircle, NotPLA, SwaytheFuture, Loliware, OriginbyOcean and others.
Vegan Leather: Carbonwave, is currently developing vegan leathers. The plant-based fabrics rely on the extraction of structural seaweed polymers to form films stronger than the seaweed itself. These textiles are competitive with other vegan textiles, without relying on polyurethane (PU) plastic for structure and strength.
Biochar: RubisCO2 and MacroCarbon are both exploring the use of Sargassum as biomass for biochar, a sustainable solution for agriculture and carbon sequestration. Biochar made from Sargassum can help improve soil health while storing carbon, aiding in the fight against climate change. Seafields is building partnerships with these companies to supply them with Sargassum biomass for biochar, which can then be used to generate carbon credits.
Seafields' Role in Tackling Methane Emissions
At Seafields, our goal is to scale up our farms across the Caribbean region, establishing key partnerships with hotels and coastal communities to tackle Sargassum influxes. Our farms are committed to providing our partners with a consistent fresh feedstock of Sargassum, enabling the production of eco-friendly products while also managing the seaweed's impact on tourism and coastal environments. We have successfully tested our pilot farm, where we deployed our innovative barrier technology to contain live Sargassum effectively, ensuring a year-round fresh supply for our partners.
In addition to providing a feedstock, Seafields is focused on tackling methane emissions by intercepting and managing Sargassum before it decomposes on beaches. By intercepting and catching Sargassum at sea using floating barriers and our innovative paddocks, Seafields prevents its decomposition, significantly reducing methane emissions. Decomposing Sargassum is known to release significant amounts of methane, a greenhouse gas 28 times more potent than CO2 over a 100-year period.
Seafields Sargassum Paddock - St.Vincent
Economic Potential and Community Impact
The economic potential of Sargassum-based products is vast. Estimates suggest that the market for biofuels alone could reach billions, particularly as the world shifts towards renewable energy sources. The construction industry, with its increasing demand for sustainable materials, could also benefit from Sargassum-based products like Sargablock and Sargacreto. Furthermore, the use of Sargassum in bioplastics and cosmetics offers opportunities for job creation and economic growth in coastal communities that have been hardest hit by Sargassum blooms.
With ongoing research and investment, Sargassum has the potential to play a critical role in global sustainability efforts, addressing challenges in various industrial sectors. By turning these menacing Sargassum influxes into an industrial asset, Sargassum could and should become an essential part of our future sustainable economy.