Source: SOS Carbon.
Sargassum spp., commonly known as sargasso or sargassum, is a brown macroalgae primarily formed in the Atlantic Ocean, in the so-called “Sargasso Sea,” which is ravaging Caribbean coasts. The massive amounts of sargassum that reach Caribbean coasts have reduced marine biodiversity, formed anoxic zones, released toxic gases and pollutants, and costed countries millions of dollars in economic and tourist losses, among other impacts. The excessive growth of sargassum blooms is due to a variety of factors, such as rising ocean surface temperatures and increasing chemical spills from human activities like agriculture. Most recently, an almost 9,000-kilometer-long belt containing 10 million tons of sargassum made headlines because of its potential to cover the entire Caribbean and some U.S. coasts, like Florida. Nonetheless, with proper management, the growing presence of this nuisance macroalgae can present an opportunity by transforming it into a raw material for value-added products.
In recent years, the algae market has grown significantly. Today, Transparency Market Research estimates the global value of the algae market at $20 billion, and they expect it to exceed $50 billion by 2031. Yet, this market faces challenges because cultivating algae raises the costs of the final products and represents a significant, lingering issue for many producers. Luckily, Caribbean sargassum does not bear these added costs, since it is a natural residual material, that can be directly harvested and processed, while retaining all the commercial possibilities of cultivated algae. As a result, residual sargassum is the ideal raw material for establishing valuable ocean harvesting, processing, transformation, and commercialization industries to benefit the region and the entire world.
Sargassum collection could create thousands of jobs by harvesting this macroalgae from the sea while it is fresh and sand-free. Additionally, sargassum management could generate many other formal jobs such as collection equipment manufacturing and repair, ground transportation, and raw-material management. Furthermore, sargassum processing and transformation are already promoting research, developing new commercial products, and establishing industrial treatment and handling plants. Finally, the commercialization will include both selling sargassum as a raw material and products derived from it. These opportunities present Caribbean economies with the added benefits of reducing the importance of imports, enabling the region to become global exporters, and propelling socioeconomic development. The fields of application of this macroalgae as a raw material are extremely wide. Several studies have shown that sargassum can be transformed into livestock feed, cosmetic products, a synthetic fertilizer substitute, biofuel and biogas, a synthetic plastic replacement, a construction material, and fabrics (Figure 1).
Sargassum has the potential for many uses for animals and humans alike. Due to the components present in this alga, such as vitamins, fatty acids, and minerals—sargassum could be an important supplement in animal feed to increase the productivity and efficiency of dairy cattle. Other algae studies have also shown that supplementing animals with these components can reduce methane emissions or cholesterol in the eggs because these compounds increase the metabolism efficiency, resulting in less residue generation. Nevertheless, its use as a food and supplement is not limited to cattle; it is also good for humans. Once again, its high concentration of various compounds and secondary metabolites makes it a raw material of high nutritional value, with properties such as bone regeneration, anti-inflammatory, antiviral, antioxidant, anti-angiogenic, anti-cancer, or hepatoprotective. It is also ideal for the creation of cosmetic compounds. Another potential application is as a biostimulant. As mentioned earlier, agricultural fertilizers are one of the major sources of ocean discharges. Every year, farmers dump more than 40 million tons of fertilizer into the ocean. Eliminating the use of fertilizers is extremely complex, but there is the possibility of finding sustainable and environmentally safe alternatives. The amino acids, polysaccharides, phytohormones, and phenols found in sargassum extracts have been shown to have eliciting and biostimulant properties, making crops more resilient to unfavorable external factors (lack of water, high temperatures, deserted substrates, etc.), in addition to increasing crop productivity.
Furthermore, due to the large sargassum quantities that arrive and are available, sargassum management organizations can supply more than one application, and many of the industrial processes for transforming sargassum into these commercial products are compatible, as they demand different compounds of interest, so the same amount of sargassum can cover multiple sustainable exploitation options. In the field of biofuels, research has proven sargassum can be used to create biogas, biofuel, and biodiesel—which could imply a breakthrough in the energy industry. In the field of construction, sargassum has already been used as a test for the creation of bricks and blocks, and in the textile world, there is the possibility of making shoes and clothing fabrics from this macroalgae.
The collection and transformation of sargassum also offers the potential to generate carbon credits. Although sargassum is a CO2 sink, when it makes landfall it starts decomposing and rotting, releasing CO2, methane, and other greenhouse gases into the atmosphere. If the sargassum is properly collected at sea and used as raw material, it never gets the chance to decompose, thus avoiding such emissions. Research suggests that each ton of dry sargassum collected prevents the emission of 0.15 to 0.45 tons of CO2. Therefore, sargassum offers many carbon sequestration opportunities, which involve promising methods to scale at the gigaton level to accelerate climate action and sustainable development goals (SDGs).
The climatic and environmental changes that the planet is undergoing are enormous. And the oceans, the source of life on Earth, are particularly endangered. Deteriorating oceans, in turn, harm the most vulnerable communities, putting their stability in danger. Thus, the sargassum crisis has the potential to become a negative-feedback loop. However, if we change our perspective and apply the principles of blue biotechnology and circular bioeconomy to support research and development, countries can transform the sargassum challenge into solutions that generate value chains from the environment and for all socioeconomic groups.
Flipping the script is possible because opportunities abound. Now we must ask ourselves what each of us can do to contribute and propel regional and global solutions.
Elena Martínez Martínez is the Research & Development Lead for SOS Carbon. She holds a BS in Marine Science from Universidad de Vigo (Spain) with an exchange at the Universidad Autónoma de Baja California (Mexico) and two MS’ in Applied Blue Biotechnology from Université de La Rochelle (France) and from Universidad Católica de Valencia (Spain). Currently, she is doing an Industrial Ph.D. program in Biotechnology & Biomedicine together with SOS Carbon and the Universidad Católica de Valencia. Elena has worked in several R&D projects related to marine biotechnology, algae, and circular bioeconomy.