Mexico has an Exclusive Marine Economic Zone of 3.15 million km² (Silva et al., 2014). Bioprospecting, i.e., the systematic search for natural components or organisms for the development of products, with applications in the pharmaceutical, biotechnological, agronomical, cosmetic, or bioremediation industries (Bhatia and Chugh, 2015), is amongst the economic activities in this zone. Such bioprospecting has been carried out on sixteen seaweed species found along the Mexican Atlantic coast (Ortega et al., 2001); however, pelagic Sargassum spp. (sargasso from now on) were not amongst them; as until 2014, its landings were sporadic, and of low to moderate biomass (Godínez-Ortega et al., 2021). The origin of the sargasso landings used to be the Sargasso Sea [see Figure 1, modified from Putman and He (2013)], but from 2011 the Great Atlantic Sargassum Belt began to form. Although the total estimated biomass in this new area of sargasso concentration was small at first (less than three million wet tons in total), it has increased over the years, reaching a maximum of 20 million wet tons of seaweed in June 2018 (Wang et al., 2019; see Figure 1).

The periodic arrival of millions of tons of sargasso masses on the shores of the Caribbean has caused alterations in the environment (Smetacek and Zingone, 2013; van Tussenbroek et al., 2017; Chávez et al., 2020), with social and economic consequences that have affected the tourist industry in particular (Chávez et al., 2020). The increasingly massive influxes arriving on the Mexican coast could be seen as an opportunity to develop products with added-value. Initially, there was uncertainty as to whether the influxes of sargasso would recur; at present it is generally accepted that periodic massive sargasso inundations on the shores is the new “normal,” and that adaptation and mitigation strategies must be developed (e.g., Oxenford et al., 2021), including the commercialization of sargasso. The hypothetical commercial value of sargasso is becoming increasingly recognized, and many local communities throughout the Caribbean are becoming aware of its remarkable potential (Desrochers et al., 2020). Bioprospecting and subsequent commercialization of sargasso could potentially cover the costs of removing it near to the shore or on beaches, thereby mitigating their impacts on the environment (Silva et al., 2016; Chávez et al., 2020; Robledo et al., 2021; Thompson et al., 2021).

The systematic search for economically valuable products is based on the scientific study of biological samples. This “added-value approach” goes alongside developments in laws on intellectual property rights, environmental protection (e.g., to avoid overexploitation), new bio-rational approaches for specimen collection, as well as product development (Scott, 2001). The ocean is currently being “re-discovered” for bioprospecting, attracting stake holders who were previously oblivious to the sea. Although the ocean has been extensively used for a range of purposes throughout human history, it is still often perceived as “no man’s land,” or “Mare Nullius,” with resources “for free” (Bennett et al., 2021). Marine, or blue, biotechnology is becoming a blue bioeconomy, which includes prospecting for macro-algae, such as sargasso (Golberg et al., 2020).

The sargasso bloom that created the Great Atlantic Sargassum Belt affects many countries across and territories the wider Caribbean, equatorial Brazil, and part of the west coast of Africa. However, the severity and nature of the environmental, and socio-economic impacts differ according to the geographic region (UNEP-CEP, 2021). The Caribbean has numerous political entities, varying from small island states to larger territories with considerable stretches of coastline; these territories also have different levels of development as well as different levels of dependence on resources from the sea, such as livelihood/sustenance, fishing industries, or tourism. The UNEP-CEP (2021) identified that the socio-economic impacts of massive sargasso beaching depend on:

The Mexican Caribbean has a coastline of >800 km, which has received sargasso yearly average volumes of 3.2 × 10³ and 1.7 × 10³ m³/km/month in the peak years, 2018 and 2019, respectively (Chávez et al., 2020). In this manuscript, we describe the massive beaching, harvesting, and commercialization efforts in Mexico, together with thoughts on the legal constraints and possibilities for the regulation of these efforts. It is hoped that the experiences in this part of Mexico may be adapted and applied elsewhere. Together with an improved understanding of the constraints and possibilities of sargasso management in other countries would facilitate coordinated management of this transboundary bloom.

Cost-effective management of sargasso demands spatially explicit information on where this alga mostly accumulates for efficient collecting, and for optimizing storage and primary processing, which ideally takes place near areas with regular mass landings, to reduce transport costs. We used remote sensing techniques to obtain the spatial distribution of frequent sargasso landings on a regional scale.

Satellite images were used to observe sargasso accumulations along the Mexican Caribbean coastline, from Cancun to the Sian Ka’an Natural Reserve. The sargasso cover was estimated in hexagonal lattices of 2 km diameter, using Landsat 8 OLI imagery from 2016 to 2019. The presence of sargasso was detected following Cuevas et al. (2018), with a temporal resolution of 16 days between images. The prevalence (number of days that sargasso accumulations were detected in a hexagon as a percentage of the total number of observed days in that hexagon), cumulative sum (the sum of hectares covered by satellite where sargasso was detected in a hexagon, considering all the processed images from 2016 to 2019), and variability of sargasso (standard deviation of the satellite detected sargasso cover in a hexagon over the study time) were calculated for each of the hexagons. Jenks-natural breaks method was used to classify the hexagons in terms of sargasso presence (Table 1).

The central part of the coastline studied, between Tulum and Puerto Morelos including Cozumel Island, almost always had large aggregations of sargasso during the periods of influx [usually from March until October (García-Sánchez et al., 2020)], although the variability in the amounts was high (class 4, red areas in Figure 2B). This part of the coastline which receiving most sargasso represents ≈20% of the coastline, with a length of ≈90 km. The remaining ≈80% of the coastline studied received smaller volumes of sargasso, but with a high prevalence and low variability (class 2, orange areas in Figure 2B), distributed in a relatively narrow strip (30 km width). Further offshore, medium-size patches with low prevalence (class 3, purple areas in Figure 2B) were detected, with a certain concentration in the sea to the west and southwest of Cozumel Island. Finally, class 1 (light yellow areas in Figure 2B) relates mainly to oceanic waters (but also includes a small part of the coast, south of Tulum) where large accumulations of sargasso do not occur. Most sargasso further offshore is probably transitory and does not reach the Mexican shore. Thus, open ocean harvesting of sargasso in the northern part of the Mexican Caribbean may be undesirable; the sargasso does not form large concentrations in fixed areas, and they are likely to stay in the ocean to be carried away, north, by the Yucatan Current.

The large variability in the sargasso landings poses a challenge for near-shore harvesting or collection from the beaches. Planning for seasonal variability may be possible to a certain degree, although the enormous interannual variations mean that planning and logistics for the acquisition, temporal storage and maintenance of machinery, as well as the contracting of workers, is more difficult. For example, the interannual irregularity of the influx produces maintenance costs for equipment in non-sargasso years, which should be included in determining viable business scenarios. Oxenford et al. (2021) have already stated that the irregular supply of sargasso is a major challenge for the valorization of sargasso on an industrial scale. The overall amount of sargasso available as a raw material for industrial development cannot be guaranteed. To overcome the irregular supply and provide a supply of the raw material in years of low influx, harvested sargasso could be stored (at a cost) or sargasso could be cultivated (at a higher cost, probably).

A biorefinery is a facility for processing biomass in a sustainable way to obtain a spectrum of high added-value products and bioenergy (Balina et al., 2017). The products with the highest added-value are obtained first, and the solid residues generated at the end of the process are used for the production of bioenergy, such as biogas and biochar. The aim of this cascade approach is that waste from the biorefinery is minimal (Rajak et al., 2020).

Brown seaweeds, including sargasso, are generally rich in polysaccharides (30–50% dry weight), and contain practically no lignin (Yanagisawa et al., 2013), in contrast to lignocellulosic biomass that comes from plants (Zoghlami and Paës, 2019), making extracting the polysaccharides easier. This feature, along with the faster growth rates of seaweeds compared to plants, has positioned macroalgae as an appropriate feedstock for biorefineries. The trend is to develop new and simple bioprocesses that allow a combination of high added-value products to be recovered, not just one product. For example, a fucoidan, with health benefits and nutritional benefits, could be placed in the market as one product (Lange et al., 2020). To achieve this, new biotechnologies specifically designed for macroalgae must be developed.

In a sargasso-based biorefinery at least two conversion processes could operate, depending on the end products it seeks to deliver: chemical conversion to extract alginates and fucoidans, and biological conversion to produce bioenergy. Operational units such as grinding, heating, decanting, solvent extraction, and centrifuging would be indispensable for extracting the value-added products in the first step, and the final solid residue could be used for biogas production (Flórez-Fernández et al., 2021). Another option could be to extract the sugars through saccharification and use them for other purposes (Davis et al., 2020), such as ethanol production; in that case, a fermentation step is required, and the operational units necessary for recovering ethanol. In this option, an anaerobic digester would also be necessary to convert the final residues into biogas (Figure 9). Although the total carbohydrate content of sargasso could be around 11% (Desrochers et al., 2020), the composition of the polysaccharides may differ between morphotypes of S. natans and S. fluitans (Davis et al., 2020). Saccharification, using the enzymes Cellic CTec2 (developed for lignocellulosic biomass) and a generic amyloglucosidase, releases galactose, glucose, and mannose from sargasso (Davis et al., 2020), which are key intermediaries for producing biofuels. Various companies or consortia in Mexico are exploring biorefinery of sargasso, such as Creamos Más S.A. de C.V. (Creamos_Más, 2020) and Metco (2021). Currently, in Mexico, there are no reports of integrated biorefineries based on sargasso that produce and commercialize high-added value products, biofuels, and other side products such as animal feed, plant stimulants, and soil improvement products.

In the evolving regulations concerning natural resources and waste in Mexico, three legal perspectives are possible concerning the valorization of sargasso: (1) as a natural resource (focusing on the ecosystem services it provides); (2) as a raw material (focusing on its extraction and transformation); (3) as waste (unclaimed beached sargasso, i.e., once beached, or destined to arrive on a beach).

When sargasso is considered a natural resource, found in the sea, it should be regulated by constitutional provisions [e.g., (DOF, 2021a, b, c, d), see Supplementary Material 1], under the federal jurisdiction of the Secretaría de Marina (the Mexican Navy). When it is considered a raw material, the Comisión Nacional de Pesca (the Ministry of Fisheries) should be the federal body with the responsibility of overseeing its exploitation.

Before sargasso can be employed as a raw material for products, it needs to be stored temporally. When it is not to be used for any purpose, it must be disposed of properly. The state government has the legal responsibility for the temporal storage or disposal of sargasso, unless it is considered as a hazardous waste. Sargasso contains heavy metals [e.g., arsenic (Rodríguez-Martínez et al., 2020)] and other toxins [e.g., chlordecone, (Devault et al., 2021a)]; if these levels are excessively high, sargasso may be considered hazardous waste and becomes subject to federal regulations. The federation would also be responsible for the (decaying) beached sargasso, which at present is cleaned by municipalities and concessionaries of the beach sections (see above). However, this potential toxicity should be further studied; although the concentrations of toxic elements may be too high for certain uses, they may be below the levels of hazardous waste.

To regulate beached sargasso as a potential resource (when collected from the beach or nearshore waters with barriers), it is best categorized as a “waste requiring special treatment” from a legal perspective, even though it may appear contradictory to consider a potential resource as a waste. The main problem in viewing beached sargasso as waste, is that the regulations concerning its management stipulate that the generator is the owner of the waste, and since no specific individual/legal entity is identified as owning or responsible for the generation of sargasso, it must be seen as “orphan waste.” As such, the Mexican federation is responsible for the regulation of this waste in all its facets: from the management of its contamination effects and potential damage to human and ecosystem health to establishment of comprehensive, circular management processes, including valorization.

Therefore, a National Strategy for the Use of Sargasso must be developed, to handle the processing cycle of sargasso from a regenerative approach, using biopolitical indicators founded on scientific evidence, rather than relying on purely administrative decisions (Pantoja, 2020, 2021). Examples of such biopolitical indicators are the climatological models and indicators of environmental vulnerability (e.g., to droughts and floods), implemented to assign microcredits from green funds to compensate for climate change, and the program for the temporary regularization of migrants from countries affected by natural disasters in the United States (Bolaños Guerra, 2018).

Recent reports (Oxenford et al., 2021; Robledo et al., 2021) have already highlighted the general challenges in the valorization, and industrialization of sargasso in the Caribbean. A strengths, weaknesses, opportunities, and threats (SWOT) analysis helps to identify the strengths, weaknesses, opportunities and threats related to the commercialization of sargasso in Mexico (Figure 10).

The strengths are: (1) the long coastline receiving enormous quantities of sargasso, which allows for valorization/commercialization on an industrial scale; (2) the need deter ecological, economic and social disaster through harvesting/collecting and disposing of sargasso in any possible way; (3) the potential of finding solutions through the ongoing development of sargasso-based products by the academic sector and entrepreneurs.

Weaknesses include: (1) the unpredictability of how much sargasso can be expected to arrive each year; (2) the lack of norms and regulations for the harvest, transport, and exploitation of sargasso. Such regulations are also essential to guarantee legal certainty for investors; (3) the lack of a comprehensive approach to the valorization of sargasso. At present there is no, or insufficient, coordination among academic institutions, industries and the (different levels of) government to promote and normalize the use of sargasso; (4) the costs of pre-treatments to enhance the properties of sargasso; (5) the lack of companies that collect and process sargasso in the Mexican Caribbean; (6) the lack of clear business models that assess whether valorization is economically viable (with, or without, the gains obtained in protecting the environment, economy and society through the collection of sargasso).

Opportunities in the commercialization of sargasso include: (1) the development of technologies and patents; creation of new “know-how” that can be passed on to other nations which face similar influxes; (2) the establishment of an alternative income for the region, as at present the economy of the Mexican Caribbean is almost entirely dependent on the conjuncture-sensitive tourism industry; and (3) the development of a technology for sargasso farming.

Threats include: (1) the uncertainty regarding the continuance of the Great Atlantic Sargasso Belt, as macro algal blooms often have at “boom-bust” cycle (Tyler et al., 2001; Human et al., 2015); however, such cycles are usually on an estuary scale, involving local nutrient recycling, whereas sargasso is drifting in the open ocean. The current consensus is that it is likely to continue, and that adaptation to periodic massive influxes is required; (2) sargasso may be unsuitable for certain uses; when it contains arsenic and/or chlordecone it should not be used in any process in the food chain (Devault et al., 2021a); (3) the factors that are thought to have caused the sargasso bloom (human-induced climate change, corresponding changes in oceanic currents, upwellings and region-wide eutrophication) may cause other environmental hazards that cannot be solved.

The circular economy is defined as the economic space where the value of products, materials, and resources is maintained in the economy for as long as possible, minimizing waste (Carus and Dammer, 2018). Reusing, recycling, remanufacturing, and optimizing the durability of products is indispensable in the circular economy framework, to ensure that the loop is closed (Sverko Grdic et al., 2020). A biorefinery aims to use the renewable carbon of biomass and minimize waste and emissions (Cherubini, 2010), coming closer to a circular bioeconomy framework (Ubando et al., 2020). In addition, sargasso fixes the (excessive) carbon in the atmosphere and takes up the (excessive) nutrients in the ocean, converting them into biomass. The natural environment will improve, if this biomass is adequately retrieved and processed, avoiding the return of carbon to the atmosphere, or nutrients to the ocean. This could be achieved with a circular, cascading approach, with zero waste, as pursued in biorefineries (Torres et al., 2019), with the valorization of bio-products. Sustainability would be assessed through life cycle, and techno-economic and social-economic analyses (Ubando et al., 2020). Currently, there are no biorefineries based on the pelagic sargasso arriving in the Caribbean, but we can learn from other experiences and adopt a biorefinery approach to process sargasso in multiple products minimizing or eliminating waste.

This economic model implies systemic transformations that call for theoretical, empirical, and political reflection on the use of assets and on human rights guarantees. Renewable resources are managed in flows, and finite resources by inventory, assuming their finite nature (Pantoja, 2020). The main drivers of the circular economy are increasing price volatility, restrictions on the supply of primary resources, environmental policies and a new consumer culture. The efficiency of a circular model can be measured by the distance between the useful life of a product and its reintegration into the production process: the shorter the distance, the higher the yield, as the product is inserted in more, and varied, life cycles (EMF, 2021).

The antithesis of the circular economy is the linear economy, “the economy of consumption,” of extract, use and throw away (EMF, 2021). The linear economy ignores the finite nature of many materials, concentrating on their recovery and valorization by analyzing the life cycles of materials and resources from a regenerative perspective. If we ignore the scarcity element of resources as a fundamental element of economic science (Balmaceda, 2017), we omit activities such as conservation, natural heritage, energy efficiency, the reduction of greenhouse gases, the recovery, valorization, and recycling of its waste. In this way we have created models of excessive resource exploitation and a disproportionate generation of waste, thus destroying the capacity of the environment to regenerate or adapt to such changes (Pantoja, 2021).

The circular economy model will allow the Mexican Federal State, and particularly the state of Quintana Roo, to face the arrival of massive quantities of sargasso on the beaches with a comprehensive management of it in all its “legal states”; i.e., as a natural resource, as raw material, and as waste.

Current available scientific evidence points to massive sargasso accumulations being the new norm at present and in the future (Oxenford et al., 2021; UNEP-CEP, 2021). The trends show seasonal variability in Mexico, with the peak times for influx being between May and September (Chávez et al., 2020). Although seasonal influx patterns are to a large degree predictable, this does not apply to the enormous interannual variability in the sargasso biomass. Regarding these uncertainties, action plans must be in place to address the influxes in critical periods, as well as in intermediate periods. The many potential uses of sargasso should be considered as green solutions that also contribute to mitigating coastal squeeze (Chávez et al., 2021; Silva et al., 2021).

The results of satellite observations over recent years, strongly suggest that it is both inefficient and futile to collect sargasso in the open sea in the northern section of the Mexican Caribbean, in front of Tulum to Cabo Catoche. Although further studies are recommended as to the effectiveness of open sea collection of sargasso in the south east of the Mexican Caribbean, which could reduce the massive influxes further north.

Mexico has sufficient institutional capacity, as well as technical, scientific, industrial and marketing talent to generate effective and lasting solutions. In September 2018, an honorary Advisory Council (Consejo Técnico Asesor) was formed to comprehensively analyze the sargasso accumulation and define a scientific, technological and innovation agenda. This initiative seeks to advise the Federal and State Government, acting efficiently and promptly, with careful planning; however, a National Strategy for the use of sargasso must be developed as soon as possible, in order to manage its life cycle using a regenerative approach based on scientific evidence.

A decisive impulse toward the consolidation of a national industry for the sustainable and regulated use of this sargasso is needed now, so that Mexico can take advantage of this biotic resource, inducing a shift in the common perception of the massive influxes. Sargasso should not be seen as a threat to the economy, rather as an opportunity, a potential means of developing a greener economy alongside improving environmental preservation.

RS, ME, VC, and BT contributed to conception of the study. JL and ME wrote the first draft of the manuscript. AU-M and EC performed the data analysis. LC, AU-M, EC, IR, LM, and CC-K wrote sections of the manuscript. VC, RS, and BT revised and edited the manuscript. All authors contributed to manuscript revision, read, and approved the submitted version.

LM and CC-K are employed by Creamos Más S.A. de C.V. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.