Seaweed resources of Mexico: current knowledge and future perspectives

International audienceAbstract High diversity of marine macroalgae is reported for Mexican coasts, including numerous endemic species. Seaweed research in Mexico has focused on the northern regions of the Pacific coast (Temperate Pacific and Gulf of California) and on the Mexican Caribbean coast, leaving aside other regions (Tropical Pacific and Gulf of Mexico). Utilization of seaweed resources within the country has been based on artisanal collection of wild populations mainly for polysaccharide extraction, fertilizers, raw material for animal feed and cosmetic products. The main exploitation has occurred along the coasts of Baja California peninsula, based on few species ( Gelidium robustum , Macrocystis pyrifera , Chondracanthus canaliculatus and Gracilariopsis lemaneiformis ). Governmental regulations for management have allowed harvesting to reach approximately 11,500 wet tons per year (2013–2016). Nevertheless, in recent years (2014–2016) the total seaweed import volume has increased (5302 tons per year in average) over the export volume (2156 tons per year in average), suggesting a notably growing demand for seaweed resources in the country and representing an opportunity for investment projects. Several pilot studies on seaweed cultivation in Mexico propose that sustainable aquaculture techniques could complement the harvest in natural populations and ensure a homogeneous production with high quality in the long term

Chemical Composition and Carbohydrate Characterization of Beach-Cast Marine Macrophytes from the Mexican Caribbean: Implications for Potential Bioethanol Production

International audienceAbstract Marine macrophytes are considered promising biomass for bioethanol production. The increases in anthropogenic nutrients and climate change have caused unprecedented blooming of ‘sargasso’ across the Atlantic since 2011. This biomass reaches the Caribbean Sea, stranding in large amounts along shorelines, and creating a serious waste management problem. The knowledge of its chemical composition is important to assess whether this material could serve as feedstock for third-generation bioethanol. The beach-cast marine macrophytes collected on the Mexican Caribbean coast in December 2018 were composed of brown seaweeds and a seagrass (23.5 and 76.5% relative abundance, respectively) including Sargassum fluitans , Sargassum natans I, Sargassum natans VIII, Turbinaria turbinata , and the angiosperm Syringodium filiforme . For valorization purposes, glucans, non-glucans carbohydrates and lignin were determined. Besides its abundance, underutilization, and low-cost this whole biomass may have potential as a promising raw material for third-generation bioethanol because it contains easily fermentable glucose such as mannitol (36.3% in whole biomass and 56% in the Sargassum species) and cellulose (36.3% on average). Other specific carbohydrates such as alginate (20–31%) and fucoidan (9.1–8.2%) were present in smaller amounts but they can also be converted to fermentable sugars with the proper methodology. Some advantages and limitations for the potential production of third-generation bioethanol from this biomass are discussed

“No todo es Sargazo”: Aprendizajes en un proyecto de ciencia ciudadana marino-costera

The effects of the abundant arrival of macroalgae, such as Sargassum, to the Yucatan Peninsula motivated the monitoring of beach-cast seaweeds through a citizen science project aimed at affected and interested populations. Questionnaires and semi-structured interviews were employed to analyse the learning outcomes of 18 participants (16 to 18 years) from the project's first stage. Among the findings, the interrelation of new disciplinary learning about macroalgae and skills for fieldwork stood out. Participants showed renewed and positive attitudes toward science and beach-cast seaweeds. We reflect on what factors drove their learning and research skills when addressing the scientific objectives, including the relevance of the problem, the introductory workshop, and the socialisation between the scientists and the participants

«No todo es sargazo» : aprendizajes en un proyecto de ciencia ciudadana marino-costera

Los efectos de la llegada abundante de macroalgas, como el sargazo, a la península de Yucatán motivó el monitoreo de los arribazones por medio de un proyecto de ciencia ciudadana dirigido a poblaciones afectadas o interesadas. Por medio de cuestionarios y entrevistas semiestructuradas, se analizaron los aprendizajes de 18 participantes (de 16 a 18 años) de la primera etapa del proyecto. Entre los hallazgos, destacó la interrelación de los nuevos aprendizajes disciplinares sobre las macroalgas y los procedimentales del trabajo de campo. Los participantes mostraron actitudes renovadas y positivas hacia la ciencia y el arribazón. Se reflexiona sobre qué factores impulsaron sus aprendizajes y habilidades para la investigación al atender los objetivos científicos, entre ellos: la relevancia del problema, el taller introductorio y la socialización entre las científicas y los participantes.The effects of the abundant arrival of macroalgae, such as Sargassum, to the Yucatan Peninsula motivated the monitoring of beach-cast seaweeds through a citizen science project aimed at affected and interested populations. Questionnaires and semi-structured interviews were employed to analyse the learning outcomes of 18 participants (16 to 18 years) in the project's first stage. Among the findings, the interrelation of new disciplinary learning about macroalgae and skills for fieldwork stood out. Participants showed renewed and positive attitudes toward science and beach-cast seaweeds. We reflect on which factors drove their learning and research skills when addressing the scientific objectives, including the relevance of the problem, the introductory workshop, and the socialisation between the scientists involved and the participants