Erika Vázquez-Delfín1,2, Daniel Robledo1, Yolanda Freile-Pelegrín1 and Román M. Vásquez-Elizondo1
1Applied Phycology Laboratory, Marine Resource Department, CINVESTAV-IPN Unit Mérida, Mérida, Mexico
2National School of Higher Studies (ENES) Unit Mérida, UNAM, Mérida, Mexico
Sargassum events in the Caribbean have caused severe socioecological affectations. The knowledge of the chemical composition of Sargassum biomass is key to develop potential applications for its biomass, describe the bioaccumulation and release of pollutants, understand the degradation process, determine nutrient limitation/enrichment to explain growth, and ultimately, to discuss about its controversial role to sequester carbon. Stranding biomass in the Mexican Caribbean is composed by holopelagic Sargassum and benthic macrophytes including macroalgae and seagrasses, whose relative abundance is spatiotemporally variable. Therefore, determining the chemical composition of the species in the strandings is a priority. In this study, we analyzed the monthly chemical composition (dry weight, carbohydrates, proteins, ashes, and C:N ratio) of the three holopelagic taxa (Sargassum fluitans III, S. natans I and S. natans VIII) which represent up to 99.6% of the stranded biomass in the Mexican Caribbean. Samplings were performed monthly in the north coast of the Quintana Roo state during the rainy season in 2018, when the biomass peak occurred. Monthly differences over the chemical constituents and between Sargassum taxa were found. Preliminary results showed that the mean carbohydrate and protein content and, the C:N ratio showed large variation ranging from 13.5-21.8%, 9.1-14.5% and 19.8-29.9% respectively, whereas the mean ash content ranged from 21.2-23.8%. These results are discussed in relation to the monthly differences found in the chemical composition and the relative abundance of the three holopelagic taxa of Sargassum for the same time frame and location, including the ecological implications and constraints for its management.