Projeção do impacto das futuras mudanças climáticas sobre o cultivo da macroalga gracilaria birdiae na costa do Brasil

Abstract

Climate change is already a reality in the present and future, thus it is necessary to understand how it will affect organisms and ecosystems. Considering this perspective, the question remains as to how these changes in climate will impact important sectors of the economy, such as aquaculture, which is based on marine organisms. One of the most cultivated organisms in aquiculture is the seaweeds, which the production has been increasing annually, being one of the most promising sectors of aquaculture. The Ecological Niche Modeling (ENM) has currently been applied as a tool to predict the future distribution of species with economic potential regarding environmental and chemical impacts driven by climate change. In this context, this study aimed to evaluate how the projected scenario of climate change (RCP8.5) will impact the cultivation of the seaweed Gracilaria birdiae in the Brazilian coast based on the ENM. The modeling was carried out by integrating the MaxEnt algorithm to the R software. The species occurrence data were obtained from the literature. Bioclimatic data were acquired through the Bio-ORACLE database. To validate whether there were significant differences among site suitability at each period, a Friedman test was also performed. The results revealed a significant increase in the suitable areas for G. birdiae cultivation in the future, mainly on the coast of the Northeast and Southeast regions of Brazil. Furthermore, the distribution of suitable areas for cultivation is directly related to the current areas of the species occurrence. The species distribution was limited by nitrate, whereas temperature and salinity were not limitig even though they are biologically important for the species. Studies have reported that the genus Gracilaria exhibits a high tolerance to extreme conditions, since it inhabits the intertidal zone where environmental conditions vary greatly. Therefore, this species will not be affected by the projected environmental conditions for the RCP 8.5 scenario. In conclusion, the seaweed Gracilaria birdiae shows a great potential for seaweed cultivation in the coast of Brazil, which could generate a significant income for coastal communities.