Seaweed Production Potential in the Brazilian Northeast: A Study on the Eastern Coast of the State of Rio Grande do Norte, RN, Brazil

Seaweed is a source of multipurpose bioresources, providing millions of dollars to the world's economy and performing various ecosystem services that aid in maintaining marine balance, reducing eutrophication, providing nutrients and mitigating atmospheric CO2. In this context, this study aims to evaluate the potentialities of the cultivation of the Crassiphycus birdiae seaweed on the eastern coast of the state of Rio Grande do Norte (RN), Brazil, considering the physical and environmental aspects. Estimates concerning suitable areas and their productive potential for the Biomass, Bioethanol, Biofertilizer and Agar bioproducts were carried out. These estimates were based on the Modular Ferry System (MFS) installed on the state coast. Suitable cultivation areas were determined by applying an Analytic Hierarchy Process (AHP) and change detection analysis based on physical and infrastructure factors, such as areas sheltered by winds, sea currents and waves, proximity to seaweed banks, road infrastructure and socioeconomic and environmental factors. Areas identified as suitable for seaweed cultivation totaled 2227.59 ha in area, with a productive potential of 195 thousand tons of fresh biomass/year, over two million liters of ethanol/year and about 43 tons of agar/year. These findings demonstrate that the northeastern coast of Brazil has the potential to generate employment and income through seaweed cultivation, stimulating the coastal region's development in a sustainable manner.