As of August 2022, there were 24 million tons of Caribbean sargassum fluitans covering the Caribbean Ocean from Mexico to Brazil. The sargassum blocks underwater seabeds from receiving sunlight and nutrients and kills marine life during decomposition. Sargassum blooms increase every year with warming oceans and offshore nutrient discharges. ProjectQRSargasso will process decomposing sargassum as a feedstock for sustainable fertilizer, biogas, and solid-state hydrogen gas. In environmental engineering processes, waste from one industrial process can serve as useful input for another process. Our circular economy technology captures greenhouse gases from entering the atmosphere during sargassum decomposition and diverts this for energy sector decarbonization.