Scientists have developed a new model for carbon capture in low-oxygen aquatic environments, such as fish farms, which could help combat climate change cost-effectively. The study, led by Mojtaba Fakhraee and Noah Planavsky, explores how enhancing iron sulfide formation can increase alkalinity, boosting CO2 capture. This method could remove at least 100 million metric tons of CO2 annually, with China alone potentially achieving that target. Additionally, it would reduce toxic hydrogen sulfide levels, improving fish health and farm profitability. The captured carbon would be stored for thousands of years, making this a durable and scalable carbon removal strategy.