Blue Nitrogen: Global Rates and Economic Importance

Ziyan WANG, Benoit Thibodeau

Nitrogen pollution drives widespread coastal ecosystem collapse. In this paper, we argue that mangrove forests represent an undervalued natural mitigation solution for nitrogen pollution. By performing a comprehensive meta-analysis, we reveal that mangroves remove 870 Gg N annually, which represents an economic value reaching $8.7 billion via nitrogen credit-based valuation. This value is more than 12 times higher than the annual carbon credits value derived from mangrove carbon sequestration. Despite the substantial economic importance of mangroves' nitrogen removal capacity, it remains largely overlooked in current conservation frameworks. Moreover, we argue that nitrogen removal by mangrove has a potential value that could reach $58 billion (over 5 million tonnes of nitrogen) under optimal conditions. We also highlight critical environmental thresholds demonstrating that this service is vulnerable: extreme eutrophication, rising mean annual temperature above 22°C, and hypersalinity all suppress mangrove nitrogen removal capacity. Our findings provide the scientific foundation to integrate “Blue Nitrogen” credits in larger nitrogen-credit framework, offering a transformative financing mechanism for coastal water quality management that could reshape both mangrove conservation and nitrogen pollution mitigation strategies, worldwide.