Fulweiler et al. (2025) reveal that these ecosystems, including lakes, rivers, wetlands, and continental shelves, contribute 40 teragrams of nitrogen annually, equivalent to 15% of global biological nitrogen fixation. This challenges decades of oversight in global nutrient budgets and demands urgent integration into climate and water security frameworks.
This hidden nitrogen production sustains entire food webs, from microscopic algae to fish stocks that feed millions. It also plays a crucial role in carbon storage, particularly in wetlands and coastal vegetation that act as natural climate solutions. Yet these vital functions remain largely absent from our current climate models and water management policies.
In the spirit of one global water-earth system, we must treat inland waters, coasts, land, and atmosphere as interconnected. Nitrogen fixation is a perfect example of this connectivity: what happens in a humble pond or a marsh can scale up to influence planetary nutrient and carbon cycles. As we address climate change impact, we can’t overlook the cyanobacteria in a lake or the microbes in wetland soil quietly doing their part to fix nitrogen and sustain life.
Fig: Distribution of biological nitrogen fixation rates across inland and coastal aquatic systems. Global distribution of study sites with colors highlighting habitat type (A) and the number of nitrogen fixation measurements by latitude and habitat type (B).
#SustainableWater #ClimateResilience #EcoPolicy #ProtectOurWaters #GlobalNitrogen
Bapon (SHM) Fakhruddin, PhD 