A global dataset of nitrogen fixation rates across inland and coastal waters

Biological nitrogen fixation is the conversion of dinitrogen (N₂) gas into bioavailable nitrogen by microorganisms with consequences for primary production, ecosystem function, and global climate. Here we present a compiled dataset of 4793 nitrogen fixation (N₂-fixation) rates measured in the water column and benthos of inland and coastal systems via the acetylene reduction assay, ¹⁵N₂ labeling, or N₂/Ar technique. While the data are distributed across seven continents, most observations (88%) are from the northern hemisphere. ¹⁵N₂ labeling accounted for 67% of water column measurements, while the acetylene reduction assay accounted for 81% of benthic N₂-fixation observations. Dataset median area-, volume-, and mass-normalized N₂-fixation rates are 7.1 μmol N₂-N m⁻² h⁻¹, 2.3 × 10⁻⁴ μmol N₂-N L⁻¹ h⁻¹, and 4.8 × 10⁻⁴ μmol N₂-N g⁻¹ h⁻¹, respectively. This dataset will facilitate future efforts to study and scale N₂-fixation contributions across inland and coastal aquatic environments.