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

Abstract

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.

Scientific Significance Statement Here we provide and describe a dataset of global nitrogen fixation rates for the water column and benthos of inland and coastal waters. This dataset is useful for understanding how nitrogen fixation varies across these ecosystems and is a resource for focusing future research questions. We anticipate this is the first version of this dataset that will continue to develop with newly published rates and expanded data on environmental drivers.