Nitrogen fixation process may supply a significant fraction of bioavailable nitrogen to surface waters, increase the oceanic sequestration of atmospheric CO₂, and alter the distribution of geochemical parameters. We report a zonal pattern of δ¹⁵N and δ¹³C in particulate organic matter (POM), and ratios of particulate ²¹⁰Po to dissolved ²¹⁰Po along a transect through the subtropical and tropical North Pacific. Both ¹⁵N and ²¹⁰Po signals indicated an enhanced N₂ fixation in the northwestern subtropical North Pacific. The eastward decrease of N₂ fixation along this transect testified the role of aeolian Fe and P in controlling marine N₂ fixation. Associated with the zonal variations of ¹⁵N and ²¹⁰Po, the δ¹³C of suspended POM increased eastward, reflecting the decrease of anthropogenic CO₂ concentration in surface seawater from west to east in the study area. Our results highlight the need to examine more closely the mechanisms of possible longitudinal variation in N₂ fixation in the ocean and the role of aeolian Fe and P in controlling marine N₂ fixation and anthropogenic CO₂.