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.