Fig. 1
From: Recycled iron fuels new production in the eastern equatorial Pacific Ocean
Tropical Pacific nitrate concentration and isotopic composition. Tropical Pacific surface nitrate concentrations for a April–June and b October–December70, with squares and stars indicating station locations. c, d show nitrate δ 15N and δ 18O measurements vs. nitrate concentration for the samples from these stations. Pink and blue symbols are ±1° of equator during boreal spring and fall, respectively. White stars indicate 2–4° S surface mixed layer measurements. Plotted data are from the upper 200 m of the water column. White circles in c, d indicate the averages of measurements of the Equatorial Under Current (EUC) at 110° W18, and these values are used to drive the Rayleigh (closed system) model of nitrate assimilation (gray lines)18 (see text for more details)
