Labile dissolved Fe (<0.22 μm) in the western (165°E) and eastern (165°W) North Pacific Ocean had nutrient‐ and apparent oxygen utilization (AOU)‐like profiles characterized by surface depletion and deep enrichment (5–3000 m depth). Dissolved Fe concentrations in the deep‐water column at the mid‐latitudes were approximately one‐half lower in the eastern region (0.5–0.8 nM) than in the western region (0.8–1.3 nM) although the dissolved Fe concentrations in the surface mixed layer in both regions were extremely depleted to 0.1–0.2 nM. Surprisingly, the labile particulate Fe concentrations (≤∼0.1 nM, total dissolvable Fe minus labile dissolved Fe) throughout the water column at low latitudes in the eastern region were extremely lower than those (∼0.5–1 nM) in the western region. It is suggested that the low Fe levels in the eastern mid‐latitude oceanic region are primarily due to the lower atmospheric Fe supply in the eastern region.

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