Benthic fluxes of dissolved ferrous iron (Fe 2+ ) and phosphate (TPO 4 ) were quantified by in situ benthic chamber incubations and pore‐water profiles along a depth transect (11°S, 80‐1000 m) across the Peruvian oxygen minimum zone (OMZ). Bottom‐water O 2 levels were −1 down to 500‐m water depth, and increased to ∼ 40 µmol L −1 at 1000 m. Fe 2+ fluxes were highest on the shallow shelf (maximum 316 mmol m −2 yr −1 ), moderate...