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Several studies have shown the importance of the microbial community in specific aspects of the biogeochemical iron (Fe) cycle such as uptake or regeneration. During FeCycle, a 10‐day study of Fe biogeochemistry within an unperturbed mesoscale in situ SF₆ labeled patch of HNLC waters, we investigated the role of both microzooplankton (herbivores and bacterivores) and viruses in regenerating Fe in the upper ocean. In summer 2003 we measured grazer‐mediated Fe regeneration rates. The proportion of bacterial Fe released via grazing was severalfold greater than that mobilized from phytoplankton during herbivory. However, as the algal Fe pool (mainly Synechococcus) was severalfold larger than the bacterial pool, the absolute Fe regeneration rates were similar for both herbivores (17 pmol Fe L⁻¹ d⁻¹) and bacterivores (20 pmol Fe L⁻¹ d⁻¹). In all grazing experiments we observed that 90% (bacterivory …