Siderophore production and utilization by marine bacteria in the North Pacific Ocean

Abstract Siderophores are strong iron‐binding molecules produced and utilized by microbes to acquire the limiting nutrient iron (Fe) from their surroundings. Despite importance as a component of ligand pool in seawater, data on distribution siderophores that use them limited. Here, we measured concentrations types dissolved during two cruises April 2016 June 2017 transited iron‐replete, low‐macronutrient North Pacific Subtropical Gyre through Transition Zone (NPTZ) iron‐deplete, high‐macronutrient Subarctic Frontal (SAFZ). Surface siderophore were higher NPTZ (4.0–13.9 pM) than SAFZ (1.2–5.1 pM), which may be partly attributed stimulated production environmental factors such dust‐derived (up 0.51 nM). Multiple identified both cruises, including ferrioxamines, amphibactins, iron‐free forms photoreactive siderophores, suggest active diverse across latitude depth. Siderophore biosynthesis uptake genes transcripts widespread latitude, abundances these at latitudes reflect siderophore‐mediated local bacterial community Pacific. The variability taxonomic composition communities transcribe putative ferrioxamine, amphibactin, salmochelin transporter different further suggests microbial groups involved usage change depending conditions.