1. Max Planck Institute for Marine Microbiology, Celsiusstraße 1, D‐28359 Bremen, Germany
2. Max Planck Institute for Iron Research, Max‐Planck‐Straße 1, D‐40237 Düsseldorf, Germany
3. Institute for Chemical Technology of Inorganic Materials, Johannes Kepler University, Altenberger Straße 69, A‐4040 Linz, Austria