Production of siderophore type chelates by mixed bacterioplankton populations in nutrient enriched seawater incubations

Siderophore type chelates were isolated from nutrient enriched seawater collected from coastal and near shore environments and detected using a novel high performance liquid chromatography – electrospray ionisation – mass spectrometric technique. Seawater was enriched with added glucose, ammonia and phosphate, and incubated for four days. Seven different siderophore type compounds were detected in the extracted supernatants and tentatively identified based on mass numbers and spectra. The compounds comprised two groups, the ferrioxamines and the amphibactins. They were produced at typical coastal iron concentrations (total dissolved iron = 2.9 ± 1.4 2 nM and 2.2 ± 0.1 nM) both in the presence and absence of the iron chelating ligand ethylene diamine-N,N′-diacetic acid.