This dataset contains dissolved iron concentrations ((Fe(II) + Fe(III); µmol/l) acquired during 2013-2014,  2014-2015 and 2016-2017 using the CHEMINI Fe, a CHEmical MINIaturized analyser (samples taken every 24 hours, with daily in situ calibration using a 25 µmol/l iron standard, Vuillemin et al., 2009). The sample inlet was positioned on the mussel bed at the base of the Tour Eiffel edifice of the Lucky Strike hydrothermal vent (1695 depth).CHEMINI Fe was mounted on the TEMPO module which was itself connected to the SeaMON East node of the EMSO-Azores observatory.