Dissolved iron measured on board with Flow injection analysis and iron-binding dissolved organic ligands from Ultra Clean CTD collected depth profiles during GEOTRACES PS94 Arctic cruise on Polarstern

• Main Authors: Gerringa, Loes J A, Rijkenberg, Micha J A, Slagter, Hans A
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2018
• Subjects: Event label; Station label; Cast number; Bottle number; Latitude of event; Longitude of event; Date/Time of event; DEPTH, water; Iron, dissolved; Iron, dissolved, standard deviation; Quality flag; Iron, inorganic, conditional stability constants; Iron, inorganic, conditional stability constants, standard deviation; Ligand concentration; Ligand concentration, standard deviation; Humic substances; Fluorescence, colored dissolved organic matter; Absorption coefficient, colored dissolved organic matter at 254 nm; Absorption coefficient, colored dissolved organic matter at 300 nm; CTD/Rosette, ultra clean; Flow injection analysis Rijkenberg et al. 2018; Cathodic stripping voltammetry Metrohm 663 VA stand, control hardware Metrohm Autolab II and IME 663; after Croot and Johansson 2000 and calculated after Gerringa et al. 2014; after Laglera et al. 2007; Spectramax M2 multimode spectrophotometer Molecular Devices; PS94; Polarstern; Global marine biogeochemical cycles of trace elements and their isotopes GEOTRACES; Arctic
• Online Access: https://dx.doi.org/10.1594/pangaea.890975; https://doi.pangaea.de/10.1594/PANGAEA.890975

Data from Polarstern cruise PS94 in the Arctic in 2015 with chief scientist Ursula Schauer. In order to explain geochemical cycles of Fe in the ocean, M. Rijkenberg, L. Gerringa and H. Slagter a.o. sampled filtered seawater using an ultra clean titanium CTD. In these samples on board measurements were executed: dissolved Fe by flow injection analysis and the characteristics of the dissolved organic Fe-binding organic ligands (totalL); characteristics being the concentration of these ligands and the conditional binding constant of the Fe-complex (K' expressed as its logarithm: logK). Moreover in order to relate the dissolved organic Fe-binding organic ligands to humic substances, fluorescence of dissolved organic matter was measured as well as humic substances using voltammetry. : Sampling of sea water was performed using the ultraclean CTD (Rijkenberg et al, 2015).Samples for dissolved metals were acidified to a pH of 1.8 using a final concentration of 0.024M ultraclean Seastar Base-line HCl (Seastar Chemicals). DFe was measured on board using flow injection analysis (FIA) based on luminol chemiluminescence (described in Rijkenberg et al., 2018). The analytical blank was on average 0.007 ± 0.004 nM DFe (n = 32) and the average detection limit (defined as 3 s of the blank pre-concentrated for 5 s) was 0.012 ± 0.007 nM DFe (n = 32).SAFe and GEOTRACES reference materials were used.K and total ligand concentrations have been calculated after Gerringa et al. (2014) using lDFe, except for stations 101, 119, 153, 161 and 173, here DFe is used.Humid substances were determined according to Laglera et al. (2007).