Water column concentrations of dissolved and particulate nickel, copper, zinc, cadmium, and dissolved macronutrients during the RV SONNE cruise SO298 (GEOTRACES GP11)

This dataset presents water column concentrations of dissolved (<0.2 µm) and particulate (>0.2 µm) trace metals (TMs), including nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd), collected during the RV SONNE SO298 cruise (GEOTRACES GP11) in the Equatorial Pacific Ocean between 14 April and 2 June 2023. The dataset also includes concentrations of dissolved macronutrients (phosphate, silicic acid, and nitrate plus nitrite).Samples for dissolved and particulate TMs, as well as macronutrients, were collected using a trace metal clean sampling system consisting of 12 L Niskin bottles (Ocean Test Equipment) mounted on a titanium CTD rosette. Surface seawater samples for dissolved TMs were additionally collected using a trace metal clean TowFish sampling system at approximately three-hour intervals during transit and prior to arrival at each sampling station. Particulate samples were obtained by filtering seawater from the Niskin bottles through acid-cleaned 0.2 µm polyether sulfone (PES) membrane filters (25 mm diameter) using pressurized, filtered N₂ gas. Filters were stored at −20°C until shore-based analysis at GEOMAR.Dissolved trace metal concentrations were determined following the procedure described by Rapp et al. (2017). Samples were preconcentrated (~10-fold) using an automated seaFAST system (SC-4 DX seaFAST pico, Elemental Scientific Inc) and subsequently analyzed by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS; Element XR, Thermo Fisher Scientific). Quantification was performed using external calibration.Particulate trace metals were operationally separated into two fractions: labile (LpTM) and refractory (RpTM) particulate TM. The LpTM fraction was extracted using a weak acid leach (25% acetic acid) combined with 0.02 M hydroxylamine solution (reducing reagent), following Berger et al. (2008). The remaining material was digested in a concentrated acid mixture (~8 M HNO₃ + 3 M HF) to determine the RpTM fraction, following Al-Hashem et al. (2022), modified after Cullen and Sherrell (1999). The total particulate trace metal concentration (TpTM) reported in the dataset represents the sum of the labile and refractory fractions, except for selected samples where TpTM was determined directly from total filter digests.Dissolved macronutrients were analyzed using a QUAATRO39 (Seal Analytical) auto-analyzer based on segmented continuous flow injection techniques, following the analytical protocols described in Becker et al. (2020).Analytical reproducibility for dissolved Ni, Cu, Zn, and Cd was estimated at 5%, 6%, 4%, and 10%, respectively. Reproducibility for particulate Ni, Cu, Zn, and Cd was 10%, 10%, 8.5%, and 9%, respectively. Analytical precision for macronutrient measurements was better than 2%. All reported data are accompanied by quality flags according to the SeaDataNet flagging scheme. Concentrations below detection limits were assigned a value of 0 and flagged with quality flag 6.