Dataset: Dissolved trace elements in profiles and surface waters collected during the Chinese GEOTRACES cruise (GP09) in the tropical northwest Pacific Ocean from April to June 2019

Sampling protocol: GEOTRACES protocols were followed and are briefly described in the cruise report: https://www.bodc.ac.uk/resources/inventories/cruise_inventory/report/17252/. Profile samples were collected using a clean rosette/CTD system using cleaned 12-liter (L) GO Niskin-X bottles. Water was filtered in a clean van through AcroPak 1000 cartridges. Clean surface water samples were obtained using a clean fish system similar to systems used on US GEOTRACES cruises. A 6-meter (m) boom kept the sampling system away from the ship and low-density polyethylene tubing was used to pump water to the clean van. Note that samples were collected and filtered by other GP09 scientists; we provided pre-cleaned bottles that were filled at sea and shipped to us.

Analytical protocol: We used high-resolution inductively coupled plasma mass spectrometry (ICP-MS) with calibration by isotope dilution, where possible. All elements except Mo and Ba were preconcentrated using a SeaFAST system. Mo and Ba were instead determined after 30-fold dilution in ultrapure water. See GEOTRACES Intercalibration Report (see Supplemental Files section of metadata) for details. Also see: Gilbert et al., 2023 (Ga); Ho et al., 2018 (Mo, V), Whitmore et al., 2022 (Ba); Rahman et al., 2022 (Ba); and Cao et al., 2024 (REEs).