Dataset: Inert copper and inorganic iodine concentrations from Leg 1 (Seattle, WA to Hilo, HI) of the US GEOTRACES Pacific Meridional Transect (PMT) cruise (GP15, RR1814) on R/V Roger Revelle from September to October 2018

Iodate and Iodide were measured along the GEOTRACES GP15 transect aboard R/V Roger Revelle. Samples were collected using the GEOTRACES trace-metal clean rosette. For the purposes of preserving the speciation, all samples were immediately frozen at -20 °C and shipped back to the United States in a cooler, overnight. The samples were kept frozen until analysis, at which point, they were defrosted. Iodate was analyzed on UV-Vis Spectrophotometer while Iodide was analyzed on the Hanging Mercury Drop Electrode with the Cathodic Square Wave Stripping Voltammetry setting. Both methods were described previously in Moriyasu et al., (2020). Inert copper was determined by ligand exchange solvent extraction (Moriyasu & Moffett, 2022).