Dataset: 13C/12C (del13C) of dissolved inorganic carbon (DIC) from samples collected on the GP17-OCE cruise on R/V Roger Revelle (RR2214) in the South Pacific and Southern Oceans from December 2022 to January 2023

Seawater samples for analysis of the 13C/12C of dissolved inorganic carbon (DIC) were collected in 250 milliliter (ml) ground glass stoppered bottles from Niskin bottles and poisoned with 100 microliters (µl) of mercuric chloride during the cruise.

In the lab, ~50 mls of the seawater sample was acidified and CO2 extracted using a REDICS system. CO₂ gas was collected cryogenically in a liquid nitrogen cold trap after removal of water vapor and transferred to an isotope ratio mass spectrometer (IRMS) for 13C/12C measurement. The measured 13C/12C of the DIC was reported as del13C in units of per mil relative to the PDB standard. The reported uncertainty of the del13C analysis was ±0.03 per mil determined from repeated measurements of a lab standard and duplicate samples measured during GP17 cruise. The del13C measurements were performed at the NOSAMS facility at WHOI.