Discrete carbonate chemistry measurements from UK GEOTRACES cruises D357 and JC068 on the South Atlantic transect GA10.

This dataset contains the discrete measurements of seawater dissolved inorganic carbon (DIC) and total alkalinity (TA) collected from the CTD rosette during UK GEOTRACES cruises D357 on the RRS Discovery and JC068 on the RRS James Cook in the South Atlantic between 2010 and 2012. Subsets of the two datasets have been combined here to make a single coherent dataset for GA10. Seawater samples were transferred from the CTD rosette bottles to 250 ml borosilicate glass bottles (Schott Duran) via silicone tubing. These glass bottles were thoroughly rinsed and allowed to overflow with excess sample before sealing shut with ground glass stoppers, which were held in place with elastic bands. The bottles were then stored in the dark until analysis using VINDTA instruments at sea usually within 24 hours of sample collection. DIC and TA are critical support variables that are measured on every GEOTRACES cruise to provide context for the trace metal and isotope work that is the main focus of the GEOTRACES project. Sample collection and analysis was carried out by C. Dumousseaud during D357 and M. P. Humphreys during JC068; M. P. Humphreys calibrated and processed the results from both cruises; E. P. Achterberg provided logistical support and oversight.