Stable carbon isotopes of dissolved inorganic carbon for RRS James Clark Ross cruise JR302 in the subpolar North Atlantic Ocean from June to July 2014.

This dataset contains 341 measurements of the stable isotope composition of dissolved inorganic carbon in seawater, from samples collected during cruise JR20140531 (JR302) on the RRS James Clark Ross in the subpolar North Atlantic between 10th June 2014 and 16th July 2014. Sample analysis was carried out at the Scottish Universities Environmental Research Centre - Isotope Community Support Facility in East Kilbride, UK. The results fall in a range from -0.07 to +1.95 per mille, relative to the Vienna Peedee Belemnite internation standard (Coplen, 1995). The 1-sigma precision of the results, calculated from measurements of samples collected in duplicate, is 0.08 per mille. Measurements and processing are documented in detail by Humphreys et al. (2015) and Humphreys et al. (in prep.). This dataset was collected to help understand the size and variability of the sources and sinks of greenhouse gases between the ocean and atmosphere in the North Atlantic Ocean as part of the UK's RAGNARoCC project.