High-resolution dataset of stable carbon isotope of dissolved inorganic carbon (δ13C-DIC) from the North Atlantic Ocean

The stable isotope ratio of dissolved inorganic carbon (δ¹³C-DIC) is a valuable tracer for investigating carbon cycling in aquatic environments. However, its potential remains underutilized due to limited data availability. Fewer than 15% of cruise samples are analyzed for δ¹³C-DIC, as isotope analysis using isotope ratio mass spectrometry is labor-intensive and restricted to onshore laboratories. We present over 3500 δ¹³C-DIC measurements from the 2023 Global Ocean Ship-based Hydrographic Investigations Program A16N cruise in the North Atlantic. Notably, three-quarters of these measurements were conducted onboard using a CO₂ extraction device coupled with cavity ring-down spectroscopy, a more efficient and cost-effective method. This extensive dataset provides δ¹³C-DIC values with spatial resolution comparable to other ocean carbonate chemistry and biogeochemical parameters. This dataset supports improved quantification of anthropogenic CO₂ uptake and storage, and may facilitate the development of algorithms to estimate δ¹³C-DIC in under sampled regions.