High‐resolution dataset of stable carbon isotope of dissolved inorganic carbon (<scp><i>δ</i>¹³C</scp>‐<scp>DIC</scp>) from the North Atlantic Ocean

Abstract The stable isotope ratio of dissolved inorganic carbon ( δ 13 C‐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 δ 13 C‐DIC, as isotope analysis using isotope ratio mass spectrometry is labor‐intensive and restricted to onshore laboratories. We present over 3500 δ 13 C‐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 CO 2 extraction device coupled with cavity ring‐down spectroscopy, a more efficient and cost‐effective method. This extensive dataset provides δ 13 C‐DIC values with spatial resolution comparable to other ocean carbonate chemistry and biogeochemical parameters. This dataset supports improved quantification of anthropogenic CO 2 uptake and storage, and may facilitate the development of algorithms to estimate δ 13 C‐DIC in under sampled regions.