In July 2022 within the framework of an Alfred-Wegener-Institute-managed expedition and the Nunataryuk project, sediment core YC22_MR_7 was taken off the coast of Herschel Island, Canada, using a hand corer. Data sets were obtained to investigate carbon feedback from the sediments to the water column and atmosphere, using DIC concentrations and isotopic values. The local sediments are supplied primarily by organic carbon previously stored in adjacent permafrost soils (biomarker and bulk data), which erode and redeposit quickly (age model) on the ocean floor.Porewater was extracted from the cores using rhizomes and quantified as described in Oni et al., (2015). Dissolved inorganic carbon isotope signatures were determined as CO2 for 13C (Torres et al., 2005) and 14C (Mollenhauer et al., 2021).