Water sampling was performed using a CTD Rosette system, consisting of 12 L Niskin bottles. This dataset contains oxygen (δ¹⁸O) and hydrogen (δD) isotope measurements conducted at the ISOLAB Facility at the Alfred Wegener Institute (AWI) Potsdam (Sample ID PCB01 to PCB23) and at ETH Zurich (Sample ID 424 to 546). Isotope analyses at AWI Potsdam were performed using DELTA-S Finnigan MAT mass spectrometers (USA) employing the equilibration method, described in Meyer et al. (2000). The isotope ratios are reported in per mil (‰) relative to the Vienna Standard Mean Ocean Water (VSMOW) as the international reference standard. Isotope analyses at ETH Zurich were performed using a PICARRO isotope and gas concentration analyzer (L2130-i). Nitrogen was used as purge gas and the vaporizer temperature was set at 110 °C. There were 12 injections per sample (1.8 µL), six injections were used to flush the vaporizer and measurement cavity of the instrument between samples. The latter six injections were injected as individual pulses for measurement with the latter four used in the data reduction. Isotope compositions were calibrated against reference materials from the International Atomic Energy Agency (IAEA) including SLAP2, GRESP, and VSMOW2 and in-house reference materials, resulting in a precision of analyses of 0.1 – 2‰. An independent quality control was carried up against reference materials from the United States Geologic Survey (USGS) which were run as quality control. In addition to the δ¹⁸O and δD values, the second-order parameter deuterium excess (d) was calculated according to the equation (after Dansgaard, 1964): d = δD − 8 × δ¹⁸O