Laukert, Georgi; Bauch, Dorothea; Damm, Ellen; Hathorne, Ed C; Simões Pereira, Patric; D'Angelo, Alessandra; Nomura, Daiki: Dissolved radiogenic neodymium isotopes, stable oxygen isotopes and rare earth element concentrations of water bottle samples collected during MOSAiC [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.966223 (dataset in review)

Seawater samples were collected from the MOSAiC Central Observatory, which consisted of sampling facilities positioned on the main sea-ice floe (including Ocean City) and on the RV Polarstern attached to it. A total of 41 large-volume (10L) seawater samples were collected during the 5 legs from October 2019 to September 2020 using a Conductivity-Temperature-Depth (CTD) rosette fitted with 24 (RV Polarstern samples) and 12 (Ocean City samples) Niskin bottles. At each station, samples were obtained from the surface (0 to 5 m) and depths of 50, 100, and 200 or 250 m. The samples were collected in acid-cleaned LDPE-cubitainers and transported to the clean room laboratory at GEOMAR. In the laboratory, filtration through 0.45 Merck Millipore® cellulose acetate filters was carried out using a peristaltic pump. After filtration, samples were acidified to pH ~2.2 with ultra-pure concentrated hydrochloric acid. Small aliquots (0.1 L) for δ18O analysis were obtained before filtration and acidification and stored in glass bottles at 4 °C until analysis. The neodymium isotopes are reported as 143Nd/144Nd and as εNd and were determined at GEOMAR using an multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS). Their internal and external reproducibility is given in the data table. Rare earth element concentrations are given in pmol/kg and were pre-concentrated offline using a SeaFAST system and determined using an inductively coupled plasma mass spectrometer (ICP-MS) at GEOMAR. Their external reproducibility is better than ~6% for La, Ce, Pr, Nd, Sm and Eu and better than ~5% for all other rare earth elements. Stable oxygen isotopes were determined at the Stable Isotope Laboratory of the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University using the CO2-water isotope equilibration technique and are reported as the measured 18O/16O ratio normalized to Vienna Standard Mean Ocean Water (V-SMOV) in δ-notation, with an external reproducibility of ± 0.05 ‰ or better.