Ex situ diffusive oxygen uptake of the Northeast Greenland (NEG) shelf sediments from POLARSTERN cruise PS109

• Main Authors: Felden, Janine, Wenzhöfer, Frank, Braeckman, Ulrike
• Format: Dataset
• Language: English
• Published: PANGAEA 2024
• Subjects: ARK-XXXI/4; Comment; Date/Time of event; DOU; Elevation of event; Event label; ex situ; FRAM; FRontiers in Arctic marine Monitoring; Latitude of event; Longitude of event; Method/Device of event; microoptode; Multicorer with television; Number; Oxygen Logger (Firesting O2-C4) equipped with retractable needle type optodes (OXR50); Pyroscience; Firesting; oxygen uptake; diffusive; Polarstern; PS109; PS109_105-1; PS109_115-3; PS109_122-1; PS109_125-2; PS109_139-2; PS109_154-1; PS109_19-4; PS109_36-3; PS109_45-3; PS109_76-1; PS109_84-2; PS109_85-1; PS109_93-3; Standard deviation; TVMUC; Arctic; Greenland
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.959545; https://doi.org/10.1594/PANGAEA.959545

Ex situ diffusive oxygen uptake (DOU) at the sediment water interface was assessed on the Northeast Greenland shelf with R/V Polarstern during PS109 between September and October 2017 using a camera-equipped multiple corer (TV-MUC; core area 0.007 m²). Upon arrival on deck, part of the overlying water of three MUC cores was collected and stored separately at in situ temperature. The remaining overlying water was adjusted to 10 cm above the sediment by gently pushing the sediment upwards while avoiding a disturbance of the surface sediment. The cores were then placed in a temperature-controlled water bath in the ship-board laboratory which had been adjusted to the in-situ temperature at the seafloor (information was retrieved from ship-board sensors). A mangetic stirrer was deployed in order to homogenise the overlying water, and a small air pump gently aerated the water. DOU was assessed with 2 oxygen optodes (Pyroscience, Firesting; tip size 50 µm) mounted on an autonomous microprofiler module. Each core was measured with two microprofilers simultaneously, usually within 2h of sampling (except for stations 139, 85, 84 and 76, where the measurement times were >24h). The sensors were two-point calibrated using on-board signals recorded in air saturated surface sea water and anoxic, dithionite-spiked bottom water at in situ temperature. Ex situ DOU fluxes across the sediment-water interface obtained were calculated from running average smoothed oxygen profiles using Fick's first law (Glud et al. (1994, doi:10.1016/0967-0637(94)90072-8).