ALBERT

Description: Density and salinity data from sea ice samples taken during MOSAiC leg 4 (PS122/4). Sea ice samples were taken from Jaridge, Alli's Ridge, and Remote Sensing site. Sea ice cores were extracted from the ridges using a 7 cm inner diameter ice corer (Kovacs Enterprise Mark III coring system) powered by a cordless electric drill. Salinity/density ice cores were stored in sterile U-Lines bags and transported back to the ship within 2 hours of sampling. Ice cores were stored in a -20°C walk-in freezer until processing. The ice cores were cut into ~5 cm sections using a stainless steel, electric butcher band saw. Sea ice density was measured using the hydrostatic weighing method from ice cores in the freezer laboratory onboard Polarstern using Kern EMB 2000 scales and YDB-02 density kit. After that, the samples were placed in plastic cups with lids and melted at room temperature. Bulk salinity was measured on the melted water sample using a calibrated Mettler Toledo SevenGo conductivity meter (practical salinity scale, unitless). The table contains the event label (1), time (2), and global coordinates (3,4) of each coring measurement. Each separate core has its local coordinates X (5) and Y (6) in [m]. For each drill hole, the depth relative to the waterline of the top (7) and bottom (8) interface of each separate layer is given together with its density (9), salinity (10), and laboratory temperature (11). The location (11) refers to the ridge name with other installations and measurements (Jaridge, Allis ridge, and Remote Sensing site). Each core has also measurements of the total ice thickness (12), ice draft (13), and snow depth (14). For Jaridge, a drill hole with local coordinates of (0,0) coincides with the ice mass balance buoy 2020M26 installation described in doi:10.1594/PANGAEA.938354. For Alli's ridge, a drill hole with local coordinates of (7.5,0) coincides with the ice mass balance buoy SIMBA 2020T61 installation described in doi:10.1594/PANGAEA.926580. The Alli's ridge drill hole with local coordinates of (2.5,10) coincides with the salinity/isotope ice core described in doi:10.1594/PANGAEA.943746. The Remote Sensing site was close to the Infrared camera installation described in doi:10.1594/PANGAEA.940717.

Description: The data has been collected during the year-long drift expedition "Multidisciplinary drifting Observatory for the Study of Arctic Climate" (MOSAiC) from September 2019 to September 2020 on research vessel Polarstern. The dataset contains abundance of pelagic marine and sea ice protists, including algae (autotrophic) and protzoa (heterotrophic). Protists were identified and counted with light microscopy using the Utermöhl method and the result are given as cells per liter (cells/L) called Abundance. The samples were collected with short-term sediment traps deployed at 3-4 depths (1, 5, 15 and 50 m) below level ice and near sea-ice ridges. The samples were preserved with a few drops of Lugol and hexamethylenetetramine-buffered formalin at a final concentrations of 1%.