ALBERT

Description: In the paper "Salinity as a tool for strain selection in recirculating land-based production of Ulva spp. from germlings to adults" (Cardoso et al. 2023) the antioxidant activity (AA) experiment aimed to test a previously selected strain, Ulva lacinulata from the NE-Atlantic, and evaluate the variations in AA under different salinity treatments. We hypothesized that by reducing the salinity level in the recirculating land-based system, it would be possible to optimize and increase the quality of the biomass being produced before it being harvested. The NE-Atlantic seaweed was collected in the Óbidos Lagoon, Portugal in January 2021 and was cultivated in laboratory conditions in the Alfred Wegener Institute (AWI), Bremerhaven, Germany. To recreate the conditions of a large-scale system, the strain was grown previously and during the experiment in a medium of artificial seawater (Seequasal-Salz, Seequasal Salz Production and Trade GmbH, Münster, Germany) enriched with a cheaper commercial fertilizer Blaukorn (COMPO SANA®, Germany). Twelve 1 L beakers were filled with artificial seawater at 4 different salinities (10, 15, 20 and 30 PSU), measured with a refractometer (Atago, Japan) (n = 3). Six discs (2 cm) of U. lacinulata were placed in each beaker and, at different times (0 h, 3 h, 24 h, 120 h, 192 h and 240 h) 1 disc was collected from each beaker to evaluate the antioxidant activity. The AA was determined by the ABTS Radical Cation Decolourisation Assay based on Re et al., 1999, and a Trolox standard curve was created by measuring the absorption of different Trolox concentrations in ethanol after being mixed with ABTS. The absorption of the samples at 734 nm was analysed with a microplate reader (Infinite 200 Microplate Reader, Tecan Trading AG, Männedorf, Switzerland) and the AA results obtained were given in Trolox Equivalent (in µg/mL).

Description: Raw data acquired by an SBE21 thermosalinograph and an auxiliary SBE38 temperature sensor (Sea-Bird Scientific, USA) installed in an underway seawater flow-through system on board RV Heincke were processed to yield a calibrated and validated data set of seawater temperature and salinity along the cruise track. The seawater inlet is located at a depth of 2 m. The raw hexadecimal data were downloaded from the DAVIS SHIP data base (https://dship.awi.de) at a resolution of 1 s, and converted to temperature and conductivity using the pre-deployment factory calibration coefficients. The converted data were averaged to 1 min values, outliers were removed, and sensor drift was corrected using coefficients obtained from a post-season calibration performed at Sea-Bird at the end of the measurement season. Salinity was calculated from internal temperature, conductivity and pressure according to the PSS-78 Practical Salinity Scale. Processed data are provided as 1 min means of seawater temperature, conductivity and salinity, aligned with position data taken from the master track. Quality flags are appended according to the SeaDataNet Data Quality Control Procedures (version from May 2010). More details are described in the attached processing report.