The water samples were taken from Niskin bottles attached to a CTD in June 2021 on the cruise AL557 in the Skagerrak and the North Sea. The trace element samples were filtered in triplicates with DigiFILTERs (trademark) (0.45 microm, 50 mL, SCP Science, Canada) and measured by seaFAST-ICP-MS (seaFAST SP2, Elemental Scientific, USA; Agilent 8900, Agilent Technologies, Japan; Przibilla et al., 2023; https://doi.org/10.1002/wer.10922). The nutrient samples were filtered with 0.47microm cellulose acetate syringe filters (Minisart, Sartorius, Germany) and analyzed with standard colorimetric techniques (Hansen and Koroleff, 2007) on a continuous flow auto analyzer (AA3, SEAL Analytical, Germany).