This dataset was collected during the cruise HE662 (24.05.2025 to 13.06.2025) with RV HEINCKE from Bremerhaven, Germany to Bremerhaven, Germany. It contains chlorophyll a measurements [µg/l] from water samples collected from discrete sampling via CTD. In total, 27 samples have been collected. To obtain chl-a concentrations water samples were filtered onboard through 0.7 µm pore size, glass fiber filters (Whatman GF/F) under low vacuum. Filters were frozen immediately at -80 °C until extraction in laboratory by 90% acetone method (measured on 07.08.2025). Concentrations were calculated from fluorescence measured with a pre-calibrated Turner Design TD 7200-02 laboratory fluorometer (EPA445.0, Turner Manual). Calibration details are given in the attached calibration document (PDF).

Michelle Albinus is responsible for data processing and publishing. Persons responsible for filtration on board are Lukas Raffelt and Shubham Sawle. Chief Scientist of RV HEINCKE cruise HE662 and PI of the publishing working group is Thomas H. Badewien.