This dataset was collected during the cruise HE533 (16.05.2019 to 11.06.2019) with RV HEINCKE from Bremerhaven, Germany to Bremerhaven, Germany. It contains chlorophyll a measurements [µg/L] from water samples collected from dicrete sampling via CTD. In total, 29 stations have been sampled. The obtain chl-a concentrations water samples were filtered onboard through 0.7 μm pore size, glass fiber filters (WhatmannWhatman GF/F) under low vacuum. Filters were frozen immediately at -80 °C until extraction in laboratory by 90% acetone method. Concentrations were calculated from fluorescence measured with a pre-calibrated Turner Design TD 700 laboratory fluorometer (EPA445.0, Arar & Collins, 1997) .Chief Scientist of HE533: Dr. Uwe John, Alfred-Wegener-Institute, Helmholtz Centre for Polar and Marine Research