Undisturbed sediment samples were obtained with a TV-guided multiple corer (TV-MUC). Upon retrieval of the MUC, the overlying water was carefully removed from each core and the upper few centimeters of sediment were cut using a steel plate and a custom-made plastic ring into the following depth horizons: 0-1 cm, 1-5 cm, 5-10 cm. For each sediment horizon, 5 biological replicates were obtained. Chloroplastic pigments were extracted from 1 ml sediment with 3x8 ml acetone (90%), including the addition of glass beads and grinding of the samples in a cell mill Boetius and Damm (1998, doi:10.1016/S0967-0637(97)00052-6). Samples were centrifuged and chlorophyll a and phaeopigment (after addition of 30 μl 20% HCl) concentrations were determined in the supernatant by fluorometric measurement with a Turner Trilogy fluorometer with the "Chlorophyll a Acidification" fluorescence module. Chlorophyll a and phaeopigment concentrations were calculated according to Bienhold et al. 2022 (doi:10.3389/fmars.2022.1004959). Chloroplastic pigment equivalents (CPE) are calculated as the sum of chlorophyll a and phaeopigment concentrations.