Sediment cores and pore water cores were taken in the Skagerrak with a multicorer on cruise HE586 (October 2021). The sediment cores were sliced onboard into 1 cm slices and frozen directly (-20°C). Pore water samples were taken with rhizon samplers (0.15 µm pore size, CSS; Rhizosphere, Netherlands) from intact sediment cores and frozen directly (-20°C). In the laboratory, the sediments were freeze-dried, sieved (<2mm) and milled. For organic carbon (after acidification) and total carbon and nitrogen contents, the samples were analyzed using an Euro EA 3000 (Euro Vector SPA) Elemental Analyzer, delta 15N was measured with a FlashEA 1112 elemental analyzer coupled to a MAT 252 (Thermo Fisher Scientific) isotope ratio mass spectrometer (https://doi.org/10.1016/j.orggeochem.2009.05.008; lab 3). The pore water nutrient concentrations (ammonia, silicate, phosphate, nitrite, nitrite+nitrate) were measured using a TECAN infinite 200 plate reader. Colorimetric methods according to Ringuet et al. (2011; https://doi.org/10.1039/C0EM00290A) for phosphate and silicate, Yu et al. (1994; http://www.sfjo-lamer.org/la_mer/32-2/32-2.pdf#page=19) for ammonia and Garcia-Robledo et al. (2014; https://doi.org/10.1016/j.marchem.2014.03.002) were applied. For trace metal analysis, the sediments were digested with HBF4+HNO3+HCl (https://doi.org/10.1039/D0AY01049A) and the pore water samples were acidified with HNO3 prior to 10-fold dilution with HNO3. Trace elements were measured by ICP-MS/MS (Agilent 8800, Agilent Technologies, Japan).