The reactivity and isotope fractionation of Ni is strongly influenced by biological and redox-related processes in the ocean, giving the isotope system (expressed as δ60 Ni) some potential for studying past ocean environments. This requires, however, a profound understanding of its modern elemental and isotopic oceanic mass balance. In order to better understand mechanisms determining fluxes of Ni and its isotopes from the sediment-porewater system in reducing ocean settings, we present trace metal concentrations and Ni isotope data from sediments, porewaters and the water column of the shallow-water Kiel Bight, in the southwestern Baltic Sea. The samples were collected during RV Alkor cruise AL543. Trace metal concentrations in porewater, bottom water and BTP bottom water samples were measured on a Thermo Scientific Element XR and Nickel isotope compositions were measured using a Thermo Scientific Neptune Plus MC-ICP-MS. Digestion solutions of sediments and suspended particulate matter were measured by ICP-OES.