Sediment and seawater (SW) samples were collected from two sites: one set from the German Wadden Sea close to the Jade Bight, Wilhelmshaven on 14 July 2021, and a second set from Isfjorden, Svalbard on 30 April 2022 and 02 May 2022. We fractionated the sediment microbial community into cells in the pore water (PW), cells loosely attached to the grains (LA), and cells firmly attached to the grains (FA). We extracted DNA from the seawater, bulk sediment, and sediment fractions and amplified the V3-V4 region of the 16S rRNA gene using previously described primers (Herlemann et al., 2011). We sequenced the amplicons on a 2x250 bp run on an Illumina MiSeq.