https://doi.pangaea.de/10.1594/PANGAEA.995830Adam-Beyer, NicoleNicoleAdam-BeyerGEOMAR - Helmholtz Centre for Ocean Research KielSkottke, CarolinCarolinSkottkeSchmidt, MarkMarkSchmidt0000-0002-4298-9617GEOMAR - Helmholtz Centre for Ocean Research KielPANGAEA2026incubationIn situmicrobial communitiesoffshore monopileDATE/TIMELATITUDELONGITUDEDEPTH, waterSulfateBromideChlorideIronAluminiumManganesePhosphateNitriteNitrateSilicateAmmoniumSulfide, totalMethaneCarbon dioxideOxygenMonitoring stationIon chromatography (Metrohm)Inductively coupled plasma atomic emission spectroscopyPhotometryGas chromatographyTitration2023-09-06T13:45:00/2024-10-10T14:30:00Dataset10.1080/09377255.2025.2554133162 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalData access is restricted (moratorium, sensitive data, license constraints)Water sampling related to microbial induced corrosion experiments was conducted inside a monopile structure located in the German North Sea (i.e. FINO-3; Skottke et al. 2023). Geochemical water column parameters were determined during 4 visits of the FINO-3 platform between 06.09.2023 and 10.10.2024 to constrain physical and chemical conditions during long-term corrosion experiments at the inner steel wall of the monopile. Strong seasonal vertical stratification inside the monopile were determined below a thermocline in summer months, accompanied by anoxia, biogenic methane and highly corrosive/toxic hydrogen sulfide accumulation.7.15869999999999755.195000000000014North SeaGerman Federal Ministry for Economic Affairs and Energyhttps://ror.org/02vgg280803EE3082AMiCorFe