https://doi.pangaea.de/10.1594/PANGAEA.996221Rump, MarcoMarcoRump0009-0004-2329-4889Alfred Wegener Institute - Biological Institute HelgolandLannig, GiselaGiselaLannig0000-0002-9210-256XAlfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, BremerhavenBock, ChristianChristianBock0000-0003-0052-3090Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, BremerhavenBenthien, AlbertAlbertBenthien0000-0002-9159-3109Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, BremerhavenPogoda, BernadetteBernadettePogoda0000-0003-3997-426XAlfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, BremerhavenAntoni, DominikDominikAntoniAlfred Wegener Institute - Biological Institute HelgolandGerdts, GunnarGunnarGerdts0000-0003-0872-3927Alfred Wegener Institute - Biological Institute HelgolandPANGAEA2026ecotoxicologyocean alkalinity enhancementOstrea edulisEvent labelType of studyTissuesSample IDIndividual IDExperiment daySampling dateTreatmentTissue, dry massVial, massSample, wet massNickelChromiumCobaltMesocosm experiment2024-04-17T00:00:00/2025-03-12T00:00:00Datasethttps://doi.pangaea.de/10.1594/PANGAEA.996264https://doi.pangaea.de/10.1594/PANGAEA.996219https://doi.pangaea.de/10.1594/PANGAEA.996220https://doi.pangaea.de/10.1594/PANGAEA.996222https://doi.pangaea.de/10.1594/PANGAEA.996218https://doi.pangaea.de/10.1594/PANGAEA.996216https://doi.pangaea.de/10.1594/PANGAEA.996217https://doi.pangaea.de/10.1594/PANGAEA.996214https://doi.pangaea.de/10.1594/PANGAEA.9962151017 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalData access is restricted (moratorium, sensitive data, license constraints)This dataset contains nickel, chromium and cobalt concentrations measured in gill, mantle and hepatopancreas tissue of individual European flat oysters (Ostrea edulis) sampled on day 63 (9 July 2024) at the end of the chronic alkalinity-enhancement exposure experiment. A total of 19 individual oysters were sampled (5 control, 5 olivine 250, 3 olivine 500, 3 dissolved 250 and 3 dissolved 500); not all three tissues could be obtained from every individual due to tissue availability. Ten measurements of the certified reference material ERM-CE278k (mussel tissue) are included across the three tissue batches for quality control. Samples for metal analysis were freeze-dried for 24 h, and dry weight was recorded prior to extraction. Extraction vials were pre-cleaned (p.a. quality) with concentrated nitric acid (65 %, single-distilled) and dried for 48 h. Approximately 2 mL of nitric acid was added to the dried tissues, followed by thermic digestion using a microwave digestion system (5 min heating at 400 W; 5 min heating to 100 °C at 800 W; 20 min heating to 175 °C and 20 min held, 1600 W). The digested solutions were transferred to clean vials and diluted to 25 mL; vials were weighed before and after filling to determine the precise sample weight. Metal concentrations of Ni, Cr and Co were measured on 12 March 2025 at the AWI ICP Facility on a Thermo Scientific iCAP 7000 Series Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Calibration was performed with an in-house standard composed of the respective individual element standards (ICP-Standards ROTI® Star, Carl Roth). The standard deviation of the control standard was 0.1 µg/l for Ni, 0.3 µg/l for Cr and 0.2 µg/l for Co. External reproducibility (RSD) was 0.5 % for Ni, 1.2 % for Cr and 0.7 % for Co. Limits of detection and quantification were 0.13 and 0.7 µg/l for Ni; 0.26 and 1.32 µg/l for Cr; and 0.10 and 0.47 µg/l for Co. Analytical accuracy was verified with the certified reference material ERM-CE278k.7.88894454.180327Helgoland, GermanyBundesamt für Naturschutzhttps://doi.org/10.13039/5011000104153522830300DEFINE2