https://doi.pangaea.de/10.1594/PANGAEA.996214Rump, 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 HelgolandTotal alkalinity and pH in the alkalization mesocosms of a chronic Ostrea edulis alkalinity-enhancement exposure experimentPANGAEA2026ecotoxicologyocean alkalinity enhancementOstrea edulisEvent labelType of studyIncubation typeExperiment daySampling date/time, experimentTreatmentReplicatespHAlkalinity, totalMesocosm 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.996221https://doi.pangaea.de/10.1594/PANGAEA.996217https://doi.pangaea.de/10.1594/PANGAEA.9962152784 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalData access is restricted (moratorium, sensitive data, license constraints)This dataset contains repeated measurements of seawater pH and total alkalinity recorded in the alkalinization mesocosms, a set of tanks without oysters that received the same alkalinity treatments as the exposure mesocosms reported in a companion dataset. Total alkalinity was raised in three alkalization cycles to reach target increases of +250 or +500 µmol/kg over unamended seawater, using either dissolved alkalinity addition (NaOH and CaCl2) or olivine-based coastal enhanced silicate weathering. The three cycles ran 17 April to 7 May 2024, 8 May to 27 May 2024 and 30 May to 19 June 2024. Measurements were taken predominantly in triplicate per treatment and sampling day. Seawater pH was measured with a pH electrode and total alkalinity by open-cell potentiometric titration, both on a Metrohm 855 Robotic Titrosampler.7.88894454.180327Helgoland, GermanyBundesamt für Naturschutzhttps://doi.org/10.13039/5011000104153522830300DEFINE2