https://doi.pangaea.de/10.1594/PANGAEA.996216Rump, 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 studyIncubation typeSampling date/time, experimentTreatmentExperiment dayOstrea edulis, aliveOstrea edulis, deadMortalityTemperature, waterOxygenConductivitySalinityChlorophyll a, totalSuspended particulate matterAmmoniaMesocosm 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.996221https://doi.pangaea.de/10.1594/PANGAEA.996217https://doi.pangaea.de/10.1594/PANGAEA.996214https://doi.pangaea.de/10.1594/PANGAEA.9962154326 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalData access is restricted (moratorium, sensitive data, license constraints)This dataset contains oyster mortality records and the main physicochemical parameters monitored in the exposure mesocosms, the tanks holding 60 oysters per treatment (unamended control, dissolved alkalinity addition with NaOH and CaCl2 at +250 or +500 µmol/kg, and olivine-based coastal enhanced silicate weathering at +250 or +500 µmol/kg). Mortality is reported as the number of oysters alive, the interval and cumulative number of oysters found dead, and the relative cumulative mortality (a proportion of the initial 60 individuals per tank). Physicochemical parameters include water temperature, dissolved oxygen, conductivity, salinity, total chlorophyll a, suspended particulate matter and ammonia concentration. Measurements span 17 April to 10 July 2024, covering the alkalinization period and the subsequent 63-day chronic exposure. Water temperature, oxygen and conductivity/salinity were recorded with a multi-probe (Xylem Analytics Germany). Total chlorophyll a was measured by fluorescence on unfiltered seawater with a bbe fluorimeter. Suspended particulate matter was determined gravimetrically from filtered seawater. Ammonia was quantified fluorometrically with a microplate reader assay kit.7.88894454.180327Helgoland, GermanyBundesamt für Naturschutzhttps://doi.org/10.13039/5011000104153522830300DEFINE2