Other language confidence: 0.9422980052669233
This dataset contains calculated carbonate chemistry parameters, including the concentrations of dissolved CO2, HCO3-, CO32- and dissolved inorganic carbon, the fugacity and partial pressure of CO2 and the saturation states of aragonite (Ωarag) and calcite (Ωcalc), for the exposure mesocosms. Values were calculated from pH, total alkalinity, salinity and temperature measured between 8 May and 10 July 2024, using the seacarb package (Orr et al., 2018) in R (V. 4.3.2). Measured pH values, which refer to the NBS scale, were first converted to the total scale using the total proton activity coefficient fH of Takahashi et al. (1982), lowering pH by 0.12 to 0.13 units across the measured salinity and temperature range. Calculations used the carbonic acid dissociation constants of Lueker et al. (2000), the bisulfate dissociation constant of Dickson (1990), the hydrogen fluoride constant of Perez & Fraga (1987), total boron after Uppström (1974) and the aragonite and calcite solubility products of Mucci (1983), all evaluated at in situ temperature and salinity. The conversion from the NBS to the total scale carries a residual uncertainty of about 0.01 to 0.02 pH units, because the liquid junction potential between the dilute calibration buffers and seawater is not fully captured by fH. This propagates to an uncertainty of roughly 5 to 15 % in calculated pCO2 and a correspondingly smaller uncertainty in the saturation states.
This dataset contains concentrations of 27 polar metabolites measured in gill and mantle tissue of individual European flat oysters (Ostrea edulis) sampled before the start of the chronic alkalinity-enhancement exposure (7 May 2024, baseline, n = 10 per tissue) and after 21, 42 and 63 days of exposure (28 May, 18 June and 9 July 2024) to one of five treatments, with 3 to 5 individuals sampled per treatment, tissue and timepoint. Extraction: Frozen gill and mantle samples were wet-weighed (100 to 400 mg WW) and, if necessary, ground to smaller pieces with a mortar and pestle pre-chilled in liquid nitrogen before being transferred to Precellys tubes. Polar metabolites were extracted following the protocol of Tripp-Valdez et al. (2017), adjusted as follows: 400 µL methanol and 125 µL MilliQ water for homogenization and 400 µL chloroform and 400 µL MilliQ water for phase separation. All steps used pre-chilled (0 to 4 °C) instruments and reagents to minimize metabolite degradation. The polar upper layer was transferred to 1.5 mL tubes and dried overnight in a SpeedVac vacuum concentrator at 30 °C (RVC 2-18, Martin Christ Freeze Dryers GmbH, Germany). Dried polar metabolites were resuspended in D2O containing 3-(trimethylsilyl)propionic-2,2,3,3-d4 acid sodium salt (TSP; 0.05 wt %; Sigma Aldrich, St. Louis, USA) as internal standard and chemical shift reference, in a 1:1 ratio of µL D2O per mg tissue WW. Measurement: Untargeted metabolite profiling was performed using an ultra-shielded vertical 9.4 T NMR spectrometer (Avance III HD 400 WB, Bruker-BioSpin GmbH, Germany) equipped with a 1.7 mm TXI MicroProbe. Metabolite spectra were acquired using TopSpin 3.2 (Bruker-BioSpin GmbH, Rheinstetten, Germany) at room temperature, with the following parameters: 1D-Carr-Purcell-Meiboom-Gill (CPMG) pulse train with f1 presaturation (cpmgpr1d), 90° pulse 8.4 µs, TD 70.656, sweep width 8802 Hz (22 ppm), acquisition time 4.01 s, relaxation delay 4 s, 4 dummy scans and 128 scans per sample. ¹H-NMR spectra were processed and analyzed in Chenomx NMR Suite V.12.0 (Chenomx Inc., Canada): automated zero-filling, exponential multiplication (0.3 Hz line broadening), phase correction, baseline correction, shim correction and TSP calibration. Spectra from each tissue type within experimental groups were overlaid in Chenomx Profiler to evaluate spectral quality, comparability, linewidths, shifts and baselines, a step critical for accurate metabolite quantification. The adenylates ATP, ADP and AMP were summed as one metabolite (adenylates), resulting in a total of 27 metabolites.
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.
This dataset contains calculated carbonate chemistry parameters, including the concentrations of dissolved CO2, HCO3-, CO32- and dissolved inorganic carbon, the fugacity and partial pressure of CO2 and the saturation states of aragonite (Ωarag) and calcite (Ωcalc), for the alkalization mesocosms. Values were calculated from pH, total alkalinity, salinity and temperature measured between 17 April and 19 June 2024, using the seacarb package (Orr et al., 2018) in R (V. 4.3.2). Measured pH values, which refer to the NBS scale, were first converted to the total scale using the total proton activity coefficient fH of Takahashi et al. (1982), lowering pH by 0.12 to 0.13 units across the measured salinity and temperature range. Calculations used the carbonic acid dissociation constants of Lueker et al. (2000), the bisulfate dissociation constant of Dickson (1990), the hydrogen fluoride constant of Perez & Fraga (1987), total boron after Uppström (1974) and the aragonite and calcite solubility products of Mucci (1983), all evaluated at in situ temperature and salinity. The conversion from the NBS to the total scale carries a residual uncertainty of about 0.01 to 0.02 pH units, because the liquid junction potential between the dilute calibration buffers and seawater is not fully captured by fH. This propagates to an uncertainty of roughly 5 to 15 % in calculated pCO2 and a correspondingly smaller uncertainty in the saturation states.
This dataset contains measurements of seawater pH and total alkalinity from a short-term factorial feeding experiment conducted independently of the main chronic alkalinity-enhancement exposure. The experiment tested whether the shellfish diet used to feed the oysters in the main experiment (Reed Mariculture SD1800, a concentrated microalgae feed) contributes to seawater total alkalinity, and whether this contribution depends on the presence of oysters. Four treatment combinations were run in parallel over a 9-day period (12 to 21 November 2024): unamended seawater without oysters or feed (control), seawater with food but without oysters (SD 1800), seawater with oysters but without feed (oysters) and seawater with both oysters and feed (oysters + SD 1800). Oysters in the unfed treatments were left entirely without feed for the full 9 days. Each treatment was sampled on six days (day 0, 1, 3, 5, 7 and 9) in triplicate. Seawater pH was measured with a pH electrode and total alkalinity by open-cell potentiometric titration, both on a Metrohm 855 Robotic Titrosampler.
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.
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.
This dataset contains repeated measurements of seawater pH and total alkalinity recorded in the exposure mesocosms, the tanks holding the oysters exposed to five treatments (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) over a 64-day chronic exposure. These treatments mirror those established in the alkalinization mesocosms. Measurements span three sampling intervals, 8 May to 27 May 2024, 29 May to 17 June 2024 and 19 June to 10 July 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.
This dataset contains glycogen concentrations measured in the labial palps of individual European flat oysters (Ostrea edulis), sampled either before the start of the chronic alkalinity-enhancement exposure (7 May 2024, baseline, n = 8) or after 63 days of exposure to one of five treatments (9 July 2024; 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; n = 15 across treatments). Glycogen was extracted from the labial palps tissue and quantified photometrically following the method of Keppler and Decker (1988). For four individuals, glycogen was quantified in two independent measurement runs on separate tissue homogenates of the same individual; all other individuals were measured in a single run. Within each measurement run, glycogen was determined from up to two technical replicate measurements of the same tissue homogenate.
Adult European flat oysters (Ostrea edulis) were exposed in indoor mesocosms to two contrasting approaches for ocean alkalinity enhancement (OAE): dissolved alkalinity addition using NaOH and CaCl2, and olivine-based coastal enhanced silicate weathering, each targeting a total alkalinity increase of +250 or +500 µmol/kg over unamended seawater. An alkalinization phase (17 April to 19 June 2024) established the target total alkalinity in each treatment tank before oysters were introduced for a subsequent chronic exposure phase (8 May to 10 July 2024). Seawater pH and total alkalinity, salinity, temperature, dissolved oxygen, chlorophyll a, suspended particulate matter and ammonia were monitored throughout both phases, alongside oyster mortality. Full carbonate system parameters (CO2, HCO3-, CO32-, dissolved inorganic carbon, pCO2 and the aragonite and calcite saturation states) were calculated from the measured pH, total alkalinity, salinity and temperature using the seacarb package in R. At the end of the chronic exposure, oyster gill, mantle and hepatopancreas tissue was sampled for trace metal accumulation (nickel, chromium and cobalt) by ICP-OES, gill and mantle tissue for untargeted polar metabolite profiling by ¹H-NMR spectroscopy, and labial palps tissue for glycogen quantification. A separate short-term feeding experiment (12 to 21 November 2024) tested whether the shellfish diet used to feed the oysters (Reed Mariculture SD1800) contributes to the total alkalinity increase observed in the treatment tanks, independent of the OAE treatments. This submission bundles nine related data tables from this study; an individual, table-specific abstract accompanies each file in the file description.
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