Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
  • BCO-DMO Curation Notes
• Data Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Project Information
• Funding

Naturally settled M. californianus (urn:lsid:marinespecies.org:taxname:367837) were manually collected from Carmet Beach, CA, USA between January 2020 and April 2022. Mussels were dissected immediately upon arrival at Bodega Marine Laboratory (BML), CA (<0.5 h transit time) to remove all body tissue. Remaining organic materials (byssal threads, epibionts) were removed by drying shells in an oven for 24 h at 60°C. M. trossulus (urn:lsid:marinespecies.org:taxname:140482) of 20–75 mm length (target length consistent with M. californianus shells) were collected from Penn Cove Shellfish Farm in Penn Cove, WA, USA in September and December of 2023. Mussels from Penn Cove were maintained in a moist, cool and insulated environment during shipment to BML (< 1 day), and were dissected immediately upon arrival at the lab using methods described above.

Abiotic dissolution experiments were conducted on mussel shells between March 2020 and March 2024. All mussel shells were incubated in seawater manipulated to a target aragonite saturation state of Ω_aragonite = 0–9 (actual Ω_aragonite = 0.05–9.03). To separate contributions of the inner or outer shell surface to dissolution, we coated the inside of a subset of shells of each species with a clear, silicone waterproof sealant (Loctite), applying a single, thin layer to the nacre. For the incubations, we first added ambient seawater to a 1 L mixing vessel, then added variable doses of sodium hydroxide (NaOH) and Hydrochloric acid (HCl) to manipulate pH and Ω_aragonite. We mixed the treatment water thoroughly and subsampled 150 ml of this water to characterize chemical conditions before incubation (described below). The remaining 850 mL of treatment water was inverted into a glass incubation jar containing a mussel shell and the jar was sealed immediately and placed in a dark incubation chamber. We removed mussel shells after a target of 42−45 h, though 25% of incubations occurred in tandem with prior experiments and had an incubation period of 108−115 h; we accounted for this difference by normalizing abiotic dissolution by time (dissolution rate). After incubation, a 150 mL subsample was again extracted from jars and used to measure chemical conditions after incubation. The treatment water mass and shell mass were recorded, with water mass derived using the equation (total mass = jar mass + shell mass +water mass).

Before and after incubation, we measured oxygen, temperature, salinity, total alkalinity and pH in each incubation vessel. The pH probe was used for routine measurements, while the Shimadzu spectrophotometer provided more precise pH measurements using m-cresol purple dye. Spectrophotometric measurements were conducted at incubation temperature periodically throughout the experiment and used to correct the probe measurements. Ammonia was measured before incubation from one of four carboys used to dispense ambient seawater for treatments (triplicate ammonia samples per carboy) and after incubation from each incubation vessel. Before and after incubation, our 150 mL subsamples were preserved in duplicate, using opaque bottles for alkalinity titration, which occurred within 24 h according to methods described in Ninokawa et al. (2024). TA was measured in triplicate, and the standard deviation among the three replicate titrations was calculated for each TA sample. Incubations were discarded if the standard deviation among the triplicate titrations exceeded 10 µmol kg⁻¹, resulting in 45 unsealed and 27 sealed M. trossulus shells and 46 unsealed and 25 sealed M. californianus shells used for analysis. Though waste excretion was not expected for abiotic shells, we measured ammonia to account for any biologically associated changes in alkalinity (i.e. microbial activity in water or on shells) using a salicylate spectrophotometric assay (Ninokawa et al. 2024). 

Sealed M. californianus shells were tested during a separate experiment by Saley & Gaylord (2025) using the same analytical methods but targeting a narrow range of Ω_aragonite< 1 and using approximately 300 mL of water. Therefore, in statistical analyses focused on comparisons across groups, our full dataset was subsampled to Ω_aragonite< 1 for consistency. We also normalized dissolution (in µmol kg⁻¹) by water mass, multiplying alkalinity change by kg treatment water before finding dissolution rate per shell mass (µmol CaCO₃ hr⁻¹ g⁻¹) across all treatments. Note that shell length but not mass was measured by Saley & Gaylord (2025); we therefore derived shell mass for this group based on the relationship between length and mass in a separate dataset of 558 M. californianus mussels initially measured for Ninokawa et al. (2024).

We calculated abiotic dissolution rate using the ammonia-corrected alkalinity anomaly technique, dividing CaCO₃ dissolution by incubation time and dry shell mass (Gazeau et al. 2015). We used chemical measurements to determine the carbonate chemistry of each incubation including Ω_aragonite and Ω_calcite using the package seacarb v 3.3.3  (Orr et al., 2003) in R v 4.5.0 (R Core Team, 2025) with constants from Lueker et al. (2000).

This section documents curation actions performed prior to publication review with the submitter, and additional information relevant to understanding and reusing this dataset. It distinguishes changes made to the submitted (meta)data from unresolved issues and/or enhancements that improve future reuse and interoperability.

CURATION ACTIONS PERFORMED ON DATA

- Loaded abiotic_dissolution_Mtrossulus_Mcalifornianus.csv, header row 1, declared "", "nd", and "NA" as missing value sentinels (needed since shell.length used "NA" for missing entries)
- Renamed columns shell.number, shell.wt, shell.length to shell_number, shell_wt, shell_length to normalize dot-separated names to underscore-separated, to conform with BCO-DMO parameter guidance
- Computed new species column: set to "Mytilus californianus" if treatment matched regex containing "californianus", "Mytilus trossulus" if treatment matched "trossulus" in order to provide more explicit labeling of treatment/species combinations
- Computed new paint_treatment column: default value "unpainted", set to "painted" if treatment matched regex containing "painted" in order to provide more explicit labeling of treatment/species combinations
- Reordered columns to: shell_number, treatment, species, paint_treatment, G, OmegaAragonite, duration, shell_wt, shell_length
- Output as 1006705_v1_abiotic_dissolution_mytilus.csv

CURATION ACTIONS PERFORMED ON METADATA

- BCO-DMO's standard metadata entry and text formatting steps were performed.
- Scientific names in the data were checked using World Register of Marine Species (WoRMS) Taxon Match. All scientific names in the data are valid and accepted names as of 2026-08-31.
- Adjusted location fields information from Penn Cove, Washington (38 N 122 W) to Penn Cove, Washington (48 N 122 W).
- Added citations for software listed.

ISSUES POTENTIALLY IMPACTING REUSE

- N/A

NSF Award Abstract:
This research is exploring the capacity of coastal organisms to cope with alterations in seawater chemistry driven by both freshwater inputs and absorption of carbon dioxide into the world's oceans (ocean acidification). The project focuses on calcification responses and behavioral impairments of shoreline animals under altered seawater chemistry, and forefronts a common mussel species (the California mussel), and a common snail (the black turban snail), each abundant on rocky shores along the west coast of North America. The target species operate as exemplar organisms for characterizing the responses of marine invertebrates more generally. Methods involve experimental decoupling of multiple components of the carbonate system of seawater to isolate drivers that are difficult to separate otherwise. Broader impacts include transfer of scientific information to policy-makers, including legislators, as well as training and skill-set development of future generations of scientists and citizens. One Ph.D. student is supported, as are UC Davis undergraduates conducting mentored research. The project also provides research internships for undergraduates from a local community college (Santa Rosa Junior College), many of whom are from underrepresented groups. The latter project component substantially bolsters an ongoing program at Bodega Marine Laboratory that includes efforts in diversity, equity, and inclusion. Data and interpretations from the project are feeding into an existing educational program that links to local K-12 schools and reaches ~10,000 members of the public each year.

Overall, the research of the project is dissecting drivers of calcification and behavioral disruption in key shoreline invertebrates, across present-day and future carbonate system conditions appropriate to coastal marine environments. Efforts are exploring the extent to which calcification depends on one versus multiple parameters of the seawater carbonate system. In particular, existing conceptual models emphasize the importance of calcium carbonate saturation state (Ω) and/or the ratio of bicarbonate to hydrogen ion concentrations ([HCO3-]/[H+]), and the project is examining these mechanisms as well as the possibility that more than one driver acts simultaneously. It is doing so both in bivalves and in gastropods to test for generality across mollusks. The project is additionally examining whether pH is the only carbonate system factor contributing to known patterns of behavioral impairment in marine invertebrates. Leading explanations for debilitating behaviors induced by ocean acidification involve altered ion channel function, but discussion in the literature continues, and studies that explicitly decouple the carbonate system are necessary.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.