FY 2025

SalishCruiseMultistressor_v2025: An updated multi-stressor data product for marine heatwave, hypoxia, and ocean acidification research, including calculated inorganic carbon parameters from the southern Salish Sea and northern California Current System from 2008-02-04 to 2024-10-22

Alin, S.R., J. Newton, R.A. Feely, C. Ikeda, A. Boyar, D. Greeley, J. Herndon, and A. Kozyr

NCEI Accession 0307626, NOAA National Centers for Environmental Information, doi: 10.25921/4y18-rw26, https://www.ncei.noaa.gov/access/ocean-carbon-acidification-data-system/oceans/SalishCruises_DataProduct.html (2025)

Northeastern Pacific coastal and estuarine ecosystems, such as the southern Salish Sea and northern California Current System, are experiencing rapidly changing ocean conditions, including intense heatwaves, increasing hypoxia, and rapid acidification (Figures 1 and 2). High-quality observations are essential for characterizing natural variability in ocean conditions and extreme events, establishing appropriate conditions for biological studies, validating coupled physical-biogeochemical models, and providing context for observed ecosystem impacts. Here we provide a climate-quality data product including measurements of temperature, salinity, nutrients (nitrate, phosphate, silicate, nitrite, and ammonium), and recommended oxygen values in all commonly used units (mg/L, mL/L, and µmol/kg-seawater), along with measured and calculated inorganic system parameters. While the original data package included only directly measured variables (and unit conversions), calculated values are often not archived with measured values for the inorganic carbon system. In this data product, we provide the most commonly used calculated parameters in the marine inorganic carbon system, with the goals of increasing accessibility of this important information about coastal and estuarine stressors and their variability to a broader audience of end users, who may not have expertise in performing inorganic carbon calculations themselves, and facilitating multiple stressor studies in the southern Salish Sea and northern California Current System.

This data product includes only the highest quality subset (i.e., with quality control flags of 2) of the (Salish cruise data package ). with complete carbon, oxygen, nutrient, and CTD observations. We used the seacarb package in R (function carb) to calculate the most commonly used derived carbonate system parameters, including pH (on the total scale), partial pressure and fugacity of carbon dioxide at in situ temperatures and pressures (pCO2insitu, and fCO2insitu, respectively), and aragonite and calcite saturation states (OmegaAragonite and OmegaCalcite, respectively; Gattuso et al., 2023). Input parameters from the updated Salish cruise compiled data set (SalishCruiseDataPackage_v2025, Alin et al. 2025a) comprised dissolved inorganic carbon (DIC_UMOL_KG), total alkalinity (TA_UMOL_KG), phosphate (PHOSPHATE_UMOL_KG), and silicate (SILICATE_UMOL_KG) content values from bottle samples analyzed in the laboratory, along with CTD measurements of temperature (CTDTMP_DEG_C_ITS90), salinity (CTDSAL_PSS78), and pressure (CTDPRS_DBAR). Within seacarb, we used the TEOS-10 thermodynamic seawater equations (IOC, SCOR, and IAPSO, 2010). We adopted the total scale for pH (pHT), the Uppstrom (1974) formulation for deriving total boron concentration from salinity, the seacarb default option for Kf (Perez and Fraga, 1987 for temperatures above 9 °C; Dickson and Goyet, 1994 for those below), and the Dickson (Dickson, 1990) option for Ks (following results of Orr et al., 2015). All input content data were first divided by 10^6 to convert from µmol kg–1 to mol kg–1, and pressure (in decibars) was divided by 10 to convert to bar, to conform with the default units of seacarb. For equilibrium constants (K1 and K2), we provide calculated values using both the Lueker et al. (2000) and the Waters et al. (2014) dissociation constants (variable names include “_Lueker” or “_Waters”, respectively). The Lueker constants (for salinity ranges of 19–43 and temperature ranges of 2–35°C) facilitate comparison with publications arising from (West Coast Ocean Acidification (WCOA) cruise data sets), whereas the Waters constants (for salinity ranges of 1–50 and temperature ranges of 0–50°C) allow users working with more brackish salinities to compare their results directly to those in the Salish cruise data product. All references above are included in the seacarb documentation (https://cran.r-project.org/web/packages/seacarb/seacarb.pdf). Alin et al. (2024b) describe the magnitude of differences in calculated values for the Salish cruise data product using the two different sets of dissociation constants.

The SalishCruiseMultistressors_v2025 data product contains 6527 complete records of DIC, TA, T, S, O2, and nutrient measurements. Of this package, all recommended oxygen values have “acceptable” quality flags, as do 6525 CTD temperature and salinity, 6433 TA, 6437 DIC, and 6522 nutrient measurements (see Metadata for details of quality flags used). Including 973 unique oceanographic profiles, the observations in this data product span wide dynamic ranges of temperature (6.0–23.0°C), recommended oxygen concentration (18–612 μmol kg−1, 0.6–19.9 mg/L, 0.4–14.0 mL/L), fCO2 (69–3465 μatm), pHT (7.14–8.59), aragonite saturation state (0.23–3.89), and calcite saturation state (0.37–6.28). The effects of seasonality and extreme events on the geographic extent, the severity, and the duration of occurrence of these multiple marine stressors, as observed during the 2014–2018 seasonal cruise time series, are described in Alin et al. (2024a,b), and a preliminary description of the 2019–2024 cruise observations can be found in Alin et al. (2025b). Sensitivity thresholds for numerous regionally valued species are crossed within the southern Salish Sea and northern California Current System (Figure 3 and Alin et al. 2024b Tables 3–4). The dashed vertical line represents a sensitivity threshold for Dungeness crab to pHT used in Berger et al. (2021 and references therein), and the horizontal line represents the thermodynamic saturation threshold for calcite (Ωcalc = 1), below which calcite may dissolve. Dungeness crab h have calcite in their exoskeletons at multiple life stages, and Bednaršek et al. (2022) documented exoskeleton dissolution in U.S. West Coast waters in Dungeness crab megalopae that appeared to be related to Ωcalc levels.

The SalishCruiseMultistressors_v2025 data product and metadata are available on the Index page accessed by clicking the Database Files link above the map: Data—Filename “SalishCruiseMultistressors_v2025_data_07252025.csv” includes all complete CTD, carbon, nutrient, and oxygen samples along with calculated carbonate system parameters. Metadata—Filename “SalishCruiseDataPackage_v2025_metadata_07252025.xlsx” includes detailed methods information for all measurements included in this data package. Changes made to data quality flags for 2008–2024 data since the previous version of the data package can be found in the SalishCruiseDataPackage_v2025 metadata file.