Data from: Brucite-inspired ocean alkalinity enhancement alters the biogeochemistry and composition of a phytoplankton community: A Santa Barbara channel case report
Data files
Nov 20, 2025 version files 54.03 KB
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BrucitePhytoManuscript_Biogeochem.csv
9.32 KB
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BrucitePhytoManuscript_CarbChem.csv
12.98 KB
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BrucitePhytoManuscript_PhytoCommunityCounts.csv
9.08 KB
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README.md
22.66 KB
Abstract
The dramatic impacts of global climate change have driven marine carbon dioxide removal (mCDR) innovation, including ocean alkalinity enhancement (OAE), in an attempt to keep global warming under 2 °C. We experimented to assess the impacts of brucite-inspired alkalinity addition (BIAA) as an OAE approach on the carbonate chemistry, biogeochemistry, and composition of the Santa Barbara Channel phytoplankton community sourced from a spring upwelling event. The BIAA treatment used MgCl2 * 6H2O and NaOH to yield a total alkalinity (TA) concentration of 3000 µmol/kg, in contrast with the untreated seawater controls (TA = 2300 µmol/kg). Our results suggest that BIAA altered the phytoplankton community composition, including reduced contribution of diatoms and enhanced numbers of Prymnesiophyceae (coccolithophores and Phaeocystis sp.). These results are in agreement with observations that biogenic silica content was lower under BIAA treatment. While the concentration of particulate inorganic carbon was consistently higher compared to controls, these differences were not statistically significant. Results revealed no differences between control and BIAA treatment in particulate organic carbon and particulate organic nitrogen concentrations. The proxy for cellular photosynthetic health, Fv/Fm, revealed that cells were photosynthetically healthy for both control and BIAA treatments, but values were lower in the BIAA treatment at the beginning of the exponential phase. While statistical power limitations of laboratory results might restrict applicability to other systems, our overall results suggest that BIAA has a differential impact on phytoplankton functional groups and their biogeochemical performance.
https://doi.org/10.5061/dryad.9cnp5hqvk
Description of the data and file structure
Files and variables
File: BrucitePhytoManuscript_CarbChem.csv
Description: Contains seawater carbonate chemistry system parameter data
Variables
- bottle_label: The label that was used to keep track of experimental samples for carbonate chemistry analysis. Serves as a single identifier that is multi-part and unique. It is composed of treatment information, sampling day information, and replicate information, in that order.
- condition: "biotic" or "abiotic". Describes if the treatment contained phytoplankton or not.
- sampling_day: 0, 3, 6, 9, 12. Sampling occurred every third day of the experiment, and the experiment ran for 12 days.
- treatment: "Ctrl", "MgSalt", "Bio", "BioMgSalt". "Ctrl" represents the abiotic control (no phytoplankton, no alkalinity addition), and is called "Control-A" (Control-Abiotic) in the manuscript. "Mgsalt" represents the abiotic alkalinity-added treatment (no phytoplankton, yes alkalinity addition), and is called "BIAA-A" (Brucite Inspired Alkalinity Addition-Abiotic) in the manuscript. "Bio" represents the biotic control (yes phytoplankton, no alkalinity addition), and is called "Control-B" (Control-Biotic) in the manuscript. "BioMgSalt" represents the biotic alkalinity-added treatment (yes phytoplankton, yes alkalinity addition), and is called "BIAA-B" (Brucite Inspired Alkalinity Addition-Biotic) in the manuscript.
- replicate: A, B, C. Three independent bottles were sacrificed from every treatment on every sampling day. These triplicates were designated A, B, or C.
- Sal_ppt: Salinity as measured via conductivity . Units are parts per thousand (ppt)
- TA_corr_umolPerkg: total alkalinity (TA) corrected for mercuric chloride addition (100 microliters of super-saturated mercuric chloride solution) in units micromoles per kilogram seawater
- pH_corr_techavg: the mean value of technical replicate measurements of seawater pH corrected for m-cresol dye batch. No units as pH is the negative logarithm of hydrogen ion (H+) concentration
- TotalPhosphate_umolPerkgSW: Total dissolved phosphate concentrations in seawater. Units are micromoles per kilogram seawater.
- TotalSilicate_umolPerkgSW: Total dissolved silicate concentrations in seawater. Units are micromoles per kilogram seawater.
- P_dbars: Pressure in the unit decibars (dbar).
- Temp_inSitu_degC: The in-situ temperature at which our experiment was run. Units are degrees Celsius.
- Temp_duringCChemAnalysis: The temperature at which our carbonate chemistry samples were analyzed for total alkalinity (TA), pH, and Salinity. Units are degrees Celsius.
- T_in: The temperature that was used for input conditions in the carbonate chemistry calculation program CO2Sys. Equivalent to temperature at which our carbonate chemistry samples were analyzed for total alkalinity (TA), pH, and Salinity and thus the same as "Temp_duringCChemAnalysis". Units are degrees Celsius.
- T_out: The temperature that was used for output conditions in the carbonate chemistry calculation program CO2Sys. Equivalent to the in-situ temperature at which our experiment was run and thus the same as "Temp_inSitu_degC". Units are degrees Celsius.
- P_out: The pressure that was used for output conditions in the carbonate chemistry calculation program CO2Sys. Pressure units are decibars (dbar).
- pH_out: The pH of seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. No units as pH is the negative logarithm of hydrogen ion (H+) concentration.
- fCO2_out: The fugacity of carbon dioxide (fCO2) in seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are microatmospheres (uatm).
- pCO2_out: The partial pressure of carbon dioxide (pCO2) in seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are micro-atmospheres (uatm).
- HCO3_out: The concentration of bicarbonate ions (HCO3-) in seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are micromoles per kilogram seawater.
- CO3_out: The concentration of carbonate ions (CO3 2-) in seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are micromoles per kilogram seawater.
- CO2_out: The concentration of carbon dioxide (CO2) in seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are micromoles per kilogram seawater.
- BAlk_out: The concentration of boron species that contribute to alkalinity in seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are micromoles per kilogram seawater.
- OH_out: The concentration of hydroxide ions (OH−) in seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are micromoles per kilogram seawater.
- PAlk_out: The concentration of phosphate species that contribute to alkalinity in seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are micromoles per kilogram seawater.
- SiAlk_out: The concentration of silicate species that contribute to alkalinity in seawater that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are micromoles per kilogram seawater.
- Revelle_out: The Revelle factor that was calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Revelle factor is influenced by temperature, salinity, total alkalinity, and total inorganic carbon dioxide (TCO2), and is calculated as the percent change in fCO2 (or pCO2) caused by a 1% change in TCO2 at constant alkalinity.
- OmegaCa_out: Omega (the degree of saturation) for calcite in seawater. Calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Unitless. Values greater than 1 (>1) indicate supersaturation and favorability towards calcification or shell formation. Values equal to 1 (=1) indicate saturation. Values less than 1 (<1) indicate undersaturation lack of favorability towards calcification or shell formation.
- OmegaAr_out: Omega (the degree of saturation) for aragonite in seawater. Calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Unitless. Values greater than 1 (>1) indicate supersaturation and favorability towards calcification or shell formation. Values equal to 1 (=1) indicate saturation. Values less than 1 (<1) indicate undersaturation lack of favorability towards calcification or shell formation.
- xCO2_out: The mole fraction of carbon dioxide (CO2) in dry air assuming 1 atm total pressure. Calculated for output conditions (a.k.a. in-situ experimental conditions) in the carbonate chemistry calculation program CO2Sys. Units are parts per million (ppm).
- TCO2_in: Total inorganic carbon dioxide (TCO2) that was calculated for input conditions (a.k.a. analysis conditions) in the carbonate chemistry calculation program CO2Sys. As it is independent of temperature or pressure, the values are the same for input and output CO2Sys conditions, and thus this value also represents TCO2 in in-situ experimental conditions.
File: BrucitePhytoManuscript_Biogeochem.csv
Description: Contains measurements relevant to biomineralization, primary production, stoichiometry, dissolved elemental concentrations in seawater, dissolved seawater nutrients, and photosynthetic health.
Variables
- treatment: "ctrl", "mgsalt", "bio", "biomgsalt". "ctrl" represents the abiotic control (no phytoplankton, no alkalinity addition), and is called "Control-A" (Control-Abiotic) in the manuscript. "mgsalt" represents the abiotic alkalinity-added treatment (no phytoplankton, yes alkalinity addition), and is called "BIAA-A" (Brucite Inspired Alkalinity Addition-Abiotic) in the manuscript. "bio" represents the biotic control (yes phytoplankton, no alkalinity addition), and is called "Control-B" (Control-Biotic) in the manuscript. "biomgsalt" represents the biotic alkalinity-added treatment (yes phytoplankton, yes alkalinity addition), and is called "BIAA-B" (Brucite Inspired Alkalinity Addition-Biotic) in the manuscript.
- condition: "biotic" or "abiotic". Describes if the treatment contained phytoplankton or not.
- day: 0, 3, 6, 9, 12. Sampling occurred every third day of the experiment, and the experiment ran for 12 days.
- replicate: A, B, C. Three independent bottles were sacrificed from every treatment on every sampling day. These triplicates were designated A, B, or C.
- bSi_umolperL: biogenic silica in units of umol/L a.k.a uM a.k.a micromolarity
- POC_uM: particulate organic carbon in units of uM a.k.a micromolarity
- PON_uM: particulate organic nitrogen in units of uM a.k.a micromolarity
- CaCO3_uM: calcium carbonate a.k.a. particulate inorganic carbon (PIC) in units of uM a.k.a micromolarity
- POCPONratio: the stoichiometric ratio of particulate organic carbon (POC) to particulate organic nitrogen (PON) in units of uM:uM a.k.a micromolarity:micromolarity
- PICPOCratio: the stoichiometric ratio of particulate inorganic carbon (PIC) (a.k.a. CaCO3) to particulate organic carbon (POC) in units of uM:uM a.k.a micromolarity:micromolarity
- bSiPOCratio: the stoichiometric ratio of biogenic silica (bSi) to particulate organic carbon (POC) in units of uM:uM a.k.a micromolarity:micromolarity
- dCa_uM: dissolved seawater calcium (Ca) concentrations in units of uM a.k.a micromolarity
- dMg_uM: dissolved seawater magnesium (Mg) concentrations in units of uM a.k.a micromolarity
- Phosphate_uM: dissolved seawater concentrations of phosphate in units of uM a.k.a micromolarity
- Silicate_uM: dissolved seawater concentrations of silicate in units of uM a.k.a micromolarity
- Nitrite_uM: dissolved seawater concentrations of nitrite in units of uM a.k.a micromolarity
- NitriteNitrate_uM: dissolved seawater concentrations of combined nitrite and nitrate in units of uM a.k.a micromolarity
- fvfm_tech_mean: the mean value of technical replicate measurements of Fv/Fm, a photosynthetic parameter that is an indicator of the quantum efficiency of photosystem II. Fv represents variable fluorescence. Fm represents maximum fluorescence. Unitless.
- fixarea_tech_mean: the mean value of technical replicate measurements of FixArea, a proxy indicator for chlorophyll a content. Unitless.
File: BrucitePhytoManuscript_PhytoCommunityCounts.csv
Description: Contains data on cell densities and phytoplankton genus-level or functional group-level identification
Variables
- Treatment: "bio", "biomgsalt". "bio" represents the biotic control (yes phytoplankton, no alkalinity addition), and is called "Control-B" (Control-Biotic) in the manuscript. "biomgsalt" represents the biotic alkalinity-added treatment (yes phytoplankton, yes alkalinity addition), and is called "BIAA-B" (Brucite Inspired Alkalinity Addition-Biotic) in the manuscript.
- Day: 0, 3, 6, 9, 12. Sampling occurred every third day of the experiment, and the experiment ran for 12 days.
- Identity: "diatomColonies", "diatomSubunits", "dinoflagellate", "coccolithophore", "unknown", "phaeocystis". Represents the level of genus-based or functional-group-based identification we were able to achieve to assess phytoplankton community structure over time. "diatomColonies" refers to diatom colony counts, and "diatomSubunits" corresponds to individual diatom cell counts (both as free-living cells and cells within colonies).
- Rep: replicate. A, B, C. Three independent bottles were sacrificed from every treatment on every sampling day. These triplicates were designated A, B, or C.
- Count: The number of individual cells of that Identity type ("diatomColonies", "diatomSubunits", "dinoflagellate", "coccolithophore", "unknown", "phaeocystis") that were counted via light microscopy method for that sample (counts were based on a 1 mL sample volume) from the given replicate from the given treatment from the given sampling day.
- GridSquares: The number of grid squares that were spatially covered when doing the cell counts for the 1 mL sample volume on a 1000 square gridded rafter slide.
- NormFactor_GridSquaresOutof1000: Normalization factor to account for the number of grid squares covered out of the possible 1000 grid squares as this varied by sample. Calculated as the GridSquares value divided by 1000.
- NormCountper1000Squares: Normalized cell counts to estimate the number of cells that would be present in the whole slide (a.k.a. 1000 grid squares) if every cell in every grid square was counted. Calculated as Count value multiplied by NormFactor_GridSquaresOutof1000 value.
- NormCount_permL: Normalized cell counts to estimate the number of cells that would be present in the whole slide (a.k.a. 1000 grid squares a.k.a 1 mL) if every cell in every grid square which would then represent the entire 1 mL sample volume was counted. Is synonymous with NormCountsper1000Squares, so can also be calculated as Count value multiplied by NormFactor_GridSquaresOutof1000 value.
- NormCount_perLRep: Normalized cell counts to estimate the number of cells that would be present in the entire culture volume (1L) of each experimental replicate bottle. Calculated as NormCount_permL multiplied by 1000 as there are 1000 mL in a liter.
Supplemental Files
File: Fig1_CarbChem.tiff
Description: Visualizes trends in seawater carbonate chemistry system parameter data over time across the four experimental treatment groups. This file provides a high resolution tiff format corresponding to the relevant manuscript figure from the main paper body.
File: Fig2_BioIndic.tiff
Description: Visualizes trends in biogeochemical and physiological parameter data over time across the two biotic experimental treatment groups. This file provides a high resolution tiff format corresponding to the relevant manuscript figure from the main paper body.
File: Fig3_DisNutrients.tiff
Description: Visualizes trends in dissolved inorganic nutrient data over time across the four experimental treatment groups. This file provides a high resolution tiff format corresponding to the relevant manuscript figure from the main paper body.
File: Fig4_PhytoCommunity.tiff
Description: Visualizes trends in phytoplankton relative community abundance and composition data over time across the two biotic experimental treatment groups. This file provides a high resolution tiff format corresponding to the relevant manuscript figure from the main paper body.
File: FigS1_StoichRatios.tiff
Description: Visualizes trends in stoichiometric ratio data (BSi:POC; PIC:POC; POC:PON) over time across the two biotic experimental treatment groups. This file provides a high resolution tiff format corresponding to the relevant manuscript figure from the Supplementary Index.
File: FigS2_SEM-EDX.tiff
Description: Image capture from SEM-EDX imaging and elemental analysis providing visual and semi-quantitative evidence of pattern differences in particle formation between the two abiotic experimental treatment groups with absence versus presence of BIAA. This file provides a high resolution tiff format corresponding to the relevant manuscript figure from the Supplementary Index.
File: TableS1_TA_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the Total Alkalinity data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS2_pH_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the pH data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS3_TCO2_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the TCO2 data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS4_CO2_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the carbon dioxide (CO2) data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS5_HCO3_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the bicarbonate (HCO3) data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS6_CO3_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the carbonate (CO3) data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS7_BSi_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the BSi data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS8_POC_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the POC data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS9_PIC_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the PIC data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS10_PON_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the PON data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS11_FvFm_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the FvFm data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
File: TableS12_FixArea_descriptive-stats.pdf
Description: This table provides the calculated mean, median, standard deviation, and variance for the FixArea data by day and treatment. This file provides a high resolution pdf format corresponding to the relevant manuscript table from the Supplementary Index.
Code/Software
Data viewing, figure generation, and statistical analysis for this work were all performed using R version 4.3.2 (R Core Team 2023-10-31), RStudio Build 494 (2023.09.1), and the following R packages: anytime v. 0.3.9 (Eddelbuettel 2020), ARTool v. 0.11.1 (Wobbrock et al. 2011; Kay et al. 2021; Elkin et al. 2021), colorblindr v. 0.1.0 (McWhite and Wilke 2024), colorspace v. 2.1.0 (Zeileis, Hornik, and Murrell 2009; Stauffer et al. 2009; Zeileis et al. 2020), conover.test v. 1.1.5 (Dinno 2017), cowplot v. 1.1.2 (Wilke 2023), devtools v. 2.4.5 (Wickham et al. 2022), effsize v. 0.8.1 (Torchiano 2020), emmeans v. 1.10.4 (Lenth 2024), FSA v. 0.9.5 (Ogle et al. 2023), ggh4x v. 0.2.8 (van den Brand 2024), ggpattern v. 1.0.1 (FC, Davis, and ggplot2 authors 2022), ggpubr v. 0.6.0 (Kassambara 2023), ggstats v. 0.6.0 (Larmarange 2024), ggtext v. 0.1.2 (Wilke and Wiernik 2022), ggthemes v. 5.1.0 (Arnold 2024), glue v. 1.6.2 (Hester and Bryan 2022), gridExtra v. 2.3 (Auguie 2017), gridGraphics v. 0.5.1 (Murrell and Wen 2020), gridpattern v. 1.1.1 (FC and Davis 2023), gtable v. 0.3.5 (Wickham and Pedersen 2024), here v. 1.0.1 (Müller 2020), hrbrthemes v. 0.8.7 (Rudis 2024), htmltools v. 0.5.8.1 (Cheng et al. 2024), janitor v. 2.2.0 (Firke 2023), kableExtra v. 1.4.0 (Zhu 2024), knitr v. 1.47 (Xie 2014, 2015, 2024), lemon v. 0.4.9 (Edwards 2024), multcomp v. 1.4.26 (Hothorn, Bretz, and Westfall 2008), patchwork v. 1.2.0 (Pedersen 2024), psych v. 2.4.6.26 (William Revelle 2024), rcompanion v. 2.4.36 (Mangiafico 2024), reshape v. 0.8.9 (Wickham 2007), scales v. 1.3.0 (Wickham, Pedersen, and Seidel 2023), tidyverse v. 2.0.0 (Wickham et al. 2019), usethis v. 3.0.0 (Wickham et al. 2024), viridis v. 0.6.5 (Garnier et al. 2024).
The associated R script ("BrucitePhytoManuscript_R-code_ Figs-and-Stats.R") included with this submission is structured according to the appearance of results groupings in the manuscript: carbonate chemistry system results, biological indicator results, dissolved nutrient results, and phytoplankton community structure results. Additionally, stoichiometric ratio results (supplementary figure 1) code is included. Each section of this R script contains annotated code to load the appropriate .csv file, subset the relevant data, calculate descriptive statistics, and generate the corresponding manuscript figure.
Access information
Other publicly accessible locations of the data:
- Not applicable
Data was derived from the following sources:
- Not applicable
This dataset comprises data from analyzed seawater samples sourced from a 12-day, laboratory-based experiment during a seasonal upwelling event in spring 2023 and examines the impacts of magnesium-based alkalinity addition upon the carbonate chemistry, biogeochemistry, and phytoplankton community of the Santa Barbara Channel (SBC). Whole water was sourced from the SBC in a single-day sourcing event, and was filtered in-field to exclude zooplankton and then immediately transported back to the lab for additional filtration and preparation for a same-day experiment start. We utilized a "brucite-inspired" alkalinity addition (BIAA) approach, which consisted of adding MgCl2 * 6H2O and NaOH to yield a total alkalinity (TA) concentration of 3000 µmol/kg, in contrast with the untreated seawater controls (TA = 2300 µmol/kg). We used a full-factorial experimental design consisting of 4 treatments: abiotic no alkalinity added (Control-A), biotic no alkalinity added (Control-B), abiotic with BIAA (BIAA-A), biotic with BIAA (BIAA-B). Sampling occurred every third day of the experiment, with 3 independent replicate bottles being sacrificed from every treatment on every sampling day. Samples were analyzed for pH, Total Alkalinity, salinity, dissolved inorganic phosphate, dissolved inorganic silicate, and temperature to then calculate the remaining parameters of the seawater carbonate chemistry system using the program CO2Sys. Samples were also analyzed for the following biological and chemical indicators that have relevance to biogeochemistry and planktonic physiology: particulate organic carbon (POC); particulate organic nitrogen (PON); particulate inorganic carbon (PIC) a.k.a. CaCO3; dissolved Ca, Mg, and Na; dissolved inorganic nutrients (silicate, phosphate, nitrite+nitrate); biogenic silica (BSi); photosynthetic properties (Fv/Fm and FixArea). Samples were also processed via light microscopy to generate phytoplankton community composition and growth data (cell densities over time with genus-based cell identifications).