Dataset: pH internal Consistency Experiment: Raw pH Data

Name: Raw pH data acquired during the pH internal consistency experiment.
Published: 2023-07-28
Keywords: ocean acidification, CO2 internal consistency, CO2sys, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.905235.1

Spatial Extent: N:39.773433 E:-70.884417 S:39.773433 W:-70.884417

Temporal Extent: 2019-10-10

Project:

Improving Accuracy and Precision of Marine Inorganic Carbon Measurements (Inorganic Carbon Meaurements)

Principal Investigator:

Ryan Woosley (Massachusetts Institute of Technology, MIT)

Contact:

Ryan Woosley (Massachusetts Institute of Technology, MIT)

BCO-DMO Data Manager:

Karen Soenen (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2023-07-28

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Raw pH data acquired during the pH internal consistency experiment.

Abstract:

These data include the measured pHt, total alkalinity, dissolved inorganic carbon, raw pHt absorbance, and calculated pHt of 25 batches of seawater as a function of temperature, salinity, and pCO2. These data were used to evaluate the internal consistency of 120 different possible combinations of CO2 system constants. The marine inorganic carbon system can be calculated with two measured parameters due to thermodynamic relationships. However, there are many different parameterizations for the required constants and the most accurate or best is not known. These data were used to evaluate the constants and make recommendations for which constants to use, and how to perform CO2 system calculations.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2023-07-28	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.905235.1	2023-08-02

Methods & Sampling

Oligotrophic Atlantic surface seawater was collected from 39° 46.406′ N and 70° 53.065′ W on October 10, 2019.

The surface seawater was modified to five different salinities and 5 different pCO2 values for a total of 25 batches. Salinity was modified through dilution or evaporation. pCO2 was modified by bubbling CO2 gas of different pCO2 concentrations (balance air).

The water was then bottled and sealed into 250 mL borosilicate glass bottles following SOPs (Dickson et al. 2007). Each batch consisted of 44 bottles.

Data Processing Description

For each batch the pHt was measured at 9 different temperatures.

pHt was measured spectrophotometricly using purified meta-cresol indicator dye with an Agilent 8454 spectrophotometer following SOP (Dickson et al. 2007 and Woosley (2021)) and the indicator calibration equations of Liu et al. (2011).

BCO-DMO Processing

* Related data DIC, TA, equilirbium pCO2 can be found in the related summary dataset.
* Adjusted column names to fit database requirements.

Data Files

File
905235_v1_rawph.csv (Comma Separated Values (.csv), 303.87 KB) MD5:adefcb2cbac5a23c4dfd118660c19f20 Primary datafile for dataset 905235

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1923312

Deployments

None available yet

Instruments

Spectrophotometer

Supplied Name: Agilent 8454 spectrophotometer

Supplied Description:

Instrument Type

Generic Name: Spectrophotometer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB20/

Generic Description:

An instrument used to measure the relative absorption of electromagnetic radiation of different wavelengths in the near infra-red, visible and ultraviolet wavebands by samples.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
Batch	Seawater batch number	unitless	sample
Bottle	sample bottle number	unitless	sample
Rep	Sample measurement repitition	unitless	replicate
Practical_Salinity	Salinity	unitless	sal
Calculated_Temperature	Temperature used to calculate pH	Degrees Celsius (˚C)	temperature
Measured_Temperature	Measured Temperature	Degrees Celsius (˚C)	temperature
A434	Absorbance at 434 nm	Absorbance units (AU)	absorbance
A578	Absorbance at 578 nm	Absorbance units (AU)	absorbance
A730	Absorbance at 730 nm	Absorbance units (AU)	absorbance
A488	Absorbance at 488 nm	Absorbance units (AU)	absorbance
R	Absorbance Ratio	Absorbance units (AU)	ratio
raw_pHt	measured pHt without indicator perturbation corection	unitless	pH
flag	quality control flag (2 = good, 3 = questionable, 4 = bad, 5 = missing)	unitless	flag
flag_reason	reason for QC flags 3-5	unitless	comment

Status message

Database

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Dataset: pH internal Consistency Experiment: Raw pH Data