Müller, Jens Daniel; Rehder, Gregor (2021): Spectrophotometric pH measurements from continuous surface water supply and discrete samples [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.928150
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Published: 2021-02-18 • DOI registered: 2021-07-03
Abstract:
The BONUS INTEGRAL field expeditions on RV Aranda took place from February 28th 2019 to March 11th 2019 (RV Aranda Cruise 04/19). The scientific program of was tailored to serve the purposes of BONUS INTEGRAL. This dataset provides surface data for the creation of maps of surface concentrations of pH via continuous surface water measurements and discrete samples.
Spectrophotometric determination of pH by using CONTROS HydroFIA pH system. The HydroFIA pH system (4H Jena Engineering, 24148 Kiel, Germany) is a continous sample flow instrument for determination of the pH value. In the dependence of the sample pH value the injekted indicator m-cresol purple (supplier of the instrument) change the coulor and from the resulting absorption ranges (ratio) the pH can be calculated. The measuring principle and calculation is based on Dickson et al. [2007] and Müller and Rehder [2018].
For the pH measurement of discrete samples 250 ml ground-glass bottles were used. These bottles are measured directly after sampling. A 5-fold measurement is performed from the same bottle. The last 3 measurements are used for averaging. According to the manufacturer an accuracy of 0.005 is guaranteed and a precision of 0.002 is possible. For control measurements, in-house buffer solutions are used, which are measured at regular intervals.
Related to:
Dickson, Andrew G; Sabine, Christopher L; Christian, J R (2007): Guide to Best Practices for Ocean CO2 Measurements. PICES Special Publication, 3, 191 pp, hdl:10013/epic.51789.d001
Müller, Jens Daniel; Rehder, Gregor (2018): Metrology of pH Measurements in Brackish Waters—Part 2: Experimental Characterization of Purified meta-Cresol Purple for Spectrophotometric pHT Measurements. Frontiers in Marine Science, 5, 177, https://doi.org/10.3389/fmars.2018.00177
Project(s):
Integrated carbon and trace gas monitoring for the Baltic Sea (BONUS_INTEGRAL)
Funding:
Bundesministerium für Bildung und Forschung, Bonn (BMBF), grant/award no. 03F0773A: Integrated carbon and trace gas monitoring for the Baltic Sea
Coverage:
Median Latitude: 61.487400 * Median Longitude: 21.260425 * South-bound Latitude: 59.166520 * West-bound Longitude: 17.635770 * North-bound Latitude: 65.244430 * East-bound Longitude: 25.235000
Date/Time Start: 2019-02-28T12:02:11 * Date/Time End: 2019-03-11T08:42:33
Minimum DEPTH, water: 0.1 m * Maximum DEPTH, water: 0.1 m
Event(s):
ARA04/2019-underway * Latitude Start: 60.161830 * Longitude Start: 24.901530 * Latitude End: 60.161800 * Longitude End: 24.901580 * Date/Time Start: 2019-02-28T03:37:00 * Date/Time End: 2019-03-11T09:46:00 * Location: Baltic Sea, Gulf of Bothnia, Gulf of Finland * Campaign: ARA04/2019 * Basis: Aranda (1989) * Method/Device: Underway cruise track measurements (CT)
Comment:
pH was measured spectrophotometrically using two flow-through instruments (HydroFIA pH, KM Contros, instruments: PH-1017-001 and PH-0218-001) operated with the pH-dye m-Cresol purple. Measurements were done at 25°C with both, water from the continuous surface seawater supply and from discrete samples.
pH was calculated according to the most recent dye characterization for brackish waters (Müller and Rehder, 2018) on the total scale. Please note that salinity for surface water measurements was arbitrarily set to 5 for the entire cruise and pH values were post-processed taking into account the true sample pH.
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | DATE/TIME | Date/Time | Rehder, Gregor | Geocode | ||
| 2 | LATITUDE | Latitude | Rehder, Gregor | Geocode | ||
| 3 | LONGITUDE | Longitude | Rehder, Gregor | Geocode | ||
| 4 | DEPTH, water | Depth water | m | Rehder, Gregor | Geocode | |
| 5 | Temperature, water | Temp | °C | Rehder, Gregor | exact measurement temperature at which pHT was determined | |
| 6 | pH, total scale | pHT | Rehder, Gregor | Spectrophotometry, CONTROS HydroFIA pH | pHT (total scale) | |
| 7 | pH, standard error | pH std e | ± | Rehder, Gregor | Spectrophotometry, CONTROS HydroFIA pH | |
| 8 | Instrument | Instrument | Rehder, Gregor |
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Size:
22704 data points
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