Spectrophotometric pH measurements from continuous surface water supply and discrete samples

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.

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.

Identifier
DOI https://doi.org/10.1594/PANGAEA.928150
PID https://hdl.handle.net/10013/epic.51789.d001
Related Identifier https://doi.org/10.3389/fmars.2018.00177
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.928150
Provenance
Creator Müller, Jens Daniel ORCID logo; Rehder, Gregor ORCID logo
Publisher PANGAEA
Publication Year 2021
Funding Reference Bundesministerium für Bildung und Forschung, Bonn https://doi.org/10.13039/501100002347 Crossref Funder ID 03F0773A https://foerderportal.bund.de/foekat/jsp/SucheAction.do?actionMode=view&fkz=03F0773A Integrated carbon and trace gas monitoring for the Baltic Sea
Rights Creative Commons Attribution 4.0 International; https://creativecommons.org/licenses/by/4.0/
OpenAccess true
Representation
Resource Type Dataset
Format text/tab-separated-values
Size 22704 data points
Discipline Earth System Research
Spatial Coverage (17.636W, 59.167S, 25.235E, 65.244N); Baltic Sea, Gulf of Bothnia, Gulf of Finland
Temporal Coverage Begin 2019-02-28T12:02:11Z
Temporal Coverage End 2019-03-11T08:42:33Z