Coastal pH variability in the Balearic Sea

• Main Authors: Hendriks, Iris E., Flecha, Susana, Pérez, Fiz F., Alou-Font, Eva, Tintoré, Joaquín
• Other Authors: Ministerio de Economía y Competitividad (España), Fundación BBVA, Govern de les Illes Balears, Ministerio de Ciencia e Innovación (España), Agencia Estatal de Investigación (España), Consejo Superior de Investigaciones Científicas (España), Hendriks, Iris E. [e-mail]
• Format: Dataset
• Language: English
• Published: DIGITAL.CSIC 2022
• Subjects: Clayton; Scripps; sami
• Online Access: http://hdl.handle.net/10261/279863; https://doi.org/10.20350/digitalCSIC/14749; https://doi.org/10.13039/501100004837; https://doi.org/10.13039/501100003329; https://doi.org/10.13039/501100003339; https://doi.org/10.13039/501100011033; https://doi.org/10.13039/100007406

[Description of methods used for collection/generation of data] In both stations a SAMI-pH (Sunburst Sensors LCC) was attached, at 1 m in the Bay of Palma and at 4 m depth in Cabrera. The pH sensors were measuring pH, in the total scale (pH????T), hourly since December 2018 in the Bay of Palma and since November 2019 in Cabrera. The sensor precision and accuracy are < 0.001 pH and ± 0.003 pH units, respectively. Monthly maintenance of the sensors was performed including data download and surface cleaning. Temperature and salinity for the Cabrera mooring line was obtained starting November 2019 with a CT SBE37 (Sea-Bird Scientific©). Accuracy of the CT is ± 0.002 ∘C for temperature and ± 0.003 mS cm−1−1 for conductivity. Additionally, oxygen data from a SBE 63 (Sea-Bird Scientific ©) sensor attached to the CT in Cabrera were used. Accuracy of oxygen sensors is ± 2% for the SBE 63. [Methods for processing the data] Periodically water samplings for dissolved oxygen (DO), pH in total scale at 25 ∘C (pH????25) and total alkalinity (TA) were obtained during the sensor maintenance campaigns. DO and (pH????25) samples were collected in order to validate the data obtained by the sensors. DO concentrations were evaluated with the Winkler method modified by Benson and Krause by potentiometric titration with a Metrohm 808 Titrando with a accuracy of the method of ± 2.9 μmol kg−1μmol kg−1 and with an obtained standard deviation from the sensors data and the water samples collected of ± 5.9 μmol kg−1μmol kg−1. pH????25T25 data was obtained by the spectrophotometric method with a Shimadzu UV-2501 spectrophotometer containing a 25 ∘C-thermostated cells with unpurified m-cresol purple as indicator following the methodology established by Clayton and Byrne by using Certified Reference Material (CRM Batch #176 supplied by Prof. Andrew Dickson, Scripps Institution of Oceanography, La Jolla, CA, USA). The accuracy obtained from the CRM Batch was of ± 0.0051 pH units and the precision of the method of ± 0.0034 pH units. The mean difference ...