DOI: 10.20350/digitalcsic/17039
title: Daily maximum, minimum, range and deviation of time series of pH and oxygen concentration in the water column and benthic compartment in the Spanish littoral

description: [Description of methods used for collection/generation of data] Water column: Water column data were acquired at 1 m depth in the Bay of Palma, at 4 m depth in Cabrera PN and at 12 m in CanOA buoy by using a SAMI-pH (Sunburst Sensors LCC) sensors attached to a mooring line. The pH sensors were measuring pH, in the total scale (pH??), hourly, since December 2018 in the Bay of Palma and since October 2019 in Cabrera, and every three hours since March 2020 in the CanOA buoy. Monthly maintenance of the sensors including data download and surface cleaning for Palma Bay and Cabrera PN and every two-three months for Gran Canaria. Since the SAMI sensor failed due to bubbles in the tubing, the pH was calculated in the total scale (pHT) with alkalinity determined from salinity and pCO2 variables for CanOA buoy data. Data were acquired at 0.8 m depth in the Ria de Arousa using a prototype instrument called SURCOM from pH Honeywell Durafet III ISFET technology. The pH sensor was measuring pH, in the total scale (pH??), every 10-5 minutes since July 2020. Monthly maintenance and cleaning of the complete mooring was performed. Temperature and conductivity data for the Cabrera PN and Palma Bay mooring line were obtained starting October 2019 and December respectively, with a CT SBE37 (SBE37SMP-ODO-RS232 Sea-Bird Scientific ©). Additionally, dissolved oxygen (DO) data from a SBE 63(Sea-Bird Scientific ©) sensor attached to the CT in Cabrera and Palma Bay were used. Sea surface temperature and salinity data for the CanOA buoy were obtained hourly starting March 2020, with a SBE 37-SI/SIP Thermosalinometer MicroCAT sensor (Sea-Bird Scientific ©). Despite the fact that the oxygen sensor was installed on the buoy, oxygen data have not been used due to their low stability and biofouling problems. Salinity data for the Ria Arousa station was obtained starting July 2020 every 10 minutes through the INTECMAR website (http://www.intecmar.gal/Plataformas/platInfo.aspx?idEst=15001) with a CTD model SBE 37-SIP. No oxygen data was provided for this dataset. Multiparametric sensors: Multiparametric sensors data were acquired by sensors located within meadow (see 5) at a height approx. 0.20 from the sediment. As multiparametric sensors a Hydrolab HL4, Hydrolab DSX5, YSI EXO2, Eureka Manta¨, SeapHOx and SAMI-pH were used. Additionally, a custom build array was used courtesy by Dr. Tommy Moore. This array was built to monitor pH variation within a 1m3 area within marine vegetation, the custom built multi-sensor array consisted of an autonomous data logger (Datataker DT85) in a water-tight housing with 16 pre-amplified pH electrodes (Omega, PHE-1304-NB) attached by 5 m long cables, for more information see (Krause-Jensen et al. 2015). The sensors were configured in-situ in a three-dimensional array on the metal frame with 1m between each side (replica), with 4 sensors at 0.1 m from the bottom, 4 sensors at 0.2 m, 4 sensors just underneath the canopy and 4 above the canopy.Ê All pH sensors were calibrated, allowing ample time between each reading for the sensors to stabilize, using NIST buffers of pHNBS 4.0, 7.0 and 10.0. Krause-Jensen D, Duarte CM, Hendriks IE, Meire L, Blicher ME, Marbˆ N, Sejr MK. 2015. Macroalgae contribute to nested mosaics of pH variability in a subarctic fjord. Biogeosciences 12:4895-4911. Data from SURCOM-pH system were acquired by a Honeywell Durafet III sensor with custom electronics described in Velo and Padin (2022). The sensor was located at about 0.8m depth on the same wire as INTECMAR CTDs. Raw data was transmitted every 10.5 min in near-real-time to IIM servers through LoRA/SIGFOX network, where itÕs calibrated by discrete spectrophotometric samples taken by CETMAR and analysed by PEACHESEA CT service at IIM-CSIC.
description: [Methods for processing the data] Raw data was recorded with a frequency between 5 and 30 minutes for multiparametric sensors and 60 to 180 minutes for water column data. Minimum, maximum and average values for all variables were calculated by extrapolating the averages from 24 hours of measurements starting from midnight (local time), unless specified otherwise. Ranges over 24 hours of pH and DO (where data available) were calculated as the differences between maximum and minimum values within the 24 hours period.
description: File List: H4.2_database_pH_T_Watercolumn.csv H4.2_database_pH_T_sensors.csv readme.txt