| Processing Steps |
- Parameter or Variable: Dissolved Inorganic Carbon; Abbreviation: TCARBN; Unit: UMOL/KG; Observation type: Discrete, bottle; Measured or calculated: Measured; Sampling instrument: Niskin Bottles; Analyzing instrument: MIDSOMMA; Detailed sampling and analyzing information: DIC was determined using a coulometric titration method (Johnson, 1993) with the MIDSOMMA system (Mintrop, 2005).; CRM manufacturer: Andrew Dickson Laboratory at SIO; CRM batch number: Batch 109; Preservation method: mercuric chloride solution; Preservative volume: 100 mL; Uncertainty: Precision for DIC, defined as the average of the differences between duplicate analyses of CRM (Figure 4), was 2.3 μmol/kg (1.8 μmol/kg stdev).; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value; Method reference: Mintrop, L., 2005. MIDSOMMA maual version 2.0, Marine Analytics and Data (MARIANDA), Kiel, Germany.; Researcher name: Leif G. Anderson; Researcher institution: University of Gothenburg.
- Parameter or Variable: Total alkalinity; Abbreviation: ALKALI; Unit: UMOL/KG; Observation type: Discrete, bottle; Measured or calculated: Measured; Sampling instrument: Niskin Bottles; Analyzing instrument: TA was determined by open-cell potentiometric titration with 0.05 M HCl, according to Haraldsson et al. (1997) based on Gran evaulation. The sample was dispensed into a titration vessel from a thermostated pipette of known volume. The titration acid was prepared on board by adding pre-weighed NaCl (75.972 g) and HCl (1 ampoule 0.1 M for 1000 mL) to a volumetric flask (2 L) diluting with Milli-Q water. New electrodes (Orion 9102AP) were used, which were quality tested in the lab prior to the cruise by their Nernst response, but not on board. The system reports TA in μmol/L using the nominal acid concentration of 0.05 M. For all samples and CRMs, molar concentrations were converted to molinity (μmol/kg-SW) using the sample salinity (from the CTD) and the certified salinity, respec- tively, and the temperature measured at the beginning of each titration. Sample results were then multiplied by the correction factor from the CRM measurements (average value divided by the CRM value). Junk samples were measured frequently to keep the instrumentation conditioned. No deviant trends were observed regarding acid concentration or performance over time.; Type of titration: potentiometric titration; Cell type (open or closed): open; CRM batch number: Batch 109; Uncertainty: The accuracy is difficult to assess, since the system is calibrated using the CRMs. Assuming that the CRMs are in the certified range (i.e. ± 0.69 μmol/kg), the accuracy is probably in the same order as the precision. Results from CRM vary quite smoothly over time, with slightly higher values at the first few stations. Different stations (days) may show an offset depending on the CRM measuremet (calibration factor) used for calibration. The final choice of calibration factors used, is based on ambient deep water profiles, normalized TA and CO2SYS calculations.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value; Method reference: Haraldsson, C., Anderson, L.G., Hassellöv, M., Hulth, S., 1997. Rapid, high-precision potentiometric titration of alkalinity in ocean and sediment pore waters. Deep-Sea Research, 44, 2031-2044.; Researcher name: Leif G. Anderson; Researcher institution: University of Gothenburg.
- Parameter or Variable: pH; Abbreviation: PH_TOT; pH scale: Total; Observation type: Discrete, bottle; Measured or calculated: Measured; Sampling instrument: Niskin Bottles; Analyzing instrument: spectrophotometry (pH); Temperature of pH measurement: 25 Deg C; Detailed sampling and analyzing information: pH was determined spectrophotometrically using the sulphonephtalien dye, m-cresol purple (mCp), as indicator (Clayton and Byrne, 1993). The method is based on the absorption ratio of the indicator at wavelengths 434 and 578 nm using a 1-cm flow cuvette. Each run consisted of three steps; i) rinsing of tubing and cuvette with sample (5 mL) ii) sample blank (25 mL) and iii) sample run (20 mL) including indicator (0.5 mL). The sample was pumped and mixed using a Kloehn pump. Sample temperature was measured after the cuvette. The spectrophotometer (Agilent 8453) was allowed to warm up (∼1 hour) when initialized and Milli-Q water was used as initial instrument blank. Determination of indicator pH was performed every other day. The indicator solution was prepared on several occasions throughout the cruise. Pre-weighed (non-purified) mCp (0.4044 g) was added to filtered (0.45 μm) seawater (500 mL) from depths below 1500 m. Indicator pH was adjusted to a range between 7.80 and 7.93 by addition of HCl and/or NaOH. The solutions were stored in airtight plastic bags and kept dark. The magnitude of the perturbation of seawater pH caused by the addition of indicator solution was calculated and corrected for using the method described in Chierici et al. (1999). The final pH values were calculated according to Clayton and Byrne (1993), including salinity correction. pH data was reported in the total (Hansson) scale at 25C. Table 1 shows the indicator pH over time used for evaluating the final pH.; At what temperature was pH reported: at SST; Uncertainty: A total of 603 duplicates were measured. The overall precision was 0.0004 (average) or 0.0006 (stdev). Each replicate was measured from the same sample bottle and the second measurement could possibly be affected by changes in CO2 concentration. However, there was only a small time lapse of ∼3 minutes between measurments, with only minor change in temperature. Triplicates were measured when one of the duplicate measurements seemed questionable.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value; Researcher name: Leif G. Anderson; Researcher institution: University of Gothenburg.
- Parameter or Variable: CTD Temperature; Abbreviation: CTDTMP; Unit: degrees celcius; Observation type: CTD sensor; Sampling instrument: CTD; Analyzing instrument: CTD; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value.
- Parameter or Variable: CTD Salinity; Abbreviation: CTDSAL; Observation type: CTD sensor; Sampling instrument: CTD; Analyzing instrument: CTD; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value.
- Parameter or Variable: Bottle Salinity; Abbreviation: SALNTY; Observation type: Bottle, discrete; Sampling instrument: CTD; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value.
- Parameter or Variable: CTD Oxygen; Abbreviation: CTDOXY; Unit: UMOL/KG; Observation type: CTD sensor; Sampling instrument: CTD; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value.
- Parameter or Variable: Bottle Oxygen; Abbreviation: OXYGEN; Unit: UMOL/KG; Observation type: Bottle, discrete; Sampling instrument: CTD; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value.
- Parameter or Variable: Nutrients; Abbreviation: SILCAT, NITRAT, NITRIT, PHSPHT; Unit: UMOL/KG; Observation type: Bottle, discrete; Sampling instrument: CTD; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value .
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