Discrete measurements (TCO2, TALK, pCO2, and pH) metadata form

• Investigator:
  • Name: Triona McGrath
  • Organization: Marine Institute
  • Address:
    Rinville, Oranmore, Galway, Ireland
  • Phone: 0035391387327;00353879858738
  • Email: triona.mcgrath@marine.ie; triona_mcgrath@hotmail.com
• Dataset Info:
  • Dataset ID: CE0903_CHEM
  • Submission Dates:
    • Initial Submission: 2012/05/03
    • Revised Submission:
• Cruise Info:
  • Experiment:
    • Experiment Name: CE0903: Standard oceanographic sections in the Rockall Trough
    • Cruise:
      • Cruise ID: 45CE20090206 (CE0903)
      • Section:
      • Geographical Coverage:
        • Geographical Region:
          Rockall Trough, Northeast Atlantic
        • Bounds:
          • Westernmost Longitude: -17.8997
            Degrees, Minutes, Seconds: E
          • Easternmost Longitude: -9.4990
            Degrees, Minutes, Seconds: E
          • Northernmost Latitude: 55.9422
            Degrees, Minutes, Seconds: N
          • Southernmost Latitude: 52.9975
            Degrees, Minutes, Seconds: N
      • Temporal Coverage:
        • Start Date: 2009/02/06
        • End Date: 2009/02/14
      • Ports of Call:
        Galway Port
  • Vessel:
    • Vessel Name: RV Celtic Explorer
    • Vessel ID: 45CE
    • Country: Ireland
    • Vessel Owner: Marine Institute
• Variables Info:
  • Variable:
    • Variable Name: Temperature (sensor)
    • Description of Variable: degrees Celcius
  • Method Description:
    • Total C02 Data:
      • TCO2 Analysis Method:
        TCO2 is measured by acidification of the sample with phosphoric acid followed by coulometric titration on a VINDTA-3C (Versatile Instrument for the Determination of Titration Alkalinity) system with UIC coulometer.
      • Standardization Technique:
        • Technique Description
          A known volume of sample is acidified with phosphoric acid in order to transfer all dissolved inorganic carbon to CO2. The resulting CO2 is forced out of the sample by a continuous flow of pure nitrogen through the sample and the extracted CO2 is passed into a titration cell in the coulometer. The CO2 is titrated coulometrically with a dimethyl sulfoxide (DMSO) based absorbent containing ethanolamine. The CO2 reacts quantitatively with the ethanolamine to produce hydroxyethylcarbanic acid. The pH of the titration is monitored by measuring the transmittance of the thymolphthalein indicator which shows when the titration is finished. The thymol blue indicator fades to the original colour due to generation of hydroxide ions at the cathode to maintain the transmittance of the solution at a constant value. The change in colour is monitored by the photodetector as a percentage of transmittance (%T). The amount of CO2 extracted from the sample is determined by the time integrated current of the hydroxide ions generated. Once the endpoint is reached, the current stops and the VINDTA LabVIEWTM software calculates the TCO2 concentrations.
        • Sample Volume(mL):
        • CRM Info:
          • Correction Magnitude: -25.6µmol/kg
          • Batch Number:
            97 99
          • CRM Analysis Info:
            Refer to plot CRM Analysis for CE0903
      • Field Replicate Info:
        
      • Poisoning Info:
        • Poisoning Correction Description:
          Samples were poisoned with saturated merucuric chloride solution.
        • Poison Volume(mL): 0.2
      • Accuracy Info:
        Precision is estimated as 1.8µmol/kg, which is the standard deviation of the absolute difference between the 64 duplicate samples analysed. Accuracy is estimated as 2.2µmol/kg, which is the mean of the absolute difference between the 64 duplicate samples analysed.
      • Method References:
        Dickson, A.G., Sabine, C.L., Christian, J.R., 2007. Guide to best practices for ocean CO2 measurements. PICES Special Publication 3, 1-191. Mintrop, L., Pérez, F.F., González-Dávila, M., Koertzinger, A., Rios, A.F., Santana-Casiano., J.M., 1999. Regional Studies: the carbon dioxide system in the Canary Islands region. Proceedings of the 2nd International Symposium CO2 in the Oceans, Tsukuba, Enero 1999. CGE-1037-99, Center for Global Environmental Research/National Institute for Environmental Studies, Japan pp. 521-524. Johnson, K.M., Körtzinger, A., Mintrop, L., Duinker, J.C., Wallace, D.W.R., 1999. Coulometric total carbon dioxide analysis for marine studies: measurement and internal consistency of underway TCO2 concentrarions. Marine Chemistry 67, 123-144.
    • Alkalinity:
      • Curve Fitting Method:
        based on Gran function
      • Type of Titration: potentiometric
      • Description of Other Titration:
        
      • Cell Type: open
      • CRM Scale:
      • Sample Volume(mL):
      • Magnitude of Blank Correction: 30
      • Accuracy Info:
        Precision is estimated as 1.3µmol/kg, which is the standard deviation of the absolute difference between the 64 duplicate samples analysed. Accuracy is estimated as 1.0µmol/kg, which is the mean of the absolute difference between the 64 duplicate samples analysed.
      • Method References:
        Dickson, A.G., Sabine, C.L., Christian, J.R., 2007. Guide to best practices for ocean CO2 measurements. PICES Special Publication 3, 1-191.
    • pCO2 Data:
      • Analysis:
        • pCO2 Analysis Method:
          
        • Sample Volume(mL):
        • Headspace Volume:
        • Measurement Temperature:
        • Temperature Normalization:
        • Temperature Correction Method:
        • Variable Reported:
        • Gas:
        • Standard Gas Concentrations:
        • Frequency of Standardization:
      • Field Replicate Info:
        
      • Storage Method:
        
      • Accuracy Info:
        
      • Method References:
        
    • pH Data:
      • pH Scale:
      • pH Analysis Method:
        
      • Calibration Info:
        • Calibration Description:
          
        • In Situ Temperature:
        • Temperature of Analysis:
        • Temperature Normalization:
        • In Situ Pressure:
      • Accuracy Info:
        
      • Method References:
        
  • Additional information:
    
  • Data Set References:
    McGrath, T., Kivimae, C., Tanhua, T., Cave, R.R., McGovern, E., in review. Inorganic carbon and pH levels in the Rockall Trough 1991-2010. Deep-Sea Research Part I.
  • Citation:
    McGrath, T. and Kivimae, C. (in prep). Measurements of carbon and nutrient chemistry in the Rockall Trough in February 2009 and 2010. Earth Science Systems Data.
  • Data Set Link:
    • URL:
    • Label: CE0903: Standard oceanographic sections in the Rockall Trough
    • Link Note: