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Method Description:
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Total C02 Data:
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TCO2 Analysis Method:
TCO2 was determined using two automated dynamic headspace sample processors (SOMMAs) with coulometric detection of the CO2 extracted from acidified samples. A description of the SOMMA Coulometry System and its calibration can be found in Johnson et al. (1987); Johnson and Wallace (1992); and Johnson et al. (1993).
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Standardization Technique:
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Technique Description:
Samples were collected in 300-mL precombusted (450±C for 24 h) glass standard Biological Oxygen Demand (BOD) bottles, poisoned with 200-ul of a 50% saturated solution of HgCl2, and analyzed for TCO2 within 24 hours of collection (DOE Hand Book of Methods, 1994).
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Sample Volume:
300 mL
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CRM Info:
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Correction Magnitude:
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Batch Number:
1011
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CRM Analysis Info:
The CRMs were supplied by Dr. Andrew Dickson of the SIO, and during Section P6 batches 10 and 11 were used. The certified values for batch 10 were S =34.5722 and Certified TCO2=1960.67 ± 0. 39 µmol/kg (n=5). The corresponding numbers for batch 11 were S=38.5 and TCO2 =2188.77 µ 0.56 µmol/kg (n=5). The CRM TCO2 concentration was determined by Vacuum-Extraction/Manometry in the laboratory of C.D. Keeling at SIO.
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Field Replicate Info:
The sample precision calculation includes the results for some samples (K = 13) that were analyzed in triplicate (i.e., two replicates analyzed on one system and the third on the second system). For these cases, the mean of the two replicate analyses was used for calculating Sp2. Averaging the replicate results reduced the degrees of freedom term by making n = 1 for each system no matter how many replicates were actually run on each system.
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Poisoning Info:
poisoned with 200-ul of a 50% saturated solution of HgCl2 200-ul
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Poisoning Correction Description:
poisoned with 200-ul of a 50% saturated solution of HgCl2
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Poison Volume:
200-ul
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Accuracy Info:
High single-system precision (<±1.0 µmol/kg), and a slightly higher imprecision for the sample precision (±1.65 µmol/kg).
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Method References:
Huffman, E. W. D., Jr. 1977. Performance of a new automatic carbon dioxide coulometer. Microchemical Journal 22:567-73. Johnson, K. M., A. E. King, and J. McN. Sieburth. 1985. Coulometric TCO2 analyses for marine studies: An introduction. Marine Chemistry 16:61-82. Johnson, K. M., P. J. Williams, and L. Brandstroem, and J. McN. Sieburth. 1987. Coulometric TCO2 analysis for marine studies: Automation and calibration. Marine Chemistry 21:117-33. Johnson, K. M., and D. W. R. Wallace. 1992. The single-operator multiparameter metabolic analyzer for total carbon dioxide with coulometric detection. DOE Research Summary No. 19. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Tenn., U.S.A. Johnson, K. M., K. D. Wills, D. B. Butler, W. K. Johnson, and C. S. Wong. 1993. Coulometric total carbon dioxide analysis for marine studies: Maximizing the performance of an automated gas extraction system and coulometric detector. Marine Chemistry 44:167-87. Johnson, K. M., D. W. R. Wallace, R. J. Wilke, and C. Goyet. 1995. Carbon dioxide, hydrographic, and chemical data obtained during the R/V Meteor Cruise 15/3 in the South Atlantic Ocean (WOCE Section A9, February March 1991). ORNL/CDIAC-82, NDP-051. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A. Johnson, K. M., B. Schneider, L. Mintrop, and D. W. R. Wallace. 1996. Carbon dioxide, hydrographic, and chemical data obtained during the R/V Meteor Cruise 18/1 in the North Atlantic Ocean (WOCE Section A1E, September 1991). NDP-056. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A. Johnson, K. M., A. G. Dickson, G. Eischeid, C. Goyet, P. R. Guenther, R. M. Key, F. J. Millero, D. Purkerson, C. L. Sabine, R. G. Schotle, D. W. R. Wallace, R. J. Wilke, and C. D. Winn. 1998a. Coulometric total carbon dioxide analysis for marine studies: Assessment of the quality of total inorganic carbon measurements made during the U.S. Indian Ocean CO2 Survey 1994-1996. Marine Chemistry 63:21-37. Johnson, K. M., B. Schneider, L. Mintrop, and D. W. R. Wallace. 1998b. Carbon dioxide, hydrographic, and chemical data obtained during the R/V Meteor Cruise 22/5 in the South Atlantic Ocean (WOCE Section A10, December 1992 January 1993). NDP-066. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A. Wallace, D. W. R. 2001. Storage and transport of excess CO2 in the oceans: The JGOFS/WOCE Global CO2 Survey. In J. Church, G. Siedler, and J. Gould (eds.)., Ocean Circulation and Climate, Academic Press, (in press). Youden, W. J. 1951. Statistical Methods for Chemists. Wiley, New York.Guenther, P. R., C. D. Keeling, and G. Emanuele. 1994. Oceanic CO2 measurements for the WOCE hydrographic survey in the Pacific Ocean, 1990-1991: Shore based analyses. SIO Reference Series, No. 94-28. Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, U.S.A. DOE (U.S. Department of Energy). 1994. Handbook of Methods for the Analysis of the Various Parameters of the Carbon Dioxide System in Sea Water. Version 2.0. ORNL/CDIAC-74. A. G. Dickson and C. Goyet (eds.). Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A.
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Citations:
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Alkalinity:
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Curve Fitting Method:
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Type of Titration:
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Description of Other Titration:
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Cell Type:
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CRM cale:
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Sample Volume:
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Magnitude of Blank Correction:
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Accuracy Info:
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Method References:
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Citations:
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pCO2 Data:
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Analysis:
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pCO2 Analysis Method:
Samples for discrete pCO2 analyses were collected by overfilling 60-mL precalibrated serum bottles in the same manner as for oxygen and TCO2.
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Sample Volume:
55 mL
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Headspace_Volume:
5 mL
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Measurement_Temperature:
20 degree C
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Temperature Normalization:
20 degree C
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Temperature Correction Method:
thermostatted shaking water bath and equilibrated
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Variable Reported:
pCO2
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Gas:
wet
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Standard Gas Concentrations:
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Frequency of Standardization:
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Field Replicate Info:
the pooled standard deviation (Sp2) for pCO2, calculated according to Youden (1951) where K was the number of samples with duplicates analyzed (n ³ 2), n was the total number of replicates analyzed from K samples, and n - K was the degrees of freedom (d.f.);
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Storage Method:
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Accuracy Info:
In all, duplicates for 109 of the 808 pCO2 samples were taken during WOCE Section P6. Based on these samples, the sample precision (Sp2) for pCO2 was ±17.4 µatm. Because of the large dynamic range of the pCO2 measurements (>1000 µatm), the geometric mean of the Rel. S. D. was considered to be the best measure of overall sample precision on a percentage basis (±0.88%). For the derived variable TALK the sample precision (Sp2) was ±3.39 µmol/kg and the Rel. S. Dev. [(Sp2 / mean) ´ 100] was 0.14%. The corresponding result for TCO2 is approximately 0.08%.
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Method References:
Johnson, K. M., J. E. Hughes, P. L. Donaghay, and J. McN. Sieburth. 1990. Bottle-calibration static head space method for the determination of methane dissolved in seawater. Analytical Chemistry 62:2408-12.Neill, C., K. M. Johnson, E. Lewis, and D. W. R. Wallace. 1997. Accurate headspace analysis of fCO2 in discrete water samples using batch equilibration. Limnology & Oceanography 42:1774-83. Lewis, E. and D. W. R. Wallace. 1998. Program developed for CO2 system calculations. ORNL/CDIAC-105. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A. Roy, R. N., L. N. Roy, K. M. Vogel, C. Porter-Moore, T. Pearson, C. E. Good, F. J. Millero, and D. M. Campbell. 1993. The dissociation constants of carbonic acid in seawater at salinities 5 to 45 and temperatures 0 to 45°C. Marine Chemistry 44:249-67. DOE (U.S. Department of Energy). 1994. Handbook of Methods for the Analysis of the Various Parameters of the Carbon Dioxide System in Sea Water. Version 2.0. ORNL/CDIAC-74. A. G. Dickson and C. Goyet (eds.). Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A. Youden, W. J. 1951. Statistical Methods for Chemists. Wiley, New York. Millero, F. J., A. G. Dickson, G. Eischeid, C. Goyet, P. R. Guenther, K. M. Johnson, K. Lee, E. Lewis, D. Purkerson, C. L. Sabine, R. Key, R. G. Schottle, D. R. W. Wallace, and C. D. Winn. 1998. Total alkalinity measurements in the Indian Ocean during the WOCE hydrographic program CO2 survey cruises 1994 1996. Marine Chemistry 63:9-20.
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pH Data:
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pH Scale:
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pH Analysis Method:
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Calibration Info:
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Calibration Description:
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In Situ Temperature:
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Temperature of Analysis:
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Temperature Normalization:
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In Situ Pressure:
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Accuracy Info:
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Method References:
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Metadata Summary
