Processing Steps |
- Parameter or Variable: Dissolved Inorganic Carbon; Abbreviation: TCARBN; Unit: UMOL/KG; Observation type: discrete; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Replicate information: Over 200 replicate samples were analyzed with a precision of 1.05 μmol/kg.; Standardization description: The coulometers were each calibrated by injecting aliquots of pure CO2 (99.99%) by means of an 8-port valve outfitted with two sample loops. The instruments were calibrated at the beginning and end of each station with a set of the gas loop injections.; CRM batch number: 73.
- Parameter or Variable: Total alkalinity; Abbreviation: ALKALI; Unit: UMOL/KG; Observation type: discrete; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Type of titration: potentiometric titration with a 0.7 M NaCl filling solution in the reference electrode to maintain a consistent junction potential between the solution and electrode; Cell type (open or closed): 2 TA systems consisting of ~ 200 mL plexiglass water jacketed closed cell; Curve fitting method: The fitting is performed using the STEPIT routine (J.P. Chandler, Oklahoma State University, Stillwater, OK 74074). The STEPIT software package minimizes the sum of squares of residuals by adjusting the parameters E*, TA, TCO2 and pK1.; Uncertainty: 1) TA(meas)- TA (crm)= -1.17 +/- 4.34 μmol/kg with n=125 2) TA(sys1) - TA(sys2) = 1.76 +/- 1.30 μmol/kg with n=61 3) delta TA(same sys) = 0.78 +/- 0.68 μmol/kg with n=124; Method reference: Dickson, A. G. 1981. An exact definition of total alkalinity and a procedure for the estimation of alkalinity and total inorganic carbon from titration data. Deep Sea Research Part A. Oceanographic Research Papers 28: 609.[ https://doi.org/10.1016/0198-0149(81)90121-7]; Johansson, O., and M. Wedborg. 1982. On the evaluation of potentiometric titrations of seawater with hydrochloric acid. Oceanol. Acta 5: 209-218; Millero, F. J., J.-Z. Zhang, K. Lee, and D. M. Campbell. 1993. Titration alkalinity of seawater. Marine Chemistry 44: 153.[ https://doi.org/10.1016/0304-4203(93)90200-8].
- Parameter or Variable: pH; Abbreviation: PH_TOT; pH scale: total scale; Observation type: discrete; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Temperature of pH measurement: 25C; Detailed sampling and analyzing information: Two different groups - University of Miami (UM) and University of South Florida (USF) - measured pH using slightly different spectrophotometric techniques on P16N leg 1. Only the USF group measured pH on P16N leg 2. The pH measurements from both groups are reported on the total scale at 25°C. Note: In the master data file p16n_2006a_hy.csv at CDIAC and CCHDO, the pH measurements from UM group reported for leg 1 (stations 1 - 43) and from USF for leg 2 (stations 44 - 84). The separate file p16n_2006a_all_ph.csv with all pH measurements from both groups is archived at NCEI at https://www.ncei.noaa.gov/archive/accession/0108062. The pH measurements of seawater were made using the spectrophotometric techniques of Clayton and Byrne (1993). The pH of the samples using the m-cresol purple (mCP).; Uncertainty: pH(CRM 73) = 7.8417 +/- 0.0020 pH(TRIS) = 8.0525 +/- 0.0033 with n=32.
- Parameter or Variable: pCO2 (fCO2) discrete; Abbreviation: FCO2; Unit: UATM; Observation type: discrete; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Storage method: Samples were drawn from Niskin bottles into 500 ml volumetric flasks using Tygon® tubing with a Silicone adapter that fit over the petcock to avoid contamination of DOM samples. Bottles were rinsed while inverted and filled from the bottom, overflowing half a volume while taking care not to entrain any bubbles. About 5 ml of water was withdrawn to allow for expansion of the water as it warms and to provide space for the stopper, tubing, and frit of the analytical system. Saturated mercuric chloride solution (0.2 ml) was added as a preservative. The sample bottles were sealed with a screw cap containing a polyethylene liner. The samples were stored in coolers at room temperature generally for no more than 5 hours.; Seawater volume: 500 mL; Headspace volume: 70 mL; Temperature of measurement: 20C; Detailed sampling and analyzing information: The discrete pCO2 system is patterned after the instrument described in Chipman et al. (1993) and is discussed in detail in Wanninkhof and Thoning (1993) and Chen et al. (1995). The major difference between the two systems is that Wanninkhof instrument uses a LI-COR® (model 6262) non-dispersive infrared analyzer, while the Chipman instrument utilizes a gas chromatograph with a flame ionization detector.; Sample replicate information: Generally when samples were taken, flasks were drawn on all the Niskins including four duplicates. Two of the duplicates were analyzed at different temperatures; Temperature correction method: See Peng et al., 1987; Uncertainty: Three types of duplicates were taken. The average difference: [ABS(sample 1-sample2)/(sample 1+sample 2) * 100], std. dev. and number for the three types are listed below: Duplicates run at 20 C: av. dif. =0.3 +/- 0.23% n = 33 (one value omitted) Duplicates run at 12 C: av. dif. = 0.3 +/- 0.18 % n= 23 (one value omitted) Duplicates run at 12 C and 20 C* av. dif = 0.7 +/- 0.75 % n= 59 (two values omitted) The omitted values were because of a problem in analysis in one of the duplicates *The duplicates run at different temperatures were normalized to 20 C and compared. Normalization was performed using the constants and procedures as outlined in Peng et al. 1987 as incorporated in the GW BASIC data reduction program. Of note is that using the constants as refit by Dickson and Millero and the salinity dependence of borate as proposed by Dickson gave an average difference of 1%, that is, these constants yielded worse agreement in temperature normalization.; Method reference: Wanninkhof, R., & Thoning, K. (1993). Measurement of fugacity of CO2 in surface water using continuous and discrete sampling methods. Marine Chemistry, 44(2–4), 189–204. https://doi.org/10.1016/0304-4203(93)90202-y.
- Parameter or Variable: PH_TMP; Abbreviation: PH_TMP; Unit: DEG_C; Controlled vocabulary name: pH; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: FCO2_TMP; Abbreviation: FCO2_TMP; Unit: DEG_C; Controlled vocabulary name: partial pressure of carbon dioxide - water; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: CTDTMP; Abbreviation: CTDTMP; Unit: DEG_C; Controlled vocabulary name: WATER TEMPERATURE; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: CTDSAL; Abbreviation: CTDSAL; Controlled vocabulary name: SALINITY; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: SALNTY; Abbreviation: SALNTY; Controlled vocabulary name: SALINITY; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: CTDOXY; Abbreviation: CTDOXY; Unit: UMOL/KG; Controlled vocabulary name: DISSOLVED OXYGEN; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: OXYGEN; Abbreviation: OXYGEN; Unit: UMOL/KG; Controlled vocabulary name: DISSOLVED OXYGEN; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: SILCAT; Abbreviation: SILCAT; Unit: UMOL/KG; Controlled vocabulary name: silicate; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: NITRAT; Abbreviation: NITRAT; Unit: UMOL/KG; Controlled vocabulary name: NITRATE; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: NITRIT; Abbreviation: NITRIT; Unit: UMOL/KG; Controlled vocabulary name: NITRITE; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: PHSPHT; Abbreviation: PHSPHT; Unit: UMOL/KG; Controlled vocabulary name: phosphate; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: CFC-11; Abbreviation: CFC-11; Unit: PMOL/KG; Controlled vocabulary name: CHLOROFLUOROCARBON-11 (CFC-11); In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: CFC-12; Abbreviation: CFC-12; Unit: PMOL/KG; Controlled vocabulary name: CHLOROFLUOROCARBON-12 (CFC-12); In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: CFC113; Abbreviation: CFC113; Unit: PMOL/KG; Controlled vocabulary name: CHLOROFLUOROCARBON-113 (CFC-113); In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: DOC; Abbreviation: DOC; Unit: UMOL/KG; Controlled vocabulary name: DISSOLVED ORGANIC CARBON; In-situ / Manipulation / Response variable: in-situ.
- Parameter or Variable: TDN; Abbreviation: TDN; Unit: UMOL/KG; Controlled vocabulary name: Total Dissolved Nitrogen (TDN); In-situ / Manipulation / Response variable: in-situ .
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