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CRUISE REPORT: AR21
(Updated APR 2012)




HIGHLIGHTS

                                      CRUISE SUMMARY INFORMATION

          WOCE Section Designation  AR21 Leg 1                     AR21 Leg 2
                           Aliases  OACES91 SATL-91
Expedition designation (ExpoCodes)  3175MB91                       3175MB91_2
                  Chief Scientists  Donald K. Atwood/AOML          Dr. Alex Pszenny/AOML
                             Dates  1991 JUL 11 - 1991 AUG 05      1991 AUG 13 - 1991 SEP 2 
                              Ship  R/V Malcolm Baldrige 
                     Ports of call  Montevideo, Uruguay - Fortaleza, Brazil

                                               5° N                         0° 5.64' S
             Geographic Boundaries  48° 33' W      24° 58.2' W     33° 27.3' W      4° 30' W
                                              42° S                        24° 7.68' S

                          Stations  33                             5
      Floats and drifters deployed  0                              0
    Moorings deployed or recovered  0                              0

                                     Recent Contact Information:

                                          Donald K. Atwood
            NESDIS Office of Research and Applications • World Weather Bldg. Room 601-18
                          5200 Auth Road • Camp Springs • MD • 20746-4304 
            Phone: 301-763-8102 Ext 206 • Fax 305-763-8580 • Email: Don.Atwood@noaa.gov 

                                          Dr. Alex Pszenny
                        Institute for the Study of Earth, Oceans, and Space
                      Morse Hall • University of New Hampshire • 8 College Road
                                       Durham, NH 03824-3525
                Tel: 603-862-1994 • Fax: 603-862-1915 • Email: alex.pszenny@unh.edu


















NOAA Data Report ERL AOML-24









HYDROGRAPHIC, CARBON DIOXIDE, NUTRIENT, AND PRODUCTIVITY
MEASUREMENTS FROM THE SOUTH ATLANTIC DURING JULY AND
AUGUST OF 1991


Evan B. Forde
James C. Hendee
Rik Wanninkhof 






Atlantic Oceanographic and Meteorological Laboratory
Miami, Florida
April 1994












noaa  NATIONAL OCEANIC AND         /  Environmental Research
      ATMOSPHERIC ADMINISTRATION  /   Laboratories










NOAA Data Report ERL AOML-24



HYDROGRAPHIC, CARBON DIOXIDE, NUTRIENT, AND PRODUCTIVITY MEASUREMENTS FROM THE 
SOUTH ATLANTIC DURING JULY AND AUGUST OF 1991



Evan B. Forde
James C. Hendee
Rik Wanninkhof









Atlantic Oceanographic and Meteorological Laboratory Miami, Florida 
April 1994





UNITED STATES              NATIONAL OCEANIC AND           Environmental Research
DEPARTMENT OF COMMERCE     ATMOSPHERIC ADMINISTRATION     Laboratories
		
Ronald H. Brown            B. James Baker                 Alan R. Thomas
Secretary                  Under Secretary for Oceans     Director
                           and Atmosphere/Administrator  








                                        







NOTICE

Mention of a commercial company, or product does not constitute an endorsement 
by NOAA Environmental Research Laboratories. Use of information from this 
publication concerning proprietary products or the tests of such products for 
publicity or advertising purposes is not authorized.











REMOTE ACCESS TO DATA LISTED IN THIS REPORT

The data presented in this report is available on a computerized Remote Bulletin 
Board System (RBBS) or via Internet FTP. For more detailed information, or for 
more information regarding electronic access to the individual data sets 
contact:

  Mr. James C. Hendee Data Manager, OACES at: U. S. Dept. of Commerce 
  NOAA/AOML/OCD 4301 Rickenbacker Causeway Miami, Florida 33149-1026
  Telephone: 305-361-4396 Internet address: Hendee@ocean.aoml.erl.gov






   For sale by the National Technical Information Service, 5285 Port Royal Road 
                               Springfield, VA 22161






                                       




PRINCIPAL INVESTIGATORS AND PROJECT PARTICIPANTS


PROJECT PRINCIPAL INVESTIGATORS

Projects       Funded Pi                       Affiliation     
-------------  ------------------------------  -------------------
DOC            Dr. R. Zika                     RSMAS (U. of Miami)
TAlk           Dr. F. Millero                  RSMAS (U. of Miami)
Productivity   Drs. P. Hitchcock and B. Balch  RSMAS (U. of Miami)
fCO2 & TCO2    Dr. R. Wanninkhof               AOML
CTD, Sal & O2  D. Wilson                       AOML
Nutrients      Dr. D. Atwood and C. Berberian  AOML


PARTICIPANTS FOR CO2 COMPONENT:

LEG 1

     Chief Scientist:  Donald K. Atwood  AOML

     Analyst           Data Type         Affiliation
     ----------------  ----------------  -----------
     Cindy Moore       DOC               RSMAS
     Lloyd Moore       Nutrients         AOML
     James McElroy     Productivity      AOML
     Raleigh Hood      Productivity      RSMAS
     Jia-Zhong Zhang   TAlk              RSMAS
     Rik Wanninkhof    fCO2 Discrete     AOML
                       fCO2 Underway
                       TCO2
     Tom Lantry        fCO2 Discrete     AOML
                       fCO2 Underway
                       TCO2
     Maureen Noonan    fCO2 Discrete     LDEO
                       fCO2 Underway
                       TCO2
     Cathy Cosca       fCO2 Discrete     PMEL
                       fCO2 Underway
                       TCO2
     Doug Wilson       CTD               AOML
                       Salinity
                       Oxygen
     Tom Miller        CTD               AOML
                       Salinity
     Bob Calvert       Carbon samples    AOML



                                      


LEG 2

     Chief Scientist:  Dr. Alex Pszenny  AOML

     Analyst           Data Type         Affiliation
     ----------------  ----------------  -----------
     Lloyd Moore       Nutrients         AOML
     James McElroy     Productivity      AOML
     Rik Wanninkhof    fCO2 Discrete     AOML
                       fCO2 Underway
                       TCO2
     Tom Lantry        fCO2 Discrete     AOML
                       fCO2 Underway
                       TCO2


DATA REDUCTION

     Analyst           Data Type         Affiliation
     ----------------  ----------------  -----------
     Cindy Moore       DOC               RSMAS
     Jia-Zhong Zhang   Talk              RSMAS
     Hua Chen          Discrete fCO2     CIMAS/AOML
     Rik Wanninkhof    Discrete fCO2     AOML
     Rik Wanninkhof    TCO2              AOML
     Tom Lantry        TCO2              AOML
     Rik Wanninkhof    Underway fCO2     AOML
     Doug Wilson       Underway fCO2     AOML
     Betty Huss        Underway fCO2     AOML
     Jim McElroy       Productivity      AOML
     Raleigh Hood      Productivity      RSMAS
     Garry Hitchcock   Productivity      RSMAS
     Doug Wilson       CTD               AOML
     Doug Wilson       Salinity          AOML
     Doug Wilson       Oxygen            AOML
     Dennis Frazel     Nutrients         AOML
     Lloyd Moore       Nutrients         AOML
     George Berberian  Nutrients         AOML
     
     
     
     
     




                                       


CONTENTS

             ABSTRACT                                                   
          
1.           INTRODUCTION                                               
  1.1        DESCRIPTION OF STUDY AREA                                  
             Figure 1. Map of track lines                               
2.           DATA COLLECTION AND ANALYTICAL METHODS                     
  2.1        HYDROGRAPHIC METHODS                                       
     2.1.1   CTD and Hydrographic operations                            
     2.1.2   Nutrient Analysis Methods                                  
             Figure 2. Latitudinal cross section sample locations 
                       for all Niskin bottle derived (discrete) data    
             Figure 3. Potential Density Cross Section from Leg 1.      
             Figure 4. Nitrate Data Cross Section from Leg 1.           
             Figure 5. Silicate Data Cross section from Leg 1.          
  2.2        CARBON PARAMETERS                                          
     2.2.1   Total Dissolved Inorganic CO2 (TCO2)                       
     2.2.2   Discrete fugacity of CO2 (fCO2)                            
     2.2.3   Methods for Potentiometric Total Alkalinity, 
             TCO2 and pH Measurements                                   
     2.2.4   Dissolved Organic Carbon Methods                           
             Figure 6. TCO2 Cross Section from Leg 1.                   
  2.3        PRODUCTIVITY                                               
     2.3.1   Methods for Chlorophyll Measurements                       
     2.3.2   Methods for Productivity Measurements                      
             Figure 7. Productivity Cross Section from Leg 1.           
             Figure 8. Chlorophyll Cross Section from Leg 1.            
  2.4        UNDERWAY MEASUREMENT METHODS                               
     2.4.1   Underway fCO2 Measurements                                 
             Figure 9. Leg 1 Underway fCO2                              
             Figure 10. Leg 2 Underway fCO2                             
3.           ACKNOWLEDGMENTS                                            
4.           REFERENCES                                                 
APPENDIX     Index of Measurements and Units                            












                                        


 HYDROGRAPHIC, CARBON DIOXIDE, NUTRIENT, AND PRODUCTIVITY MEASUREMENTS FROM THE 
                 SOUTH ATLANTIC DURING JULY AND AUGUST OF 1991

               Ryan B. Forde, James C. Hendee and Rik Wanninkhof 
              Atlantic Oceanographic and Meteorological Laboratory 
                              Miami, Florida 33169



ABSTRACT

From July 11 to September 2, 1991, the National Oceanic and Atmospheric 
Administration's (NOAA) Carbon Dioxide (CO2) and Radiatively Important Trace 
Species (RITS) programs participated in an oceanographic research cruise 
conducted aboard the NOAA ship MALCOLM BALDRIGE. This report presents the 
research from that cruise that was conducted for the CO2 program, which has 
recently been renamed the Ocean-Atmosphere Carbon Exchange Study (OACES). During 
Leg 1 of this cruise, (Fortaleza, Brazil to Montevideo, Uruguay), 33 CTD 
hydrographic casts and 17 Go-Flo(TM) hydrographic (productivity) casts were 
conducted. Samples were also collected while underway on Leg 1, for the 
determination of the fugacity of CO2 (fCO2) of the air and surface water. Leg 2, 
(Montevideo, Uruguay-Fortaleza, Brazil), collected 21 days of underway fCO2 
measurements, conducted five CTD hydrographic casts and nine Go-Flo(TM) 
hydrographic (productivity) casts. This report contains tables* of the following 
data: hydrography from each CTD cast at the bottle trip depths, (including 
salinity, oxygen and nutrients), discrete carbon parameters, underway carbon 
parameter values, and data from productivity casts. Descriptions of the sampling 
techniques and analytical methods used in the collection and processing of these 
data are also presented in this report.

KEY WORDS: alkalinity, CO2 carbon dioxide, chlorophyll, CTD, dissolved organic 
carbon, hydrography, nutrients, productivity, salinity, sigma-theta, South 
Atlantic, temperature



*See data files













1.  INTRODUCTION

Human activity is producing gases, most notably carbon dioxide (CO2), and other 
trace gases including chlorofluorocarbons, nitrous oxide and methane, which are 
being released into the atmosphere and causing more of the radiation being 
emitted by the earth to be absorbed. This increased absorption is resulting in a 
net warming of the earth's atmosphere and creating a phenomenon commonly known 
as the "Green House Effect". Only about half of all of the anthropogenic CO2 
that is released into the atmosphere each year remains there. The global ocean 
is thought by many to be the ultimate destination, or "sink" for the 'missing' 
CO2. The understanding of the absorption and storage properties of the oceans is 
therefore essential to assessing the potential for climatic change due to man's 
effect on the radiation balance of the atmosphere.

The National Oceanic and Atmospheric Administration's (NOAA) Carbon Dioxide 
(CO2) program and Radiatively Important Trace Species (FITS) programs 
participated in a multifaceted oceanographic research cruise conducted aboard 
the NOAA ship MALCOLM BALDRIGE from July 11 to September 2, 1991. The NOAA CO2 
program has been recently renamed and is now called Ocean-Atmosphere Carbon 
Exchange Study (OACES). The two primary objectives of the cruise were to: (1) 
assess the role of biomass burning emissions from surrounding continents in 
controlling the distribution of ozone in the tropical South Atlantic atmospheric 
boundary layer for the FITS program and (2) to measure and establish baseline 
values and determine source and sink regions of CO2 in the equatorial and the 
South Atlantic Ocean for OACES. This report presents only the OACES-related data 
from that cruise. These data include: hydrography, nutrients, discrete carbon, 
underway carbon parameters and productivity data from both legs of the cruise.

1.1.	DESCRIPTION OF STUDY AREA

This study was conducted on two consecutive research cruise legs during 1991. 
Leg 1 sailed from Fortaleza, Brazil on July 11, 1991, proceeded NE to 
approximately 5°N and 25°W and then turned south and steamed along the 25°W 
line to 28°S. At 28°5, the track line turned SW to 32°W and continued South to 
42°S before turning NW and ending in Montevideo, Uruguay on August 5, 1991. Leg 
2 departed Montevideo, Uruguay on August 13, 1991 and proceeded NE to a point 
about 2°S and 4°W before subsequently steaming NW, and then SW ending in 
Fortaleza, Brazil on September 2, 1991. The cruise tracks for Legs 1 and 2 are 
shown on Figure 1.


2.	DATA COLLECTION AND ANALYTICAL METHODS

Thirty-three CTD hydrographic stations on Leg 1, and five CTD hydrographic 
stations on Leg 2 were occupied to collect discrete water sample data. A 
CTD/rosette unit with a Neil Brown CTD instrument equipped with 24, 10-L Niskin(TM) 
bottles was utilized for these casts. Water samples were collected from the 
Niskin(TM) bottles for salinity, oxygen and nutrient measurements as well as carbon 
related parameters including total dissolved inorganic CO2 (TCO2), fugacity of 
CO2 (fCO2), total alkalinity (TAlk) and Dissolved Organic Carbon (DOC). 
Continuous underway air and seawater surface samples for fugacity of CO2 (fCO2) 
analysis were collected during both legs of the cruise. GoFlo(TM) hydrographic 
casts were also conducted on both legs for productivity measurements. These 
casts were made using 10-L Go-Flo(TM) bottles mounted on Kevlar(TM) hydrowire. 
Salinities and sea surface temperatures were also measured continuously during 
the entire cruise by a thermosalinograph. In most cases, if there was no bottle 
salinity value available for a given sample position, the electronically derived 
CTD value was used in calculations requiring a salinity measurement. More 
detailed information on individual data collection, or analyses procedures may 
be found in the respective data sections.


Figure 1: Study area and cruise track lines for NOAA Ship MALCOLM BALDRIGE.


2.1  HYDROGRAPHIC METHODS

2.1.1  CTD and Hydrographic Operations

All CTD operations were conducted using the same Neil Brown(TM) Instrument Systems 
Mark III CTD equipped with standard temperature and conductivity sensors, a 
Beckman(TM) polarographic dissolved oxygen sensor, and an auxiliary Seabird(TM) 
temperature sensor. Laboratory calibrations were performed, before and after the 
cruise, and were used in conjunction with Niskin(TM) bottle data, to calibrate the 
CTD data. Pressure and temperature data listed in this report are based on the 
post-cruise calibration. Temperature accuracy is estimated to be ± .005°C, and 
pressure accuracy to be ± 5 decibars.

Water sampling

Water samples were collected in 10-L sampling bottles using a General Oceanics 
24-place rosette system. Bottles were electronically fired during the upcast, 
with markers placed in the digital file for use in determining exact bottle trip 
CTD values for calibration. Once on deck, aliquots were taken for laboratory 
analyses. Figure 2 shows the CTD cast bottle trip locations used for 
hydrographic and other discrete water sample measurements collected during Leg 1 
of the cruise. More detailed information about the subsampling and analysis 
procedures for the various water property measurements may be found below. 

Oxygen

Dissolved oxygen samples were the first samples collected from 10-L Niskin(TM) 
bottles once the CTD unit was back on deck. The oxygen samples were collected, 
in 150-mL ground-glass stoppered sample bottles and were analyzed using the 
method described by Carpenter (1965), with computer-controlled colorimetric 
endpoint determination as described in Friederich, Sherman, and Codispoti 
(1984). Oxygen samples that have been collected and analyzed using the above 
methodology have a precision greater than one percent. Values are marked as 
questionable by italicizing them in the data tables for any of the following 
reasons: High or low photometric endpoints in the titration process due to 
improper light levels; possible contamination during processing (air bubbles 
seen in bottle, etc.); inexplicable large differences between bottle sample data 
values and apparently valid electronic CTD values.


Figure 2: Sampling positions for all Niskin(TM) Bottle derived data. The coarse 
          smoothing grid for bottom topography causes sharp topographic     
          features, such as the mid Atlantic Ridge at 0°N, to be eliminated.


Salinity

Salinity samples were collected in 200-mL bottles. New caps were used for each 
sample. Bottle salinities were measured using a Guildline(TM) 8400 Autosal and P114 
standard seawater in a temperature controlled van. Conductivity ratios were 
converted to salinities conforming to the PSS78 standard. Since CTD conductivity 
was relatively stable (except casts 32 and 33), bottle salinities that differed 
substantially from CTD salinity measurements are marked as questionable in the 
data tables.

Temperature Density and Depth

Depth, Potential Temperature and Density (sigma-theta) values listed in the 
tables were calculated using standard Woods Hole Oceanographic Institute 
(W.H.O.I.) hydrographic subroutines. Depth is calculated from pressure using 
methods based on Saunders and Fofonoff (1976); density is determined by methods 
presented in F. Millero and A. Poisson (1981); and potential temperature 
referenced to zero pressure (theta) is calculated by integrating the adiabatic 
lapse rate using a fourth-order Runge-Kutta algorithm. Sigma-theta values, (ten 
meter averages), from the Leg 1 CTD casts are contoured and presented in Figure 3.

2.1.2 Nutrient Analysis Methods

Nutrient samples were collected from l0-L Niskin  bottles in aged 60-mL. linear 
polyethylene bottles after three complete seawater rinses and stored in the dark 
at 4°C until analysis was completed (within 24 hours of sample collection). 
Concentrations of dissolved inorganic nitrite (NO2), dissolved inorganic nitrate 
(NO3), and silicate (Si04), reported in micromoles/liter, were determined using 
an AlpKem(TM) RFA/2 Auto-Analyzer aboard ship.

Nitrates

The automated colorimetric procedures and methodologies used in the analysis of 
nitrite and nitrate are essentially similar to those described by Armstrong et 
al. (1967), with modifications described in Atlas et al. (1971). 
Standardizations were performed prior to each sample run with working solutions 
prepared aboard ship from pre-weighed "Baker Analyzed" reagent grade standards. 
Nitrite (NO2) was determined by diazotizing with sulfanilamide and coupling with 
N-1 napthylethelendiamine dihydrochloride to form an azo dye. The color produced 
is proportional to the nitrite concentration. Samples for nitrate (NO3) analysis 
were passed through a copperized cadmium column, which reduces nitrate to 
nitrite and the resulting nitrite concentration was then determined as described 
above. The detection limits for nitrite and nitrate were 0.1 µmoles/L and 0.4 
µmoles/L, respectively. The precision of duplicate standards measurements was ±
0.25% at 8 µmoles/L for nitrite and ± 0.2% at 40 µmoles/L for nitrate. The 
accuracy for both analytes was assumed to be ±1 % since no absolute standards 
were available. Contoured nitrate values from Leg 1 of this study are presented 
in Figure 4.


Figure 3: Potential density cross section utilizing 10 decibar averaged sigma-
          theta data from CTD stations on Leg 1. Contour interval = 0.15. See 
          Figure 2 caption for comment regarding bottom topography.

Figure 4: Nitrate data cross section for Leg 1. Contour interval = 2 µmol/L. 
          See Figure 2 caption for comment regarding bottom topography.


Silicates

The analytical procedures and methodologies used in the analysis of silicate are 
essentially similar to those described by Armstrong et al. (1967), with 
modifications described in Atlas et al. (1971). Silicate was determined from the 
reduction of silicomolybdate in acidic solution to molybdenum blue by ascorbic 
acid. The color produced is proportional to the concentration of silicate in the 
sample, with a detection limit of 0.4 µmoles/L. The precision of duplicate 
measurements was ±0.17%, at 120 µmoles/L of silicate, with an assumed accuracy 
of ±1%, since no absolute standards were available. Figure 5 is a contour plot 
of the silicate values from Leg 1 of this cruise.


2.2  CARBON PARAMETERS

2.2.1 Total Dissolved Inorganic CO2

Sampling

Samples for dissolved inorganic CO2 (TCO2) analysis were drawn from l0-L Niskin(TM) 
bottles into 500-mL Pyrex(TM) bottles using Tygon(TM) tubing. Bottles were rinsed 
once, and while being careful to not create bubbles, they were filled from the 
bottom until half of the bottles' volume had overflowed. The tube was pinched 
off and withdrawn, creating a 5-mL headspace volume. Each sample had 0.2 mL of a 

saturated HgCl2 solution added to act as a sample preservative. The sample 
bottles were then sealed with glass stoppers lightly covered with Silastic(TM) 
grease. The samples were then stored in darkness at ambient (room) temperature 
for a maximum of two days prior to being analyzed.

Analysis

CO2 analysis was performed by extracting the inorganic carbon in the sea water 
samples by acidification and subsequent displacement of the gaseous CO2 into a 
coulometer cell. Two coulometers were used on the cruise. One was patterned 
after that of D. Chipman of Lamont-Doherty Earth Observatory (L.D.E.O.) and 
shall hereafter be referred to as the "Chipman" system; the other had a Single 
Operator Multiparameter Metabolic Analyzer (SOMMA) inlet system developed by K. 
Johnson of Brookhaven National Laboratories (B.N.L.) and shall be called the 
"Johnson" system.

The samples were introduced into the "Chipman" system by injecting a 23-mL 
aliquot from a 500-mL bottle with a glass syringe. A metal syringe guide/stopper 
assured that the injection volume was constant and reproducible. The temperature 
of the water remaining in the bottle was measured immediately after withdrawing 
the sample and was used to determine the density of the sample injected into the 
extraction tube. Subsequently, 1 mL of 10% phosphoric acid was injected into the 
extraction tube. The acid was purged with N2 prior to use and stored in a bottle 
with CO2-free headspace. The CO2 was extracted with ultra high purity N2 which 
was run through a Malcosorb(TM) CO2 scrubber. The evolved CO2 gas went through a 
PFTE(TM) 0.2 micron filter to remove water droplets and aerosols and then titrated 
coulometrically using an UIC (model 5011) CO2 coulometer. The gas stream was not 
dried prior to introduction into the cell. Sample analyses time was set to 20 
minutes.

Prior to analysis on the automated "Johnson" system, each 500-mL sample bottle 
was inserted into a water bath at 20°C. Water from the bottle was displaced 
into a thermostatted pipette with a (500 ppm CO2 in air) pressure gas. The water 
was then injected into an extraction chamber which contained 1 mL of 10% H3PO4 
solution which had been stripped of CO2 prior to injection of the sample. The 
evolved gas was run through a condenser and a MgClO4 drying column to dry the 
gas stream, and through an ORBO-53(TM) tube to remove volatile acids. Additional 
details concerning this system and procedures are presented in Johnson (1992), 
and Johnson et al. (1993).

Both the "Johnson" and "Chipman" coulometers were calibrated by injecting 
aliquots of pure CO2 using an 8-port or 10-port valve with two sample loops of 
known volume. The CO2 gas volumes bracketed the amount of CO2 extracted from the 
water samples. The gas loops of the "Johnson" system were calibrated by weight 
with water at B.N.L. (Wilke et al., 1993). The gas loop volumes on the "Chipman" 
system were calibrated by alternating gas loop injections from the two gas 
sampling valves with the same coulometer using the "Johnson" loop volume as a 
reference. Liquid reference materials (RM's) consisting of bicarbonate in sodium 
chloride solution were supplied by A. Dickson of Scripps Institute of 
Oceanography (S.I.O.) and were run on each coulometer cell during the cruise. 
The results were close to the values determined manometrically by C.D. Keeling 
at S.I.O.

       Av. value of RM's run on "Chipman"    2306.18 ± 1.47   n =  30
       Av. value of RM's run on "Johnson"    2304.58 ± 1.50   n = 100
       Manometric value [Dickson Batch #6]   2304.74 ± 0.94   n =  10

Note: All determinations, including replicates from the same bottle are pooled 
      for the averages.


Figure 5: Silicate data cross section for Leg 1. Contour interval = 5 µmol/L. 
          See Figure 2 caption for comment regarding bottom topography.


Calculations

The instrument was calibrated three times for each cell solution with a set of 
gas loop injections. Calculation of the amount of CD2 injected was determined 
according to methods described in the Department of Energy (DOE) CO2 handbook 
(1991). The gas loops yielded a calibration factor for the instrument defined 
as:

                      calculated moles of CO2 injected from gas loop
        Cal. factor = ----------------------------------------------
                            measured moles of CO2 injected

The concentration of CO2 ([CO2]) in the samples was determined according to:

                                                                 -4
             Cal. factor * (Counts-Blank * Run Time * 2.0728 * 10  µmol/count
     [CO2] = ----------------------------------------------------------------
                           pipette volume * density of sample


where Counts is equal to the instrument reading at the end of the analysis; 
Blank is the counts/minute determined from blank runs performed at least once 
for each cell solution; Run Time is the minutes the sample is run; 2.0728 * 10-4 
is the conversion factor from counts to µmol. The pipette volume (or syringe 
volume) was determined by taking aliquots of distilled water at a known 
temperature from the volumes prior to, during, and after the cruise. No trend 
was observed in the change in volumes. Standard deviation in the series of 
measurements over three months was 0.03% of the total weight. The weights with 
the appropriate densities were used to determine the volume of the syringes and 
pipette. Calculations of pipette and syringe volumes, of densities, and of final 
CO2 concentrations were all performed according to procedures outlined in the 
DOE CO2 handbook (1991). All total CO2 values are corrected for dilution by 0.2 
mL of mercuric chloride solution assuming the solution is saturated with 
atmospheric CO2 levels and total water volume is 540 mL yielding a correction 
factor of 1.00037. Figure 6 shows a contour plot of the coulometer derived TCO2 
values from Leg 1 of this study.


2.2.2  Discrete fugacity of CO2 (fCO2)

Sampling

Samples were drawn from 10-L Niskin  bottles into 500-mL Pyrex  volumetric 
flasks using Tygon(TM) tubing. Bottles were rinsed once and while taking care not 
to entrain air bubbles, were filled from the bottom until half the bottles' 
volume overflowed. Five mL of water was then withdrawn with a pipette to create 
a small expansion volume. A saturated HgCl2 solution, (0.2 mL), was added to the 
samples as a preservative. The sample bottles were then sealed with a screw cap 
containing a polyethylene liner and stored in darkness at room temperature for a 
maximum of two days prior to analysis.

Discrete fCO2 analyzer

The AOML discrete fCO2 system is patterned after the design described in Chipman 
et al. (1993) and is discussed in detail in Wanninkhof and Thoning (1993). 
The major difference between the systems is that the AOML system uses a Licor  
(model 6262) non-dispersive infrared analyzer, while the Chipman et al. system 
utilizes a gas chromatograph with a flame ionization detector and a methanizer, 
which quantitatively converts CO2 into CH4 for analysis.

Samples are collected in 500-mL volumetric flasks and are brought to a 
temperature of 20.00 ± 0.02°C, using a pre-bath at 19-21°C and a Neslab(TM) 
(model RT-220) controlled temperature bath. A 60-mL headspace is created in the 
flask by replacing the water using a compressed standard gas with a CO2 mixing 
ratio close to the fCO2 of the water. The headspace is circulated in a closed 
loop through the infrared analyzer (IR), which measures CO2 and water vapor 
levels in the sample cell. The headspaces of the two flasks are equilibrated 
simultaneously in channels A and B. While headspace from the flask in channel A 
goes through the IR analyzer, the headspace of the flask in channel B is 
recirculated in a closed loop. The sample in the A channel is equilibrated for 
17 minutes while the air from the headspace of the flask flows through the IR 
analyzer. The sample in the B channel is circulated in a closed loop for 10 
minutes and through the IR for 8 minutes. An expandable volume, consisting of a 
balloon, keeps the contents of the flasks at room pressure.

In order to maintain measurement accuracy and precision, a set of six gas 
standards is run through the system after every four to ten seawater samples. 
The standards have mixing ratios of 201.4, 354.1, 517.0, 804.5, 1012.2, and 1529 
ppm, which bracket the fCO2 at 20°C (fCO2, 20) values observed in the water 
column of the South Atlantic.

The determination of fCO2 in water from the discrete analyses involves several 
steps. The mixing ratio and detector response for the standards are normalized 
for temperature and pressure. The IR voltage output for samples are normalized 
with regard to pressure and are corrected for the presence of water vapor and 
converted to a mixing ratio. The mixing ratio in the headspace is converted to 
fugacity and corrected to fugacity of CO2 in the water sample prior to 
equilibration by accounting for change in total CO2 in water during the 
equilibration process (for details see, Wanninkhof and Thoning, 1993). The 
change in the fCO2 of water, (fCO2w), caused by the change in TCO2 is calculated 
using the constraint that total alkalinity (TAlk), remains constant during 
exchange of CO2 gas between the headspace and the water. The calculation is 
outlined in the appendix of Peng et al. (1987).


2.2.3  Methods for Potentiometric Total Alkalinity, TCO2 and pH Measurements

The total alkalinity and inorganic carbon (Dickson, 1981) in the water samples 
was determined during the cruise by making potentiometric titrations. The two 
systems used consisted of a Metrohm(TM) 615 titrator and Metrohm(TM) 605 pH meter that 
are operated by an Apple(TM) computer (Thurmond and Millero, 1982). The titration 
is done by adding HCl to the seawater past the carbonic acid end point. Seawater 
samples were contained in a water jacketed cell controlled to a constant 
temperature of 25°C with a Forma(TM) water bath. Due to the large number of 
samples to be measured, the titrations were not made over the entire pH range. 
This allowed a complete titration to be made in about 10 minutes. Unfortunately 
during the cruise the disk reader of the Apple(TM) computers failed and the 
titrations had to be run by hand.

The titrant solution was prepared from standard HC1 and reagent grade NaCl. The 
0.25 M HCl contained 0.45 M NaCl to yield an ionic strength equivalent to the 
seawater (0.7 M). The acid was standardized with weighed amounts of Na2CO3 
dissolved in 0.7 M NaCl solution in the laboratory. A blank titration was made 
to evaluate the residual alkalinity (14 µM) due to impurities in the NaCl. The 
normality of the acid was found to be 0.2514 ± 0.0001 M). Measurements made in 
the laboratory after the cruise yielded the same concentration of the HCl.

The electrode system used to measure the emf of the sample during a titration 
consisted of a ROSS(TM) glass pH electrode and an Orion(TM) double junction reference 
electrode. The response of the electrodes were determined by HC1 titration in 
0.7 M NaC1 solution. Electrodes with non-Nernstian behavior were discarded 
(slope larger than ± 0.5 mV of the theoretical slope). Three cells were used 
during the cruise (Cell 1, 2 and 3). They had volumes (V) and standard emf's, 
(E*), in seawater of V = 231.10 ± 0.02 cm , 238.99 ± 0.02 cm3, 239.64 ± 0.02 
cm3; E* = 592, 585, 580 mV (± 1 mV), respectively.

The total alkalinity and total CO2 were calculated from the volumes of acid 
added and the measured emf's using a least-squares Gran technique. A chemical 
model (Dickson, 1981) was used to determine the equivalence points on the 
titration curve.

The initial emf reading of the seawater solution before the titration began was 
used to determine the pH. The pH at 25°C was determined using the E* calculated 
for each titration. The concentrations of H+ are in mol/kg and are on the 
seawater scale ([H+])T = [H+]F + [HSO4 + [HF]). The electrodes were calibrated 
before going to sea by making titrations of 0.7 M NaCl with 0.25 M HCl (with 
0.45 M NaCl) and TRIS buffer. The TRIS buffer was made up in the laboratory and 
calibrated with hydrogen electrode system before the cruise (Millero, 1986). The 
total seawater pH scale (Dickson, 1984) was used for all the measurements.


Figure 6: Dissolved inorganic carbon dioxide, TCO2 (AOML value) cross section 
          for Leg 1. Contour interval = 15 µmo1/Kg. See Figure 2 caption for 
          comment regarding bottom topography.


2.2.4  Dissolved Organic Carbon Methods

A Shimadzu(TM) DOC-5000 Total Organic Carbon Analyzer with the ASI-5000(TM) Automated 
Sample Injector was purchased for use on this cruise. This is an automated DOC 
instrument utilizing high temperature catalytic combustion (680°C) and non-
dispersive infrared detection. It was installed on the ship and operated in NPOC 
mode (Non-purgable organic carbon) which means the "DOC" reported does not 
include volatile species. The only modification to the standard operating 
procedures for this commercial instrument was that "zero" (high-purity) oxygen 
was used instead of compressed air for the carrier stream.

The water column was sampled using Niskin(TM) water sampling bottles mounted on 
the 24 bottle rosette/CTD package that was described in the Hydrographic Methods 
section of this report. Samples for the DOC analysis were collected on deck in 
the 40-mL glass vials which fit the autosampler carousel. The samples were free-
flowed from the Niskin(TM) bottle into the vial. Care was taken so that the inner 
surfaces of the vial and the water stream from the valve did not come into 
contact with any other surfaces. Each vial was filled and rinsed with sample 
three times, before being filled for analysis. The sample was immediately 
acidified to pH of 2 by addition of vacuum-distilled HCl, and sealed with 
Parafilm(TM) and a plastic snap ring. Sample levels were kept far enough below 
the top of the vial to insure that the water did not come into contact with the 
Parafilm(TM) during subsequent handling.

The samples were moved to the autosampler for immediate processing, or were 
stored at 4°C if a delay was necessary. The autosampler was set to purge each 
sample of inorganic carbon species by bubbling high purity oxygen through the 
sample for five minutes immediately before the analysis. The gas stream 
continued to be introduced during the analytical process, except when the water 
was being transferred to the instrument by the sipper. Samples and standards 
were run in replicate, (usually six per determination). Peak area for each 
replicate was recorded for later statistical handling.

Data calibrations on this cruise were produced by the standard addition method; 
three levels of known concentrations of KHP (Potassium Hydrogen Phthalate) were 
added to aliquots of a sample and the series run as if they were discrete 
samples. This procedure insures that matrix effects and artifacts due to 
handling of the samples are reflected in the calibrations. The single largest 
problem in calibrating the DOC instrument is evaluating the "instrument blank", 
the part of the reported signal which is NOT due to organic carbon. Low organic 
carbon water produced by redistillation of research grade distilled water over 
potassium permanganate, and batch UV-irradiated Gulf Steam seawater were run 
daily as samples to monitor this apparent blank (which was usually <4 µmol/L). 


2.3  PRODUCTIVITY

2.3.1  Methods for Chlorophyll Measurements

Chlorophyll a concentrations were determined from duplicate 250-mL and 300-mL 
aliquots taken from a flow-through system and Go-Flo(TM) hydrographic casts 
respectively. The samples were filtered through Whatman GF/F filters which were 
then placed in 5 mL of a 40/60 (vol.:vol.) mixture of dimethyl sulfoxide (DMSO) 
:90% Acetone solution and placed in the dark for one hour. This is a 
modification of the Shoaf and Lium, (1976) and Burnison, (1980) procedure. The 
fluorescence of the DMSO/Acetone extracts were measured at sea with a Turner 
Designs(TM) fluorometer model 111. The fluorometer was calibrated at sea with 
Sigma chlorophyll a, following the method of Parsons et al., (1984).

Water was collected hourly from the seawater flow-through system for chlorophyll 
a analysis. The intake valve is located in the bow of the ship at about 3 m 
below the surface. The Go-Flo(TM) hydrographic casts for both chlorophyll a and 
production rate measurements were made using 10-L Go-Flo(TM) bottles mounted on 
Kevlar hydrowire. Six sampling depths were selected according to light levels. 
Seawater samples were collected at 100, 50, 30, 15, 6, and 1% of the incident 
surface irradiance (I0). Diffuse vertical attenuation coefficients (K), in 
reciprocal meters, were estimated at all stations using a Secchi disk and the 
relation K = l.4/Secchi depth. Photosynthetically available radiation (PAR) was 
also measured with depth using a Lambda Instruments(TM) LI-190S 4π spherical 
collector. Calculations for this measurement were done after each cast. All Go-
Flo(TM) hydrocasts were performed within a three hour time window (between 7-10 
am local), to help ensure uniform sampling conditions throughout the cruise. 
Contour plots of chlorophyll values from Leg 1 of this cruise are found in 
Figure 7.


2.3.2  Methods for Productivity Measurements

Productivity measurements were made using the  Carbon method, as originally 
described by Steemann-Nielsen (1952), with modifications by Fitzwater et al. 
(1982) to minimize trace metal contamination. All materials were acid-cleaned in 
dilute (0.1 N) HC1, then rinsed with Milli-Q(TM) water. Incubation bottles were 
rinsed with the seawater sample prior to being filled. Samples were collected 
from the Go-Flo bottles in darkened 2-L acid-cleaned polycarbonate bottles. 
Approximately 250 mL of sample was transferred to each of three (two light, one 
dark) acid cleaned polycarbonate bottles and inoculated with 5 µCi of NaH14CO3 
with acid cleaned Eppendorf(TM) pipettes. The Amersham-Serlet(TM) isotope (14C-
bicarbonate) was prepared in a carrier solution of 0.3 g/L Baker Instra 
Analyzed(TM) NaHCO3. The three incubation bottles were then placed into small 
Plexiglas(TM) tubes that were wrapped with blue film, (#TS-5l-xsr from Madico 
Inc.). The number of wraps were calibrated to simulate the 100, 50, 30, 15, 6, 
and 1% of the incident surface 10 , corresponding to optical depths listed in 
Appendix C of 0, -0.69, -1.20, -1.90, -2.81, and -4.60. The samples were 
incubated on deck for 24 hours in clear Plexiglas(TM) cylinders filled with 
circulating surface seawater. The samples were then taken to the lab where they 
were filtered, in darkness, through Whatman GF/F filters, and rinsed with 
filtered seawater without being exposed to air.

Filtrations were performed under a pressure differential of <50 mm Hg to 
minimize cell breakage (Goldman and Dennett, 1985). The filters were transferred 
to Nalgene(TM) scintillation bags, and acidified with 0.5N HC1. After one hour, 
a 3-mL aliquot of Universol(TM) (ICN radiochemicals) scintillation cocktail was 
added to each bag as described in Hitchcock (1986)

Isotope activity of the samples was measured aboard ship with a Tracor model 300 
scintillation counter. Production rate (mg C/m3/h1) was calculated from the mean 
value of the two light bottles minus the dark bottle activity. A contour plot of 
productivity measurements from Leg 1 of this cruise is presented in Figure 8. 


Figure 7: Chlorophyll a cross section from Leg 1. Dots represent sample 
          locations. Contour interval = 0.05 mg/m3.



2.4  UNDERWAY MEASUREMENT METHODS

Sampling

During Legs 1 and 2 of the S. ATL-91 cruise, underway measurements of fugacity 
of CO2 in surface seawater, (fCO2w), and air, (fCO2a) were performed with an 
automated system. The seawater intake was located in the ship's bow bubble, 
approximately 3 m below the water line. A thermosalinograph, which records 
temperature and salinity was placed in a shunt off the main seawater intake 
line, in the bow bubble as well. Since there was evidence of seawater being 
heated prior to its reaching the thermosalinograph, water temperature was 
acquired from a hull mounted probe used for acoustic Doppler current profile 
data reduction. On Leg 2, discrete samples were taken from the underway system 
at six-hour intervals and analyzed for TCO2, fCO2, and major nutrients in 
addition to the continuous fCO2 measurements. Cruise tracks from Legs 1 and 2, 
with the range of fCO2w-fCO2a values represented by stick diagrams, are 
presented in Figures 9 and 10. 

2.4.1  Underway fCO2 Measurements

The shipboard automated underway fCO2 system runs on an hourly cycle during 
which three gas standards, a headspace sample from the equilibrator, and an 
ambient air sample are analyzed. The equilibrator, which was designed by R. 
Weiss of S.I.O., is made from a large (58 cm H x 23 cm ID) Plexiglas(TM) chamber. 

The equilibrator has a shower head in the top through which surface seawater is 
forced at a rate of 20-30 L/min. The water spray through the 16-L head space and 
the turbulence created by the jets impinging on the surface of 8-L of water, 
cause the gases in water and headspace to equilibrate. A drain 20 cm from the 
bottom of the equilibrator discharges excess water from the system over the side 
of the ship. Air in the equilibrator head space is circulated with an 
Aircadet(TM) pump (model 7530-40) at 6 L/min in a closed loop through a mass 
flow meter (MFM) and back pressure regulator. During 23 minutes of each hour, 75 
mL/min is teed off upstream of the back pressure regulator through a mass flow 
controller (MFC) and into the 12-mL sample cell of a Licor(TM) (model 6251) non-
dispersive infrared analyzer. The air removed from the equilibrator through the 
IR analyzer is replaced with ambient air through an intake/vent line that runs 
to the outside of the ship. The introduction of the ambient air into the 
equilibrator chamber during sampling of the headspace results in an error in the 
determination of the equilibrated head space composition no greater than one 
micro atmosphere. The total time required to fully replace equilibrator air 
through the ambient air intake/vent line is 213 minutes. The headspace 
equilibration time, as determined by return to equilibrium after perturbation by 
adding nitrogen to the head space, is approximately 2.5 minutes. The intake/vent 
line also assures that the pressure in the head space of the equilibrator 
remains at atmospheric value.

During underway sampling operations ambient air is drawn through 100 m of 0.37 
cm OD Dekoron(TM) tubing from the bow mast of the ship at a rate of 6 to 8 L/min. 
During 22 minutes of each hour, ambient air mixing ratios are measured in the IR 
analyzer by teeing off the air line at a flow rate of 75 mL/min. Compressed gas 
standards with nominal mixing ratios of 300, 350, and 400 ppm (parts per million 
by volume) flow through the IR analyzer for five minutes each hour at 75 mL/min 
for calibration. The 300 ppm standard flows continuously at 50 mL/min through 
the reference side of the IR analyzer (detector) as well. All reference tanks 
undergo a pre- and post-cruise calibration at CMDL against standards certified 
by the World Meteorological Organization (WMO).

The IR analyzer/detector's voltage output is measured once per second with a 
Keithley(TM) (model 195 A) digital multimeter; 1-minute averages are calculated 
and stored on the hard disk of an MS-DOS computer. The MFC's connected to the 
reference and sample inlet of the IR, the MFM's measurement of the intake rate 
of ambient air and recirculation rate of the headspace of the equilibrator, the 
back pressure in the air and equilibrated air lines, and two thermistors 
readings of the water temperature in the equilibrator are all logged at 1-minute 
intervals as well.

fCO2 Calculations

The mixing ratios of ambient air and equilibrated headspace air are calculated 
by fitting a second-order polynomial fit through the response of the detector 
versus mixing ratio of the standards. Due to the need for sufficient time to 
flush the sample cell and lines leading to the IR from the previous gas, the 
first three minutes of each analysis run are not used in the calculations. The 
subsequent one-minute readings for each analysis are averaged, yielding one 19-
minute average ambient air mixing ratio and one 20-minute average equilibrated 
headspace mixing ratio per hour. Typical standard deviations for air values are 
± 0.1 ppm and for equilibrated headspace ± 0.3 ppm.

Mixing ratios of dried equilibrated headspace and air must be converted to 
fugacity of CO2 in water and water saturated air in order to determine the 
driving force for the air-sea CO2 flux. For ambient air, assuming 100% water 
vapor content, the conversion is:

             fCO2a = XCO2a (P-pH2O) exp(B11 + 2 δ12) P/RT    (1)

where pH2O is the water vapor pressure at the sea surface temperature, and P is 
the atmospheric pressure. The exponential term is the fugacity correction where 
B11 is the second virial coefficient of pure CO2 (B11=1636.75 + 12.0408 T - 
0.0327957 T2 + 3.16528 x 10-5 T3) and δ12 (= 57.7 - 0.118 T) is the correction 
for an air-CO2 mixture (Weiss, 1974). The calculation for the fugacity in water 
includes an empirical temperature correction term for the increase of fCO2 due 
to heating (dfCO2w/dT = 4.23% / °C. D. Chipman and T. Takahashi, personal 
communication), of the water from passing through the pump and through 5 cm ID 
PVC tubing within the ship. The water in the equilibrator is typically 0.3°C 
warmer than sea surface temperature. The fugacity in water is calculated 
according to:

fCO2w = xCO2w (P-pH2Oeq) (exp[(Tsw - Teq) 0.0428]) exp(B11 + 2 δl2) P/RT     (2)

where pH2Oeq is the water vapor pressure at the temperature of the water in the 
equilibrator, Tsw is the temperature of the surface seawater, Teq is the 
temperature of the water in the equilibrator. 



ACKNOWLEDGMENTS

The dedication and assistance of the officers and crew of the NOAA ship MALCOLM 
BALDRIGE is gratefully appreciated and hereby acknowledged. The authors also 
thank Ms. Betty Huss for her expertise and efforts in the processing of the 
initial data sets. This research was supported by the climate and Global Change 
Program of NOAA.


Figure 8:  Productivity cross section from Leg 1. Dots represent sample 
           locations. Contour interval = 0.1 mg C m-3 h-1

Figure 9:  Underway fCO2(w-a) measurements from Leg 1. Stick height, above, or 
           to the left of track line equals fCO2(w-a). Negative fCO2(w-a) values 
           depict sinks and appear below, or to the right of the track line.

Figure 10: underway fCO2(w-a) measurements from Leg 2. Stick height above track 
           line equals fCO2(w-a). Negative fCO2(w-a) values appear below the 
           track line.


4.  REFERENCES

Armstrong, F.A.J., C.R. Stearns, and J.D.H. Strickland, The measurement of 
    upwelling and subsequent biological processes by means of the Technicon 
    Auto-Analyzer and associated equipment, Deep-Sea Res., 14, 381-389, 1967.

Atlas, E.L., J.C. Callaway, R.D. Tomlinson, L.I. Gordon, L. Barstow, and P.K. 
    Park, A practical manual for use of the Technicon Autoanalyzer for Nutrient 
    Analysis, revised, Oregon State University Technical Report 215, Reference 
    No. 71-22, 1971.

Burnison, B.K., Modified dimethylsulfoxide (DMSO) extraction for chlorophyll 
    analysis of phytoplankton, Can. J. Fish. Aquat. Sci. 37, 729-733, 1980.

Carpenter, J.H., The Chesapeake Bay Institute technique for the Winkler 
    Dissolved Oxygen method, Limnol. Oceanogr., 10, 141-143, 1965.

Chipman, D.W., J. Marra, and T. Takahashi, Primary production at 47°N and 20°W 
    in the North Atlantic Ocean: A comparison between the 14C incubation method 
    and mixed layer carbon budget observations, Deep-Sea Res. II, 40, 151-169, 
    1993.

Dickson, A.G., An exact definition of total alkalinity and a procedure for the 
    estimate of alkalinity and total CO2 from titration data, Deep-Sea Res., 28, 
    609-623, 1981.

Dickson, A.G., pH scales and proton-transfer reactions in saline media such as 
    seawater, Geochim. Cosmochim. Acta, 48, 2299-2308, 1984.

DOE, Handbook of methods for the analysis of the various parameters of the 
    carbon dioxide system in sea water, version 1.0, (A. Dickson and C. Goyet 
    ed.), 1991.

Fitzwater, S.E., G.A. Knauer, and J.B. Martin, Metal contamination and it's 
    effect on primary production measurements, Limn. Oceanogr., 27, 544-551, 
    1982.

Friederich, G.E., P. Sherman and L.A. Codispoti, A high precision automated 
    Winkler titration system based on an HP-85 computer, a simple colorimeter 
    and an inexpensive electromechanical buret, Bigelow Lab. for Ocean Sciences, 
    Tech. Report 42, 24 pp, 1984.

Goldman, J.C. and M.R. Dennet, Susceptibility of some marine phytoplankton 
    species to cell breakage during filtration and post filtration rinsing, J. 
    Exp. Mar. Biol. Ecol., 86, 47-58, 1985.

Hitchcock, G.L., Methodological aspects of time course measurements of C-14 
    fixation in marine phytoplankton, J. Exp. Mar. Biol. Ecol., 95, 233-243, 
    1986.

Johnson, K.M., Operator's manual; Single operator multiparameter metabolic 
    analyzer (SOMMA) for total carbon dioxide (CT) with Coulometric detection, 
    70 pp, Brookhaven N.Y., 1992.

Johnson, K.M., K.D. Wills, D.B. Butler, W.K. Johson, and C.S. Wong, Coulometric 
    total carbon dioxide analysis for marine studies: maximizing the performance 
    of an automated continuous gas extraction system and coulometric detector, 
    Mar. Chem. 44, 167-189, 1993.

Millero, F.J., The thermodynamics of the carbonic acid system in seawater, 
    Geochim. Cosmochim. Acta, 43, 1651-1661, 1979.

Millero, F.J., and A. Poisson, International one-atmosphere equation of state of 
    seawater, Deep-Sea Res., 28A, 625-629, 1981.

Millero, F.J., The pH of estuarine waters, Limnol. Oceangr., 31, 839-847, 1986.

Parsons, T.R., Y. Maita, and C.M. Lalli, A Manual of Chemical and Biological 
    Methods for Seawater Analysis, Pergamon, Elmsford, New York, 1984.

Peng, T.-H., P. Takahashi, W.S. Broecker, and J. Olafsson, Seasonal variability 
    of carbon dioxide, nutrients and oxygen in the northern North Atlantic 
    surface water: observations and a model, Tellus, 395, 439-458, 1987.

Shoaf, W.T. and B.W. Lium, Improved extraction of chlorophyll a and b from algae 
    using dimethyl sulfoxide, Limnol. Oceanogr. 21, 926928, 1976.

Saunders, P.M., and N.P. Fofonoff, Conversion of pressure to depth in the ocean, 
    Deep-Sea Res., 23, 109-111, 1976.

Steeman-Nielsen, E., The use of radioactive carbon (C14) for measuring organic 
    carbon production in the sea, J. Cons. Int. Explor. Mer., 18, 117-140, 1952.

Thurmond, V.L., The carbonate system in Ca-Mg-Na-Cl brines up to 6.0 molal NaCl 
    at 25°C. Thesis, 1982.

Thurmond, V.L., and F.J. Millero, The ionization of carbonic acid in sodium 
    chloride solutions at 25°C, J. Solution Chem., 11, 447-456, 1982.

Wanninkhof, R., and K. Phoning, Surface water fCO2 measurements using continuous 
    and discrete sampling methods, Marine Chem. 44, 189-204, 1993.

Weiss, R.F., Carbon dioxide in water and seawater: the solubility of a non-ideal 
    gas, Mar. Chem., 2, 203-215, 1974.

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    the determination of gas loop volume. Analytical Chem. 65, 2403-2406, 1993.



APPENDIX A:   Index of Measurements and Units

List of measurements

Column heading or abbreviation  Explanation


------------------------------  ------------------------------------------------
Hydrography, Appendix B
    TCO2(coul.)                 dissolved inorganic carbon dioxide (coulometer)
    TCO2(titr.)                 dissolved inorganic carbon dioxide (titrated)
    fCO2,20                     fugacity of CO2 at 20 degrees
    TAlk                        total alkalinity
    calc.                       means the value has been calculated
    coul.                       coulometer
    DOC                         dissolved organic carbon
Productivity measurements, Appendix C
    OPT DEPTH                   optical depth
    PROD-RATE                   organic carbon production rate
    CARB-DAY                    organic carbon production per day (= PROD_RATE*24) 
    CHLORO_A                    chlorophyll
    CHLOR_DAY                   chlorophyll production per day
    TOT-PIGS                    chlorophyll + phaopigments
    INCUB-TIME                  incubation time for productivity measurements
Underway measurements, Appendix D
    Lat                         latitude in decimal degrees
    Lon                         longitude in decimal degrees
    XCO2,a                      the volume fraction of CO2 in air
    XCO2,w                      the volume fraction of CO2 in equilibrator headspace   
    fCO2.w-a                    fugacity of CO2 (water value minus the air value)
    SST                         sea surface temperature
    SST-Eq.T                    sea surface Temperature-Equilibrator temperature
    Sal (CTD)                   salinity from CTD measurement at stations
    Sal (TSG)                   salinity measurement from thermosalinograph
    



Hydrographic  and Carbon System parameters, Appendix B

Parameter       Units        Unit spelled out
--------------  -----------  ----------------------------------
Depth           m            meters
Pres.           db           decibars
Temp.           °C           degrees centigrade
Pot. T.         °C           degrees centigrade
Salinity        (none)       salinity
Sigma theta     (none)       potential density
Oxygen          mL/L         milliliters per liter
NO2             umol/L       micro moles per liter
NO3             umol/L       micro moles per liter
SiO4            umol/L       micro moles per liter
TCO2 (coul.)    umol/kg      micro moles per kilogram


fCO2 (20 deg.)  uatm         micro atmospheres at 20°C
pH              (none)          
TAlk            uEq/Kg       micro equivalents per kilogram
TCO2 (titr.)    umol/Kg      micro moles per kilogram
DOC             umol/L       micro moles per liter


Productivity parameters, Appendix C  

Parameter       Units        Unit spelled out
--------------  -----------  ----------------------------------
SALINITY        (none)       salinity
INCUB TIME      HRS          hours
DEPTH           m            meters
OPT DEPTH       (none)       optical depth
PROD-RATE       mgC/m^3/h^1  milligrams of carbon per m3 per hr
CARB_DAY        mgC/m^3      milligrams per cubic meter
CHLORO_A        mgC/m^3      milligrams per cubic meter
CHLORO_DAY      mgC/m^3      milligrams per cubic meter
TOT-PIGS        mgC/m^3      milligrams per cubic meter


Underway parameters, Appendix D  

Parameter       Units        Unit spelled out
--------------  -----------  ----------------------------------
Lat             Dec. Deg.    decimal degrees
Lon             Dec. Deg.    decimal degrees
XCO2,a          ppm          parts per million
XCO2,W          ppm          parts per million
SST             deg. C       degrees centigrade
SST-Eq.T        deg. C       degrees centigrade
Sal (CTD)       none          
Pressure        mb           millibars
fCO2,w          uatm         microatmospheres
fCO2,w-a        uatm         microatmospheres




DATA PROCESSING NOTES (Leg 1)

Date        Person            Data Type    Action            Summary

2000-01-11  Rik Wanninkhof    CTD          Submitted         needs reformatting 

2000-05-06  Rik Wanninkhof    CTD          Status Update     Data are Public
            I did not realize that the data were in non-public status. Feel free 
            to release it to the community at large (recognizing that not all 
            data meets "WOCE specifications"). Don't hesitate to contact us if 
            there are further questions.

2000-06-12  Danie Bartolacci  CTD          Website Updated:  data are public 

2000-12-20  Heidi Buck  Cruise Report      Website Updated:  txt version online 

2002-05-01  Danie Bartolacci  CTD/BTL/SUM  Update Needed:    Correct Data Status Fields 
            Database does not reflect having BOT in. DOC is for CTD only. 
            Correct database to indicate BOT is in and all params. WOCE fmt all 
            files. Create SUM. Create exchg.

2002-10-17  Karla Uribe       CTD/SUM       Website Updated:  CTD converted to 
                                                              WOCE, unformatted 
                                                              SUM put online 
            CTD was converted to WOCE format using the header information, 
            documentation and sumfile. The original CTD zip contains a file 
            called LOCATION.CSV which is a sumfile, I put a copy of that file on 
            the website. That sumfile is still unformatted and it is required to 
            finish testing the CTDs. The original CTD files contained 3 OXY 
            values, the ML/L was selected to be put in the WOCE format which 
            means those units must be converted before converting to exchange.

2002-10-30  Karla Uribe       SUM           Website Updated:  SUM created, 
                                                              Lat/Lon converted 
                                                              from decimal values 
            Sumfile was created from a CSV file that was found in the CTD zip. 
            Lat/Lon data was converted from decimal values. Sumfile in WOCE 
            format. 

2005-01-04  Robert  Key       BTL            Status Update    Available for 
                                                              submission
            On the same page you have listed the 1991 M. Baldrige cruise. Under 
            the data link there is no bottle data. These data are public and i 
            have a copy of everything with WOCE flags added. I can provide a 
            copy if you need it or alternately, it should be available from 
            Kozyr at CDIAC. 

2005-01-05  Robert  Key       DELC13/DELC14  Submitted        Updated data files 
            Here are the similar (to AR21_1993) files for AR21a (leg 1 and 2 
            separate). I also attach my README as well as the NOAA final report. 
            Nutrients and oxygen from these early 90s NOAA cruises tend to be 
            below WOCE standard. This cruise pre-dated development of CRMs for 
            carbon, so final calibration on those data are not as accurate as 
            we'd expect today. 

2011-02-10  Dave Muus         CTD            Website Update   Exchange and 
                                                              NetCDF files 
                                                              online, sum 
                                                              corrected 
            "Notes on Malcolm Baldridge cruise July 11 - Sept 2, 1991. 
            Expocode 3175MB91 110210/dm

            Section ID AR21 per Documentation file.

            1. Summary file dated 20021029 failed sumchk test.
               WOCE SECT column was blank. Added AR21.
               LONGITUDE not Left Justified. Realigned longitude values.
               sumchk okay.
               Stations 1 - 31 plot on African continent. Original summary file 
                 (ar21_asu_replaced20021030.txt) shows longitudes negative - 
                 West not East.
               Changed longitudes from E to W.

            2. WOCE format CTD files are named "CAST-0cc.CAL" where cc is CASTNO 
                 in summary file.
               Renamed CTD files to WOCE CTD filename format: AR21_a00ss.wct 
                 where ss is STNNBR.

            3. First 9 casts had end-of-line "*" in wrong column for 2nd line. 
                 Corrected.

            4. Removed "_1 _2" between EXPOCODE and WHP-ID to make EXPOCODE 
                 agree with summary file.

            5. NUMBER OBS. column not lined up properly. Moved one space to 
                 right.

            6. Converted CTDOXY ML/L to UMOL/KG.

            7. No bottom depth. Used 99999 in summary file to make exchange 
                 file, then changed summary file to -9 and exchange file bottom 
                 depth to -999.

            8. No quality flags in original data set. Apparently all flags set 
                 to "2" in 2002-10-17 WOCE format CTD file. Left flags 
                 unchanged.
               Note caution in Documentation file re CTD Oxygen data.

            9. Made Exchange and NetCDF format CTD files. Checked with Java 
                 OceanAtlas."

2011-03-10  Dave Muus         BTL            Website Update   Exchange and WOCE files online 
            Notes on AR21 Leg 1 bottle data   EXPOCODE 3175MB91   110309/dm

            1. Original bottle data received from Bob Key as AR21a.leg1.Z on 
                 January 5, 2005.

            2. pH and DOC have no quality flags. Used flag 2 for pH and DOC 
                 values. Used PH_SWS and PH_TMP = 25 Degrees per README.AR21a.

            3. CASTNOs do not match Summary file cast numbers from CTD data and  
                 NOAA    
                 Data Report ERL AOML-24(dated April 1994) 
               Bottle file has Station numbers: 8, 14, 20, 25, 30 and 32. Not on  
                 CTD file Summary file or Data Report.
               Changed bottle data file cast numbers from all "1"s to CTD and 
                 Data Report station and cast numbers.
               Data Report has Station 38 for casts 31, 32 and 33. CTD and 
                 AR21a.leg1.Z have casts 32 and 33 in Station 39.
              Station 38/31 is more than 1400km from casts 32 and 33. Casts 32 
                 and 33 have same position and bottom depth.
              Used Station 39 for casts 32 and 33.

            4. Bottom depths in AR21a.leg1.Z file differ from bottom depths in 
                 Data Report.
               Used Data Report bottom depths to Summary file.

            5. Compared Summary File to Data Report and made following 
                 corrections assuming Data Report is correct:
               Station Cast 
                  2    2   Changed Longitude from 36 10.80 W to 35 10.80 W
                  5    5   Changed longitude from 25  0.60 W to 25  0.00 W
                  9    8   Changed latitude from  0  0.60 S to  0  0.00 S    
                 11   10   Changed latitude from  2  0.00 S to  1 59.40 S
                 11   10   Changed longitude from 24  0.00 S to 25  0.00 W
                 18   15   Changed latitude from 11. 0.00 S to 10 59.40 S
                 18   15   Changed longitude from 25  0.60 W go 





DATA PROCESSING NOTES (Leg 2)

Event Date  Person      Date Type  Summary 
----------  ----------  ---------  ---------------------------------------------
2011-03-10  Muus, Dave  BTL        Exchange & WOCE files online 
            Notes on AR21 Leg 2 bottle data EXPOCODE 3175MB91_2 110309/dm
            1. Original bottle data received from Bob Key as AR21a.leg2.Z on 
               January 5, 2005.
            2. AR21a.leg2.Z has no ALKALI data. TALK are in NOAA Data Report ERL 
               AOML-24(dated April 1994) but are calculated data (uEq/Kg) and 
               were not used.
            3. DELC13 have no quality flags. Used flag 2. 
            4. CASTNOs do not match Summary file cast numbers from CTD data and 
               NOAA Data Report ERL AOML-24 (dated April 1994) Changed bottle 
               data file cast numbers from all "1"s to Data Report cast numbers.
            5. Bottom depths in AR21a.leg2.Z file differ from bottom depths in 
               NOAA Data Report. Used Data Report values since they have better 
               agreement with deepest bottle depths. For example, Station 4 
               deepest bottle is 5645m(5765db), Data Report bottom depth is 5908 
               and data file bottom depth is 3589m.

2011-03-22  Muus, Dave  BTL        Cast numers changed
            Corrected WOCE format bottle file placed on line:  
              Cast numbers changed from "1"s to Data Report cast numbers.
              Data reordered from surface to bottom.
