If symbols do not display correctly change your browser character encoding to unicode 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. Wilke, B.J., D.W.R. Wallace and K.M. Johnson, Water-based gravimetric method for 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.