| Processing Steps |
- Parameter or Variable: Dissolved Inorganic Carbon; Abbreviation: DIC_UMOL_KG; Unit: micro-mol/kg; Observation type: Profile and underway (flow through); In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through system; Analyzing instrument: Two systems consisting of a coulometer (UIC Inc.) coupled with a Dissolved Inorganic Carbon Extractor (DICE) inlet system. DICE was developed by Esa Peltola and Denis Pierrot of NOAA/AOML and Dana Greeley of NOAA/PMEL to modernize a carbon extractor called SOMMA (Johnson et al. 1985, 1987, 1993, and 1999; Johnson 1992); Detailed sampling and analyzing information: Samples for total dissolved inorganic carbon (DIC) measurements were drawn according to procedures outlined in the Guide to best practices for ocean CO2 measurements (Dickson et al., 2007) from Niskin bottles into cleaned 294-ml glass bottles. Bottles were rinsed and filled from the bottom, leaving 6 ml of headspace; care was taken not to entrain any bubbles. After 0.2 ml of saturated HgCl2 solution was added as a preservative, the sample bottles were sealed with glass stoppers lightly covered with Apiezon-L grease and were stored at room temperature to be analyzed within 48 hours of collection. The analysis was done by coulometry with two analytical systems (AOML3 and AOML4) used simultaneously. In the coulometric analysis of DIC, all carbonate species are converted to CO2 (gas) by addition of excess hydrogen ion (acid) to the seawater sample, and the evolved CO2 gas is swept into the titration cell of the coulometer with pure air or compressed nitrogen, where it reacts quantitatively with a proprietary reagent based on ethanolamine to generate hydrogen ions. In this process, the solution changes from blue to colorless, triggering a current through the cell and causing coulometrical generation of OH minus ions at the anode. The OH ions react with the H+, and the solution turns blue again. A beam of light is shone through the solution, and a photometric detector at the opposite side of the cell senses the change in transmission. Once the percent transmission reaches its original value, the coulometric titration is stopped, and the amount of CO2 that enters the cell is determined by integrating the total charge during the titration. The volume of the pipette used to deliver the sample in each system was determined with aliquots of distilled water at known temperature. The weights with the appropriate densities were used to determine the volume of the pipette. Calculation of the amount of CO2 injected was according to the CO2 handbook (Dickson et al., 2007).The instrument has a salinity sensor, but all DIC values were recalculated to a molar weight (micro-mol/kg) using density obtained from the CTD salinity. The DIC values were corrected for dilution by 0.2 ml of saturated HgCl2 used for sample preservation (Measured DIC*1.00037). A correction was also applied for the offset from the CRM. This additive correction was applied for each cell using the CRM value obtained in the beginning of the cell.; Replicate information: Duplicates were collected on every station as well as on the underway discrete sampling. In total, 1899 samples were run, each 250-ml, 222 sets of duplicate samples.; Standardization description: The coulometers were calibrated by injecting aliquots of pure CO2 (99.99%) by means of an 8-port valve outfitted with two sample loops with known gas volumes bracketing the amount of CO2 extracted from the water samples for the two AOML systems.; Standardization frequency: The stability of each coulometer cell solution was confirmed three different ways: two sets of gas loops were measured at the beginning; also the Certified Reference Material (CRM), supplied by Dr. A. Dickson of UCSD, were measured at the beginning; and the duplicate samples at the beginning, middle, and end of each cell solution. The coulometer cell solution was replaced after 25 mg of carbon was titrated, typically after 9 to 12 hours of continuous use.; CRM manufacturer: Dr. A. Dickson of UCSD; CRM batch number: Batch 153; Preservation method: saturated HgCl2; Preservative volume: 0.2 ml; Preservative correction: The DIC values were corrected for dilution by 0.2 ml of saturated HgCl2 used for sample preservation. The total water volume of the sample bottles was 288 ml (calibrated by Esa Peltola, AOML). The correction factor used for dilution was 1.00037.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Dickson, A.G., Sabine, C.L. and Christian, J.R. (Eds.) 2007. Guide to best practices for ocean CO2 measurements. PICES Special Publication 3, 191 pp. Johnson, K.M., Kortzinger, A.; Mintrop, L.; Duinker, J.C.; and Wallace, D.W.R. (1999). Coulometric total carbon dioxide analysis for marine studies: Measurement and internal consistency of underway surface TCO2 concentrations. Marine Chemistry 67:123 to 44. Johnson, K.M., Wills, K.D.; Butler, D.B.; Johnson, W.K.; and Wong, C.S. (1993). Coulometric total carbon dioxide analysis for marine studies: Maximizing the performance of an automated gas extraction. Johnson, K.M. (1992). Operator Manual: Single-Operator Multiparameter Metabolic Analyzer (SOMMA) for Total Carbon Dioxide (CT) with Coulometric Detection. Brookhaven National Laboratory, Brookhaven, N.Y. Johnson, K.M.; Williams, P.J.; Brandstrom, L.; and McN. Sieburth, J. (1987). Coulometric total carbon analysis for marine studies: Automation and calibration. Marine Chemistry 21:117 to 33.; Researcher name: Rik Wanninkhof; Leticia Barbero; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration (NOAA).
- Parameter or Variable: Total alkalinity; Abbreviation: TA_UMOL_KG; Unit: micro-mol/kg; Observation type: Profile and surface underway (flow through); In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through system; Analyzing instrument: Semi-automatic titration systems, System 1 consists of a Metrohm 765 Dosimat titrator, a pH meter (Orion 720A, ThermoScientific), a ROSS half cell pH glass electrode (Orion 9101BN, ThermoScientific) and a reference electrode (Orion 900200, ThermoScientific). System 2 consists of a Metrohm 665 Dosimat titrator, a pH meter (Orion 2 star pH Benchtop, ThermoScientific), a ROSS half cell pH glass electrode (Orion 9101BN, ThermoScientific) and a reference electrode (Orion 900200, ThermoScientific).; Type of titration: Full Titration; Cell type (open or closed): Open; Curve fitting method: Least-Square Analysis; Detailed sampling and analyzing information: Samples for total alkalinity (TAlk) measurements were drawn according to procedures outlined in the Guide to best practices for ocean CO2 measurements (Dickson et al., 2007) from Niskin bottles into cleaned 500-ml glass bottles. Bottles were rinsed and filled from the bottom, leaving approximately 6 ml of headspace; care was taken not to entrain any bubbles. After 0.2 ml of saturated HgCl2 solution was added as a preservative, the sample bottles were sealed with glass stoppers lightly covered with Apiezon-L grease and were stored at room temperature for analysis onboard within 48 hours of collection. For each measurement, approximately 200 ml of water sample were titrated with an HCl solution in ~0.55 molal NaCl solution provided by Dr. Andrew Dickson of UCSD (0.25175 moles per kilogram-solution).; Replicate information: 1452 samples each 500-ml, 86 sets of duplicate samples.; Standardization description: 2 CRM samples were run daily on each cell, before and after the seawater samples. The Total Alkalinity for the water samples was corrected using the daily averaged ratios between the certified and measured values of the 2 CRMs run on each cell. This TA titration system has a precision of 0.1 %. All the TA values were directly measured with reference to Certified Reference Material. The accuracy after correction is 0.1%.; Standardization frequency: All values were directly measured with reference to Certified Reference Material (Dickson, UCSD). 2 CRM samples were run daily on each cell.; CRM manufacturer: Dr. A. Dickson of UCSD; CRM batch number: CRM batch: 153; Preservation method: saturated HgCl2; Preservative volume: 0.2 ml; Uncertainty: The precision of this method is better than 0.1% and accuracy is 0.1%.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Millero, F. J., Zhang, J. Z., Lee, K., and Campbell, D. M. (1993). Titration alkalinity of seawater. Marine Chemistry, 44(2), 153-165.; Researcher name: Denis Pierrot: Leticia Barbero; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration (NOAA).
- Parameter or Variable: pH; Abbreviation: PH_TOT_MEA; pH scale: Total; Observation type: Profile and surface underway (flow through); In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through system; Analyzing instrument: Agilent 8453 spectrometer setup with a custom-made temperature-controlled cell holder; Temperature of pH measurement: 25 (+/- 0.05) degrees Celsius; Detailed sampling and analyzing information: Samples were collected for pH analysis immediately following O2 in the Niskin/Rosette sampling sequence. Seawater samples were collected from the Niskin bottles directly in 10-cm cylindrical optical cells (~30 mL volume) using a section of silicone tubing (about 15 cm long). One end of the silicone tubing was attached to the optical cell and the other end was attached to the nipple of the Niskin bottle. The Niskin bottle nipple was pushed in to initiate flow and the silicone tubing was squeezed to eliminate air bubbles. The optical cell was agitated to eliminate bubbles and, after 15 seconds of sample flow, the cell was capped at one end. The silicone tubing was then detached from the optical cell and, with the water still flowing, the cap was rinsed and used to seal the optical cell. Samples collected this way were not exposed to the atmosphere, and each cell was flushed with approximately three cell volumes of seawater. The samples were collected, taken into the lab, and rinsed with tap water to get rid of salt outside of the cells. The cells were dried and the optical windows were cleaned with Kimwipes. Samples were thermostatted at 25 (+/-0.05) oC in a custom made 36-position cell warmer. A custom macro program running on Agilent ChemStation was used to guide the measurements and data processing. The macro automated the procedures of sample input, blank and sample scans, quality control, and data archiving. The quality control steps included checking the baseline shift after dye injection and monitoring the standard deviation of multiple scans. Absorbance blanks were taken for each sample and 10 uL of purified m-cresol purple (10 mmol kg-1) were added for the analysis. pHT (total scale) was calculated according to Liu et al. (2011).; Replicate information: A total of 1,530 pH samples were collected from the 107 stations, and 154 underway samples during transits. Duplicate pH samples, collected from discrete samples taken from Bullister bottles (N = 173), displayed a standard deviation of 0.001.; Standardization description: The pH is calibration-free.; At what temperature was pH reported: 25 degrees Celsius; Uncertainty: Precision was equal to +/-0.0004.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Liu, X.; Patsavas, M.C.; and Byrne, R. H. (2011). Purification and characterization of meta-cresol purple for spectrophotometric seawater pH measurements. Environmental Science and Technology, 45(11), 4862-4868. https://doi.org/10.1021/es200665d; Researcher name: Robert Byrne; Researcher institution: University of South Florida.
- Parameter or Variable: pCO2 (fCO2) discrete; Abbreviation: PCO2_MEA_UATM; Unit: microatmospheres; Observation type: Profile and surface underway; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Calculation method and parameters: Niskin bottle and flow through pump; Analyzing instrument: LI-COR (model 840); Storage method: The sample bottles were sealed with glass stoppers lightly covered with Apiezon-L grease and were stored at room temperature for a maximum of twelve hours prior to analysis. When twelve bottles were moved into the primary water bath for analyses, the next twelve bottles were moved into the secondary water bath. No sample bottle spent less than one hour in the secondary water bath prior to being moved to the analytical water bath.; Seawater volume: 500 ml; Headspace volume: 5 ml; Temperature of measurement: 20 oC; Detailed sampling and analyzing information: Samples were drawn from 10-L Niskin bottles into 500 ml glass bottles using Tygon tubing with a Silicone adapter that fit over the drain cock to avoid contamination of DOM samples. Bottles were rinsed twice, the second time while inverted. They were filled from the bottom, overflowing half a volume while taking care not to entrain any bubbles. About 5 ml of water was withdrawn to allow for expansion of the water as it warms and to provide space for the stopper and tubing of the analytical system. Saturated mercuric chloride solution (0.2 ml) was added as a preservative. The sample bottles were sealed with glass stoppers lightly covered with Apiezon-L grease and were stored at room temperature for a maximum of twelve hours prior to analysis.The analyses for pCO2 were done with the discrete samples at 20oC. A primary water bath was kept within 0.03oC of the analytical temperature; a secondary bath was kept within 0.15oC the analytical temperature. The majority of the samples were analyzed in batches of twelve bottles, which with standards took approximately 2.5 hours. When twelve bottles were moved into the primary water bath for analyses, the next twelve bottles were moved into the secondary water bath. No sample bottle spent less than one hour in the secondary water bath prior to being moved to the analytical water bath.; Sample replicate information: Over 1300 samples were drawn from 113 CTD casts. From the UW seawater line, 153 samples were drawn. Seventy-eight sets of duplicate bottles were drawn at numerous depths. The average relative standard error was 0.21%, while the median relative error was 0.15%.; Gas detector manufacturer: LiCOR 840 infrared analyzer. The system was built by Colm Sweeney and Tim Newberger; Gas detector model: Prototype; Gas detector uncertainty: The average relative standard error was 0.21%, while the median relative error was 0.15%.; Standardization technique: To ensure analytical accuracy, a set of six gas standards (ranging from 248 to 1534 ppm) was run through the analyzer before and after every sample batch. The standards were obtained from Scott-Marin and referenced against primary standards purchased from C.D. Keeling in 1991, which are on the WMO-78 scale.; Standardization frequency: Before and after each batch of 12 samples.; Standard gas manufacturer: Scott Marin; Standard gas concentration: 248.73, 384.14, 567.40, 792.51, 1036.95, and 1533.7 ppm; Water vapor correction method: The details of the data reduction are described in Pierrot, et.al. (2009).; Temperature correction method: The details of the data reduction are described in Pierrot, et.al. (2009).; At what temperature was pCO2 reported: 20 oC; Uncertainty: The average relative standard error was 0.21%, while the median relative error was 0.15%.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Wanninkhof, R.; and Thoning, K. (1993). Measurement of fugacity of CO2 in surface water using continuous and discrete sampling methods. Mar. Chem., v. 44, no. 2-4, pp. 189-205. Pierrot, D.; Neill, C.; Sullivan, K.; Castle, R.; Wanninkhof, R.; Lüger, H.; Johannessen, T.; Olsen, A.; Feely, R.A.; and Cosca, C.E. (2009). Recommendations for autonomous underway pCO2 measuring systems and data-reduction routines. Deep-Sea Res., II, v. 56, pp. 512-522.; Researcher name: Rik Wanninkhof; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: CTD pressure; Abbreviation: CTDPRS_DBAR; Unit: dbars; Observation type: Profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: CTD; Analyzing instrument: Sea-Bird SBE-911plus CTD system; Detailed sampling and analyzing information: A detailed and more complete description is available in the cruise report at: http://www.aoml.noaa.gov/ocd/gcc/GOMECC3/Cruise_Report.pdf. CTD/rosette casts were performed with a package consisting of a 24-place, 10-liter rosette frame (AOML's white frame), a 24-place water sampler/pylon (SBE32) and 24, 10-liter Bullister/Niskin-style bottles. This package was deployed on all stations/casts. Underwater electronic components consisted of a Sea-Bird Electronics (SBE) 9 plus CTD with dual pumps and the following sensors: dual temperature (SBE3), dual conductivity (SBE4C), dual dissolved oxygen (SBE43), and a Paroscientific Digiquartz Pressure Sensor. The CTDs supplied a standard Sea-Bird format data stream at a data rate of 24 frames/second. The SBE9plus CTD was connected to the SBE32 24-place pylon providing for single-conductor sea cable operation. Power to the SBE9plus CTD, SBE32 pylon, auxiliary sensors, and altimeter was provided through the sea cable from the SBE11plus deck unit in the computer lab. Shipboard CTD data processing was performed automatically at the end of each deployment using SEABIRD SBE Seasave software version 7.23.2 and AOML Matlab processing software.; Uncertainty: Pressure sensor calibration coefficients derived from the pre-cruise calibrations were applied to raw pressure data during each cast. Residual pressure offsets between the first and last near surface pressures and before and after on deck pressures were examined to check for calibration shifts. Pressure sensor s/n 1292 was used for the entirety of the cruise with an initial pressure offset of 0.47 dbar applied to the configuration file for a total offset of -0.3. On deck pressure before and after the cast were stable at -0.04 +/- 0.03 dbar and -0.03 +/- 0.07 dbar, respectively. Near surface pressure values at the start and end of the cast were stable at 3.02 +/- 0.63 dbar and 3.02 +/- 0.53 dbar, respectively.; Researcher name: Molly Baringer; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: CTD temperature; Abbreviation: CTDTMP_ITS-90_DEG_C; Unit: degree C; Observation type: profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: CTD; Analyzing instrument: Sea-Bird SBE-911plus CTD system; Detailed sampling and analyzing information: A detailed and more complete description is available in the cruise report at: http://www.aoml.noaa.gov/ocd/gcc/GOMECC3/Cruise_Report.pdf. CTD/rosette casts were performed with a package consisting of a 24-place, 10-liter rosette frame (AOML's white frame), a 24-place water sampler/pylon (SBE32) and 24, 10-liter Bullister/Niskin-style bottles. This package was deployed on all stations/casts. Underwater electronic components consisted of a Sea-Bird Electronics (SBE) 9 plus CTD with dual pumps and the following sensors: dual temperature (SBE3), dual conductivity (SBE4C), dual dissolved oxygen (SBE43), and a Paroscientific Digiquartz Pressure Sensor. The CTDs supplied a standard Sea-Bird format data stream at a data rate of 24 frames/second. The SBE9plus CTD was connected to the SBE32 24-place pylon providing for single-conductor sea cable operation. Power to the SBE9plus CTD, SBE32 pylon, auxiliary sensors, and altimeter was provided through the sea cable from the SBE11plus deck unit in the computer lab. Shipboard CTD data processing was performed automatically at the end of each deployment using SEABIRD SBE Seasave software version 7.23.2 and AOML Matlab processing software.; Uncertainty: Temperature sensor calibration coefficients derived from the pre-cruise calibrations were applied to raw primary and secondary temperature data during each cast. Calibration accuracy was examined by comparing T1-T2 over a range of station numbers and pressures (bottle trip locations) for each cast. The median temperature difference between the two sensors was 0.001 oC with a standard deviation of 0.02 oC (0.0015 oC and a standard deviation of 0.0007 oC below 1000m).; Researcher name: Molly Baringer; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: CTD salinity; Abbreviation: CTDSAL_PSS78; Observation type: profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Calculated from conductivity measurements.; Sampling instrument: CTD; Analyzing instrument: Sea-Bird SBE-911plus CTD system; Detailed sampling and analyzing information: A detailed and more complete description is available in the cruise report at: http://www.aoml.noaa.gov/ocd/gcc/GOMECC3/Cruise_Report.pdf. CTD/rosette casts were performed with a package consisting of a 24-place, 10-liter rosette frame (AOML's white frame), a 24-place water sampler/pylon (SBE32) and 24, 10-liter Bullister/Niskin-style bottles. This package was deployed on all stations/casts. Underwater electronic components consisted of a Sea-Bird Electronics (SBE) 9 plus CTD with dual pumps and the following sensors: dual temperature (SBE3), dual conductivity (SBE4C), dual dissolved oxygen (SBE43), and a Paroscientific Digiquartz Pressure Sensor. The CTDs supplied a standard Sea-Bird format data stream at a data rate of 24 frames/second. The SBE9plus CTD was connected to the SBE32 24-place pylon providing for single-conductor sea cable operation. Power to the SBE9plus CTD, SBE32 pylon, auxiliary sensors, and altimeter was provided through the sea cable from the SBE11plus deck unit in the computer lab. Shipboard CTD data processing was performed automatically at the end of each deployment using SEABIRD SBE Seasave software version 7.23.2 and AOML Matlab processing software.; Uncertainty: Conductivity sensor calibration coefficients derived from the pre-cruise calibrations were applied to raw primary and secondary conductivities. Comparisons between the primary and secondary sensors and between each of the sensors to check sample conductivities (conductivity calculated from bottle salinities) were used to derive conductivity corrections. For the entire cruise, only one set of conductivity sensors was used. The two sensors show a median difference of -0.001 mS/cm and a standard deviation of 0.05 mS/cm (-0.001 mS/cm and a standard deviation of 0.0006 mS/cm below 1000m).; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value.; Researcher name: Molly Baringer; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: Bottle salinity; Abbreviation: SALINITY_PSS78; Observation type: Profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Calculation method and parameters: Niskin bottle; Sampling instrument: Guildline Autosal, model 8400B salinometer (S/N 60843); Detailed sampling and analyzing information: The salinity samples were collected in 200 ml Kimax high-alumina borosilicate bottles that had been rinsed at least three times with sample water prior to filling. The bottles were sealed with custom-made plastic insert thimbles and Nalgene screw caps. This assembly provides very low container dissolution and sample evaporation. Prior to sample collection, inserts were inspected for proper fit and loose inserts replaced to insure an airtight seal. Laboratory temperature was also monitored electronically throughout the cruise. PSS-78 salinity UNES81, was calculated for each sample from the measured conductivity ratios. The offset between the initial standard seawater value and its reference value was applied to each sample. The difference (if any) between the initial and final vials of standard seawater was then applied to each sample as a linear function of elapsed run time. Salinity analyses were performed after samples had equilibrated to laboratory temperature, usually at least 24 hours after collection. The salinometer was standardized for each group of samples analyzed (usually 2 casts and up to 50 samples) using two bottles of standard seawater: one at the beginning and end of each set of measurements. The salinometer output was logged to a computer file. The software prompted the analyst to flush the instrument's cell and change samples when appropriate. For each sample, the salinometer cell was initially flushed at least 3 times before a set of conductivity ratio readings were taken. IAPSO Standard Seawater Batch P-160 was used to standardize all casts.; Replicate information: 679 salinity measurements were taken, including 31 duplicates, and approximately 40 vials of standard seawater were used. Up to two duplicate samples were drawn, primarily for the deep casts (>1000 m), to determine total analytical precision.; Uncertainty: Throughout the course of the cruise, the autosal standards had a range of 0.0002 in conductivity ratio (about 0.003 in salinity). The duplicates for the bottle salinity had a median of 0.0003 psu +/- 0.001 psu.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Researcher name: Molly Baringer; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: CTD oxygen; Abbreviation: CTDOXY_UMOL_KG; Unit: micromol/kg; Observation type: Profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: CTD; Analyzing instrument: Sea-Bird SBE-911plus CTD system; Detailed sampling and analyzing information: A detailed and more complete description is available in the cruise report at: http://www.aoml.noaa.gov/ocd/gcc/GOMECC3/Cruise_Report.pdf. CTD/rosette casts were performed with a package consisting of a 24-place, 10-liter rosette frame (AOML's white frame), a 24-place water sampler/pylon (SBE32) and 24, 10-liter Bullister/Niskin-style bottles. This package was deployed on all stations/casts. Underwater electronic components consisted of a Sea-Bird Electronics (SBE) 9 plus CTD with dual pumps and the following sensors: dual temperature (SBE3), dual conductivity (SBE4C), dual dissolved oxygen (SBE43), and a Paroscientific Digiquartz Pressure Sensor. The CTDs supplied a standard Sea-Bird format data stream at a data rate of 24 frames/second. The SBE9plus CTD was connected to the SBE32 24-place pylon providing for single-conductor sea cable operation. Power to the SBE9plus CTD, SBE32 pylon, auxiliary sensors, and altimeter was provided through the sea cable from the SBE11plus deck unit in the computer lab. Shipboard CTD data processing was performed automatically at the end of each deployment using SEABIRD SBE Seasave software version 7.23.2 and AOML Matlab processing software.; Uncertainty: Two SBE43 dissolved O2 (DO) sensors were used on this cruise. Both sensors tracked each other well. The sensors show a median difference of 1.92 umol/kg and a standard deviation of 0.66 umol/kg.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Researcher name: Molly Baringer; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: bottle dissolved oxygen; Abbreviation: OXYGEN_UMOL_KG; Unit: micromol/kg; Observation type: Profile and surface underway; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through pump; Analyzing instrument: Automated oxygen titrator using amperometric end-point detection (Langdon 2010).; Detailed sampling and analyzing information: Samples were drawn from all casts and all Niskin bottles into volumetrically calibrated 125 ml iodine titration flasks using Tygon tubing with a silicone adaptor that fit over the petcock to avoid contamination of DOC samples. Bottles were rinsed three times and filled from the bottom, overflowing three volumes while taking care not to entrain any bubbles. The draw temperature was taken using a digital thermometer with a flexible thermistor probe that was inserted into the flask while the sample was being drawn during the overflow period. These temperatures were used to calculate concentrations, and a diagnostic check of Niskin bottle integrity. One ml of MnCl2 and one ml of NaOH/NaI were added immediately after drawing of the sample was concluded using a Repipetor, the flasks were then stoppered and shaken well. DIW was added to the neck of each flask to create a water seal. The flasks were stored in the lab in plastic totes at room temperature for at least 1 hour before analysis. Twenty-four samples plus duplicates were drawn from each station except the shallow coastal stations where fewer samples were drawn depending on the depth or as directed by the chief scientist. Dissolved oxygen analyses were performed with an automated oxygen titrator using amperometric end-point detection (Langdon 2010). The titration of the samples and the data logging and graphical display was performed on a PC running a LabView program written by Ulises Rivero of AOML. The titrations were performed in a climate controlled lab at 18.5oC-20oC. Thiosulfate was dispensed by a 2 ml Gilmont syringe driven with a stepper motor controlled by the titrator. Tests in the lab were performed to confirm that the precision and accuracy of the volume dispensed were comparable or superior to the Dosimat 665. The whole-bottle titration technique of Carpenter (1965) with modifications by Culberson et al. (1991) was used. Four to three replicate 10 ml iodate standards were run 13 times during the cruise. The reagent blank was determined at the beginning and end of the cruise. A titration was made to 1 ml of iodate standard. The volume of thiosulfate required for the titration is V1. An additional 1 ml of standard was added to the titrated sample and titrated again. The volume of thiosulfate used for the second titration is V2. The reagent blank was determined as the difference between V1 and V2.; Replicate information: Duplicate samples were drawn at two depths on every cast. The Bullister bottles selected for the duplicates and hence the oxygen flasks were changed for each cast. However, if the CTD tripped less than four Bullister bottles at a certain station, then only one depth was duplicated. A total of 189 duplicates were run during the cruise. The average standard deviation of all duplicates was 0.164 umol kg-1.; Uncertainty: A total of 14 standardizations were performed (mean=706.120, mean SD=0.359 uL). Reagent blanks were run at the beginning of the cruise (2.1+/-1.0 uL), and at the end. The average standard deviation of all duplicates was 0.164 umol kg-1.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Carpenter, J.H. (1965). The Chesapeake Bay Institute technique for the Winkler dissolved oxygen method. Limnol. Oceanogr. 10: 141-143 Culberson, C.H. and Huang, S. (1987). Automated amperometric oxygen titration. Deep-Sea Res. 34: 875-880. Culberson, C.H.; Knapp, G.; Stalcup, M.; Williams, R.T. and Zemlyak, F. (1991). A comparison of methods for the determination of dissolved oxygen in seawater. WHP Operations and Methods. Langdon, C. (2010). Determination of dissolved oxygen in seawater by Winkler titration using the amperometric technique. The GO-SHIP Repeat Hydrography Manual: A Collection of Expert Reports and Guidelines. E. M. Hood, C. L. Sabine and B. M. Sloyan, IOCCP Report Number 14, ICPO Publication Series Number 134.; Researcher name: Chris Langdon; Researcher institution: Rosenstiel School of Marine and Atmospheric Science/University of Miami.
- Parameter or Variable: Orthosilicic acid; Abbreviation: SILICATE_UMOL_KG; Unit: micromol/kg; Observation type: Profile and surface underway; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through pump; Analyzing instrument: Continuous flow analyzer (CFA) using the standard and analysis protocols for the WOCE hydrographic program as set forth in the manual by L.I. Gordon, et al. (1993).; Detailed sampling and analyzing information: Nutrient samples were collected from Niskin bottles, after at least three seawater rinses. Sample analysis typically began within a few hours of sample collection after the samples had warmed to room temperature. Those samples not analyzed within 3 hours were refrigerated for later analysis. Samples were analyzed for phosphate (PO4 3-), nitrate (NO3-), nitrite (NO2-) and orthosilicic acid (H4SiO4). Silicic acid was analyzed using a modification of Armstrong et al. (1967). The sample is reacted with ammonium molybdate in an acidic solution to form molybdosilicic acid. The molybdosilicic acid was then reduced with ascorbic acid to form molybdenum blue. The absorbance of the molybdenum blue was measured at 660 nm.; Uncertainty: A mixed stock standard consisting of silicic acid, phosphate and nitrate was prepared by dissolving high purity standard materials (KNO3, KH2PO4 and Na2SiF6) in deionized water using a two step dilution for phosphate and nitrate. This standard was stored at room temperature. A nitrite stock standard was prepared dissolving NaNO2 in distilled water, and this standard was stored in the ship's refrigerator. Working standards were prepared fresh daily by diluting the stock solutions in low nutrient seawater. The mixed standards were verified against commercial standards, and in-lab standards.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Armstrong, F.A.J., Stearns, C.R. and Strickland, J.D.H. (1967). The measurement of upwelling and subsequent biological processes by means of the Technicon AutoAnalyzer and associated equipment. Deep-Sea Res. 14:381-389. Gordon, L.I., Jennings Jr., J.C., Ross, A.A. and Krest, J.M. (1993). A suggested protocol for the continuous automated analysis of seawater nutrients (phosphate, nitrate, nitrite and silicic acid) in the WOCE Hydrographic program and the Joint Global Ocean Fluxes Study. WOCE Operations Manual, vol. 3: The Observational Programme, Section 3.2: WOCE Hydrographic Programme, Part 3.1.3: WHP Operations and Methods. WHP Office Report WHPO 91-1; WOCE Report No. 68/91. November 1994, Revision 1, Woods Hole, MA., USA, 52 loose-leaf pages.; Researcher name: Jia-Zhong Zhang; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: Nitrite; Abbreviation: NITRITE_UMOL_KG; Unit: micromol/kg; Observation type: Profile and surface underway; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through pump; Analyzing instrument: Continuous flow analyzer (CFA) using the standard and analysis protocols for the WOCE hydrographic program as set forth in the manual by L.I. Gordon, et al. (1993).; Detailed sampling and analyzing information: Nutrient samples were collected from Niskin bottles, after at least three seawater rinses. Sample analysis typically began within a few hours of sample collection after the samples had warmed to room temperature. Those samples not analyzed within 3 hours were refrigerated for later analysis. Samples were analyzed for phosphate (PO4 3-), nitrate (NO3-), nitrite (NO2-) and orthosilicic acid (H4SiO4). Nitrite was determined by diazotizing the sample with sulfanilamide and coupling with N-1 naphthyl ethylenediamine dihydrochloride to form an azo dye. The color produced is measured at 540 nm.; Uncertainty: A mixed stock standard consisting of silicic acid, phosphate and nitrate was prepared by dissolving high purity standard materials (KNO3, KH2PO4 and Na2SiF6) in deionized water using a two step dilution for phosphate and nitrate. This standard was stored at room temperature. A nitrite stock standard was prepared dissolving NaNO2 in distilled water, and this standard was stored in the ship's refrigerator. Working standards were prepared fresh daily by diluting the stock solutions in low nutrient seawater. The mixed standards were verified against commercial standards, and in-lab standards.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Armstrong, F.A.J., Stearns, C.R. and Strickland, J.D.H. (1967). The measurement of upwelling and subsequent biological processes by means of the Technicon AutoAnalyzer and associated equipment. Deep-Sea Res. 14:381-389. Gordon, L.I., Jennings Jr., J.C., Ross, A.A. and Krest, J.M. (1993). A suggested protocol for the continuous automated analysis of seawater nutrients (phosphate, nitrate, nitrite and silicic acid) in the WOCE Hydrographic program and the Joint Global Ocean Fluxes Study. WOCE Operations Manual, vol. 3: The Observational Programme, Section 3.2: WOCE Hydrographic Programme, Part 3.1.3: WHP Operations and Methods. WHP Office Report WHPO 91-1; WOCE Report No. 68/91. November 1994, Revision 1, Woods Hole, MA., USA, 52 loose-leaf pages.; Researcher name: Jia-Zhong Zhang; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: nitrate; Abbreviation: NITRATE_UMOL_KG; Unit: micromol/kg; Observation type: Profile and surface underway; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through pump; Analyzing instrument: Continuous flow analyzer (CFA) using the standard and analysis protocols for the WOCE hydrographic program as set forth in the manual by L.I. Gordon, et al. (1993).; Detailed sampling and analyzing information: Nutrient samples were collected from Niskin bottles, after at least three seawater rinses. Sample analysis typically began within a few hours of sample collection after the samples had warmed to room temperature. Those samples not analyzed within 3 hours were refrigerated for later analysis. Samples were analyzed for phosphate (PO4 3-), nitrate (NO3-), nitrite (NO2-) and orthosilicic acid (H4SiO4). Samples for nitrate analysis were passed through a cadmium column, which reduced nitrate to nitrite, and the resulting nitrite concentration (i.e. the sum of nitrate + nitrite which is signified as N+N) was then determined as described above. Nitrate concentrations were determined from the difference of N+N and nitrite.; Uncertainty: A mixed stock standard consisting of silicic acid, phosphate and nitrate was prepared by dissolving high purity standard materials (KNO3, KH2PO4 and Na2SiF6) in deionized water using a two step dilution for phosphate and nitrate. This standard was stored at room temperature. A nitrite stock standard was prepared dissolving NaNO2 in distilled water, and this standard was stored in the ship's refrigerator. Working standards were prepared fresh daily by diluting the stock solutions in low nutrient seawater. The mixed standards were verified against commercial standards, and in-lab standards.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Armstrong, F.A.J., Stearns, C.R. and Strickland, J.D.H. (1967). The measurement of upwelling and subsequent biological processes by means of the Technicon AutoAnalyzer and associated equipment. Deep-Sea Res. 14:381-389. Gordon, L.I., Jennings Jr., J.C., Ross, A.A. and Krest, J.M. (1993). A suggested protocol for the continuous automated analysis of seawater nutrients (phosphate, nitrate, nitrite and silicic acid) in the WOCE Hydrographic program and the Joint Global Ocean Fluxes Study. WOCE Operations Manual, vol. 3: The Observational Programme, Section 3.2: WOCE Hydrographic Programme, Part 3.1.3: WHP Operations and Methods. WHP Office Report WHPO 91-1; WOCE Report No. 68/91. November 1994, Revision 1, Woods Hole, MA., USA, 52 loose-leaf pages.; Researcher name: Jia-Zhong Zhang; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: Sum of nitrate + nitrite; Abbreviation: NITRATE_NITRITE_UMOL_KG; Unit: micromol/kg; Observation type: Profile and surface underway; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through pump; Analyzing instrument: Continuous flow analyzer (CFA) using the standard and analysis protocols for the WOCE hydrographic program as set forth in the manual by L.I. Gordon, et al. (1993).; Detailed sampling and analyzing information: Nutrient samples were collected from Niskin bottles, after at least three seawater rinses. Sample analysis typically began within a few hours of sample collection after the samples had warmed to room temperature. Those samples not analyzed within 3 hours were refrigerated for later analysis. Samples were analyzed for phosphate (PO4 3-), nitrate (NO3-), nitrite (NO2-) and orthosilicic acid (H4SiO4). Samples were passed through a cadmium column, which reduced nitrate to nitrite, and the resulting nitrite concentration (i.e. the sum of nitrate + nitrite which is signified as N+N) was then determined as described above.; Uncertainty: A mixed stock standard consisting of silicic acid, phosphate and nitrate was prepared by dissolving high purity standard materials (KNO3, KH2PO4 and Na2SiF6) in deionized water using a two step dilution for phosphate and nitrate. This standard was stored at room temperature. A nitrite stock standard was prepared dissolving NaNO2 in distilled water, and this standard was stored in the ship's refrigerator. Working standards were prepared fresh daily by diluting the stock solutions in low nutrient seawater. The mixed standards were verified against commercial standards, and in-lab standards.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Armstrong, F.A.J., Stearns, C.R. and Strickland, J.D.H. (1967). The measurement of upwelling and subsequent biological processes by means of the Technicon AutoAnalyzer and associated equipment. Deep-Sea Res. 14:381-389. Gordon, L.I., Jennings Jr., J.C., Ross, A.A. and Krest, J.M. (1993). A suggested protocol for the continuous automated analysis of seawater nutrients (phosphate, nitrate, nitrite and silicic acid) in the WOCE Hydrographic program and the Joint Global Ocean Fluxes Study. WOCE Operations Manual, vol. 3: The Observational Programme, Section 3.2: WOCE Hydrographic Programme, Part 3.1.3: WHP Operations and Methods. WHP Office Report WHPO 91-1; WOCE Report No. 68/91. November 1994, Revision 1, Woods Hole, MA., USA, 52 loose-leaf pages.; Researcher name: Jia-Zhong Zhang; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: phosphate; Abbreviation: PHOSPHATE_UMOL_KG; Unit: micromol/kg; Observation type: Profile and surface underway; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through pump; Analyzing instrument: Continuous flow analyzer (CFA) using the standard and analysis protocols for the WOCE hydrographic program as set forth in the manual by L.I. Gordon, et al. (1993).; Detailed sampling and analyzing information: Nutrient samples were collected from Niskin bottles, after at least three seawater rinses. Sample analysis typically began within a few hours of sample collection after the samples had warmed to room temperature. Those samples not analyzed within 3 hours were refrigerated for later analysis. Samples were analyzed for phosphate (PO4 3-), nitrate (NO3-), nitrite (NO2-) and orthosilicic acid (H4SiO4). Phosphate was determined by reacting the sample with molybdic acid to form phosphomolybdic acid. This complex was subsequently reduced with hydrazine, and the absorbance of the resulting phosphomolybdous acid was measured at 710 nm.; Uncertainty: A mixed stock standard consisting of silicic acid, phosphate and nitrate was prepared by dissolving high purity standard materials (KNO3, KH2PO4 and Na2SiF6) in deionized water using a two step dilution for phosphate and nitrate. This standard was stored at room temperature. A nitrite stock standard was prepared dissolving NaNO2 in distilled water, and this standard was stored in the ship's refrigerator. Working standards were prepared fresh daily by diluting the stock solutions in low nutrient seawater. The mixed standards were verified against commercial standards, and in-lab standards.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Armstrong, F.A.J., Stearns, C.R. and Strickland, J.D.H. (1967). The measurement of upwelling and subsequent biological processes by means of the Technicon AutoAnalyzer and associated equipment. Deep-Sea Res. 14:381-389. Gordon, L.I., Jennings Jr., J.C., Ross, A.A. and Krest, J.M. (1993). A suggested protocol for the continuous automated analysis of seawater nutrients (phosphate, nitrate, nitrite and silicic acid) in the WOCE Hydrographic program and the Joint Global Ocean Fluxes Study. WOCE Operations Manual, vol. 3: The Observational Programme, Section 3.2: WOCE Hydrographic Programme, Part 3.1.3: WHP Operations and Methods. WHP Office Report WHPO 91-1; WOCE Report No. 68/91. November 1994, Revision 1, Woods Hole, MA., USA, 52 loose-leaf pages.; Researcher name: Jia-Zhong Zhang; Researcher institution: Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: carbonate ion concentration; Abbreviation: CARBONATE_UMOL_KG; Unit: micromol/kg; Observation type: Profile and surface underway; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle and flow through pump; Analyzing instrument: Agilent 8453 spectrometer setup with a custom-made temperature-controlled cell holder.; Detailed sampling and analyzing information: The carbonate ion samples were sampled into quartz cells in the same manner as the pH samples. After the pH samples were taken, the quartz cells were attached to the silicone tubing to collect samples for carbonate ion concentration measurements. Samples were analyzed on an Agilent 8453 spectrophotometer. A UV blank was taken for each sample and 20 uL of 0.022 M PbClO4 were added (Acros Organics, Lot A0301399 - 99% purity). Absorbances, A, were measured at two wavelengths (1 lambda = 234 nm and 2 lambda = 250 nm), along with the absorbance at a non-absorbing wavelength (350 nm).; Replicate information: Duplicates were drawn at each station and for underway discrete measurements.; Uncertainty: All spectrophotometric CO32- measurements were tentatively flagged if the baseline shifted more than 0.004 absorbance units for carbonate ion measurements. A series of at least three spectra were averaged for each determination and samples were rerun if the overall standard deviations were higher than 0.002. This process was repeated until the standard deviation of multiple readings was within 0.002. Absorbance values were saved so that the quality criteria can be evaluated in the future. Data for directly measured carbonate are reported in terms of both concentrations and the R-Ratios taken at 250 nm and 234 nm. Data for CO32-, are reported at the analysis temperature of 25 oC.; Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 = questionable value, 4 = bad value, 5 = value not reported, 6 = mean of replicate measurements, 9 = sample not drawn.; Method reference: Byrne, R.H.; and Yao, W. (2008). Procedures for measurement of carbonate ion concentrations in seawater by direct spectrophotometric observations of Pb(II) complexation. Marine Chemistry, 112(1-2), 128-135. Clayton, T.D.; and Byrne, R.H. (1993). Spectrophotometric seawater pH measurements: total hydrogen ion concentration scale calibration of m-cresol purple and at-sea results. Deep Sea Research Part I: Oceanographic Research Papers, 40(10), 2115-2129. https://doi.org/10.1016/0967-0637(93)90048-8 Liu, X.; Patsavas, M.C.; and Byrne, R. H. (2011). Purification and characterization of meta-cresol purple for spectrophotometric seawater pH measurements. Environmental Science and Technology, 45(11), 4862-4868. https://doi.org/10.1021/es200665d.; Researcher name: Robert Byrne; Researcher institution: University of South Florida.
- Parameter or Variable: Chlorophyll a concentration; Abbreviation: CHLA_MG_M3; Unit: microgram/liter; Observation type: Profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle; Analyzing instrument: Turner Designs Fluorometer (10-AU); Detailed sampling and analyzing information: 100-150 ml was filtered from whole seawater (WSW) and 20 micron-screened samples that were collected at the surface, the depth of the chlorophyll maximum, and below the chlorophyll maximum (where appropriate) for extracted Chlorophyll-a. WSW and less than 20 micron samples were each filtered in duplicate onto glass-fiber filters (total: 4 filters/depth), extracted overnight in 90% acetone at -20C, and quantified using a Turner Designs Fluorometer calibrated with chlorophyll in acetone standards and checked with a blank and solid secondary standards before each set of analyses. Chlorophyll-a in the > 20 micron size-fraction is calculated as the difference between the WSW and less than 20 micron average concentrations. 231 average values were reported to the database.; Replicate information: No duplicates were taken; Researcher name: Beth Stauffer; Researcher institution: University of Louisiana at Lafayette.
- Parameter or Variable: Chlorophyll a concentration for fraction size smaller than 20 microns; Abbreviation: CHLA_MG_M3; Unit: microgram/liter; Observation type: Profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle; Analyzing instrument: Turner Designs Fluorometer (10-AU); Detailed sampling and analyzing information: 100-150 ml was filtered from whole seawater (WSW) and 20 micron-screened samples that were collected at the surface, the depth of the chlorophyll maximum, and below the chlorophyll maximum (where appropriate) for extracted Chlorophyll-a. WSW and less than 20 micron samples were each filtered in duplicate onto glass-fiber filters (total: 4 filters/depth), extracted overnight in 90% acetone at -20C, and quantified using a Turner Designs Fluorometer calibrated with chlorophyll in acetone standards and checked with a blank and solid secondary standards before each set of analyses. Chlorophyll-a in the larger than 20 micron size-fraction is calculated as the difference between the WSW and less than 20 micron average concentrations. 231 average values were reported to the database.; Replicate information: No duplicates were taken; Researcher name: Beth Stauffer; Researcher institution: University of Louisiana at Lafayette.
- Parameter or Variable: Chlorophyll a concentration for fraction size larger than 20 microns; Abbreviation: CHLA_MG_M3 >20; Unit: microgram/liter; Observation type: Profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle; Analyzing instrument: Turner Designs Fluorometer (10-AU); Detailed sampling and analyzing information: 100-150 ml was filtered from whole seawater (WSW) and 20 micron-screened samples that were collected at the surface, the depth of the chlorophyll maximum, and below the chlorophyll maximum (where appropriate) for extracted Chlorophyll-a. WSW and less than 20 micron samples were each filtered in duplicate onto glass-fiber filters (total: 4 filters/depth), extracted overnight in 90% acetone at -20C, and quantified using a Turner Designs Fluorometer calibrated with chlorophyll in acetone standards and checked with a blank and solid secondary standards before each set of analyses. Chlorophyll-a in the > 20 micron size-fraction is calculated as the difference between the WSW and less than 20 micron average concentrations. 231 average values were reported to the database.; Replicate information: No duplicates were taken; Researcher name: Beth Stauffer; Researcher institution: University of Louisiana at Lafayette .
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