Processing Steps |
- Parameter or Variable: Dissolved Inorganic Carbon; Abbreviation: DIC_umol_kg; Unit: micromoles per kilogram of seawater (umol/kg-SW); Observation type: Discrete measurements from samples collected on CTD casts; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Calculation method and parameters: Not applicable; Sampling instrument: Niskin bottle; Analyzing instrument: Two systems consisting of a coulometer (UIC, Inc.) coupled with a SOMMA (Single Operator Multiparameter Metabolic Analyzer) inlet system developed by K.M. Johnson (Johnson et al., 1985, 1987, 1993, 1999; Johnson,1992) of Brookhaven National Laboratory (BNL).; Detailed sampling and analyzing information: PLEASE NOTE: DIC may be referred to as TCO2, TCARBN, or C(sub)T in other data sets. All of these abbreviations refer to the total dissolved inorganic carbon concentration (i.e., the combined concentration of dissolved CO2, bicarbonate ion, and carbonate ion). Inorganic carbon samples were collected from Niskins after oxygen samples. A combined sample for dissolved inorganic carbon (DIC) and total alkalinity (TA) measurements was drawn into ~540 mL borosilicate glass flasks using silicone tubing according to procedures outlined in the Guide to Best Practices for Ocean CO2 Measurements (SOP 1, Dickson et al. 2007). Briefly, flasks were rinsed once and filled from the bottom with care not to entrain any bubbles, overflowing by at least one-half volume. The sample tube was pinched and withdrawn, creating a small headspace, and 0.2 mL of saturated mercuric chloride (HgCl2) solution was added as a preservative. Sample bottles were then sealed with glass stoppers lightly covered with Apiezon-L grease. Stoppers were held in place until analysis with a thick rubber band over the stopper attached to a plastic clamp around the neck of the sample flask. Sample bottles were inverted several times to ensure mixing of the HgCl2 throughout the sample. DIC samples were collected from variety of depths, with approximately 5% of samples drawn in duplicate (or occasionally triplicate). All samples were stored under cool, dark conditions until analysis. DIC concentrations were measured at PMEL on analytical systems consisting of a coulometer (UIC Inc.) coupled with a Single Operator Multiparameter Metabolic Analyzer (SOMMA). The SOMMA was developed to extract DIC from seawater by Ken Johnson and colleagues (Johnson et al. 1985, 1987, 1993, and 1999; Johnson 1992) of Brookhaven National Laboratory. Each coulometer was calibrated at the beginning of each analysis day, when a fresh coulometric cell was prepared, by injecting aliquots of pure CO2 (99.999%) by way of an eight-port valve (Wilke et al., 1993) outfitted with two calibrated sample loops of different sizes (~1 mL and ~2 mL). Roughly 20-25 samples were typically analyzed per coulometric cell.; Replicate information: Duplicate samples were collected from approximately 5% of the Niskins sampled, as a check of our precision. These replicate samples were interspersed throughout the station analysis for quality assurance and integrity of the coulometer cell solutions. The average absolute difference from the mean of these replicates is 1.5 µmol/kg. No systematic differences between the replicates were observed.; Standardization description: Each coulometer was calibrated by injecting aliquots of pure CO2 (99.999%) by means of an 8-port valve (Wilke et al., 1993) outfitted with two calibrated sample loops of different sizes (~1 mL and ~2 mL. The instruments were each separately calibrated at the beginning of each cell with a minimum of two sets of these gas loop injections and then again at the end of each cell to ensure no drift during the life of the cell.; Standardization frequency: 1) Gas loops were run at the beginning and end of each cell; 2) CRM's supplied by Dr. A. Dickson of SIO, were measured near the beginning; and 3) Duplicate samples were typically run throughout the life of the cell solution.; CRM manufacturer: Dr. Andrew Dickson (Scripps Institution of Oceanography); CRM batch number: Various; Preservation method: Mercuric Chloride Solution (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 ~540 mL. The correction factor used for dilution was 1.00037.; Uncertainty: +/-0.1%; Quality flag convention: DIC_QC, 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., C.L. Sabine, and J.R. Christian (eds.). 2007. Guide to best practices for ocean CO2 measurements. PICES Special Publication 3, 191 pp; Johnson, K.M., A.E. King, and J. McN. Sieburth. 1985. Coulometric DIC analyses for marine studies: An introduction. Mar. Chem., 16, 61-82; Johnson, K.M., P.J. Williams, L. Brandstrom, and J. McN. Sieburth. 1987. Coulometric total carbon analysis for marine studies: Automation and calibration. Mar. Chem., 21, 117-133; Johnson, K.M. 1992. Operator's manual: Single operator multiparameter metabolic analyzer (SOMMA) for total carbon dioxide (CT) with coulometric detection. Brookhaven National Laboratory, Brookhaven, N.Y., 70 pp; Johnson, K.M., K.D. Wills, D.B. Butler, W.K. Johnson, and C.S. Wong. 1993. Coulometric total carbon dioxide analysis for marine studies: Maximizing the performance of an automated continuous gas extraction system and coulometric detector. Mar. Chem., 44, 167-189; 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(1):123-144.; Researcher name: Dana Greeley; Researcher institution: Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: Total alkalinity; Abbreviation: TA_umol_kg; Unit: micromoles per kilogram of seawater (umol/kg-SW); Observation type: Discrete measurements from samples collected on CTD casts; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Calculation method and parameters: Not applicable; Sampling instrument: Niskin bottle; Analyzing instrument: Custom instrument, built at PMEL and modeled after an earlier generation of those made in Dr. Andrew Dickson's laboratory at Scripps Oceanographic Institution.; Type of titration: Two-stage, potentiometric, open-cell titration using coulometrically analyzed hydrochloric acid; Cell type (open or closed): Open; Curve fitting method: Non-linear least squares; Detailed sampling and analyzing information: Seawater total alkalinity (TA) was measured by acidimetric titration. The specific method used was based upon the open-cell method described by Dickson et al (2003). This method involves first acidifying the sample to reduce the sample pH to less than 3.6 followed by bubbling CO2-free air through the sample to facilitate removal of the CO2 evolved by the acid addition. After removal of the carbonate species from solution, the titration proceeds until a pH of less than 3.0 is attained, and the equivalence point evaluated from titration points in the pH region 3.0-3.5 using a non-linear least squares procedure that corrects for the reactions with sulfate and fluoride ions (Dickson et al. 2003). Titration progress is monitored by measuring the electromotive force (E) of a combination glass-reference electrode. Samples were drawn from the Niskin-type bottles into cleaned 250-ml borosilicate glass bottles using Tygon tubing with silicone ends. Bottles were rinsed twice and filled from the bottom, overflowing half a volume and taking care not to entrain any bubbles. The sample tube was closed off and withdrawn from the sample bottle, creating a 5 ml headspace. Samples were preserved by poisoning with 0.12 ml of a saturated HgCl2 solution. Sample bottles were sealed with glass stoppers lightly coated with Apiezon-L grease, and were stored at room temperature (21-25 °C) for a maximum of 12 hours prior to analysis. Titrations were carried out in water-jacketed, 250-ml beakers. The beakers were kept at 24.0 ± 0.2 °C with water from a constant temperature bath. Prior to analysis, samples were placed in the water bath to bring them to the same temperature as the reaction beakers. Seawater samples were dispensed into the water-jacketed beaker using a fixed-volume glass syringe. A Metrohm Dosimat 765 was used to deliver acid to the sample beaker in increments of 0.040 ml. The acid titrant used was 0.1 mol/kg HCl prepared in 0.6 mol/kg NaCl background to approximate the ionic strength of seawater (0.7 mol/kg). Instrument control and data acquisition was with custom software developed in Andrew Dickson's laboratory at Scripps Institution of Oceanography and modified by a former employee of the NOAA/PMEL Carbon Group using the National Instruments LabView programming environment. Typical titrations were completed in 10-14 minutes and required 20-24 acid additions to reach a pH of 3.0.; Replicate information: Duplicate samples were collected from approximately 10% of the Niskins sampled as a check of our precision.; Standardization description: Analytical accuracy was assessed by routine analysis of Certified Reference Materials (CRMs). CRMs were analyzed approximately every 10 to 24 samples. The average offset for samples run on our analytical systems is less than 2 µmol/kg.; Standardization frequency: All values were directly measured with reference to Certified Reference Material (Dickson, SIO); CRM manufacturer: Dr. Andrew Dickson (Scripps Institution of Oceanography); CRM batch number: Various; Preservation method: Mercuric Chloride Solution; Preservative volume: 0.12-0.24 ml; Preservative correction: The TA values were corrected for dilution by 0.12-0.24 ml of saturated HgCl2 used for sample preservation.; TA blank correction: Not applicable; Uncertainty: The precision of this method is better than 0.1% and accuracy is 0.1%.; Quality flag convention: TA_QC, 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: Bates, R.G. Determination of pH. Theory and Practice. A Wiley-Interscience Publication, Second Edition; Dickson A.G. (1981). An exact definition of total alkalinity, and a procedure for the estimation of alkalinity and total inorganic carbon from titration data. Deep-Sea Res. 28, 609-623; Dickson A.G. (1992). The development of the alkalinity concept in marine chemistry. Marine chemistry 40:1-21-2, 49-63; Dickson, A. G., Afghan, J. D. and Anderson, G. C. (2003). Reference materials for oceanic CO2 analysis: A method for the certification of total alkalinity. Marine Chemistry 80, 185-197; Gran G. (1952). Determination of the equivalence point in potentiometric titrations. Part II. The analyst, 77, 661-671; Wolf-Gladrow, D.A. et al. (2007). Total alkalinity: The explicit conservative expression and its application to biogeochemical process.; Researcher name: Morgan Ostendorf; Researcher institution: Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: CTD pressure; Abbreviation: PRESS_DB; Unit: dbars (=decibars); Observation type: Water column profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Calculation method and parameters: Not applicable; Sampling instrument: Sea-Bird Scientific SBE 9plus CTD; Detailed sampling and analyzing information: This file contains the up cast data collected using the CTD package and any additional sensors attached to a rosette cage deployed on a research vessel. The up cast data correspond to when the bottles on the rosette cage were fired and water samples were collected. All up casts during the cruise are contained in this file and are sorted by station. CTD data were processed using Sea-Bird's proprietary data processing software.; Uncertainty: Pressure: initial accuracy = +/- 0.015% of full scale range; typical stability = 0.02% of full scale per year; master clock error contribution = Pressure 0.3 dbar (for 6800 meter depth-rated sensor).; Quality flag convention: No data flags were applied to CTD data; Method reference: Sea-Bird Scientific web site: http://www.seabird.com/sbe911plus-ctd; Researcher name: Jan Newton; Researcher institution: University of Washington Applied Physics Laboratory.
- Parameter or Variable: CTD temperature, ITS-90 scale; Abbreviation: CTD_TMP_deg_C; Unit: degrees celsius, ITS-90 scale; Observation type: Water column profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Sea-Bird Scientific SBE 9plus CTD; Detailed sampling and analyzing information: This file contains the up cast data collected using the CTD package and any additional sensors attached to a rosette cage deployed on a research vessel. The up cast data correspond to when the bottles on the rosette cage were fired and water samples were collected. All up casts during the cruise are contained in this file and are sorted by station. CTD data were processed using Sea-Bird's proprietary data processing software.; Uncertainty: Temperature: initial accuracy = +/- 0.001 degrees Celsius; typical stability = 0.0002 degrees Celsius per month; master clock error contribution = 0.00016 degrees Celsius; Quality flag convention: No data flags were applied to CTD data; Method reference: Sea-Bird Scientific web site: http://www.seabird.com/sbe911plus-ctd; Researcher name: Jan Newton; Researcher institution: University of Washington Applied Physics Laboratory.
- Parameter or Variable: CTD salinity; Abbreviation: CTD_SAL_PSU_PSS-78; Unit: 1978 Practical Salinity Scale; Observation type: Water column profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Calculated from conductivity measurements.; Sampling instrument: Sea-Bird Scientific SBE 4 Conductivity Sensor; Detailed sampling and analyzing information: This file contains the up cast data collected using the CTD package and any additional sensors attached to a rosette cage deployed on a research vessel. The up cast data correspond to when the bottles on the rosette cage were fired and water samples were collected. All up casts during the cruise are contained in this file and are sorted by station. CTD data were processed using Sea-Bird's proprietary data processing software.; Uncertainty: Conductivity: initial accuracy = +/- 0.0003 S/m; typical stability = 0.0003 S/m per month; master clock error contribution = 0.00005 S/m; Quality flag convention: No data flags were applied to CTD data; Method reference: Sea-Bird Scientific web site: http://www.seabird.com/sbe911plus-ctd; Researcher name: Jan Newton; Researcher institution: University of Washington Applied Physics Laboratory.
- Parameter or Variable: phosphate (PO4); Abbreviation: PHOSPHATE_umol_kg; Unit: micromoles per kilogram of seawater (umol/kg-SW); Observation type: Discrete measurements from samples collected in Niskin bottles on CTD casts; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle; Analyzing instrument: Seal Analytical AA3; Detailed sampling and analyzing information: From the Niskin bottle, seawater was drawn into 60 mL HDPE sample bottles to rinse the bottle and cap twice. Plungers were removed from 60 mL syringes with Nalgene filters attached (surfactant-free cellulose, 25 mm, 0.45 micron pore size) and rinsed twice with seawater from the Niskin. The syringe was filled with sample water from the Niskin. The plunger was inserted, the syringe inverted, and the filter removed to remove the air bubble. With the filter re-attached, about 5 mL of of sample water was filtered into sample bottle to rinse and then discarded. 45-50 mL of sample was filtered into sample bottle, such that it was less than 2/3 full. The cap was secured and the bottle frozen upright in a -10 degree Celsius freezer until analyzed. Analyses and calibration followed the protocols of the WOCE Hydrographic Program using a Seal Analytical AA3 (UNESCO 1994).; Replicate information: No replicate samples were collected or analyzed.; Uncertainty: Accreditation codes and detection limits: EPA 365.5_1.4_1997, NELAC Code WM920270, MDLs 0.014uM, 0.0004mg/L (from https://www.ocean.washington.edu/story/Marine+Chemistry+Laboratory).; Quality flag convention: Data have not been quality controlled after laboratory analysis. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994).; Method reference: UNESCO (1994). Protocols for the joint global ocean flux study (JGOFS) core measurements. Vol. 29.; Researcher name: Kathy Krogsland; Researcher institution: University of Washington School of Oceanography.
- Parameter or Variable: Orthosilicic acid (Si(OH)4); Abbreviation: SILICATE_umol_kg; Unit: micromoles per kilogram of seawater (umol/kg-SW); Observation type: Discrete measurements from samples collected in Niskin bottles on CTD casts; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle; Analyzing instrument: Seal Analytical AA3; Detailed sampling and analyzing information: From the Niskin bottle, seawater was drawn into 60 mL HDPE sample bottles to rinse the bottle and cap twice. Plungers were removed from 60 mL syringes with Nalgene filters attached (surfactant-free cellulose, 25 mm, 0.45 micron pore size) and rinsed twice with seawater from the Niskin. The syringe was filled with sample water from the Niskin. The plunger was inserted, the syringe inverted, and the filter removed to remove the air bubble. With the filter re-attached, about 5 mL of of sample water was filtered into sample bottle to rinse and then discarded. 45-50 mL of sample was filtered into sample bottle, such that it was less than 2/3 full. The cap was secured and the bottle frozen upright in a -10 degree Celsius freezer until analyzed. Analyses and calibration followed the protocols of the WOCE Hydrographic Program using a Seal Analytical AA3 (UNESCO 1994).; Replicate information: No replicate samples were collected or analyzed.; Uncertainty: Accreditation codes and detection limits: EPA 366, NELAC Code WM920240, MDLs 0.23uM, 0.0063mg/L (from https://www.ocean.washington.edu/story/Marine+Chemistry+Laboratory).; Quality flag convention: Data have not been quality controlled after laboratory analysis. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994).; Method reference: UNESCO (1994). Protocols for the joint global ocean flux study (JGOFS) core measurements. Vol. 29.; Researcher name: Kathy Krogsland; Researcher institution: University of Washington School of Oceanography.
- Parameter or Variable: nitrate (NO3); Abbreviation: NITRATE_umol_kg; Unit: micromoles per kilogram of seawater (umol/kg-SW); Observation type: Discrete measurements from samples collected in Niskin bottles on CTD casts; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle; Analyzing instrument: Analyses and calibration follow the protocols of the WOCE Hydrographic Program using a Seal Analytical AA3.; Detailed sampling and analyzing information: From the Niskin bottle, seawater was drawn into 60 mL HDPE sample bottles to rinse the bottle and cap twice. Plungers were removed from 60 mL syringes with Nalgene filters attached (surfactant-free cellulose, 25 mm, 0.45 micron pore size) and rinsed twice with seawater from the Niskin. The syringe was filled with sample water from the Niskin. The plunger was inserted, the syringe inverted, and the filter removed to remove the air bubble. With the filter re-attached, about 5 mL of of sample water was filtered into sample bottle to rinse and then discarded. 45-50 mL of sample was filtered into sample bottle, such that it was less than 2/3 full. The cap was secured and the bottle frozen upright in a -10 degree Celsius freezer until analyzed. Analyses and calibration followed the protocols of the WOCE Hydrographic Program using a Seal Analytical AA3 (UNESCO 1994).; Replicate information: No replicate samples were collected or analyzed.; Uncertainty: Accreditation codes and detection limits: EPA 353.4_2_1997, NELAC Code 10068209, MDLs 0.288uM, 0.0040mg/L (from https://www.ocean.washington.edu/story/Marine+Chemistry+Laboratory).; Quality flag convention: Data have not been quality controlled after laboratory analysis. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994).; Method reference: UNESCO (1994). Protocols for the joint global ocean flux study (JGOFS) core measurements. Vol. 29.; Researcher name: Kathy Krogsland; Researcher institution: University of Washington School of Oceanography.
- Parameter or Variable: nitrite (NO2); Abbreviation: NITRITE_umol_kg; Unit: micromoles per kilogram of seawater (umol/kg-SW); Observation type: Discrete measurements from samples collected in Niskin bottles on CTD casts; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Calculation method and parameters: We converted nutrient concentrations provided in �mol/L at analytical temperatures (22 degrees Celsius) to �mol/kg units by dividing nutrient concentrations in �mol/L by the density of the sample seawater at the CTD salinity value and analytical temperature.; Sampling instrument: Niskin bottle; Analyzing instrument: Seal Analytical AA3; Detailed sampling and analyzing information: From the Niskin bottle, seawater was drawn into 60 mL HDPE sample bottles to rinse the bottle and cap twice. Plungers were removed from 60 mL syringes with Nalgene filters attached (surfactant-free cellulose, 25 mm, 0.45 micron pore size) and rinsed twice with seawater from the Niskin. The syringe was filled with sample water from the Niskin. The plunger was inserted, the syringe inverted, and the filter removed to remove the air bubble. With the filter re-attached, about 5 mL of of sample water was filtered into sample bottle to rinse and then discarded. 45-50 mL of sample was filtered into sample bottle, such that it was less than 2/3 full. The cap was secured and the bottle frozen upright in a -10 degree Celsius freezer until analyzed. Analyses and calibration followed the protocols of the WOCE Hydrographic Program using a Seal Analytical AA3 (UNESCO 1994).; Replicate information: No replicate samples were collected or analyzed.; Uncertainty: Accreditation codes and detection limits: EPA 353.4_2_1997, NELAC Code 10068209, MDLs 0.011uM, 0.0002mg/L (from https://www.ocean.washington.edu/story/Marine+Chemistry+Laboratory).; Quality flag convention: Data have not been quality controlled after laboratory analysis. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994).; Method reference: UNESCO (1994). Protocols for the joint global ocean flux study (JGOFS) core measurements. Vol. 29.; Researcher name: Kathy Krogsland; Researcher institution: University of Washington School of Oceanography.
- Parameter or Variable: ammonia (NH3); Abbreviation: AMMONIA_umol_kg; Unit: micromoles per kilogram of seawater (umol/kg-SW); Observation type: Discrete measurements from samples collected in Niskin bottles on CTD casts; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Sampling instrument: Niskin bottle; Analyzing instrument: Seal Analytical AA3; Detailed sampling and analyzing information: From the Niskin bottle, seawater was drawn into 60 mL HDPE sample bottles to rinse the bottle and cap twice. Plungers were removed from 60 mL syringes with Nalgene filters attached (surfactant-free cellulose, 25 mm, 0.45 micron pore size) and rinsed twice with seawater from the Niskin. The syringe was filled with sample water from the Niskin. The plunger was inserted, the syringe inverted, and the filter removed to remove the air bubble. With the filter re-attached, about 5 mL of of sample water was filtered into sample bottle to rinse and then discarded. 45-50 mL of sample was filtered into sample bottle, such that it was less than 2/3 full. The cap was secured and the bottle frozen upright in a -10 degree Celsius freezer until analyzed. Analyses and calibration followed the protocols of the WOCE Hydrographic Program using a Seal Analytical AA3 (UNESCO 1994).; Replicate information: No replicate samples were collected or analyzed.; Uncertainty: Accreditation codes and detection limits: EPA 349, NELAC Code WM920220, MDLs 0.047uM, 0.0007mg/L (from https://www.ocean.washington.edu/story/Marine+Chemistry+Laboratory).; Quality flag convention: Data have not been quality controlled after laboratory analysis. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994).; Method reference: UNESCO (1994). Protocols for the joint global ocean flux study (JGOFS) core measurements. Vol. 29.; Researcher name: Kathy Krogsland; Researcher institution: University of Washington School of Oceanography.
- Parameter or Variable: uncorrected oxygen concentration from CTD-O2 sensor; Abbreviation: CTD_OXY_mg_L; Unit: milligrams per liter (mg/L); Observation type: Water column profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Calculation method and parameters: Not applicable; Sampling instrument: Sea-Bird Scientific SBE43 Dissolved Oxygen Sensor; Detailed sampling and analyzing information: This file contains the upcast data collected using the CTD package and any additional sensors attached to a rosette cage deployed on a research vessel. The upcast data correspond to when the bottles on the rosette cage were fired and water samples were collected. All upcasts during the cruise are contained in this file and are sorted by station. CTD data were processed using Sea-Bird's proprietary data processing software using the Data Conversion and Bottle Summary modules. Data Conversion converts raw data from the CTD to engineering units, storing the converted data in a .ros file. Bottle Summary reads the .ros file created by Data Conversion, derives dependent variables and writes a bottle data summary to a .btl file. The CTDOXY_MG_L column contains CTD O2 data that have been processed post-cruise but NOT corrected to bottle oxygen values. Please see section CTDOXY_UMOL_KG_ADJ for more information about post-cruise processing of oxygen data.; Uncertainty: Initial accuracy = +/- 2% of saturation; typical stability = 0.5% per 1000 hours of deployed time (clean membrane); Quality flag convention: CTD_OXY_flag, 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: Sea-Bird Scientific web site: http://www.seabird.com/sbe43-dissolved-oxygen-sensor; Researcher name: Jan Newton; Researcher institution: University of Washington Applied Physics Laboratory.
- Parameter or Variable: oxygen concentration in discrete bottle samples; Abbreviation: BOT_OXY_avg_mg_L; Unit: milligrams per liter (mg/L); Observation type: Water column profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Measured; Calculation method and parameters: We followed the calculations of Carpenter (1965), as described by Codispoti: https://www.ioos.noaa.gov/wp-content/uploads/2016/04/codispoti1988_oxygenprotocol_a.pdf; Sampling instrument: Niskin bottle; Analyzing instrument: Brinkman Dosimat automated titrator; Detailed sampling and analyzing information: A tygon tube was attached to the Niskin bottle and flushed so no air remained. A 125-mL iodine flask was inverted over the upward-pointing tube and flushed, rinsing and reverting the bottle to allow it to fill, overflowing three times its volume. The tube was withdrawn without turbulence, maintaining an overfull bottle. A repipettor was used to dispense 1 mL of MgCl2 and 1 mL of NaOH-NaI with Azide added. The flask was capped without introducing a bubble, inverted and mixed thoroughly, about a dozen times. The bottle was allowed to settle, then remixed, and a bead of DI water added to the lid for an airtight seal. The analysis method is based upon the Carpenter (1965) whole flask titration of iodine, which is produced by an equivalent amount of dissolved oxygen. An automated titrator (Brinkman Dosimat) uses an amperometric end-point detection as described by Culberson and Huang (1987) and modified for IBM-PC computers by Knapp et al. (1990). The nominal 125-mL iodine flasks are used for sampling are pre-calibrated so their volumes are precisely known. Samples were titrated within a day or two of being collected, allowing the samples to come to room temperature where the titration occured. Discrete oxygen samples were used to validate sensor O2 observations on the CTD package.; Replicate information: We collected and analyzed replicate samples from approximately 10% of the Niskins sampled. * The number at the end of the variable abbreviation refers to the replicate number.; Quality flag convention: BOT_OXY_flag, 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: Jan Newton; Researcher institution: University of Washington Applied Physics Laboratory.
- Parameter or Variable: Dissolved oxygen concentration measured by CTD sensors and corrected for an offset from bottle oxygen values; Abbreviation: CTD_OXY_corr_umol_kg; Unit: micromoles per kilogram of seawater (umol/kg-SW); Observation type: Water column profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Calculated from bottle and SBE 43 sensor dissolved oxygen measurements.; Calculation method and parameters: First, all CTD and bottle dissolved oxygen (O2) data were converted from original units (typically milligrams O2 per liter seawater [mg/L] but occasionally milliliters O2 per liter seawater [mL/L]) to micromoles O2 per kilogram of seawater (hereafter umol/kg). In cases where CTD oxygen data were provided in mL/L, we converted them to mg/L for consistency in the submitted data set using this conversion: (O2 in mg/L) = (O2 in mL/L) / 1.42903 To convert from units of mg/L to µmol/kg, we used the potential density (= [1000 + sigma theta], which is the density calculated with in situ salinity, potential temperature, and pressure = 0, minus 1000 kg/m^3 as in http://www.oc.nps.edu/nom/day1/parta.html). The potential density is hereafter abbreviated as rhoTheta. Corrections were done as follows (Garcia and Gordon, 1992): (O2 in µmol/kg) = ((O2 in mg/L) x 44.6596 x 1000)/(rhoTheta x 1.42903) We note that Garcia and Gordon use rhoTheta in units of kg/L, hence the conversion factor of 1000 in our equations above. Next, the converted CTD and bottle O2 data (i.e., Var9 and Var10, after conversion to µmol/kg units, we refer to as CTD_O2 and BOT_O2) were plotted together, with CTD_O2 on the x-axis and BOT_O2 on the y-axis. We eliminated strong outliers after close inspection of each outlying data point in the context of the depth profiles at each station. With the remaining data points, we generated a linear regression equation and used this relationship to correct the CTD_O2 data for the offset and slope differences from BOT_O2 values. In other words, while we had bottle O2 data for only a subset of all Niskin bottle samples, we generated the bottle-O2-equivalent value for ALL samples by applying the regression relationship to the uncorrected but unit-converted CTD_O2 data. Thus, CTD_OXY_corr_umol_kg is the corrected CTD oxygen value, in units of µmol/kg. The equations used for specific cruises are included below: Feb 2008 cruise: CTD_OXY_corr_umol_kg (= BOT_O2) = 1.0218 x CTD_O2 + 1.8714 Aug 2008 cruise: CTD_OXY_corr_umol_kg (= BOT_O2) = 0.9176 x CTD_O2 + 5.6326 Sept 2009 cruise: CTD_OXY_corr_umol_kg (= BOT_O2) = 0.9968 x CTD_O2 + 12.058 Oct 2010 cruise: CTD_OXY_corr_umol_kg (= BOT_O2) = 1.0408 x CTD_O2 - 0.1491 Oct 2011 cruise: CTD_OXY_corr_umol_kg (= BOT_O2) = 1.1068 x CTD_O2 - 1.0869; Sampling instrument: SBE 43 sensor details described under Var9 above.; Analyzing instrument: Winkler bottle oxygen details described under Var10 above.; Detailed sampling and analyzing information: Described in sections above.; Quality flag convention: Apply CTD_OXY_flag information described in section Var9 above.; Method reference: Alin, S.R., J.A. Newton. 2018. A decade-long biogeochemical cruise time-series from the northern California Current System and southern Salish Sea, North America, from 2008 to 2017. Earth System Data Science, https://doi.org/XXXXXXXX.; Researcher name: Simone Alin; Researcher institution: NOAA Pacific Marine Environmental Laboratory.
- Parameter or Variable: this column contains DENSITY ANOMALY data, also known as SIGMA THETA values, and is related to POTENTIAL DENSITY by this equation: potential density = sigma theta + 1000.; Abbreviation: CTD_DEN_kg_m3; Unit: kilograms per meter cubed (kg/m3); Observation type: Water column profile; In-situ / Manipulation / Response variable: In-situ observation; Measured or calculated: Calculated; Calculation method and parameters: Calculated within Sea-Bird Scientific's SeaSAVE or SBE Data Processing software using TEOS-10 equations for cruises after 2013 and EOS-80 equations prior to 2013 (per web site: http://www.seabird.com/software/sbe-data-processing).; Method reference: http://www.oc.nps.edu/nom/day1/parta.html, http://www.seabird.com/software/sbe-data-processing; Researcher name: Jan Newton; Researcher institution: University of Washington Applied Physics Laboratory.
- Parameter or Variable: Longitude in decimal degrees East (negative for Western Hemisphere); Abbreviation: LONGITUDE_DEC.
- Parameter or Variable: Latitude in decimal degrees North (negative for Southern Hemisphere); Abbreviation: LATITUDE_DEC.
- Parameter or Variable: Station number, corresponds to the numerical value after the P in PRISM Station numbers found at http://nvs.nanoos.org/CruiseSalish; Abbreviation: STATION_NO.
- Parameter or Variable: Niskin bottle number. The sequence of trip depths starts with deepest bottle trip = 1.; Abbreviation: NISKIN_NO.
- Parameter or Variable: Date (mm/dd/yyyy) in Coordinated Universal Time (UTC); Abbreviation: DATE_UTC.
- Parameter or Variable: Time (HH:mm:ss) in Coordinated Universal Time (UTC). NB: time reflects CTD system power up, not individual Niskin bottle fire times.; Abbreviation: TIME_UTC.
- Parameter or Variable: Date (mm/dd/yyyy) in Local Time; Abbreviation: DATE_LOCAL.
- Parameter or Variable: Time (HH:mm:ss) in Local Time. NB: time reflects CTD system power up, not individual Niskin bottle fire times.; Abbreviation: TIME_LOCAL .
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