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 The sample tube was pinched and withdrawn, creating a small headspace, and 0.2 mL of saturated mercuric chloride (HgCl2) solution was added as a preservative.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_FLAG_W, WOCE water sample quality codes are used: 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = mean of replicate measurements, 9 = sample not drawn for measurement from this Niskin bottle. These QC codes were initially assigned on the basis of the observed quality of laboratory analysis. These codes do not account for field sampling aberrations. Adjustments to quality codes were made after careful inspection of the data set after data processing. Where sample values were observed to be strong outliers in cross-plots with other variables, the quality codes have been updated from a 2 to a 3 or 4 after close inspection of the profile at that station, including other parameters. Those flagged 3 represent values that are questionable due to being out of expected ranges or having inverted profile values from what would normally be expected in this region. Those flagged 4 are either values that clearly represent a Niskin misfire at an unknown depth or were flagged 4 due to analytical problems. Measurements with quality codes of 4 have been expunged and replaced with quality codes of 5 prior to submission.; 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, Julian Herndon, and Morgan Ostendorf; PIs: Simone Alin and Richard Feely; 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 of just over 3.5 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 just below 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. 838 values were reported to the database.; 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_FLAG_W, WOCE water sample quality codes are used: 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = mean of replicate measurements, 9 = sample not drawn for measurement from this Niskin bottle. These QC codes were initially assigned on the basis of the observed quality of laboratory analysis. These codes do not account for field sampling aberrations. Adjustments to quality codes were made after careful inspection of the data set after data processing. Where sample values were observed to be strong outliers in cross-plots with other variables, the quality codes have been updated from a 2 to a 3 or 4 after close inspection of the profile at that station, including other parameters. Those flagged 3 represent values that are questionable due to being out of expected ranges, having inverted profile values from what would normally be expected in this region, or being strong outliers in TA vs. S cross-plot and regression analyses. Those flagged 4 are either values that clearly represent a Niskin misfire at an unknown depth or were flagged 4 due to analytical problems. Measurements with quality codes of 4 have been expunged and replaced with quality codes of 5 prior to submission.; 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 and Julian Herndon; PIs: Simone Alin and Richard Feely; Researcher institution: Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration.
- Parameter or Variable: Hydrostatic pressure recorded from CTD at the depth where the sample is taken; Abbreviation: CTDPRS_DBAR; 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 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.; 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: CTDTMP_ITS90_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 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.; 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: CTDTMP_FLAG_W, WOCE CTDO data quality codes are used: 1 = not calibrated, 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = interpolated over a pressure interval larger than 2 dbar, 7 = despiked, 9 = not sampled. We note that during data processing with Sea Bird software, data alignment is improved to prevent spiking. All data quality codes contained in this data set were assigned after data processing and were given a value of 2 by default. Those flagged 3 represent values that are questionable due to being out of expected ranges or having inverted profile values from what would normally be expected in this region. Adjustments to quality codes were made after careful inspection of the data set after data processing.; 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: CTDSAL_PSS78; 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 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.; 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: CTDSAL_FLAG_W, WOCE CTDO data quality codes are used: 1 = not calibrated, 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = interpolated over a pressure interval larger than 2 dbar, 7 = despiked, 9 = not sampled. We note that during data processing with Sea Bird software, data alignment is improved to prevent spiking. All data quality codes contained in this data set were assigned after data processing and were given a value of 2 by default. Those flagged 3 represent values that are questionable due to being out of expected ranges, having inverted profile values from what would normally be expected in this region, or being outliers on TA-S plots where TA values look as expected. Adjustments to quality codes were made after careful inspection of the data set after data processing.; 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: Concentration of phosphate (PO4--) measured from discrete bottles; Abbreviation: PHOSPHATE_UMOL_L; Unit: micromoles per liter of seawater (umol/L or uM); 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: To convert units from umol per L to umol per kg, we divided PHOSPHATE_UMOL_L by the value of sigma theta (potential density anomaly, kg per m3) calculated for laboratory conditions (i.e. using laboratory temperature [22 degrees C] and sample salinity) and multiplied by 1000 L per m3. The concentration is also provided in umol per kg units, under the column header PHOSPHATE_UMOL_KG.; 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: NUTRIENTS_FLAG_W, WOCE water sample quality codes are used: 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = mean of replicate measurements, 9 = sample not drawn for measurement from this Niskin bottle. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994). These QC codes were assigned values of 2 by default initially. However, where sample measurements were observed to be outliers in cross-plots with other variables or in transect depth profiles, the quality codes have been updated from a 2 to a 3 or 4 after close inspection of the profile at that station, including other parameters.; 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: Concentration of silicate (Si(OH)4, H4SiO4, SiO2, Sil) measured from discrete bottles; Abbreviation: SILICATE_UMOL_L; Unit: micromoles per liter of seawater (umol/L or uM); 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: To convert units from umol per L to umol per kg, we divided SILICATE_UMOL_L by the value of sigma theta (potential density anomaly, kg per m3) calculated for laboratory conditions (i.e. using laboratory temperature [22 degrees C] and sample salinity) and multiplied by 1000 L per m3. The concentration is also provided in umol per kg units, under the column header SILICATE_UMOL_KG.; 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: NUTRIENTS_FLAG_W, WOCE water sample quality codes are used: 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = mean of replicate measurements, 9 = sample not drawn for measurement from this Niskin bottle. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994). These QC codes were assigned values of 2 by default initially. However, where sample measurements were observed to be outliers in cross-plots with other variables or in transect depth profiles, the quality codes have been updated from a 2 to a 3 or 4 after close inspection of the profile at that station, including other parameters.; 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: Concentration of nitrate (NO3-) measured from discrete bottles; Abbreviation: NITRATE_UMOL_L; Unit: micromoles per liter of seawater (umol/L or uM); 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: To convert units from umol per L to umol per kg, we divided NITRATE_UMOL_L by the value of sigma theta (potential density anomaly, kg per m3) calculated for laboratory conditions (i.e. using laboratory temperature [22 degrees C] and sample salinity) and multiplied by 1000 L per m3. The concentration is also provided in umol per kg units, under the column header NITRATE_UMOL_KG.; 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: NUTRIENTS_FLAG_W, WOCE water sample quality codes are used: 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = mean of replicate measurements, 9 = sample not drawn for measurement from this Niskin bottle. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994). These QC codes were assigned values of 2 by default initially. However, where sample measurements were observed to be outliers in cross-plots with other variables or in transect depth profiles, the quality codes have been updated from a 2 to a 3 or 4 after close inspection of the profile at that station, including other parameters.; 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: Concentration of nitrite (NO2-) measured from discrete bottles.; Abbreviation: NITRITE_UMOL_L; Unit: micromoles per liter of seawater (umol/L or uM); 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: To convert units from umol per L to umol per kg, we divided NITRITE_UMOL_L by the value of sigma theta (potential density anomaly, kg per m3) calculated for laboratory conditions (i.e. using laboratory temperature [22 degrees C] and sample salinity) and multiplied by 1000 L per m3. The concentration is also provided in umol per kg units, under the column header NITRITE_UMOL_KG.; 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: NUTRIENTS_FLAG_W, WOCE water sample quality codes are used: 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = mean of replicate measurements, 9 = sample not drawn for measurement from this Niskin bottle. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994). These QC codes were assigned values of 2 by default initially. However, where sample measurements were observed to be outliers in cross-plots with other variables or in transect depth profiles, the quality codes have been updated from a 2 to a 3 or 4 after close inspection of the profile at that station, including other parameters.; 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: Concentration of ammonium (NH4+) measured from discrete bottles; Abbreviation: AMMONIUM_UMOL_L; Unit: micromoles per liter of seawater (umol/L or uM); 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: To convert units from umol per L to umol per kg, we divided AMMONIUM_UMOL_L by the value of sigma theta (potential density anomaly, kg per m3) calculated for laboratory conditions (i.e. using laboratory temperature [22 degrees C] and sample salinity) and multiplied by 1000 L per m3. The concentration is also provided in umol per kg units, under the column header AMMONIUM_UMOL_KG.; 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: NUTRIENTS_FLAG_W, WOCE water sample quality codes are used: 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = mean of replicate measurements, 9 = sample not drawn for measurement from this Niskin bottle. Laboratory quality assurance procedures were followed, as detailed in UNESCO (1994). These QC codes were assigned values of 2 by default initially. However, where sample measurements were observed to be outliers in cross-plots with other variables or in transect depth profiles, the quality codes have been updated from a 2 to a 3 or 4 after close inspection of the profile at that station, including other parameters.; 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. NB: On this cruise, CTD data were processed by ship's technical support at the time of the cruise and have not been reprocessed to take into account Sea Bird's latest recommendations with regards to corrections for oxygen hysteresis or other updates.; Uncertainty: Initial accuracy = +/- 2% of saturation; typical stability = 0.5% per 1000 hours of deployed time (clean membrane); Quality flag convention: CTDOXY_FLAG_W, WOCE CTDO data quality codes are used: 1 = not calibrated, 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = interpolated over a pressure interval larger than 2 dbar, 7 = despiked, 9 = not sampled. We note that during data processing with Sea Bird software, data alignment is improved to prevent spiking. All data quality codes contained in this data set were assigned after data processing and were given a value of 2 by default. Adjustments to quality codes were made after careful inspection of the data set after data processing. Those flagged 3 represent values that are questionable due to being out of expected ranges, having inverted profile values from what would normally be expected in this region, or being strong outliers in the CTD vs. BOTTLE oxygen plot and regression analysis. Please see more information in the section for CTDOXY_UMOL_KG_ADJ about post-cruise processing of oxygen data, including the regression analysis.; 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: OXYGEN_MG_L_1, OXYGEN_MG_L_2, OXYGEN_MG_L_3; 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.; Uncertainty: Precision of 1% calculated as average SD of triplicate analyses; Quality flag convention: OXYGEN_FLAG_W, WOCE water sample quality codes are used: 2 = acceptable measurement, 3 = questionable measurement, 4 = bad measurement, 5 = not reported, 6 = mean of replicate measurements, 9 = sample not drawn for measurement from this Niskin bottle. These QC codes were initially assigned on the basis of the observed quality of laboratory analysis. These codes do not account for field sampling aberrations. Adjustments to quality codes were made after careful inspection of the data set after data processing. Where sample values were observed to be strong outliers in cross-plots with other variables, the quality codes have been updated from a 2 to a 3 or 4 after close inspection of the profile at that station, including other parameters. Those flagged 3 represent values that are questionable due to being out of expected ranges, having inverted profile values from what would normally be expected in this region, or being strong outliers in the CTD vs. BOTTLE oxygen plot and regression analysis. Those flagged 4 are either values that clearly represent a Niskin misfire at an unknown depth or samples that had notes about analytical problems associated with them. Please see more information under CTDOXY_UMOL_KG_ADG on post-cruise processing of oxygen data. Measurements with quality codes of 4 have been expunged and replaced with quality codes of 5 prior to submission.; Method reference: Carpenter, J.H. 1965. The accuracy of the Winkler method for dissolved oxygen. Limnology and Oceanography 10: 135-140. Codispoti, L. 1988. One man's advice on the determination of dissolved oxygen in seawater. https://www.ioos.noaa.gov/wp-content/uploads/2016/04/codispoti1988_oxygenprotocol_a.pdf Culberson, G.H. and S. Huang. 1987. Automated Amperometric Oxygen titration. Deep-Sea Research 34: 875-880. Knapp, G.P., M.C. Stalcup, and R.J. Stanley. 1990. Automated oxygen titration and salinity determination. Report WHOI-90-35. Woods Hole Oceanographic Institution, Woods Hole, MA (https://darchive.mblwhoilibrary.org/bitstream/handle/1912/1020/WHOI-90-35.pdf?sequence=1).; Researcher name: Jan Newton; Researcher institution: University of Washington Applied Physics Laboratory.
- Parameter or Variable: Dissolved oxygen concentration measured by CTD sensors and adjusted for an offset from bottle oxygen values. Units converted to umol/kg.; Abbreviation: CTDOXY_UMOL_KG_ADJ; 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: Units for both bottle and CTD oxygen concentration measurements were first converted to micromoles per kilogram. Average values for bottle oxygen measurements were used, where replicates were taken. Then CTD oxygen concentrations were adjusted on the basis of their offset from Winkler titration oxygen measurements from discrete bottle samples. The correction was done by way of a linear regression after outliers were excluded (all outliers were flagged as below). All methods for doing these adjustments were described in greater detail in Alin et al. Earth System Data Science, 2018.; 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 on CTDOXY_MG_L and OXYGEN_MG_L_#.; Replicate information: Described in sections above on CTDOXY_MG_L and OXYGEN_MG_L_#.; Quality flag convention: NOTE: Oxygen flags were not generally assigned based on factors present at the time of analysis, although in some cases, notes were taken on problems encountered at the time of analysis (e.g., bubbles in titrator or running out of reagent) and these are among the samples flagged with 3s or 4s. Rather oxygen data were QC'ed during the course of adjusting the slope and intercept of CTD oxygen data to the bottle data by way of a linear regression. As such, the QC flags have a slightly different meaning in this context. We applied a QC flag of 3, denoting questionable values, strictly on the basis that the CTD-bottle oxygen data pair was an outlier in the regression. In many cases the data may be fine and simply reflect the strong stratification in surface conditions in Puget Sound. In other cases, one value or the other may not be good. For those oxygen data flagged 4 (bad values), the bottle oxygen data were recognized to be bad, for reasons that may include bubbles or reagent issues or perhaps a Niskin closing at the wrong depth. The 4s were identified on the basis of being samples from subsurface waters (>25 m depth) with concentrations that appeared to be from a substantially different depth within a given profile (whether the value was substantially too low or too high). All other samples were presumed to be of QC level 2, although future data analyses may determine additional values to be questionable.; Method reference: Alin, S. R., Newton, J. A., Feely, R. A., Greeley, D., Curry, B., Herndon, J., & Warner, M. (2024). A decade-long cruise time series (2008–2018) of physical and biogeochemical conditions in the southern Salish Sea, North America. Earth System Science Data, 16(2), 837–865. https://doi.org/10.5194/essd-16-837-2024; Researcher name: Simone Alin; Researcher institution: NOAA Pacific Marine Environmental Laboratory.
- Parameter or Variable: Potential density anomaly, also known as sigma theta, referenced to 0 db pressure; Abbreviation: SIGMATHETA_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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