http://lod.bco-dmo.org/id/dataset/772513
eng; USA
utf8
dataset
Highest level of data collection, from a common set of sensors or instrumentation, usually within the same research project
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
2019-07-03
ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data
ISO 19115-2:2009(E)
DIC, TA, pH from R/V Pelican cruise conducted in the northern Gulf of Mexico in April and July 2017
2019-12-20
publication
2019-12-20
revision
Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)
2019-07-11
publication
https://doi.org/10.1575/1912/bco-dmo.772513.1
Wei-Jun Cai
University of Delaware
principalInvestigator
Katja Fennel
Dalhousie University
principalInvestigator
Nancy Rabalais
Louisiana State University
principalInvestigator
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
publisher
Cite this dataset as: Cai, W., Rabalais, N., Fennel, K. (2019) DIC, TA, pH from R/V Pelican cruise conducted in the northern Gulf of Mexico in April and July 2017. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 2) Version Date 2019-12-20 [if applicable, indicate subset used]. doi:10.1575/1912/bco-dmo.772513.2 [access date]
DIC, TA, pH from nGOM cruise conducted in April 2017 and July 2017 Dataset Description: <p>Dissolved inorganic carbon, total alkalinity and pH from R/V Pelican cruises conducted in the northern Gulf of Mexico (27.5 N, 30 N, 88 W, 94 W ) from April 5 to 16 and July 7 to 21 in 2017.</p> Methods and Sampling: <p><strong>DIC and TA</strong></p>
<p>Measure of DIC using NDIR method and of TA using Gran titration. DIC and TA were measured using the instruments from Apollo Scitech Inc. Briefly, for DIC analysis, samples were analyzed at room temperatures. Each seawater sample (0.5 mL) was acidified using phosphoric acid and the evolved CO2 gas was extracted and carried by pure N2 gas to an infrared CO2 detector (Li-Cor 6262) for quantification. TS was determined on 25 mL seawater sample by potentiometric titration, using 0.1 M hydrochloric acid and an open-cell titration system. All TA samples were analyzed in pre-thermostated (25 °C) glass cells. For each DIC or TA sample, sub-samples were sequentially analyzed 2 or 3 times until we obtained two replicates with a precision within 0.1%. The average of the two values is reported. The precision of both the TA and DIC measurements was +/- 2 umol/kg. The accuracies of the TA and DIC measurements were determined by routine analysis of certified reference material (CRM) provided by A. G. Dickson, Scripps Institution of Oceanography.</p>
<p><strong>DO_spec</strong></p>
<p>Winkler titration was used for DO analysis. Samples were drawn from Niskin bottles directly into 60 ml BOD bottles and pickled using manganese chloride and sodium iodide/sodium hydroxide. Iodine liberated by acidifying pickled sample was then measured spectrophotometrically using Genesis 30 (Thomas Scientific) spectrophotometer at 466 nm. Blank absorbance from sample turbidity was obtained by adding a few drops of sodium thiosulfate to the sample solution and subtracted from sample absorbance. Calibration was performed by spiking known amounts of potassium iodate. Error on DO was from the uncertainty of measuring absorbance (0.001), which is equivalent of 0.7 uM. Samples which had blank absorbance exceeding 5% of sample absorbance were flagged.</p>
<p><strong>pH_elec </strong></p>
<p>pH samples were drawn in 60 ml glass bottles and temperature equilibrated at 25 oC. An Orion Combination electrode connected to a pH meter (Orion Star A211) was used to measure the potential (EMF, mV) generated by the H+ ions. EMF was calibrated using three NBS buffer solutions at pH 4.01, 7.0, and 10.01 purchased from Fisher Scientific. Probe was kept immersed in the sample until the EMF stabilized. Two EMF readings at a difference of 1 minute were obtained for each sample and average value used with calibration to calculate the pH. Precision on pH is estimated from the standard deviation of the mean of two EMF readings. Samples where such deviation exceeded 0.16% of the mean EMF are flagged.</p>
<p><strong>pH_spec </strong></p>
<p>Discrete sample pH_spec was measured spectrophotometrically at 25 degrees Celsius on the total pH scale using purified M-Cresol Purple purchased from R. Byrne at the University of South Florida [Clayton and Byrne, 1993; Liu et al., 2011]. The spectrophotometric pH (25 oC, total scale) was calculated from the ratio of the measured absorbances of mCP at wavelengths l2 = 578 nm and l1 = 434 nm following the dissociation constants proposed by Liu et al 2011].</p>
<p><strong>Sampling and analytical procedures: </strong></p>
<p>Measure of DIC using NDIR method and of TA using Gran titration. DIC and TA were measured using the instruments from Apollo Scitech Inc. Briefly, for DIC analysis, samples were analyzed at room temperatures. Each seawater sample (0.5 mL) was acidified using phosphoric acid and the evolved CO2 gas was extracted and carried by pure N2 gas to an infrared CO2 detector (Li-Cor 6262) for quantification. TS was determined on 25 mL seawater sample by potentiometric titration, using 0.1 M hydrochloric acid and an open-cell titration system. All TA samples were analyzed in pre-thermostated (25 °C) glass cells. For each DIC or TA sample, sub-samples were sequentially analyzed 2 or 3 times until we obtained two replicates with a precision within 0.1%. The average of the two values is reported. The precision of both the TA and DIC measurements was +/- 2 umol/kg. The accuracies of the TA and DIC measurements were determined by routine analysis of certified reference material (CRM) provided by A. G. Dickson, Scripps Institution of Oceanography.</p>
<p>Winkler titration was used for DO analysis. Samples were drawn from Niskin bottles directly into 60 ml BOD bottles and pickled using manganese chloride and sodium iodide/sodium hydroxide. Iodine liberated by acidifying pickled sample was then measured spectrophotometrically using Genesis 30 (Thomas Scientific) spectrophotometer at 466 nm. Blank absorbance from sample turbidity was obtained by adding a few drops of sodium thiosulfate to the sample solution and subtracted from sample absorbance. Calibration was performed by spiking known amounts of potassium iodate. Error on DO was from the uncertainty of measuring absorbance (0.001), which is equivalent of 0.7 uM. Samples which had blank absorbance exceeding 5% of sample absorbance were flagged.</p>
<p>pH samples were drawn in 60 ml glass bottles and temperature equilibrated at 25 oC. An Orion Combination electrode connected to a pH meter (Orion Star A211) was used to measure the potential (EMF, mV) generated by the H+ ions. EMF was calibrated using three NBS buffer solutions at pH 4.01, 7.0, and 10.01 purchased from Fisher Scientific. Probe was kept immersed in the sample until the EMF stabilized. Two EMF readings at a difference of 1 minute were obtained for each sample and average value used with calibration to calculate the pH. Precision on pH is estimated from the standard deviation of the mean of two EMF readings. Samples where such deviation exceeded 0.16% of the mean EMF are flagged. Discrete sample pH_spec was measured spectrophotometrically at 25 degrees Celsius on the total pH scale using purified M-Cresol Purple purchased from R. Byrne at the University of South Florida (Clayton and Byrne, 1993; Liu et al., 2011).</p>
<p><strong>Instruments: </strong></p>
<ol>
<li>24-bottle rosette equipped with a SeaBird CTD 911.</li>
<li>DIC and TA were measured using the instruments from Apollo Scitech Inc.</li>
<li>Certified reference material (CRM) provided by A. G. Dickson, Scripps Institution of Oceanography was used to check the accuracies of the TA and DIC measurements.</li>
<li>Winkler titration was used for DO_spec analysis. DO_spec samples were measured spectrophotometrically using Genesis 30 (Thomas Scientific) spectrophotometer at 466 nm.</li>
<li>M-Cresol Purple purchased from R. Byrne at the University of South Florida was used for pH_spec measurement.</li>
</ol>
<p>&nbsp;</p>
Funding provided by NSF Division of Ocean Sciences (NSF OCE) Award Number: OCE-1559279 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=1559279
completed
Wei-Jun Cai
University of Delaware
302-831-2839
School of Marine Science and Policy Office: 014 Lammot DuPont Laboratory
Newark
DE
19716
USA
wcai@udel.edu
pointOfContact
Katja Fennel
Dalhousie University
+1 (902) 494 4526
1355 Oxford Street
Halifax
Nova Scotia
B3H 4J1
Canada
Katja.Fennel@dal.ca
pointOfContact
Nancy Rabalais
Louisiana State University
9858512801
Room 3161, Energy, Coast and Environment Building
Baton Rouge
LA
70803
US
nrabalais@lumcon.edu
pointOfContact
asNeeded
Dataset Version: 2
Unknown
Cruise
Date
Time
Station
Longitude
Latitude
Bottom_Depth
Sample_Depth
Temperature
Salinity
OxygenSBE1
OxygenSBE2
FluorescenceChl
wetCDOM
SPAR
PAR
Turbidity
Attenuation
Transmission
TA
flag_TA
DIC
flag_DIC
pH_Electrode
flag_pHelec
pH_Spec
flag_pHspec
DO_Spec
flag_DOspec
ISO_DateTime_UTC
theme
None, User defined
cruise name
date
time of day
station
longitude
latitude
depth
temperature of sample or a generic measurement (not in-situ water temp)
salinity
dissolved Oxygen
fluorescence
colored or chromophoric dissolved organic matter
SPAR
PAR
turbidity
beam attenuation
transmission
total alkalinity (TA)
flag
dissolved inorganic Carbon
pH
ISO_DateTime_UTC
featureType
BCO-DMO Standard Parameters
CTD Sea-Bird 911
Niskin bottle
Spectrophotometer
Winkler Oxygen Titrator
instrument
BCO-DMO Standard Instruments
PE17-18
PE18-02
service
Deployment Activity
Cocodrie, Louisiana
place
Locations
otherRestrictions
otherRestrictions
Access Constraints: none. Use Constraints: Please follow guidelines at: http://www.bco-dmo.org/terms-use Distribution liability: Under no circumstances shall BCO-DMO be liable for any direct, incidental, special, consequential, indirect, or punitive damages that result from the use of, or the inability to use, the materials in this data submission. If you are dissatisfied with any materials in this data submission your sole and exclusive remedy is to discontinue use.
Collaborative Research: pH Dynamics and Interactive Effects of Multiple Processes in a River-Dominated Eutrophic Coastal Ocean
https://osprey.bco-dmo.org/project/751332
Collaborative Research: pH Dynamics and Interactive Effects of Multiple Processes in a River-Dominated Eutrophic Coastal Ocean
<p><strong>NSF Award Abstract:</strong></p>
<p>Ocean acidification (OA) refers to the lowering of ocean pH (or increasing acidity) due to uptake of atmospheric carbon dioxide (CO2). A great deal of research has been done to understand how the open ocean is influenced by OA, but coastal systems have received little attention. In the northern Gulf of Mexico (nGOM) shelf region, pH in bottom waters can measure up to 0.45 units less than the pH of the pre-industrial surface ocean, in comparison to the 0.1 overall pH decrease across the entire ocean. Carbonate chemistry in the ocean is greatly influenced by even small changes in pH, so these seemingly minor changes lead to much greater impacts on the biology and chemistry of the ocean. The researchers plan to study coastal OA in the nGOM, a region subject to high inputs of nutrients from the Mississippi River. These inputs of anthropogenic nitrogen mostly derived from fertilizers leads to increased respiration rates which decreases oxygen concentrations in the water column to the point of hypoxia in the summer. This study will inform us how OA in coastal waters subject to eutrophication and hypoxia will impact the chemistry and biology of the region. The researchers are dedicated to outreach programs in the Gulf and east coast regions, interacting with K-12 students and teachers, undergraduate/graduate student training, and various outreach efforts (family workshops on OA, lectures for the public and federal, state, and local representatives). Also, a project website will be created to disseminate the research results to a wider audience.</p>
<p>Increased uptakes of atmospheric carbon dioxide (CO2) by the ocean has led to a 0.1 unit decrease in seawater pH and carbonate mineral saturation state, a process known as Ocean Acidification (OA), which threatens the heath of marine organisms, alters marine ecosystems, and biogeochemical processes. Considerable attention has been focused on understanding the impact of OA on the open ocean but less attention has been given to coastal regions. Recent studies indicate that pH in bottom waters of the northern Gulf of Mexico (nGOM) shelf can be as much as 0.45 units lower relative to pre-industrial values. This occurs because the acidification resulting from increased CO2 inputs (both atmospheric inputs and in-situ respiration) decreases the buffering capacity of seawater. This interactive effect will increase with time, decreasing summertime nGOM bottom-water pH by an estimated 0.85 units and driving carbonate minerals to undersaturation by the end of this century. Researchers from the University of Delaware and the Louisiana Universities Marine Consortium will carry out a combined field, laboratory, and modeling program to address the following questions. (1) What are the physical, chemical, and biological controls on acidification in coastal waters impacted by the large, nutrient-laden Mississippi River?; (2) What is the link between coastal-water acidification, eutrophication, and hypoxia; (3) How do low pH and high CO2 concentrations in bottom waters affect CO2 out-gassing during fall and winter and storm periods when the water column is mixed?; and (4) What are the influences of changing river inputs under anthropogenic forcing on coastal water acidification? Results from this research aim to further our understanding of the processes influencing ocean acidification in coastal waters subject to eutrophication and hypoxia both in the GOM and river-dominated shelf ecosystems globally.</p>
<p><strong>Related Project note:</strong></p>
<p>There are overlapping cruises with the project "Sed Control on OA" <a href="https://www.bco-dmo.org/project/815333">https://www.bco-dmo.org/project/815333</a>. Thus, while some water column data can be found under this project "nGOMx acidification", all benthic data can be found under the "Sed Control on OA" project.</p>
nGOMx acidification
largerWorkCitation
project
eng; USA
oceans
Cocodrie, Louisiana
-93.4167
-88.5901
27.4999
29.6415
2017-04-06
2017-07-21
northern Gulf of Mexico, 27.5 N, 30 N, 88 W, 94 W
0
BCO-DMO catalogue of parameters from DIC, TA, pH from R/V Pelican cruise conducted in the northern Gulf of Mexico in April and July 2017
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
http://lod.bco-dmo.org/id/dataset-parameter/772668.rdf
Name: Cruise
Units: unitless
Description: <p>Cruise name</p>
http://lod.bco-dmo.org/id/dataset-parameter/772669.rdf
Name: Date
Units: unitless
Description: <p>Date in format YYYY-MM-DD</p>
http://lod.bco-dmo.org/id/dataset-parameter/772670.rdf
Name: Time
Units: unitless
Description: <p>Time in format HH:MM:SS</p>
http://lod.bco-dmo.org/id/dataset-parameter/772671.rdf
Name: Station
Units: unitless
Description: <p>Station name</p>
http://lod.bco-dmo.org/id/dataset-parameter/772672.rdf
Name: Longitude
Units: decimal degrees
Description: <p>Longitude, west is negative</p>
http://lod.bco-dmo.org/id/dataset-parameter/772673.rdf
Name: Latitude
Units: decimal degrees
Description: <p>Latitude, south is negative</p>
http://lod.bco-dmo.org/id/dataset-parameter/772674.rdf
Name: Bottom_Depth
Units: meter (m)
Description: <p>Bottom depth</p>
http://lod.bco-dmo.org/id/dataset-parameter/772675.rdf
Name: Sample_Depth
Units: meter (m)
Description: <p>Sampling depth</p>
http://lod.bco-dmo.org/id/dataset-parameter/772676.rdf
Name: Temperature
Units: degrees Celsius (°C)
Description: <p>Temperature in sampling depth</p>
http://lod.bco-dmo.org/id/dataset-parameter/772677.rdf
Name: Salinity
Units: PSU
Description: <p>Salinity in sampling depth</p>
http://lod.bco-dmo.org/id/dataset-parameter/772678.rdf
Name: OxygenSBE1
Units: micromole per kilogram (umol/kg)
Description: <p>CTD Dissolved oxygen concentration</p>
http://lod.bco-dmo.org/id/dataset-parameter/772679.rdf
Name: OxygenSBE2
Units: milligram per liter (mg/L)
Description: <p>CTD Dissolved oxygen concentration</p>
http://lod.bco-dmo.org/id/dataset-parameter/772680.rdf
Name: FluorescenceChl
Units: microgram per liter (ug/L)
Description: <p>CTD Fluorescence Chl</p>
http://lod.bco-dmo.org/id/dataset-parameter/772681.rdf
Name: wetCDOM
Units: milligram per cubic meters (mg/m^3)
Description: <p>CTD wetCDOM</p>
http://lod.bco-dmo.org/id/dataset-parameter/772682.rdf
Name: SPAR
Units: microEinsteins per square meter per second (uEinsteins/m^2/second)
Description: <p>CTD Surficial Photosynthetically Available</p>
http://lod.bco-dmo.org/id/dataset-parameter/772683.rdf
Name: PAR
Units: microEinsteins per square meter per second (uEinsteins/m^2/second)
Description: <p>CTD Photosynthetically Available [Active] Radiation</p>
http://lod.bco-dmo.org/id/dataset-parameter/772684.rdf
Name: Turbidity
Units: FTU
Description: <p>CTD Turbidity</p>
http://lod.bco-dmo.org/id/dataset-parameter/772685.rdf
Name: Attenuation
Units: 1 per meter (1/m)
Description: <p>CTD Attenuation</p>
http://lod.bco-dmo.org/id/dataset-parameter/772686.rdf
Name: Transmission
Units: %
Description: <p>CTD Transmission</p>
http://lod.bco-dmo.org/id/dataset-parameter/772687.rdf
Name: TA
Units: micromole per kilogram (umol/kg)
Description: <p>Total Alkalinity</p>
http://lod.bco-dmo.org/id/dataset-parameter/772688.rdf
Name: flag_TA
Units: unitless
Description: <p>Total Alkalinity final flag - flag_2 means precision <0.1%; Flag_3 means precision>0.1%</p>
http://lod.bco-dmo.org/id/dataset-parameter/772689.rdf
Name: DIC
Units: micromole per kilogram (umol/kg)
Description: <p>Total dissolved inorganic carbon</p>
http://lod.bco-dmo.org/id/dataset-parameter/772690.rdf
Name: flag_DIC
Units: unitless
Description: <p>Total dissolved inorganic carbon final flag - flag_2 means precision <0.1%; Flag_3 means precision>0.1%</p>
http://lod.bco-dmo.org/id/dataset-parameter/772691.rdf
Name: pH_Electrode
Units: unitless
Description: <p>pH measured by electrode (NBS scale)</p>
http://lod.bco-dmo.org/id/dataset-parameter/772692.rdf
Name: flag_pHelec
Units: unitless
Description: <p>pH measured by electrode final flag - flag_2 means precision <+-0.02; Flag_3 means precision>+-0.02</p>
http://lod.bco-dmo.org/id/dataset-parameter/772693.rdf
Name: pH_Spec
Units: unitless
Description: <p>Total scale pH measured by spectrometer</p>
http://lod.bco-dmo.org/id/dataset-parameter/772694.rdf
Name: flag_pHspec
Units: unitless
Description: <p>pH measure by spectrometer final flag - flag_2 means precision <+-0.005; Flag_3 means precision>+-0.005</p>
http://lod.bco-dmo.org/id/dataset-parameter/772695.rdf
Name: DO_Spec
Units: umol/L
Description: <p>Dissolved oxygen measured by spectrometer at 25 degrees celcius</p>
http://lod.bco-dmo.org/id/dataset-parameter/772696.rdf
Name: flag_DOspec
Units: unitless
Description: <p>Dissolved oxygen final flag - flag_2 means precision <+-0.7 umol L-1; Flag_3 means precision>0.7umol L-1</p>
http://lod.bco-dmo.org/id/dataset-parameter/772697.rdf
Name: ISO_DateTime_UTC
Units: YYYY-MM-DDTHH:MM:SSZ
Description: <p>Date/Time UTC in ISO format (YYYY-MM-DDTHH:MM:SSZ)</p>
GB/NERC/BODC > British Oceanographic Data Centre, Natural Environment Research Council, United Kingdom
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
194459
https://darchive.mblwhoilibrary.org/bitstream/1912/25281/1/dataset-772513_discrete-samples__v2.tsv
download
68512
https://darchive.mblwhoilibrary.org/bitstream/1912/24345/1/dataset-772513_discrete-samples__v1.tsv
download
https://doi.org/10.1575/1912/bco-dmo.772513.1
download
onLine
dataset
<p><strong>DIC and TA</strong></p>
<p>Measure of DIC using NDIR method and of TA using Gran titration. DIC and TA were measured using the instruments from Apollo Scitech Inc. Briefly, for DIC analysis, samples were analyzed at room temperatures. Each seawater sample (0.5 mL) was acidified using phosphoric acid and the evolved CO2 gas was extracted and carried by pure N2 gas to an infrared CO2 detector (Li-Cor 6262) for quantification. TS was determined on 25 mL seawater sample by potentiometric titration, using 0.1 M hydrochloric acid and an open-cell titration system. All TA samples were analyzed in pre-thermostated (25 °C) glass cells. For each DIC or TA sample, sub-samples were sequentially analyzed 2 or 3 times until we obtained two replicates with a precision within 0.1%. The average of the two values is reported. The precision of both the TA and DIC measurements was +/- 2 umol/kg. The accuracies of the TA and DIC measurements were determined by routine analysis of certified reference material (CRM) provided by A. G. Dickson, Scripps Institution of Oceanography.</p>
<p><strong>DO_spec</strong></p>
<p>Winkler titration was used for DO analysis. Samples were drawn from Niskin bottles directly into 60 ml BOD bottles and pickled using manganese chloride and sodium iodide/sodium hydroxide. Iodine liberated by acidifying pickled sample was then measured spectrophotometrically using Genesis 30 (Thomas Scientific) spectrophotometer at 466 nm. Blank absorbance from sample turbidity was obtained by adding a few drops of sodium thiosulfate to the sample solution and subtracted from sample absorbance. Calibration was performed by spiking known amounts of potassium iodate. Error on DO was from the uncertainty of measuring absorbance (0.001), which is equivalent of 0.7 uM. Samples which had blank absorbance exceeding 5% of sample absorbance were flagged.</p>
<p><strong>pH_elec </strong></p>
<p>pH samples were drawn in 60 ml glass bottles and temperature equilibrated at 25 oC. An Orion Combination electrode connected to a pH meter (Orion Star A211) was used to measure the potential (EMF, mV) generated by the H+ ions. EMF was calibrated using three NBS buffer solutions at pH 4.01, 7.0, and 10.01 purchased from Fisher Scientific. Probe was kept immersed in the sample until the EMF stabilized. Two EMF readings at a difference of 1 minute were obtained for each sample and average value used with calibration to calculate the pH. Precision on pH is estimated from the standard deviation of the mean of two EMF readings. Samples where such deviation exceeded 0.16% of the mean EMF are flagged.</p>
<p><strong>pH_spec </strong></p>
<p>Discrete sample pH_spec was measured spectrophotometrically at 25 degrees Celsius on the total pH scale using purified M-Cresol Purple purchased from R. Byrne at the University of South Florida [Clayton and Byrne, 1993; Liu et al., 2011]. The spectrophotometric pH (25 oC, total scale) was calculated from the ratio of the measured absorbances of mCP at wavelengths l2 = 578 nm and l1 = 434 nm following the dissociation constants proposed by Liu et al 2011].</p>
<p><strong>Sampling and analytical procedures: </strong></p>
<p>Measure of DIC using NDIR method and of TA using Gran titration. DIC and TA were measured using the instruments from Apollo Scitech Inc. Briefly, for DIC analysis, samples were analyzed at room temperatures. Each seawater sample (0.5 mL) was acidified using phosphoric acid and the evolved CO2 gas was extracted and carried by pure N2 gas to an infrared CO2 detector (Li-Cor 6262) for quantification. TS was determined on 25 mL seawater sample by potentiometric titration, using 0.1 M hydrochloric acid and an open-cell titration system. All TA samples were analyzed in pre-thermostated (25 °C) glass cells. For each DIC or TA sample, sub-samples were sequentially analyzed 2 or 3 times until we obtained two replicates with a precision within 0.1%. The average of the two values is reported. The precision of both the TA and DIC measurements was +/- 2 umol/kg. The accuracies of the TA and DIC measurements were determined by routine analysis of certified reference material (CRM) provided by A. G. Dickson, Scripps Institution of Oceanography.</p>
<p>Winkler titration was used for DO analysis. Samples were drawn from Niskin bottles directly into 60 ml BOD bottles and pickled using manganese chloride and sodium iodide/sodium hydroxide. Iodine liberated by acidifying pickled sample was then measured spectrophotometrically using Genesis 30 (Thomas Scientific) spectrophotometer at 466 nm. Blank absorbance from sample turbidity was obtained by adding a few drops of sodium thiosulfate to the sample solution and subtracted from sample absorbance. Calibration was performed by spiking known amounts of potassium iodate. Error on DO was from the uncertainty of measuring absorbance (0.001), which is equivalent of 0.7 uM. Samples which had blank absorbance exceeding 5% of sample absorbance were flagged.</p>
<p>pH samples were drawn in 60 ml glass bottles and temperature equilibrated at 25 oC. An Orion Combination electrode connected to a pH meter (Orion Star A211) was used to measure the potential (EMF, mV) generated by the H+ ions. EMF was calibrated using three NBS buffer solutions at pH 4.01, 7.0, and 10.01 purchased from Fisher Scientific. Probe was kept immersed in the sample until the EMF stabilized. Two EMF readings at a difference of 1 minute were obtained for each sample and average value used with calibration to calculate the pH. Precision on pH is estimated from the standard deviation of the mean of two EMF readings. Samples where such deviation exceeded 0.16% of the mean EMF are flagged. Discrete sample pH_spec was measured spectrophotometrically at 25 degrees Celsius on the total pH scale using purified M-Cresol Purple purchased from R. Byrne at the University of South Florida (Clayton and Byrne, 1993; Liu et al., 2011).</p>
<p><strong>Instruments: </strong></p>
<ol>
<li>24-bottle rosette equipped with a SeaBird CTD 911.</li>
<li>DIC and TA were measured using the instruments from Apollo Scitech Inc.</li>
<li>Certified reference material (CRM) provided by A. G. Dickson, Scripps Institution of Oceanography was used to check the accuracies of the TA and DIC measurements.</li>
<li>Winkler titration was used for DO_spec analysis. DO_spec samples were measured spectrophotometrically using Genesis 30 (Thomas Scientific) spectrophotometer at 466 nm.</li>
<li>M-Cresol Purple purchased from R. Byrne at the University of South Florida was used for pH_spec measurement.</li>
</ol>
<p>&nbsp;</p>
Specified by the Principal Investigator(s)
<p>Dataset processing notes:</p>
<ul>
<li>The software to do data processing is Microsoft Excel.</li>
<li>CTD data was downloaded from CTD directly without any further data processing.</li>
<li>Both TA and DIC was converted to units of µmol/kg from µmol/L with density equation.</li>
<li>DO_spec was converted to unit of µmol L-1 at 25°C.</li>
<li>pH_spec was calibrated based on Douglas and Byrne [2017] or Müller and Rehder [2018]. The difference between Douglas and Byrne (2017) and Müller and Rehder (2018) was 0.002±0.001 for 2017 April cruise.</li>
</ul>
<p>Data manager processing notes:</p>
<ul>
<li>Added ISO_DateTime_UTC column</li>
<li>Negative sign added to longitudinal values (locations at western part of prime meridian) to data acquired during April 2017</li>
<li>&nbsp;4 digits after the decimal for latitude and longitude values</li>
<li>Version History:
<ul>
<li>Version 1: Original data received 2019-06-07, discrete data acquired during April 2017</li>
<li>Version 2: Data received 2019-10-22, added discrete data acquired during July 2017</li>
</ul>
</li>
</ul>
Specified by the Principal Investigator(s)
asNeeded
7.x-1.1
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
PI Supplied Instrument Name: PI Supplied Instrument Description:24-bottle rosette equipped with a SeaBird CTD 911 Instrument Name: CTD Sea-Bird 911 Instrument Short Name:CTD SBE 911 Instrument Description: The Sea-Bird SBE 911 is a type of CTD instrument package. The SBE 911 includes the SBE 9 Underwater Unit and the SBE 11 Deck Unit (for real-time readout using conductive wire) for deployment from a vessel. The combination of the SBE 9 and SBE 11 is called a SBE 911. The SBE 9 uses Sea-Bird's standard modular temperature and conductivity sensors (SBE 3 and SBE 4). The SBE 9 CTD can be configured with auxiliary sensors to measure other parameters including dissolved oxygen, pH, turbidity, fluorescence, light (PAR), light transmission, etc.). More information from Sea-Bird Electronics. Community Standard Description: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0035/
PI Supplied Instrument Name: PI Supplied Instrument Description:24-bottle rosette Instrument Name: Niskin bottle Instrument Short Name:Niskin bottle Instrument Description: A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc. Community Standard Description: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/
PI Supplied Instrument Name: PI Supplied Instrument Description:Genesis 30 (Thomas Scientific) spectrophotometer at 466 nm Instrument Name: Spectrophotometer Instrument Short Name:Spectrophotometer Instrument Description: An instrument used to measure the relative absorption of electromagnetic radiation of different wavelengths in the near infra-red, visible and ultraviolet wavebands by samples. Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB20/
PI Supplied Instrument Name: PI Supplied Instrument Description:Used for DO_spec analysis Instrument Name: Winkler Oxygen Titrator Instrument Short Name:Winkler Titrator Instrument Description: A Winkler Oxygen Titration system is used for determining concentration of dissolved oxygen in seawater. Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB12/
Cruise: PE17-18
PE17-18
R/V Pelican
Community Standard Description
International Council for the Exploration of the Sea
R/V Pelican
vessel
PE17-18
Baoshan Chen
University of Delaware
Cruise: PE18-02
PE18-02
R/V Pelican
Community Standard Description
International Council for the Exploration of the Sea
R/V Pelican
vessel
PE18-02
Wei-Jun Cai
University of Delaware
R/V Pelican
Community Standard Description
International Council for the Exploration of the Sea
R/V Pelican
vessel