http://lod.bco-dmo.org/id/dataset/3828
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
2012-12-31
ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data
ISO 19115-2:2009(E)
Seawater dissolved 232Thorium, 230Thorium and 231Protactinium from R/V Knorr KN193-06 and KN195-08 in the eastern N. Pacific and Sargasso Sea from 2008-2009 (GEOTRACES IC project)
2012-12-31
publication
2012-12-31
revision
BCO-DMO Linked Data URI
2012-12-31
creation
http://lod.bco-dmo.org/id/dataset/3828
Robert F. Anderson
Lamont-Doherty Earth Observatory
principalInvestigator
Martin Q. Fleisher
Lamont-Doherty Earth Observatory
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: Anderson, R. F., Fleisher, M. Q. (2012) Seawater dissolved 232Thorium, 230Thorium and 231Protactinium from R/V Knorr KN193-06 and KN195-08 in the eastern N. Pacific and Sargasso Sea from 2008-2009 (GEOTRACES IC project). Biological and Chemical Oceanography Data Management Office (BCO-DMO). Version Date 2012-12-31 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/3828 [access date]
Seawater dissolved 232Thorium, 230Thorium and 231Protactinium in the subtropical North Pacific Dataset Description: <p>GEOTRACES Baseline profiles of seawater dissolved thorium and protactinium in the forms 232Th, 230Th, and 231Pa at SAFe in the SAFe station in the subtropical N. Pacific and the BATS station in the subtropical N.Atlantic.</p>
<p><strong>BCO-DMO Note: "Trace Metal Pump - Towed" removed as an instrument.<br />
Was inadvertently included.<br />
20Oct2014/srg</strong></p> Methods and Sampling: <p><strong>Sampling and Analytical Methodology - BATS station:&nbsp; </strong><br />
Water samples were collected with a Sea-Bird Electronics CTD carousel fitted with<br />
24 10-liter PVC Niskin bottles. The carousel was lowered from the ship with steel wire. Niskin bottles were equipped with nylon-coated closure springs and Viton O-rings. After collection seawater was filtered by in-line filtration (47 mm 0.45 µm pore diameter Supor polysulfone membranes in acid cleaned Teflon filter holders) from pressurized Niskin bottles. Bottles were pressurized at 8-10 psi (54-70 kPa) with a system that distributed filtered air from a compressor via a manifold to each bottle through a fitting placed in its air vent. Each distribution line from the manifold was fitted with a valve so that each bottle could be pressurized or vented independently, while still allowing for the possibility to simultaneously filter all the bottles. Pressurized bottles were held closed with Irwin Quick-Grip bar clamps spanning the endcaps. No attempt was made to evaluate the blank contributed by the pressurization scheme.&nbsp; Filtered water was collected in low-density polyethylene cubitainers (10 liter volume; Hedwin Corp.). Approximately 9-10 L was collected per desired depth. Prior to the cruise, the tubing, filters and cubitainers were cleaned by immersion in 1.2 M HCl (Fisher Scientific Trace Metal Grade) for 4-5 days. Once filtered, samples were adjusted to a pH ~2 with ultra-clean 6 M HCl (Fisher Scientific OPTIMA grade) and were double bagged for storage at room temperature until analysis.<br />
<br />
In the on-shore laboratory, samples were weighed to determine sample size, taking into account the weight of the cubitainer and of the acid added at sea.&nbsp; Then weighed aliquots of the artificial isotope yield monitors 229Th (20 pg) and 233Pa (0.5 pg) and 15 mg dissolved Fe were added to each sample. After allowing 1 day for spike equilibration, the pH of each sample was raised to 8-8.5 (checked with pH paper) by adding concentrated NH4OH (Fisher Scientific OPTIMA grade) which caused iron (oxy)hydroxide precipitates to form. This precipitate was allowed to settle for 1-2 days before the overlaying seawater was siphoned off. The Fe precipitate was transferred to centrifuge tubes for centrifugation and rinsing with Milli-Q H2O (&gt;18 MO) to remove the major seawater ions. The precipitate was then dissolved in 16 M HNO3 (Fisher Scientific OPTIMA grade) and transferred to a Teflon beaker for a high-temperature (180-200°C) digestion with HClO4 and HF (Fisher Scientific OPTIMA grade) on a hotplate in a HEPA-filtered laminar flow hood. After total dissolution of the sample, another precipitation of iron (oxy)hydroxide followed and the precipitate was washed with Mill-Q H2O, centrifuged, and dissolved in 12 M HCl for a series of anion-exchange chromatography using 6 mL polypropylene columns each containing Bio-rad resin (AG1-X8, 100-200 mesh size) and a 45 µm porous polyethylene frit (for details see Anderson et al., 2012). The final column elutions were dried down at 180°C in the presence of 2 drops of HClO4 and taken up in approximately 1 mL of 0.16 M HNO3/0.026 M HF for mass spectrometric analysis.&nbsp;<br />
&nbsp;&nbsp;<br />
Concentrations of 232Th, 230Th and 231Pa were calculated by isotope dilution using nuclide ratios determined on a VG Elemental AXIOM Single Collector Magnetic Sector ICP-MS with a Resolving Power of ~400 to ensure the highest sensitivity. All measurements were done using a peak jumping routine in ion counting mode. A solution of SRM129, a natural U standard, was run to determine<br />
the mass bias correction (assuming that the mass fractionation for Th and Pa are the same as for U). Each sample measurement was bracketed by measurement of an aliquot of the run solution,<br />
used to correct for the instrument background count rates on the masses measured.<br />
To correct for potential tailing of 232Th into the minor Th and Pa isotopes, beam intensities were measured at the half masses above and below each mass for 230Th, 231Pa, and 233Pa. Tailing under each minor isotope was estimated as the log mean intensity of the half masses on either side of each minor isotope.<br />
<br />
Water samples were analyzed in batches of 10-12. Procedural blanks were determined by processing 4-5 L of Milli-Q water in an acid-cleaned cubitainer acidified to pH ~2 with 6 M HCl as a sample in each batch.&nbsp; Total procedural blanks for 232Th, 230Th, and 231Pa ranged from 63-93 pg, 12.1-12.4 fg, and 1.9-2.4 fg respectively.<br />
&nbsp;</p>
<p><strong>Sampling and Analytical Methodology - SAFe station:</strong>&nbsp;<br />
Water samples were collected with a Sea-Bird Electronics CTD carousel fitted with<br />
24 10-liter PVC Niskin bottles. The carousel was lowered from the ship with steel wire. Niskin bottles were equipped with nylon-coated closure springs and Viton O-rings. After collection seawater was drained with Teflon-lined TygonTM tubing and filtered through Pall AcropakTM 500 filters on deck (gravity filtration, 0.8/0.45 µm pore size) into low-density polyethylene cubitainers (1 gallon volume; Hedwin Corp.). Approximately 4 L was collected per desired depth. Prior to the cruise, the tubing, filters and cubitainers were cleaned by immersion in 1.2 M HCl (Fisher Scientific Trace Metal Grade) for 4-5 days. Once filtered, samples were adjusted to a pH ~2 with ultra-clean 6 M HCl (Fisher Scientific OPTIMA grade) and were double bagged for storage at room temperature until analysis.<br />
<br />
In the on-shore laboratory, samples were weighed to determine sample size, taking into account the weight of the cubitainer and of the acid added at sea. Then weighed aliquots of the artificial isotope yield monitors 229Th (20 pg) and 233Pa (0.5 pg) and 15 mg dissolved Fe were added to each sample. After allowing 1 day for spike equilibration, the pH of each sample was raised to 8-8.5 (checked with pH paper) by adding concentrated NH4OH (Fisher Scientific OPTIMA grade) which caused iron (oxy)hydroxide precipitates to form. This precipitate was allowed to settle for 1-2 days before the overlaying seawater was siphoned off. The Fe precipitate was transferred to centrifuge tubes for centrifugation and rinsing with Milli-Q H2O (&gt;18 MO) to remove the major seawater ions. The precipitate was then dissolved in 16 M HNO3 (Fisher Scientific OPTIMA grade) and transferred to a Teflon beaker for a high-temperature (180-200°C) digestion with HClO4 and HF (Fisher Scientific OPTIMA grade) on a hotplate in a HEPA-filtered laminar flow hood. After total dissolution of the sample, another precipitation of iron (oxy)hydroxide followed and the precipitate was washed with Mill-Q H2O, centrifuged, and dissolved in 12 M HCl for a series of anion-exchange chromatography using 6 mL polypropylene columns each containing a bed of Bio-rad resin (AG1-X8, 100-200 mesh size) and a 45 µm porous polyethylene frit (for details see Anderson et al., 2012). The final column elutions were dried down at 180°C in the presence of 2 drops of HClO4 and taken up in approximately 1 mL of 0.16 M HNO3/0.026 M HF for mass spectrometric analysis.&nbsp;<br />
&nbsp;&nbsp;<br />
Concentrations of 232Th, 230Th and 231Pa were calculated by isotope dilution using nuclide ratios determined on a VG Elemental AXIOM Single Collector Magnetic Sector ICP-MS with a Resolving Power of ~400 to ensure the highest sensitivity. All measurements were done using a peak jumping routine in ion counting mode. A solution of SRM129, a natural U standard, was run to determine<br />
the mass bias correction (assuming that the mass fractionation for Th and Pa are the same as for U). Each sample measurement was bracketed by measurement of an aliquot of the run solution,<br />
used to correct for the instrument background count rates on the masses measured.<br />
To correct for potential tailing of 232Th into the minor Th and Pa isotopes, beam intensities were measured at the half masses above and below each mass for 230Th, 231Pa, and 233Pa. Tailing under each minor isotope was estimated as the log mean intensity of the half masses on either side of each minor isotope.<br />
<br />
Water samples were analyzed in batches of 10-12. Procedural blanks were determined by processing 3-4 L of Milli-Q water in an acid-cleaned cubitainer acidified to pH ~2 with 6 M HCl as a sample in each batch. An aliquot of an intercalibrated working standard solution of 232Th, 230Th and 231Pa, SW STD 2010-1 referred to by Anderson et al. (2012), was added to a separate cubitainer with 4 L of Milli-Q water (acidified to pH 2) and also processed like a sample in each batch. Total procedural blanks for 232Th, 230Th, and 231Pa ranged from 19-24 pg, 1.4-2.8 fg, and 0.4 fg respectively.<br />
<br />
To test the overall method, an aliquot of an intercalibrated working standard solution of 232Th, 230Th and 231Pa, SW STD 2010-1 referred to by Anderson et al. (2012), was added to a separate cubitainer with 3 L of Milli-Q water (acidified to pH 2) and also processed like a sample.<br />
<br />
Further details on sampling and analysis are given by Anderson et al. (2012).<br />
&nbsp;</p>
Funding provided by NSF Division of Ocean Sciences (NSF OCE) Award Number: OCE-0752402 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=0752402
completed
Robert F. Anderson
Lamont-Doherty Earth Observatory
845-365-8508
61 U.S. Route 9W, P.O. Box 1000 231 Comer Building
Palisades
NY
10964-8000
USA
boba@ldeo.columbia.edu
pointOfContact
Martin Q. Fleisher
Lamont-Doherty Earth Observatory
845-365-8632
233 Comer Bldg. 61 Route 9W
Palisades
NY
10964
USA
martyq@ldeo.columbia.edu
pointOfContact
asNeeded
Unknown
cruise_id
station
lat
lon
depth_max
depth
event
date_collected
year
month
day
yrday_gmt
bottle
sample
date_U_separation
Th232
Th232_err
Th232_flag
Th230
Th230_err
Th230_flag
Pa231
Pa231_err
Pa231_flag
CTD Sea-Bird
Mass Spectrometer
theme
None, User defined
Cruise identfier
station
latitude
longitude
depth_max
depth
event
date
year
month of year
day of month
day of year and decimal time (time zone GMT)
bottle
sample identification
Thorium-232
standard error
flag
Thorium-230
Protactinium-231
featureType
BCO-DMO Standard Parameters
CTD Sea-Bird
Mass Spectrometer
instrument
BCO-DMO Standard Instruments
KN195-08
KN193-06
service
Deployment Activity
eastern North Pacific, North Pacific SAFe Station at 30 deg N 140 deg W, Santa Barbara Basin, 34.25 deg N 120 deg W
Sargasso Sea
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.
U.S. GEOTRACES
http://www.geotraces.org/
U.S. GEOTRACES
GEOTRACES is a SCOR sponsored program; and funding for program infrastructure development is provided by the U.S. National Science Foundation.
GEOTRACES gained momentum following a special symposium, S02: Biogeochemical cycling of trace elements and isotopes in the ocean and applications to constrain contemporary marine processes (GEOSECS II), at a 2003 Goldschmidt meeting convened in Japan. The GEOSECS II acronym referred to the Geochemical Ocean Section Studies To determine full water column distributions of selected trace elements and isotopes, including their concentration, chemical speciation, and physical form, along a sufficient number of sections in each ocean basin to establish the principal relationships between these distributions and with more traditional hydrographic parameters;
* To evaluate the sources, sinks, and internal cycling of these species and thereby characterize more completely the physical, chemical and biological processes regulating their distributions, and the sensitivity of these processes to global change; and
* To understand the processes that control the concentrations of geochemical species used for proxies of the past environment, both in the water column and in the substrates that reflect the water column.
GEOTRACES will be global in scope, consisting of ocean sections complemented by regional process studies. Sections and process studies will combine fieldwork, laboratory experiments and modelling. Beyond realizing the scientific objectives identified above, a natural outcome of this work will be to build a community of marine scientists who understand the processes regulating trace element cycles sufficiently well to exploit this knowledge reliably in future interdisciplinary studies.
Expand "Projects" below for information about and data resulting from individual US GEOTRACES research projects.
U.S. GEOTRACES
largerWorkCitation
program
GEOTRACES InterCalibration
http://www.geotraces.org/science/intercalibration
GEOTRACES InterCalibration
<p>An international intercalibration effort has been assigned a high priority during the initial phase of GEOTRACES to ensure that results from different cruises, and from different labs, can be compared in a meaningful way.</p>
<p>While the original data from the Intercalibration cruises are not available online, consensus values for the SAFe and North Atlantic GEOTRACES Reference Seawater Samples are available from the GEOTRACES Program Office: <a href="http://www.geotraces.org/science/intercalibration/322-standards-and-reference-materials?acm=455_215" target="_blank">Standards and Reference Materials</a></p>
<p>The ultimate goal for the intercalibration component of the international GEOTRACES program is to achieve the best accuracy possible (lowest random and systematic errors) for the suite of GEOTRACES' Trace Elements and Isotopes (TEI) as a prelude to the sampling program, and continuing effort throughout the sampling and analysis program. To achieve this goal, there will be two primary efforts:</p>
<p>(1) Evaluate and develop GEOTRACES sample acquisition, handling, and storage protocols during initial Intercalibration Cruises;</p>
<p>(2) Identify existing GEOTRACES primary standards and certified reference materials (CRMs) for the TEI suite (and where needed, producing reference materials or primary standards), including the establishment of GEOTRACES Baseline Stations that can be used to evaluate accuracy from sampling to analysis (to facilitate intercalibration for TEIs that do not have CRMs).</p>
<p>Tentative schedule of Intercalibration events:<br />
• June - July 2008. 1st Intercalibration cruise (Sargasso Sea): evaluate sampling apparati and handling methods (diss and part), collect and distribute intercalibration samples, sample storage experiments, establish Baseline Station at BATS<br />
• Dec. 2008. Second Intercalibration workshop (AGU): evaluate and interpret intercalibration results, planning for 2nd cruise<br />
• Spring 2009. 2nd Intercalibration cruise (eastern North Pacific): final testing of complete sampling system and procedures, intercalibrate with other (non-US) sampling systems, speciation + total TEI intercalibration, determine the time to occupy one GEOTRACES station (for cruise planning purposes)<br />
• Jan.-Feb 2010. Third Intercalibration workshop: finalize complete intercalibration results, begin assembling GEOTRACES User Manuals</p>
<p><strong>GEOTRACES intercalibration cruise 1</strong> <em>June 2008</em><br />
GEOTRACES completed the first Intercalibration cruise from June 8 to July 12, 2008 to collect intercalibration water and particle samples. This intercalibration exercise aimed to provide reference materials that could be distributed to the international community and reference profiles of Trace Elements and their Isotopes to ensure compatibility and consistency of GEOTRACES data.</p>
<p><strong>GEOTRACES intercalibration cruise 2</strong> <em>May 2009</em><br />
The second intercalibration cruise is planned for May 2009 in the eastern North Pacific and will include sampling near the North Pacific SAFe Station at 30°N, 140°W.</p>
<p>If you are interested in participating in this exercise, note that selected samples for intercalibration will also be available after the cruise. For general information about the intercalibration effort please contact Greg Cutter.</p>
GEOTRACES IC
largerWorkCitation
project
eng; USA
oceans
eastern North Pacific, North Pacific SAFe Station at 30 deg N 140 deg W, Santa Barbara Basin, 34.25 deg N 120 deg W; Sargasso Sea
2012-12-31
Sargasso Sea, eastern North Pacific
0
BCO-DMO catalogue of parameters from Seawater dissolved 232Thorium, 230Thorium and 231Protactinium from R/V Knorr KN193-06 and KN195-08 in the eastern N. Pacific and Sargasso Sea from 2008-2009 (GEOTRACES IC 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
http://lod.bco-dmo.org/id/dataset-parameter/31524.rdf
Name: cruise_id
Units: dimensionless
Description: <p>cruise ID number</p>
http://lod.bco-dmo.org/id/dataset-parameter/31525.rdf
Name: station
Units: dimensionless
Description: <p>station number within cruise</p>
http://lod.bco-dmo.org/id/dataset-parameter/31526.rdf
Name: lat
Units: decimal degrees
Description: <p>station latitude; North is positive</p>
http://lod.bco-dmo.org/id/dataset-parameter/31527.rdf
Name: lon
Units: decimal degrees
Description: <p>station longitude; East is positive</p>
http://lod.bco-dmo.org/id/dataset-parameter/31528.rdf
Name: depth_max
Units: meters
Description: <p>station water depth</p>
http://lod.bco-dmo.org/id/dataset-parameter/31529.rdf
Name: depth
Units: meters
Description: <p>water depth at which bottle tripped</p>
http://lod.bco-dmo.org/id/dataset-parameter/31530.rdf
Name: event
Units: dimensionless
Description: <p>event number from event log</p>
http://lod.bco-dmo.org/id/dataset-parameter/31531.rdf
Name: date_collected
Units: mm/dd/yy
Description: <p>date sample was collected</p>
http://lod.bco-dmo.org/id/dataset-parameter/31532.rdf
Name: year
Units: yyyy
Description: <p>year sample was collected</p>
http://lod.bco-dmo.org/id/dataset-parameter/31533.rdf
Name: month
Units: 1 to 12
Description: <p>month sample was collected</p>
http://lod.bco-dmo.org/id/dataset-parameter/31534.rdf
Name: day
Units: 1 to 31
Description: <p>day of month sample was collected</p>
http://lod.bco-dmo.org/id/dataset-parameter/31535.rdf
Name: yrday_gmt
Units: 1 t 365
Description: <p>year day sample was collected; 1 is Jan. 1 and 365 is Dec. 31</p>
http://lod.bco-dmo.org/id/dataset-parameter/31536.rdf
Name: bottle
Units: dimensionless
Description: <p>Niskin bottle of 24-bottle sequence</p>
http://lod.bco-dmo.org/id/dataset-parameter/31537.rdf
Name: sample
Units: integer
Description: <p>GEOTRACES sample identification number</p>
http://lod.bco-dmo.org/id/dataset-parameter/31538.rdf
Name: date_U_separation
Units: mm/dd/yy
Description: <p>date Uranium was separated from Th/Pa</p>
http://lod.bco-dmo.org/id/dataset-parameter/31539.rdf
Name: Th232
Units: picograms 232Th per kilogram seawater
Description: <p>Dissolved 232Thorium concentration (<0.45um)</p>
http://lod.bco-dmo.org/id/dataset-parameter/31540.rdf
Name: Th232_err
Units: picograms 232Th per kilogram seawater
Description: <p>1 sigma uncertainty in dissolved 232Th</p>
http://lod.bco-dmo.org/id/dataset-parameter/31541.rdf
Name: Th232_flag
Units: 1 = good; 2 = questionable; 3 = rejected; 4=blanks too large to obtain data; 5=232Th tail too large to obtain data
Description: <p>Data quality flag for dissolved 232Th</p>
http://lod.bco-dmo.org/id/dataset-parameter/31542.rdf
Name: Th230
Units: femtograms 230Th per kilogram seawater
Description: <p>Dissolved 230Thorium conc. (<0.45um)</p>
http://lod.bco-dmo.org/id/dataset-parameter/31543.rdf
Name: Th230_err
Units: femtograms 230Th per kilogram seawater
Description: <p>1 sigma uncertainty in dissolved 230Th</p>
http://lod.bco-dmo.org/id/dataset-parameter/31544.rdf
Name: Th230_flag
Units: 1 = good; 2 = questionable; 3 = rejected; 4=blanks too large to obtain data; 5=232Th tail too large to obtain data
Description: <p>Data quality flag for dissolved 230Th</p>
http://lod.bco-dmo.org/id/dataset-parameter/31545.rdf
Name: Pa231
Units: femtograms 231Pa per kilogram seawater
Description: <p>Dissolved 231Protactinium conc. (<0.45um)</p>
http://lod.bco-dmo.org/id/dataset-parameter/31546.rdf
Name: Pa231_err
Units: femtograms 231Pa per kilogram seawater
Description: <p>1 sigma uncertainty in dissolved 231Pa</p>
http://lod.bco-dmo.org/id/dataset-parameter/31547.rdf
Name: Pa231_flag
Units: 1 = good; 2 = questionable; 3 = rejected; 4=blanks too large to obtain data; 5=232Th tail too large to obtain data
Description: <p>Data quality flag for dissolved 231Pa</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
4650
https://datadocs.bco-dmo.org/file/WWW1E3nF7zDkm/GT_IntCal_ThPa.csv
GT_IntCal_ThPa.csv
Primary data file for dataset ID 3828
download
https://osprey.bco-dmo.org/dataset/3828/data/download
download
onLine
dataset
<p><strong>Sampling and Analytical Methodology - BATS station:&nbsp; </strong><br />
Water samples were collected with a Sea-Bird Electronics CTD carousel fitted with<br />
24 10-liter PVC Niskin bottles. The carousel was lowered from the ship with steel wire. Niskin bottles were equipped with nylon-coated closure springs and Viton O-rings. After collection seawater was filtered by in-line filtration (47 mm 0.45 µm pore diameter Supor polysulfone membranes in acid cleaned Teflon filter holders) from pressurized Niskin bottles. Bottles were pressurized at 8-10 psi (54-70 kPa) with a system that distributed filtered air from a compressor via a manifold to each bottle through a fitting placed in its air vent. Each distribution line from the manifold was fitted with a valve so that each bottle could be pressurized or vented independently, while still allowing for the possibility to simultaneously filter all the bottles. Pressurized bottles were held closed with Irwin Quick-Grip bar clamps spanning the endcaps. No attempt was made to evaluate the blank contributed by the pressurization scheme.&nbsp; Filtered water was collected in low-density polyethylene cubitainers (10 liter volume; Hedwin Corp.). Approximately 9-10 L was collected per desired depth. Prior to the cruise, the tubing, filters and cubitainers were cleaned by immersion in 1.2 M HCl (Fisher Scientific Trace Metal Grade) for 4-5 days. Once filtered, samples were adjusted to a pH ~2 with ultra-clean 6 M HCl (Fisher Scientific OPTIMA grade) and were double bagged for storage at room temperature until analysis.<br />
<br />
In the on-shore laboratory, samples were weighed to determine sample size, taking into account the weight of the cubitainer and of the acid added at sea.&nbsp; Then weighed aliquots of the artificial isotope yield monitors 229Th (20 pg) and 233Pa (0.5 pg) and 15 mg dissolved Fe were added to each sample. After allowing 1 day for spike equilibration, the pH of each sample was raised to 8-8.5 (checked with pH paper) by adding concentrated NH4OH (Fisher Scientific OPTIMA grade) which caused iron (oxy)hydroxide precipitates to form. This precipitate was allowed to settle for 1-2 days before the overlaying seawater was siphoned off. The Fe precipitate was transferred to centrifuge tubes for centrifugation and rinsing with Milli-Q H2O (&gt;18 MO) to remove the major seawater ions. The precipitate was then dissolved in 16 M HNO3 (Fisher Scientific OPTIMA grade) and transferred to a Teflon beaker for a high-temperature (180-200°C) digestion with HClO4 and HF (Fisher Scientific OPTIMA grade) on a hotplate in a HEPA-filtered laminar flow hood. After total dissolution of the sample, another precipitation of iron (oxy)hydroxide followed and the precipitate was washed with Mill-Q H2O, centrifuged, and dissolved in 12 M HCl for a series of anion-exchange chromatography using 6 mL polypropylene columns each containing Bio-rad resin (AG1-X8, 100-200 mesh size) and a 45 µm porous polyethylene frit (for details see Anderson et al., 2012). The final column elutions were dried down at 180°C in the presence of 2 drops of HClO4 and taken up in approximately 1 mL of 0.16 M HNO3/0.026 M HF for mass spectrometric analysis.&nbsp;<br />
&nbsp;&nbsp;<br />
Concentrations of 232Th, 230Th and 231Pa were calculated by isotope dilution using nuclide ratios determined on a VG Elemental AXIOM Single Collector Magnetic Sector ICP-MS with a Resolving Power of ~400 to ensure the highest sensitivity. All measurements were done using a peak jumping routine in ion counting mode. A solution of SRM129, a natural U standard, was run to determine<br />
the mass bias correction (assuming that the mass fractionation for Th and Pa are the same as for U). Each sample measurement was bracketed by measurement of an aliquot of the run solution,<br />
used to correct for the instrument background count rates on the masses measured.<br />
To correct for potential tailing of 232Th into the minor Th and Pa isotopes, beam intensities were measured at the half masses above and below each mass for 230Th, 231Pa, and 233Pa. Tailing under each minor isotope was estimated as the log mean intensity of the half masses on either side of each minor isotope.<br />
<br />
Water samples were analyzed in batches of 10-12. Procedural blanks were determined by processing 4-5 L of Milli-Q water in an acid-cleaned cubitainer acidified to pH ~2 with 6 M HCl as a sample in each batch.&nbsp; Total procedural blanks for 232Th, 230Th, and 231Pa ranged from 63-93 pg, 12.1-12.4 fg, and 1.9-2.4 fg respectively.<br />
&nbsp;</p>
<p><strong>Sampling and Analytical Methodology - SAFe station:</strong>&nbsp;<br />
Water samples were collected with a Sea-Bird Electronics CTD carousel fitted with<br />
24 10-liter PVC Niskin bottles. The carousel was lowered from the ship with steel wire. Niskin bottles were equipped with nylon-coated closure springs and Viton O-rings. After collection seawater was drained with Teflon-lined TygonTM tubing and filtered through Pall AcropakTM 500 filters on deck (gravity filtration, 0.8/0.45 µm pore size) into low-density polyethylene cubitainers (1 gallon volume; Hedwin Corp.). Approximately 4 L was collected per desired depth. Prior to the cruise, the tubing, filters and cubitainers were cleaned by immersion in 1.2 M HCl (Fisher Scientific Trace Metal Grade) for 4-5 days. Once filtered, samples were adjusted to a pH ~2 with ultra-clean 6 M HCl (Fisher Scientific OPTIMA grade) and were double bagged for storage at room temperature until analysis.<br />
<br />
In the on-shore laboratory, samples were weighed to determine sample size, taking into account the weight of the cubitainer and of the acid added at sea. Then weighed aliquots of the artificial isotope yield monitors 229Th (20 pg) and 233Pa (0.5 pg) and 15 mg dissolved Fe were added to each sample. After allowing 1 day for spike equilibration, the pH of each sample was raised to 8-8.5 (checked with pH paper) by adding concentrated NH4OH (Fisher Scientific OPTIMA grade) which caused iron (oxy)hydroxide precipitates to form. This precipitate was allowed to settle for 1-2 days before the overlaying seawater was siphoned off. The Fe precipitate was transferred to centrifuge tubes for centrifugation and rinsing with Milli-Q H2O (&gt;18 MO) to remove the major seawater ions. The precipitate was then dissolved in 16 M HNO3 (Fisher Scientific OPTIMA grade) and transferred to a Teflon beaker for a high-temperature (180-200°C) digestion with HClO4 and HF (Fisher Scientific OPTIMA grade) on a hotplate in a HEPA-filtered laminar flow hood. After total dissolution of the sample, another precipitation of iron (oxy)hydroxide followed and the precipitate was washed with Mill-Q H2O, centrifuged, and dissolved in 12 M HCl for a series of anion-exchange chromatography using 6 mL polypropylene columns each containing a bed of Bio-rad resin (AG1-X8, 100-200 mesh size) and a 45 µm porous polyethylene frit (for details see Anderson et al., 2012). The final column elutions were dried down at 180°C in the presence of 2 drops of HClO4 and taken up in approximately 1 mL of 0.16 M HNO3/0.026 M HF for mass spectrometric analysis.&nbsp;<br />
&nbsp;&nbsp;<br />
Concentrations of 232Th, 230Th and 231Pa were calculated by isotope dilution using nuclide ratios determined on a VG Elemental AXIOM Single Collector Magnetic Sector ICP-MS with a Resolving Power of ~400 to ensure the highest sensitivity. All measurements were done using a peak jumping routine in ion counting mode. A solution of SRM129, a natural U standard, was run to determine<br />
the mass bias correction (assuming that the mass fractionation for Th and Pa are the same as for U). Each sample measurement was bracketed by measurement of an aliquot of the run solution,<br />
used to correct for the instrument background count rates on the masses measured.<br />
To correct for potential tailing of 232Th into the minor Th and Pa isotopes, beam intensities were measured at the half masses above and below each mass for 230Th, 231Pa, and 233Pa. Tailing under each minor isotope was estimated as the log mean intensity of the half masses on either side of each minor isotope.<br />
<br />
Water samples were analyzed in batches of 10-12. Procedural blanks were determined by processing 3-4 L of Milli-Q water in an acid-cleaned cubitainer acidified to pH ~2 with 6 M HCl as a sample in each batch. An aliquot of an intercalibrated working standard solution of 232Th, 230Th and 231Pa, SW STD 2010-1 referred to by Anderson et al. (2012), was added to a separate cubitainer with 4 L of Milli-Q water (acidified to pH 2) and also processed like a sample in each batch. Total procedural blanks for 232Th, 230Th, and 231Pa ranged from 19-24 pg, 1.4-2.8 fg, and 0.4 fg respectively.<br />
<br />
To test the overall method, an aliquot of an intercalibrated working standard solution of 232Th, 230Th and 231Pa, SW STD 2010-1 referred to by Anderson et al. (2012), was added to a separate cubitainer with 3 L of Milli-Q water (acidified to pH 2) and also processed like a sample.<br />
<br />
Further details on sampling and analysis are given by Anderson et al. (2012).<br />
&nbsp;</p>
Specified by the Principal Investigator(s)
<p><strong>Data Processing: </strong><br />
The reported errors for radionuclide concentrations represent the propagation of one sigma errors based on the standard deviation of five sequences of isotope ratios collected by ICP-MS, estimated error in the 229Th or 233Pa spike concentration, and the blank correction of the individual isotopes for each sample batch.<br />
<br />
Analysis of all samples was completed over the course of 2 years. A correction was made to account for the ingrowth of 230Th and 231Pa due to the decay of the natural 234U and 235U preserved in the acidified samples during the period of time between sample collection and U-Th/Pa separation during anion exchange chromatography. Thus, the reported 230Th and 231Pa concentrations have been corrected to represent their concentrations at the time of sampling. U concentrations in the samples were estimated using the bottle salinity (S) measured from the CTD and the U-Salinity relationship of North Pacific seawater (Chen et al., 1986), [U] = (0.1115*S – 0.6356) ng U (g seawater)-1. We used seawater U-isotopic compositions of 234U/238 U = 1.1468 activity ratio (Andersen et al., 2010), and 238U/235U = 137.824 mole ratio (Weyer et al., 2008), to calculate [234U] and [235U] respectively based on [U]. In our manuscript (Anderson et al., 2012) we converted gravimetric concentration (fg/kg) into volumetric activities (dpm m-3) for easier comparison to historical data. The half-lives used were 75,690 yrs for 230Th (Cheng et al., 2000), 32,760 yrs for 231Pa (Robert et al., 1969), 245,250 yrs for 234U (Cheng et al., 2000), and 7.0381 x 108 yrs for 235U (Jaffey et al. 1971).<br />
&nbsp;</p>
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
CTD Sea-Bird
CTD Sea-Bird
PI Supplied Instrument Name: CTD Sea-Bird PI Supplied Instrument Description:The carousel was fitted with 24-liter Niskin bottles. The carousel was lowered from the ship with steel wire. Niskin bottles were equipped with nylon-coated closure springs and Viton O-rings. Instrument Name: CTD Sea-Bird Instrument Short Name:CTD Sea-Bird Instrument Description: A Conductivity, Temperature, Depth (CTD) sensor package from SeaBird Electronics. This instrument designation is used when specific make and model are not known or when a more specific term is not available in the BCO-DMO vocabulary. Refer to the dataset-specific metadata for more information about the specific CTD used. More information from: http://www.seabird.com/ Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/130/
Mass Spectrometer
Mass Spectrometer
PI Supplied Instrument Name: Mass Spectrometer PI Supplied Instrument Description:VG Elemental AXIOM Single Collector Magnetic Sector ICP-MS with a Resolving Power of ~400 Instrument Name: Mass Spectrometer Instrument Short Name:Mass Spec Instrument Description: General term for instruments used to measure the mass-to-charge ratio of ions; generally used to find the composition of a sample by generating a mass spectrum representing the masses of sample components. Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/
Cruise: KN195-08
KN195-08
R/V Knorr
Community Standard Description
International Council for the Exploration of the Sea
R/V Knorr
vessel
KN195-08
Gregory A. Cutter
Old Dominion University
Cruise: KN193-06
KN193-06
R/V Knorr
Community Standard Description
International Council for the Exploration of the Sea
R/V Knorr
vessel
KN193-06
Gregory A. Cutter
Old Dominion University
R/V Knorr
Community Standard Description
International Council for the Exploration of the Sea
R/V Knorr
vessel