<div><p><strong>Water column sampling:</strong><br />
Radium and thorium isotopes were collected on manganese-coated cartridges filtered at depth using an adapted McLane in situ pump (WTS-LV). The pumps were programmed to filter 1500-2000L of seawater per deployment. Water (15-25 L) was also collected at the same depth using a 30L Niskin bottle; these samples were filtered (at <1L/min) through a manganese-coated acrylic fiber and used to calculate radium extraction efficiency of the pumped samples. The cartridges were rinsed with radium-free fresh water and excess moisture was removed using compressed air. Samples were analyzed three times using a delayed coincidence counter (RaDeCC) for 223Ra, 224Ra, 228Th, and 227Ac. The cartridge and fiber media were ashed at 820 degrees C and measured on gamma detectors for long lived radium (226Ra, 228Ra) and thorium isotopes. 226Ra was determined via alpha scintillation counting of the Niskin bottle Mn fiber samples.</p>
<p><strong>Surface water sampling:</strong><br />
Surface water radium samples (280 L) were collected from approximately 2 m using a submersible surface pump and filtered through a manganese coated acrylic fiber, which quantitatively scavenges radium from the seawater. Fiber samples were then ashed in a muffle furnace at 820 degrees C for 24 hours and the fiber ash was transferred to polystyrene vials, sealed with epoxy (to prevent 222Rn loss), and counted on high purity, well-type germanium detectors to measure 228Ra, using the lines of 228Ac (338 KeV and 911 KeV), and 226Ra, using the line for 214Pb (352 KeV). Detector efficiencies were determined by measuring ashed fiber standards prepared with a standard solution containing 226Ra and 232Th with daughters in equilibrium.</p></div>
Radium and thorium isotopes measured in the Western Arctic as part of the 2015 US GEOTRACES Arctic Cruise on the USCGC Healy
<div><p>Radium and thorium isotopes measured in the Western Arctic as part of the 2015 US GEOTRACES Arctic Cruise. </p>
<p><strong>Please contact the PI and Co-PI (Charette and Moore) prior to use of these data in publications.</strong></p></div>
GN01 Radium and Thorium
<div><p><strong>Data Processing:</strong><br />
The data were corrected for decay from the time of sampling. 223Raxs was corrected for 227Ac, 224Raxs was corrected for 228Th. When possible, total 228Th was used for the 224Raxs correction (total = dissolved + SSF particulate + LSF particulate); for samples collected using the surface pump, only dissolved 228Th was available. The radium activity of the water samples (cartridges) were corrected from the measured radium on acrylic fiber (<1L/min) using the emanation technique.</p>
<p>Data were flagged using the SeaDataNet quality flag scheme. For more information on SeaDataNet flags, see: <a href="https://www.geotraces.org/geotraces-quality-flag-policy/" target="_blank">https://www.geotraces.org/geotraces-quality-flag-policy/</a> and <a href="https://www.seadatanet.org/Standards/Data-Quality-Control" target="_blank">https://www.seadatanet.org/Standards/Data-Quality-Control</a></p>
<p><strong>SeaDataNet quality flag definitions:</strong><br />
0 = No quality control;<br />
1 = Good value;<br />
2 = Probably good value;<br />
3 = Probably bad value;<br />
4 = Bad value;<br />
5 = Changed value;<br />
6 = Value below detection;<br />
7 = Value in excess;<br />
8 = Interpolated value;<br />
9 = Missing value;<br />
A = Value phenomenon uncertain.</p>
<p><strong>Problem report:</strong><br />
Pump failures during sampling resulted in some gaps in data, these samples have been flagged as missing values (quality flag 9). In cases where low volumes (<600L) were filtered due to pump malfunctions, data has been flagged as questionable (quality flag 3). Samples with activities below detection limits have also been flagged (quality flag 6), and no value is reported for those samples.</p>
<p><strong>BCO-DMO Processing:</strong><br />
- replaced blanks (missing data) with "nd"; replaced "ND" with "nd";<br />
- added start and end date/times in ISO 8601 format.<br />
Version history:<br />
- 2019-07-02: replaced version 1 of dataset with version 2 (additional data columns reported; additional columns for units in dpm/L and mBq/kg);<br />
- 2020-04-06: replaced version 2 of dataset with version 3 (GEOTRACES IDP-formatted).<br />
- 2021-07-06: made correction to Sample_Depth for Sample_ID 10509; published as version 4. The depth for 10509 was previously reported as 427, but the correct value is 274.</p></div>
718440
GN01 Radium and Thorium
2017-10-31T14:02:40-04:00
2017-10-31T14:02:40-04:00
2023-07-07T16:10:26-04:00
urn:bcodmo:dataset:718440
Radium and thorium isotopes measured in the Western Arctic as part of the 2015 US GEOTRACES Arctic Cruise on the USCGC Healy (HLY1502) from August to October 2015
Radium and thorium isotopes measured in the Western Arctic as part of the 2015 US GEOTRACES Arctic Cruise on the USCGC Healy (HLY1502) from August to October 2015.
false
Charette, M. A., Moore, W. S. (2021) Radium and thorium isotopes measured in the Western Arctic as part of the 2015 US GEOTRACES Arctic Cruise on the USCGC Healy (HLY1502) from August to October 2015. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 4) Version Date 2021-07-06 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.718440.4 [access date]
true
4
10.26008/1912/bco-dmo.718440.4
false
2021-07-06
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