<div><p>Water column samples were taken from the GEOTRACES carousel and filtered through pre-cleaned, 0.2 um Pall Acropak Supor filter capsules as described elsewhere (e.g., Cutter et al., 2012; Hatta et al., 2015). Near surface water samples were collected using an underway towed-fish pumped seawater system (Bruland et al., 2005) with samples filtered through sequential 0.45 um Osmonics and 0.2 µm Polycarbonate (PCTE) cartridge filters. Filtered water was collected in 125 mL HDPE bottles (Nalgene) that had been precleaned by soaking in hot 1.2 M HCl (reagent grade) for at least 8 h with subsequent thorough rinsing with ultrapure distilled deionized water (Barnstead E-pure). Samples were acidified in a laminar flow bench aboard ship using 0.5 mL of ultrapure HCl per 125 mL sample.</p>
<p>Barium was measured using a ThermoFisher Element 2 Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and the isotope dilution method as described by Jacquet et al. (2005). Aliquots (50 uL) of each sample were spiked with 25 uL of a 135Ba-enriched solution (~170 nM) and then diluted 30-fold with 0.2 um ultrapure filtered water. A sample of ~93% enriched 135Ba was obtained from Oak Ridge National Laboratories for use as the enriched isotope spike. The ICP-MS was operated in low resolution and both 135Ba and 138Ba were determined. The samples were bracketed every 10 samples with a blank and the spike 135Ba solution. The volumes of the spikes, samples and dilution water were accurately assessed by calibrating each pipette by weight. The reproducibility error of this method was estimated by comparing samples collected at the same depths on different casts at the same station. For 42 pairs of these replicate samples, the average absolute deviation of 1.4 nmol/kg or typically 1.5%. Repeated runs of runs of US GEOTRACES intercalibration samples and in-house reference solutions suggest a precision of ±2.0%; the limit of detection for barium was 0.7 nmol/kg. Our precision is similar to that reported by other labs for Ba (e.g., Jacquet et al., 2005).</p></div>
Dissolved Barium (Ba) in US GEOTRACES East Pacific Zonal Transect, GP16.
<div><p>A section of dissolved Ba concentrations comprised of 36 stations and additional surface water sampling across the Eastern Tropical Pacific from Ecuador to Tahiti.</p></div>
GP16 Barium Dissolved
<div><p><strong>Data quality flags: </strong><br />
2 = Good data;<br />
3 = Questionable data;<br />
4 = Bad data.</p>
<p><strong>Intercalibration:</strong><br />
See the <a href="https://datadocs.bco-dmo.org/d3/data_docs/GEOTRACES/EPZT/shiller/Barium_table1.PNG" target="_blank">Table 1 Supplement File</a> (.PNG), which lists intercalibration data for reference waters, both our results and results we were able to find from collaborators. Results are reasonably comparable within the 2% precision generally given for Ba analysis. Note that European labs analyzing Ba tend to report values for one of the SLRS reference waters as well as an in house standard. We are hopeful that other data from the BATS crossover station will soon be available to make a better comparison.</p>
<p><strong>BCO-DMO Processing:</strong><br />
- modified parameter names to conform to BCO-DMO and GEOTRACES IDP parameter naming conventions;<br />
- separated Barium columns in _BOTTLE and _FISH, in accordance with the GEOTRACES IDP conventions;<br />
- replaced blanks (missing data) with "nd" ("no data");<br />
- correction made on 10 November 2016: removed duplicate data for sample number 9981;<br />
- 04 March 2019: removed embargo on dataset.</p>
<p><strong>Additional GEOTRACES Processing by BCO-DMO: </strong><br />
As was done for the GEOTRACES-NAT data, BCO-DMO added standard US GEOTRACES information, such as the US GEOTRACES event number, to each submitted dataset lacking this information. To accomplish this, BCO-DMO compiled a 'master' dataset composed of the following parameters: cruise_id, EXPOCODE,SECT_ID, STNNBR, CASTNO, GEOTRC_EVENTNO, GEOTRC_SAMPNO, GEOTRC_INSTR, SAMPNO, GF_NO, BTLNBR, BTLNBR_FLAG_W, DATE_START_EVENT, TIME_START_EVENT, ISO_DATETIME_UTC_START_EVENT, EVENT_LAT, EVENT_LON, DEPTH_MIN, DEPTH_MAX, BTL_DATE, BTL_TIME, BTL_ISO_DATETIME_UTC, BTL_LAT, BTL_LON, ODF_CTDPRS, SMDEPTH, FMDEPTH, BTMDEPTH, CTDPRS, CTDDEPTH.</p>
<p>This added information will facilitate subsequent analysis and inter-comparison of the datasets.</p>
<p>Bottle parameters in the master file were taken from the GT-C_Bottle and ODF_Bottle datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the TN303 Event Log (version 30 Oct 2014). Where applicable, pump information was taken from the PUMP_Nuts_Sals dataset.</p>
<p>A standardized BCO-DMO method (called "join") was then used to merge the missing parameters to each US GEOTRACES dataset, most often by matching on sample_GEOTRC or on some unique combination of other parameters.</p>
<p>If the master parameters were included in the original data file and the values did not differ from the master file, the original data columns were retained and the names of the parameters were changed from the PI-submitted names to the standardized master names. If there were differences between the PI-supplied parameter values and those in the master file, both columns were retained. If the original data submission included all of the master parameters, no additional columns were added, but parameter names were modified to match the naming conventions of the master file.</p>
<p>See the dataset parameters documentation for a description of which parameters were supplied by the PI and which were added via the join method.</p></div>
648753
GP16 Barium Dissolved
2016-06-13T16:09:52-04:00
2016-06-13T16:09:52-04:00
2023-07-07T16:10:26-04:00
urn:bcodmo:dataset:648753
Dissolved Barium (Ba) from R/V Thomas G. Thompson cruise TN303 (GP16) in the Eastern Tropical Pacific in 2013 (U.S. GEOTRACES EPZT project)
Dissolved Barium (Ba) from R/V Thomas G. Thompson cruise TN303 (GP16) in the Eastern Tropical Pacific in 2013 (U.S. GEOTRACES EPZT project).
false
Shiller, A. M. (2021) Dissolved Barium (Ba) from R/V Thomas G. Thompson cruise TN303 (GP16) in the Eastern Tropical Pacific in 2013 (U.S. GEOTRACES EPZT project). Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 2) Version Date 2016-11-10 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.648753.2 [access date]
true
2
10.26008/1912/bco-dmo.648753.2
false
2016-11-10
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