<div><p><strong>Sample Collection</strong><br />
Aerosol samples were collected on acid-washed Whatman 41 (W41) cellulose ester filter papers deployed in one of two high-volume aerosol samplers (model 5170-VBL, Tisch Environmental) simultaneously operating at approximately 1.2 cubic meters air per minute. The aerosol samplers were deployed on the ship’s flying bridge (14 m above sea level) as high off the water as possible. Contamination from the ship’s stack exhaust was avoided by controlling aerosol sampling with respect to wind sector and wind speed using an anemometer interfaced with a Campbell Scientific CR800 datalogger and PC. The samplers were allowed to run when the wind was +/- 60 degrees from the bow and > 0.5 m/s. When the wind failed to meet these two criteria, the motors were shut off automatically and not allowed to restart until the wind met both the speed and direction criteria for 5 continuous minutes. The anemometer was deployed nearby on a separate pole in 'free air' where turbulence from the wind crossing the bow did not cause the wind vane to wobble excessively.</p>
<p><strong>Trace Element Determination</strong><br />
The fractional solubility of aerosol trace elements was estimated using the flow-through deionized water leaching protocol of Buck et al. (2006), conducted under a Class-100 laminar flow hood within 1 week of sample collection. Ultrapure deionized water (100 mL, >18 MΩ cm resistivity, pH ~ 5.5, Barnstead Nanopure) was rapidly passed through an aerosol-laden W41 filter held in a polysulfone vacuum filtration assembly (Nalgene). Operationally defined dissolved (≤0.45 um) trace elements were collected in the filtrate (leachate) by positioning a GN-6 Metricel backing filter (cellulose esters) below the aerosol-laden W41 disc in the filtration assembly. Ninety mL of the leachate was immediately transferred into an acid-cleaned 100 mL low density polyethylene bottle and acidified to ~0.024 M HCl (pH ~ 1.7) with ultrapure HCl and double-bagged for storage until analysis. Filters for both the soluble aerosol concentration measurements were stored frozen prior to performing the leaches. Trace element concentrations in the leachate solutions were determined by inductively coupled plasma mass spectrometry (Thermo Element-2) at the National High Magnetic Field Laboratory at Florida State University. Blank solutions were prepared by passing 100 mL of deionized water through W41 filters that had been deployed in the aerosol sampler while not in operation for 1 h. Blank leachates averaged e.g., 0.007 ± 0.004 pmol dissolved Fe and 0.073 ± 0.007 pmol dissolved Al (representing averages of 1.6 ± 0.38% and 9.1 ± 0.40% of the Fe and Al sample concentrations, respectively), and were subtracted from all leachate sample concentrations. Analysis of replicate filters for soluble Fe and Al produced relative standard deviations of 10% and 11%, respectively.</p>
<p><strong>Major seawater anion determination</strong><br />
Following the DI water leach a 10 mL aliquot was taken for determination of DI soluble Cl-, NO3- and (SO4)2-. The aliquot was decanted into 15 mL HDPE bottles, double-bagged and immediately frozen at -20 degrees C for sample preservation and storage. Prior to major anion determination by ion chromatography (Dionex), samples were left to defrost at room temperature. Non-sea salt sulphate (nss-(SO4)2-) was calculated using the concentration of DI water soluble Na (as determined by ICP-MS, see above) as the reference element to correct for aerosol sea spray content. The following equation was used:</p>
<p>nss-(SO4)2-= (SO4)2-measured−[( (SO4)2-/Na)seawater* (SO4)2-measured]</p>
<p><strong>References:</strong><br /><strong>Buck</strong>, C. S., Landing, W.M., Resing, J. A., Lebon, G. T. 2006. Aerosol iron and aluminum solubility in the northwest Pacific Ocean: Results from the 2002 IOC cruise. Geochemistry, Geophysics, Geosystems. 7. doi:<a href="http://dx.doi.org/10.1029/2005GC000977" target="_blank">10.1029/2005GC000977</a>.</p></div>
DI water soluble aerosol trace elements for the North Atlantic GEOTRACES cruises.
<div><p>DI water soluble aerosol trace metals (Li, Na, Mg, Al, P, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Zr, Cd, Sn, Sb, Cs, Ba, La, Nd, Pb, Th, U) from the 2010 and 2011 U.S. GEOTRACES North Atlantic Transect cruises.</p>
<p><strong>27 February 2015</strong>: Values in the Cl, NO3, and nss_SO4 columns were corrected.</p>
<p>Please note that some US GEOTRACES data may not be final, pending intercalibration results and further analysis. If you are interested in following changes to US GEOTRACES NAT data, there is an RSS feed available via the BCO-DMO <a href="http://www.bco-dmo.org/project/2066">US GEOTRACES project page</a> (scroll down and expand the "Datasets" section).</p></div>
GT10-11 - DI Water Soluble Aerosol Trace Elements
<div><p>Concentrations below the detection limit are flagged as "BDL" (originally " <_DL") in the data columns. Representative detection limits were calculated using an air volume of 1200 cubic meters. See <a href="http://bcodata.whoi.edu/US_GEOTRACES/AtlanticSection/Landing/DI-soluble_aerosol_detection_limits.pdf" target="_blank">PDF of detection limits for this dataset</a>.</p>
<p>Quality flag definitions:<br />
BDL = below detection limit.<br />
0 = No QC performed.<br />
1 = Good data.<br />
2 = Probably good data.<br />
3 = Probably bad data that is potentially correctable.<br />
4 = Bad data.<br />
5 = Value changed.<br />
6 = Sample < blank.<br />
8 = Interpolated value.<br />
9 = Missing value.</p>
<p>BCO-DMO made the following modifications:<br />
- Replaced blanks with 'nd'.<br />
- Replaced ' < DL' with 'BDL'. Replaced '< blank' with 'lt_blank'.<br />
- Changed PI-supplied cruise IDs of KN204-2 and KN204-5 to KN204-01A and KN204-01B. Added 'cruise_part' column to distingush between parts A and B of cruise KN204-01.<br />
- Copied averages and variances to all rows containing data for that sample (where applicable).<br />
- 27 February 2015: Values in the Cl, NO3, and nss_SO4 columns were corrected.</p>
<p><strong>Additional GEOTRACES Processing:</strong> After the data were submitted to the International Data Management Office, BODC, the office noticed that important identifying information was missing in many datasets. With the agreement of BODC and the US GEOTRACES lead PIs, 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: station_GEOTRC, cast_GEOTRC (bottle and pump data only), event_GEOTRC, sample_GEOTRC, sample_bottle_GEOTRC (bottle data only), bottle_GEOTRC (bottle data only), depth_GEOTRC_CTD (bottle data only), depth_GEOTRC_CTD_rounded (bottle data only), BTL_ISO_DateTime_UTC (bottle data only), and GeoFish_id (GeoFish data only). 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_GT10, GT-C_Bottle_GT11, ODF_Bottle_GT10, and ODF_Bottle_GT11 datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the Event_Log_GT10 and Event_Log_GT11 datasets. McLane pump cast numbers missing in event logs were taken from the Particulate Th-234 dataset submitted by Ken Buesseler.</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 name 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>
529106
GT10-11 - DI Water Soluble Aerosol Trace Elements
2014-10-01T16:12:30-04:00
2014-10-01T16:12:30-04:00
2023-07-07T16:10:26-04:00
urn:bcodmo:dataset:529106
DI water soluble aerosol trace elements from R/V Knorr cruises KN199-04 and KN204-01 in the Subtropical northern Atlantic Ocean from 2010-2011 (U.S. GEOTRACES NAT project)
false
Landing, W. M. (2015) DI water soluble aerosol trace elements from R/V Knorr cruises KN199-04 and KN204-01 in the Subtropical northern Atlantic Ocean from 2010-2011 (U.S. GEOTRACES NAT project). Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 27 Feb 2015) Version Date 2015-02-27 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/529106 [access date]
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27 Feb 2015
false
2015-02-27
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