<div><p>Sea ice was collected using a trace metal clean Kovacs T-handle corer to collect 1 m long cores at 6 sea ice stations along the Canada Basin transect. Snow was collected into precleaned HDPE bottles, while seawater was pumped from beneath the sampled sea ice hole into a carboy and filtered into pre-cleaned bottles aboard the Healy. All samples were stored frozen until analyses or further sample prep could take place. Ice cores were bagged and stored at -20 degrees celsius onboard until cores could be cut and sub-sectioned in a cold room at University of Washington in Seattle prior to shipment back to Brown University.</p>
<p>Concentration analysis of samples was completed using an automated colorimetric system (WestCo SmartChem 200); the pooled standard deviation of control standards run within each sample set run was 0.3 micromoles per Liter (6.2 ppb nitrate); detection limit was 0.09 micromoles per Liter. Based upon nitrate concentration, 20 nmol of N were injected into vials containing denitrifying bacteria to convert nitrate to nitrous oxide for isotopic analysis on a ThermoFisher Delta V isotope ratio mass spectrometer. Analysis for d15N and d18O of nitrate are described in Sigman et al. (Analytical Chemistry; 2001), Casciotti et al. (Analytical Chemistry; 2002), McIlvin and Casciotti (Analytical Chemistry; 2011). Kaiser et al. (Analytical Chemistry; 2007) describes similar methodology for the determination of D17O of nitrate. D17O analyses require 50 nmol of N for complete analysis.</p></div>
Nitrate (NO3), ammonium (NH4), and oxygen & deuterium isotopic composition from snow collected on the US GEOTRACES Arctic cruise, HLY1502
<div><p>This dataset contains nitrate and ammonium concentrations, as well as the complete isotopic composition of nitrate (d15N, d18O, D17O) and ammonium (d15N) and the oxygen & deuterium isotopic composition (d18O, dD) from snow collected during the U.S. GEOTRACES ARCTIC research cruise in 2015.</p></div>
GN01 Snow NO3 NH4 H2O
<div><p>NOTES: Not enough nitrate for D17O analysis. Ammonium concentrations were below detection for stations 43 and 46. Due to low concentrations/no detectable ammonium, no icehole seawater samples were measured for d15N-NH4. Sample 59 had no sample left to conduct NH4 or H2O isotope sample analysis. Of the sample volume available and concentration, only two snow samples were measured for d15N-NH4.</p>
<p>As described in Kaiser et al. (2007), isotopic data is corrected and standardized to international reference materials IAEA-N3, USGS34, and USGS35, which are run 3-9 times with each sample run. For d15N, samples are corrected for isobaric interferences and a blank associated with the bacteria. For d18O, samples are corrected for isobaric interferences, blank, and exchange between sample nitrate and background water that takes place during denitrification to nitrous oxide. The pooled standard deviation for the reference materials are (n=88): 0.2 per mil for d15N and 0.7 per mil for d18O of IAEA-N3; 0.3 per mil for d15N and 0.7 per mil for d18O of USGS34; and 0.7 per mil for d18O of USGS35 (sample d15N is not corrected for d15N of USGS35, this is used as an internal quality check and pooled standard deviation across all runs in 0.2 per mil). 10 samples were run in duplicate or triplicate and the paired pooled standard deviation (n=10) is 0.2 per mil for d15N and 0.4 per mil for d18O. Pooled standard deviation for USGS34 and USGS35 run for D17O is 0.6 and 0.9 per mil each (n=14 and 15, respectively), and replicate samples were 0.9 per mil (n=4).</p>
<p>Due to low sample volume and concentrations, only 3 samples were analyzed for d15N-NH4 using hypobromite oxidation to nitrite coupled with the denitrifier method (Felix et al., 2013; Zhang et al., 2007; Sigman et al., 2001). Briefly, ammonium is oxidized to nitrite with hypobromite, and nitrite is quantitatively converted to nitrous oxide with denitrifying bacteria. For the three samples with sufficient analyte, oxidations were conducted in triplicate. Samples were calibrated using ammonium reference materials USGS25 and IAEA-N2. Precision for d15N-NH4 of reference materials was ≤ 2.7 per mil and based on the standard deviation of reference replicates. The d15N-NH4 is then computed from the weighted difference from d15N-NO3.</p>
<p>Oxygen and hydrogen isotope ratios of water (d18O-H2O <em>vs.</em> VSMOW, dD-H2O vs. VSMOW) were measured using wavelength-scanned cavity-down ring spectroscopy on a Picarro L1102-I liquid analyzer calibrated to international reference standards USGS46, USGS49 and VSMOW. Raw data are corrected for memory and drift effects followed by normalization using a standard calibration (Vaughn and Claymoore, INSTAAR, University of Colorado). Precision for d18O and dD was better than ±0.1 and ±0.4 per mil, respectively, based upon repeated measures of an internal standard (BW-1). </p>
<p>BCO-DMO Processing:<br />
- modified parameter names (replaced spaces with underscores);<br />
- separated Dates_of_collection field into Date_Start and Date_End (yyyy-mm-dd).</p></div>
753356
GN01 Snow NO3 NH4 H2O
2019-01-22T16:13:29-05:00
2019-01-22T16:13:29-05:00
2023-07-07T16:10:26-04:00
urn:bcodmo:dataset:753356
Nitrate (NO3), ammonium (NH4), and oxygen & deuterium isotopic composition from snow collected on the US GEOTRACES Arctic cruise (HLY1502) from August to October 2015
false
Hastings, M., Granger, J. (2019) Nitrate (NO3), ammonium (NH4), and oxygen & deuterium isotopic composition from snow collected on the US GEOTRACES Arctic cruise (HLY1502) from August to October 2015. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2019-01-22 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/753356 [access date]
true
1
false
2019-01-22
HTML
https://www.bco-dmo.org/dataset/753356
text/html
Datapackage.json
Frictionless Data Package
https://www.bco-dmo.org/dataset/753356/datapackage.json
application/vnd.datapackage+json
PDF
https://www.bco-dmo.org/dataset/753356/Dataset_description.pdf
application/pdf
JSON-LD
https://www.bco-dmo.org/dataset/753356.json
application/ld+json
Turtle
https://www.bco-dmo.org/dataset/753356.ttl
text/turtle
RDF/XML
https://www.bco-dmo.org/dataset/753356.rdf
application/rdf+xml
ISO 19115-2 (NOAA Profile)
https://www.bco-dmo.org/dataset/753356/iso
application/xml
http://www.isotc211.org/2005/gmd-noaa
Dublin Core
https://www.bco-dmo.org/dataset/753356/dublin-core
application/xml
http://purl.org/dc/elements/1.1/
753356
http://lod.bco-dmo.org/id/dataset/753356
2015-08-09 - 2015-10-12
2015-08-09
2015-08-09
---09
220
--08
2015
2015-10-12
2015-10-12
---12
284
--10
2015
OSPREY
http://www.opengis.net/def/crs/OGC/1.3/CRS84
<http://www.opengis.net/def/crs/OGC/1.3/CRS84> POLYGON((176.67 82.49, 3.529 82.49, 3.529 82.49, 3.529 89.96, 176.67 89.96, 176.67 82.49))
176.67
82.49
3.529
89.96
86.225000000000
-89.900500000000