Dempsey, Britton; Kam, Kitty; Rondón, Anadiuska N; Wallace, Douglas WR; Buchwald, Carolyn (2026): Nitrate concentration and nitrate stable isotopic signatures in seawater in the Labrador Sea in spring 2022 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.986850
Always quote citation above when using data! You can download the citation in several formats below.
Published: 2026-02-12 • DOI registered: 2026-02-13
Abstract:
Seawater was collected for nitrate concentration and stable isotopic analyses between May 20th and May 25th, 2022 aboard RV Celtic Explorer in an area between 58 - 59 degrees N and 49 - 50 degrees W. Nitrate concentration samples were collected from the Niskin unfiltered into 15ml centrifuge tubes and immediately frozen at -20 degrees C. After the survey, these samples were then thawed to room temperature and analyzed using standard colorimetric protocols coupled with a continuous flow nutrient analyzer at the Canada Excellence Research Chairs (CERC) laboratory at Dalhousie University. Sampling for nitrate stable isotopic measurements was conducted by filtering seawater directly from the Niskin-rosette using 0.22 µm polyethersulfone (PES) syringe filters (VWR Cat. no. 76479-018) and collected into 60 mL HDPE bottles, which were then immediately frozen upright at -20 degrees C. Isotopic analyses were prepared in duplicate using the denitrifier method (McIlvin and Casciotti, 2011; doi:10.1021/ac1028984), and analyzed using isotope ratio mass spectrometery (IRMS) on a Thermo Delta V located in the Canada Excellence Research Chairs (CERC) laboratory at Dalhousie University. Samples with detectable nitrite (>0.1 µmol/l) concentrations were first treated with sulfamic acid to remove potential interference on the 15N-NO3 pool as the denitrifier method does not discriminate between nitrate or nitrite (Granger and Sigman, 2009; doi:10.1002/rcm.4307). Isotopic analyses were referenced against USGS32, USGS34, and IAEA-NO3 reference materials.
References:
Granger, Julie; Sigman, Daniel M (2009): Removal of nitrite with sulfamic acid for nitrate N and O isotope analysis with the denitrifier method. Rapid Communications in Mass Spectrometry, 23(23), 3753-3762, https://doi.org/10.1002/rcm.4307
McIlvin, Matthew R; Casciotti, Karen L (2011): Technical Updates to the Bacterial Method for Nitrate Isotopic Analyses. Analytical Chemistry, 83(5), 1850-1856, https://doi.org/10.1021/ac1028984
Funding:
Natural Sciences and Engineering Research Council (NSERC), grant/award no. NWA-BCP: The Northwest Atlantic Biological Carbon Pump
Coverage:
Median Latitude: 58.677783 * Median Longitude: -49.290600 * South-bound Latitude: 58.483300 * West-bound Longitude: -49.610100 * North-bound Latitude: 58.816700 * East-bound Longitude: -49.110000
Date/Time Start: 2022-05-20T16:47:00 * Date/Time End: 2022-05-25T14:15:00
Minimum DEPTH, water: 5 m * Maximum DEPTH, water: 2000 m
Event(s):
CE22009_4_Day (CTD_cast_8) * Latitude: 58.816700 * Longitude: -49.110000 * Date/Time: 2022-05-20T16:47:00 * Location: Labrador Sea * Campaign: CE22009 (BELAS-1) * Basis: Celtic Explorer * Method/Device: CTD/Rosette (CTD-RO)
CE22009_6_Day (CTD_cast_11) * Latitude: 58.816700 * Longitude: -49.443400 * Date/Time: 2022-05-21T16:28:00 * Location: Labrador Sea * Campaign: CE22009 (BELAS-1) * Basis: Celtic Explorer * Method/Device: CTD/Rosette (CTD-RO)
CE22009_8_Day (CTD_cast_17) * Latitude: 58.650000 * Longitude: -49.610100 * Date/Time: 2022-05-23T12:14:00 * Location: Labrador Sea * Campaign: CE22009 (BELAS-1) * Basis: Celtic Explorer * Method/Device: CTD/Rosette (CTD-RO)
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | Event label | Event | Buchwald, Carolyn | |||
| 2 | Latitude of event | Latitude | Buchwald, Carolyn | |||
| 3 | Longitude of event | Longitude | Buchwald, Carolyn | |||
| 4 | Date/Time of event | Date/Time | Buchwald, Carolyn | |||
| 5 | DEPTH, water | Depth water | m | Buchwald, Carolyn | Geocode | |
| 6 | Nitrate | [NO3]- | µmol/l | Wallace, Douglas WR | Automated wet chemistry analyzer, SKALAR, SAN++ | |
| 7 | δ15N, nitrate | δ15N NO3 | ‰ air | Buchwald, Carolyn | Denitrifier method (McIlvin and Casciotti, 2011); measured with an isotope ratio mass spectrometer (IRMS), Thermo delta V | Vs. 15N of N2 in air |
| 8 | δ15N, nitrate, standard deviation | δ15N NO3 std dev | ± | Buchwald, Carolyn | Denitrifier method (McIlvin and Casciotti, 2011); measured with an isotope ratio mass spectrometer (IRMS), Thermo delta V | Vs. 15N of N2 in air |
| 9 | δ18O, nitrate | δ18O NO3 | ‰ | Buchwald, Carolyn | Denitrifier method (McIlvin and Casciotti, 2011); measured with an isotope ratio mass spectrometer (IRMS), Thermo delta V | Vs. 18O of Vienna standard mean ocean water (VSMOW) |
| 10 | δ18O, nitrate, standard deviation | δ18O NO3 std dev | ± | Buchwald, Carolyn | Denitrifier method (McIlvin and Casciotti, 2011); measured with an isotope ratio mass spectrometer (IRMS), Thermo delta V | Vs. 18O of Vienna standard mean ocean water (VSMOW) |
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Status:
Curation Level: Enhanced curation (CurationLevelC)
Size:
345 data points