Nitrate concentration and nitrate stable isotopic signatures in seawater in the Labrador Sea in spring 2022

DOI

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.

Identifier
DOI https://doi.pangaea.de/10.1594/PANGAEA.986850
Related Identifier References https://doi.org/10.1002/rcm.4307
Related Identifier References https://doi.org/10.1021/ac1028984
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.986850
Provenance
Creator Dempsey, Britton ORCID logo; Kam, Kitty; Rondón, Anadiuska N; Wallace, Douglas WR; Buchwald, Carolyn
Publisher PANGAEA
Publication Year 2025
Funding Reference Natural Sciences and Engineering Research Council https://doi.org/10.13039/501100000038 Crossref Funder ID NWA-BCP The Northwest Atlantic Biological Carbon Pump; Ocean Frontier Institute https://doi.org/10.13039/501100010784 Crossref Funder ID NWA-BCP https://www.ofi.ca/programs/safe-and-sustainable/project/the-northwest-atlantic-biological-carbon-pump The Northwest Atlantic Biological Carbon Pump
Rights Creative Commons Attribution 4.0 International; Data access is restricted (moratorium, sensitive data, license constraints); https://creativecommons.org/licenses/by/4.0/
OpenAccess false
Representation
Resource Type Dataset
Format text/tab-separated-values
Size 345 data points
Discipline Chemistry; Natural Sciences
Spatial Coverage (-49.610W, 58.483S, -49.110E, 58.817N); Labrador Sea
Temporal Coverage Begin 2022-05-20T16:47:00Z
Temporal Coverage End 2022-05-25T14:15:00Z