PANGAEA_986850 Nitrate concentration and nitrate stable isotopic signatures in seawater in the Labrador Sea in spring 2022 Dempsey, Britton; Kam, Kitty; Rondón, Anadiuska N; Wallace, Douglas WR; Buchwald, Carolyn Nitrate concentration and nitrate stable isotopic signatures in seawater in the Labrador Sea in spring 2022 2026-02-12 PANGAEA Dataset https://doi.pangaea.de/10.1594/PANGAEA.986850 Investigator Carolyn Buchwald Investigator Douglas WR Wallace douglas.wallace@dal.ca Earth Science Event label Latitude of event Longitude of event Date/Time of event DEPTH, water Nitrate δ15N, nitrate δ15N, nitrate, standard deviation δ18O, nitrate δ18O, nitrate, standard deviation geoscientificInformation CE22009 CE22009_11_Day CE22009_12_Day CE22009_4_Day CE22009_6_Day CE22009_8_Day CE22009_9_Day CTD_cast_11 CTD_cast_14 CTD_cast_17 CTD_cast_21 CTD_cast_25 CTD_cast_8 CTD/Rosette Labrador Sea nitrate concentration in sea water stable nitrogen isotope (δ15N) Automated wet chemistry analyzer, SKALAR, SAN++ Denitrifier method (McIlvin and Casciotti, 2011); measured with an isotope ratio mass spectrometer (IRMS), Thermo delta V Celtic Explorer 2022-05-20 2022-05-25 Complete 58.4833 58.8167 -49.61009999999999 -49.110000000000014 5.0 m (DEPTH, water) 2000.0 m (DEPTH, water) unrestricted CC-BY-4.0: Creative Commons Attribution 4.0 International English PANGAEA Data Publisher for Earth & Environmental Science https://www.pangaea.de/ Data Center Contact Michael Diepenbroek info@pangaea.de

Leobener Str.

Bremen Bremen 28359 Germany online 345 data points text/tab-separated-values 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

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. ** For all details see the full metadata description at "https://doi.pangaea.de/10.1594/PANGAEA.986850"!

http://oceanography.dal.ca/person/Wallace_Douglas.html https://doi.org/10.1002/rcm.4307 Removal of nitrite with sulfamic acid for nitrate N and O isotope analysis with the denitrifier method https://doi.org/10.1021/ac1028984 Technical Updates to the Bacterial Method for Nitrate Isotopic Analyses https://download.pangaea.de/reference/134405/attachments/nwa-bcp_cruise_report_CE22009.pdf CE22009 https://www.marine.ie/site-area/infrastructure-facilities/research-vessels/celtic-explorer Celtic Explorer DIF 9.4 2026-02-12 2026-02-13