©2020 Biological and Chemical Oceanography Data Management Office.These data include nitrate δ15N and δ18O along US GEOTRACES GP15, a meridional transect at ~152°W in the Pacific Ocean. The Pacific hosts significant rates of all the fluxes that are relevant to the global N cycle: the N budget fluxes (those that either generate or consume fixed N; N2 fixation and denitrification) as well as the N fluxes from the internal N cycle (those that generate or consume nitrate but leave the fixed N pool unaltered; nitrate regeneration and assimilation). The nitrate δ15N...
Show moreSeawater samples were collected using a 36-bottle ODF (Ocean Data Facility) conventional rosette equipped with 10.4-liter (L) Niskin bottles.
HDPE nalgene bottles were acid washed (10% HCl) and rinsed three times (3X) with high-purity water (HPW) before being shipped at sea. Sampling at sea followed the GEOTRACES cookbook indications for nitrate isotopes. Bottles and caps were rinsed three times (3X) with seawater samples from the Niskin before being filled up to shoulder. Samples were then stored kept upright and frozen at -20 degrees Celsius (°C).
Seawater samples were processed in accordance with the published Denitrifier Method (Casciotti et al., 2002). All isotope analyses were performed on a MAT253 Thermo IRMS equipped with a custom-sample preparation system. With this system, we were able to achieve an overall standard deviation of 0.04 per mil for d15N-NO3 analyses and 0.11 per mil for d18O-NO3 analyses. Individual data points have been averaged with standard deviations reported. Please see the papers cited under Related Publications for equations applied to derive final data.
Sigman, D. M., Casciotti, K. L., Marconi, D., Lawrence, R., Wang, W., Oleynik, S., Karolewski, J., Martinez Garcia, A. (2024) Nitrate d15N and d18O from Niskin bottle samples collected on Leg 2 (Hilo, HI to Papeete, French Polynesia) of the US GEOTRACES Pacific Meridional Transect (PMT) cruise (GP15, RR1815) on R/V Roger Revelle from October to November 2018. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2024-05-21 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.928099.1 [access date]
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