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

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 and δ18O provide a useful tool to separate and possibly quantify the overlapping impacts of all these co-occurring processes. GP15 was a 60-day research cruise that took place in 2018 along a transect form Alaska to Tahiti at 152° W on board of the R/V Revelle. The cruise was completed in two legs (RR1814 and RR1815), which started on the 18th of September and on the 24th of October 2018, respectively. This dataset includes data from Leg 2 (RR1815). Leg 1 data (RR1814) are provided in a separate, related dataset.本数据集包含沿美国全球海洋示踪剂研究计划（US GEOTRACES）GP15断面采集的硝酸盐δ¹⁵N与δ¹⁸O数据，该断面位于太平洋约152°W经度处，为经向断面。太平洋是全球氮循环相关各类通量的重要发生区：包括氮收支通量（即产生或消耗固定氮的过程，如固氮作用与反硝化作用），以及来自内部氮循环的氮通量（即产生或消耗硝酸盐但不改变固定氮库的过程，如硝酸盐再生与同化作用）。硝酸盐δ¹⁵N与δ¹⁸O是区分并可量化上述共存过程叠加影响的有效工具。 GP15断面科考航次为期60天，于2018年执行，沿152°W经度从阿拉斯加延伸至塔希提岛，搭载平台为“雷维尔号”（R/V Revelle）研究船。本次航次分为两个航段（RR1814与RR1815），分别于2018年9月18日和10月24日起航。本数据集包含第二航段（RR1815）的相关数据，第一航段（RR1814）的数据已在另一相关数据集内发布。