Nitrogen and carbon isotopes of particulate organic matter during the K-Axis voyage of the Aurora Australis, 2016

Water samples were collected from the seawater line on the Aurora Australis during the K-Axis voyage. They were filtered so that two fractions of each sample were collected: a fraction that was between 1.2 and 210 um and a fraction that was between 210 and 1000 um. A 47 mm diameter 1000 um mesh was placed upstream of all samples, and this prevented larger particles (e.g. zooplankton) from entering the samples. The underway water was taken from the pCO2 rig at 1.4 to 1.5 atmospheres.    All samples were collected on 25 mm diameter 1.2um Sterlitech silver membrane filters. The greater than 210 samples were collected on mesh and refiltered onto silver filters. The filters were stored frozen until they were processed in Hobart. Subsamples of the filters were analysed at the Central Science Laboratories, University of Tasmania to determine elemental N and C. The remainder of the filters were analysed by ANSTO (NSW) to determine delta15N and delta13C.Volumes are in litres, and the values for the nitrogen isotopes are presented as ratios.

本数据集的样品采集于K轴航次（K-Axis voyage）期间，取自南极光号（Aurora Australis）科考船的海水采样管路。对采集的海水样品进行分级过滤，得到两组粒径分级组分：粒径介于1.2~210微米（μm）的组分，以及粒径介于210~1000微米（μm）的组分。所有样品的上游均安装有直径47毫米、孔径1000微米的筛网，以阻挡更大粒径的颗粒（例如浮游动物（zooplankton））进入样品。走航采集的海水取自二氧化碳分压采样装置（pCO2 rig），采样压力为1.4~1.5标准大气压。
所有样品均采用直径25毫米、孔径1.2微米的Sterlitech银质微孔滤膜（Sterlitech silver membrane filters）进行过滤。其中粒径大于210微米的样品先经筛网截留，再重新过滤至银质滤膜上。滤膜样品全程冷冻保存，直至在霍巴特（Hobart）完成预处理。随后，滤膜的子样本被送至塔斯马尼亚大学中央科学实验室（Central Science Laboratories, University of Tasmania），用于测定总氮与总碳元素含量；剩余滤膜样品则由澳大利亚核科学与技术组织（新南威尔士州，ANSTO (NSW)）开展δ15N与δ13C同位素比值分析。本数据集的采样体积单位为升，氮同位素数据以比值形式呈现。