Abstract Nickel and copper are cofactors in key phytoplankton enzymes and the stable isotope composition of Ni and Cu (δ60Ni and δ65Cu) in seawater have the potential to identify major processes that influence their biogeochemistry. However, accurate analysis of δ60Ni and δ65Cu is challenging because of the difficulties in separating these metals from interfering elements in the seawater matrix. Here we report a fast and simple method for purification of Ni and Cu from seawater samples that is able to completely remove interfering elements Mn, Ti, Cr, and Fe. This method was verified by analyzing four reference materials that contain significant levels of interfering elements (powdered plankton, natural soils, and two marine sediments). Using this technique, we generated a dataset of 49 seawater δ60Ni and δ65Cu measurements from the upper water column of the North Pacific Ocean, which show preferential uptake of light Ni isotopes by phytoplankton (αbio-sw = 0.9997 ± 1) but no net fractionation of Cu isotopes. This new method simplifies treatment of seawater samples for Ni and Cu isotope analysis, enabling high-throughput investigations of δ60Ni and δ65Cu throughout the global ocean.

中文翻译：

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海水中镍和铜稳定同位素的一种新纯化方法为北太平洋浮游植物广泛分离镍同位素提供了证据

摘要 镍和铜是浮游植物关键酶的辅助因子，海水中镍和铜的稳定同位素组成（δ60Ni 和 δ65Cu）有可能确定影响其生物地球化学的主要过程。然而，δ60Ni 和 δ65Cu 的准确分析具有挑战性，因为很难将这些金属与海水基质中的干扰元素分离。在这里，我们报告了一种从海水样品中纯化 Ni 和 Cu 的快速而简单的方法，该方法能够完全去除干扰元素 Mn、Ti、Cr 和 Fe。该方法通过分析含有显着水平干扰元素（粉状浮游生物、天然土壤和两种海洋沉积物）的四种参考材料进行了验证。使用这种技术，我们生成了来自北太平洋上部水柱的 49 个海水 δ60Ni 和 δ65Cu 测量值的数据集，显示浮游植物优先吸收轻 Ni 同位素（αbio-sw = 0.9997 ± 1），但没有对 Cu 同位素进行净分离。这种新方法简化了用于 Ni 和 Cu 同位素分析的海水样品的处理，从而能够对整个全球海洋中的 δ60Ni 和 δ65Cu 进行高通量研究。