Abstract Long chain alkyl diols (LCDs) have previously been used to develop several diol indices as a proxy for upwelling or stratification conditions and sea surface temperatures. However, there is still a lack of data on the distribution of LCDs in the Pacific Ocean, which calls into question to what extent these diol indices can serve as a proxy in the Pacific Ocean. Hence, we investigated the distribution of LCDs in suspended particulate matter (SPM) samples collected in July 2015 along a south-north transect ranging from the East Sea of Korea to the Bering Sea in the northwestern Pacific region. Our results showed that both saturated and unsaturated C28 and C30 1,14-diols were dominant in most SPM samples investigated. The principal component analysis (PCA) results of the SPM data revealed that the C28:1 and C30:1 1,14-diols were positively associated with nutrient concentrations. However, only the C28:1 1,14-diol in addition to the C28 1,14-diol was positively associated with nutrient concentrations in the global surface sediment data set previously published, while the C30:1 1,14-diol was related to sea surface temperature (SST). Based on these observations, we defined a new diol index, i.e., the nutrient diol index (NDI), which included the C28 1,14-diol as well as the C28:1 1,14-diol in the numerator and all the 1,13-, 1,14-, and 1,15-diols, excluding the C32 1,15-diol, in the denominator. The NDI was positively associated with the ocean atlas values of surface water phosphate and nitrate concentrations for the SPM and surface sediment data sets. Accordingly, the results of our study showed that the NDI has potential as a quantitative nutrient proxy for estimating sea surface phosphate (or nitrate) changes. Further studies should be undertaken in order to assess the applicability of the NDI as a paleo-nutrient proxy for confidently reconstructing surface water nutrient variations in the past, by analyzing more SPM, surface sediments, and sediment cores collected from various oceanic settings.

中文翻译：

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沿西北太平洋地区南北横断面的长链烷基二醇的分布：对古海表养分代理的洞察

摘要 长链烷基二醇 (LCD) 先前已被用于开发几种二醇指数，作为上升流或分层条件和海面温度的代表。然而，目前还缺乏关于太平洋液晶显示器分布的数据，这令人怀疑这些二醇指数在多大程度上可以作为太平洋的代理。因此，我们调查了 2015 年 7 月沿从韩国东海到西北太平洋地区白令海的南北横断面收集的悬浮颗粒物 (SPM) 样本中 LCD 的分布。我们的结果表明，在所研究的大多数 SPM 样品中，饱和和不饱和 C28 和 C30 1,14-二醇均占主导地位。SPM 数据的主成分分析 (PCA) 结果显示，C28:1 和 C30:1 1，14-二醇与营养浓度呈正相关。然而，在先前公布的全球表层沉积物数据集中，除了 C28 1,14-二醇之外，只有 C28:1 1,14-二醇与养分浓度呈正相关，而 C30:1 1,14-二醇与海面温度 (SST)。基于这些观察，我们定义了一个新的二醇指数，即营养二醇指数 (NDI)，其中包括分子中的 C28 1,14-二醇以及 C28:1 1,14-二醇以及所有 1 ,13-、1,14- 和 1,15- 二醇，不包括 C32 1,15-二醇，在分母中。NDI 与 SPM 和表层沉积物数据集的表层水磷酸盐和硝酸盐浓度的海洋图谱值呈正相关。因此，我们的研究结果表明，NDI 有潜力作为估算海面磷酸盐（或硝酸盐）变化的定量营养指标。应该进行进一步的研究，通过分析从各种海洋环境收集的更多 SPM、表层沉积物和沉积物核心，评估 NDI 作为古营养物替代品的适用性，用于自信地重建过去地表水营养物变化。