Global temperature calibration of the Long chain Diol Index in marine surface sediments
Global temperature calibration of the Long chain Diol Index in marine surface sediments
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DOI：
10.1016/j.orggeochem.2020.103983
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发表时间：
2020-04-01
影响因子：
3
通讯作者：
Schouten, Stefan
中科院分区：
文献类型：
--
作者：
de Bar, Marijke W.;Weiss, Gabriella;Schouten, Stefan
长链二醇指数（LDI）是一种相对较新的海洋表面温度（SST）的有机地球化学代用指标，基于C-30 1，15-二醇相对于C-28 1，13-、C-30 1，13-和C-30 1，15-二醇的总丰度的丰度。在这里，我们通过将原始数据集与来自先前发表的研究的172个数据点和262个新生成的数据点相结合，大大扩展并重新评估了初始岩心顶部校准。总的来说，我们考虑了595个全球分布的表层沉积物，与原始校准相比，其地理覆盖范围有所增强。与SST的关系与原始校准的关系相似，但分散性大大增加。淡水输入的影响（例如，河流径流）和长链二醇的贡献长鼻硅藻的LDI进行了评估。排除沉积在盐度< 32 ppt的核心顶部，以及具有高长鼻鱼衍生的C（28）1，12-二醇丰度的核心顶部，导致LDI和年平均SST之间的关系有了实质性的改善。这意味着LDI不能直接应用于具有强烈淡水影响或高C-28 1，12-二醇丰度的区域，从而限制了LDI的适用性。最终LDI校准（LDI = 0.0325 x SST + 0.1082; R-2 = 0.88; n = 514）与Rampen等人（2012）（http：//doi.org/10.1016/j.gca.2012.01.024）的原始校准无统计学差异，但校准误差较大，为3 ℃。这一较大的校准误差来自于几个地区，在这些地区，LDI似乎与年平均SST没有很强的温度依赖性，这对LDI的应用造成了限制。(C)2020爱思唯尔有限公司版权所有。
The Long chain Diol Index (LDI) is a relatively new organic geochemical proxy for sea surface temperature (SST), based on the abundance of the C-30 1,15-diols relative to the summed abundance of the C-28 1,13-, C-30 1,13- and C-30 1,15-diols. Here we substantially extend and re-evaluate the initial core top calibration by combining the original dataset with 172 data points derived from previously published studies and 262 newly generated data points. In total, we considered 595 globally distributed surface sediments with an enhanced geographical coverage compared to the original calibration. The relationship with SST is similar to that of the original calibration but with considerably increased scatter. The effects of freshwater input (e.g., river runoff) and long-chain diol contribution from Proboscia diatoms on the LDI were evaluated. Exclusion of core-tops deposited at a salinity < 32 ppt, as well as core-tops with high Proboscia-derived C(28 )1,12-diol abundance, resulted in a substantial improvement of the relationship between LDI and annual mean SST. This implies that the LDI cannot be directly applied in regions with a strong freshwater influence or high C-28 1,12-diol abundance, limiting the applicability of the LDI. The final LDI calibration (LDI = 0.0325 x SST + 0.1082; R-2 = 0.88; n = 514) is not statistically different from the original calibration of Rampen et al. (2012) (http://doi.org/10.1016/j.gca.2012.01.024), although with a larger calibration error of 3 degrees C. This larger calibration error results from several regions where the LDI does not seem to have a strong temperature dependence with annual mean SST, posing a limitation on the application of the LDI. (C) 2020 Elsevier Ltd. All rights reserved.