Data from the Arctic biomarker IP25 and associated open water and marginal ice biomarkers brassicasterol and HBI III from the eastern Bering Sea during the Pleistocene

The data was generated using samples from International Ocean Discovery Program Site U1343 (Leg 323) in the eastern Bering Sea. The highly branched isoprenoid (HBI) lipids were extracted from 3g freeze dried sediment as described in (Belt et al., 2012). Additionally sulphur removal using tetrabutylammonium sulphite reagent (TBA) (Cabedo-Sanz and Belt, 2015) was performed for all samples prior to silica column chromatographic purification of the total organic extracts. The samples were measured on the gas chromatography mass spectrometer (Agilent 7890A GC coupled to a 5975 series mass selective detector fitted with an Agilent HP-5ms column) at Plymouth University using the operating conditions specified in Belt et al. (2012). The identification of individual lipids was based on their characteristic retention time and mass spectra and quantification was achieved by integrating the peak area of selected ions (m/z 350 (IP25); 346 (HBI III); 470 (brassicasterol)) in comparison to the peak area of the internal standards added to each sample (Belt et al., 2012). Quantification of individual lipids also considers an instrumental response factor obtained from known concentrations of biomarker lipids in the standard sediments (Belt et al., 2012). The data is provided in ng g-1 dry sediment (sed).

本数据集采用采自白令海东部国际大洋发现计划（International Ocean Discovery Program, IODP）U1343站位（323航次）的样品生成。按照Belt等（2012）的方法，从3g冻干沉积物中提取高分支类异戊二烯（highly branched isoprenoid, HBI）脂质。所有样品在进行硅胶柱层析纯化总有机萃取物之前，均采用亚硫酸四丁基铵试剂（tetrabutylammonium sulphite reagent, TBA）完成脱硫处理（Cabedo-Sanz与Belt, 2015）。样品于普利茅斯大学的气相色谱-质谱联用仪（gas chromatography mass spectrometer, GC-MS）上完成检测，该仪器由Agilent 7890A气相色谱耦合5975系列质谱选择检测器组成，并搭载Agilent HP-5ms色谱柱，检测操作参数遵循Belt等（2012）的规定。单体脂质的鉴定基于其特征保留时间与质谱图；定量分析则通过积分选定离子的峰面积实现：m/z 350（IP25）、346（HBI III）、470（菜籽甾醇(brassicasterol)），并与添加至每个样品的内标峰面积进行比对（Belt等, 2012）。此外，单体脂质的定量还需结合从标准沉积物中已知浓度的生物标志物脂质得到的仪器响应因子（Belt等, 2012）。本数据集以ng g⁻¹干沉积物（sed）为单位提供。