牙釉质羟磷灰石的稳定同位素分析被广泛应用于古生物学研究之中,以重建古生态和古环境信息。在对不同研究中的同位素结果进行对比分析时,往往会忽略不同实验室、不同前处理方法可能引发的数据误差。为了探讨这些因素对牙釉质羟磷灰石同位素值的影响,重新测量了湖北省龙骨洞步氏巨猿动物群动物牙釉质样本的碳氧稳定同位素值,该批样本曾使用不同的前处理和实验方法进行过测试(Zhao et al., 2011;Nelson, 2014)。研究结果显示,重测的数据与Zhao et al. (2011)、Nelson (2014)发表的数据结果均存在一定差异。前处理方法与实验室测试差异都会造成牙釉质碳、氧稳定同位素结果的偏差。相较氧同位素而言,碳同位素值会更容易被前处理过程中反应试剂、反应时间等的不同所影响。但上述因素所导致的数据差异较小,不会对后续的分析产生实质性影响。本研究为直接对比不同来源牙釉质同位素值的可行性提供了初步的理论支持。建议为减少由于样品前处理和实验测试方案引发的数据误差,获得更加精确的研究结果,应尽可能采用同样的前处理与测试方案,多进行实验室间数据校正对比分析。

Stable isotopic (C, O) analysis of fossil enamel bioapatite has been widely used in paleontological fields to reconstruct the paleoecology and paleoenvironment. It is common to compare the isotopic data of enamel bioapatite made by different pretreatment and measuring methods in different labs, without considering the isotopic variations possibly caused by different protocols. Here, we chose the same samples from Gigantopithecus fauna in the Longgu Cave (Longgudong), Hubei and remeasured their δ¹³C and δ¹⁸O values, which had been previously reported in Zhao et al. (2011) and Nelson (2014) with different pretreatment and measuring methods, in order to evaluate the effects of the above factors on the isotopic variability. The comparison among three isotopic dataset indicates that there did exist small isotopic variations on the δ ¹³C and δ ¹⁸O values. It seems that the δ ¹³C values were more influenced, probably due to differential practices to eliminate the diagenetic effects using varied chemicals and retaining reaction time during the process of bioapatite preparation. However, we should emphasize that the small isotopic variations observed here do not have produced substantial isotopic variance among fossil taxa and localities, providing the preliminarily theoretical foundation to make isotopic comparison directly. Even so, we still recommend that it is best to compare the isotopic data according to the same preparing and measuring protocols to remove the systematic errors or to re-measure samples again in different labs to calibrate the data.