The relative abundance of n-alkanes of different chain lengths obtained from ancient soils and sediments have been used to reconstruct past environmental changes. However, interpretation of ancient n-alkane patterns relies primarily on modern plant wax n-alkane patterns measured from leaves. Little is still known about how n-alkane patterns, and environmental information therein, might be altered during the process of transfer from leaves into soil. We studied the n-alkane patterns extracted from leaves, necromass, and soil samples from an altitudinal gradient in the tropical Andes to clarify if the n-alkane pattern, and the local environmental information reflected, is altered as the plant source material degrades. We considered the (dis)similarity between n-alkane patterns in soil, necromass, and leaves and specifically explored whether a temperature and/or precipitation signal is reflected in their n-alkane patterns. The n-alkane patterns showed degradation in soil as reflected by a reduced carbon preference index (CPI). The lower CPI in soils as compared to leaves and necromass was significantly correlated with temperature and precipitation along the transect, most likely because of increased microbial activity under warmer and wetter conditions. Despite degradation, all sample types showed a systematic shift in longer vs. shorter n-alkanes when moving up the transect. Further examination revealed the systematic shift correlated with transect temperature and precipitation. Since transect vegetation is constant along the transect, this would appear to indicate the recording of a climatic signal within the n-alkane patterns that is preserved in the soil, albeit that the correlation was weaker there. The study results warrant further research into a possible underlying causal relationship that may lead to the development of n-alkane patterns as a novel palaeoecological proxy.

中文翻译：

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从叶到土壤：尽管在热带安第斯山脉沿环境梯度退化，但正烷信号保留

从古代土壤和沉积物中获得的不同链长的正构烷烃的相对丰度已用于重建过去的环境变化。然而，对古代正构烷烃模式的解释主要依赖于从叶子测得的现代植物蜡正构烷烃模式。小仍然是被如何ñ烷烃的模式，和环境信息在其中，可能会转移从叶子到土壤的过程中被改变。我们研究了从热带安第斯山脉海拔梯度上的叶子，坏死生物和土壤样品中提取的正构烷烃模式，以弄清是否n烷烃模式和反映的当地环境信息会随着植物原料的降解而改变。我们考虑之间的（DIS）相似ñ在土壤烷烃图案，necromass和叶和具体探讨的温度和/或沉淀信号是否被反映在它们Ñ烷烃图案。所述Ñ烷烃图案表明在土壤中降解降低的碳偏好指数（CPI）所反映的。与叶片和坏死病相比，土壤中较低的CPI与横断面的温度和降水显着相关，最可能的原因是在温暖和潮湿的条件下微生物活性增加。尽管退化，所有样本类型均显示出较长或较短的n的系统变化-向上移动样线时的烷烃。进一步的检查显示出与样带温度和降水相关的系统位移。由于样带植被沿着样带是恒定的，因此这似乎表明在土壤中保留的正构烷烃模式中记录了气候信号，尽管那里的相关性较弱。研究结果值得进一步研究可能的潜在因果关系，这种因果关系可能导致正构烷烃模式发展为新型的古生态替代物。