Abstract. Lignin oxidation products (LOPs) are widely used as vegetation proxies in climate archives, such as sediment and peat cores. The total LOP concentration, Σ8, provides information on the abundance of vegetation, while the ratios C / V and S / V of the different LOP groups also provide information on the type of vegetation. Recently, LOP analysis has been successfully applied to speleothem archives. However, there are many open questions concerning the transport and microbial degradation of LOPs on their way from the soil into the cave system. These processes could potentially alter the original source-dependent LOP signals, in particular the C / V and S / V ratios, and thus complicate their interpretation in terms of past vegetation changes. We analyzed LOPs in leaf litter and different soil horizons as well as dripwater and flowstone samples from four different cave sites from different vegetation zones in New Zealand using ultrahigh performance liquid chromatography coupled to high resolution mass spectrometry. We test whether the original source-dependent LOP signal of the overlying vegetation is preserved and can be recovered from flowstone samples and investigate how the signal is altered by the transport from the soil to the cave. The LOP concentrations range from mg/g in the soil to ng/g in the flowstones. Our results demonstrate that, from the soil to the flowstone, the C / V and S / V ratios both increase, while the total lignin content, Σ8, strongly decreases. This shows that the LOP signal is strongly influenced by both transport and degradation processes. Nevertheless, the relative LOP signal from the overlying soil at the different cave sites is preserved in the flowstone. We emphasize that for the interpretation of C / V and S / V ratios in terms of past vegetation changes, it is important to compare only samples of the same type (e.g., speleothem, dripwater or soil) and to evaluate only relative variations.

中文翻译：

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新西兰四个不同地点的土壤，滴水和鞘脂中的木质素氧化产物

摘要。木质素氧化产物（LOP）被广泛用作气候档案中的植被代理，例如沉积物和泥炭芯。LOP的总浓度Σ8提供了有关植被丰富度的信息，而不同LOP组的C / V和S / V之比也提供了有关植被类型的信息。最近，LOP分析已成功地应用于speleothem档案。但是，关于LOP从土壤进入洞穴系统的运输和微生物降解存在许多悬而未决的问题。这些过程可能会改变原始的依赖于源的LOP信号，特别是C / V和S / V比率，从而使它们对过去植被变化的解释变得复杂。我们使用超高效液相色谱与高分辨率质谱联用技术分析了新西兰不同植被带的四个不同溶洞部位的凋落物和不同土壤层中的LOP以及滴水和流石样品。我们测试了上覆植被的原始依赖于源的LOP信号是否被保留并可以从流石样品中恢复，并研究了从土壤到洞穴的运输如何改变该信号。LOP浓度范围从土壤中的mg / g到流石中的ng / g。我们的结果表明，从土壤到流石，C / V和S / V比均增加，而总木质素含量Σ8则大大降低。这表明LOP信号受传输和降级过程的强烈影响。不过，来自不同洞穴位置上覆土壤的相对LOP信号保留在the石中。我们强调，要根据过去的植被变化来解释C / V和S / V比率，重要的是仅比较相同类型的样本（例如，鞘石，滴水或土壤），并仅评估相对变化。