Lipid and PAH composition as indicators for conditions of thermal degradation

脂类是土壤和沉积物中新鲜植物生物量和有机质的主要成分。个别植物和植物组携带特定的脂肪分布模式，这使得它们可以作为生物标记物应用。植物生物量的热降解，即在人为或野火期间，会根据燃烧条件改变分布模式。因此，可以根据主要脂类成分(如醇和酸)及其降解产物(包括脂肪族和多环芳烃(PAHs))的模式重建燃烧条件。土壤和沉积物中就地并入的烧焦生物质将接受生物标志物分析。在一项实验中，将研究热降解过程中温度、持续时间和氧气可用性对几种植物类脂分布模式改变的影响。实验结果与含有烧焦生物质的现代土壤和化石土壤和沉积物进行了比较。选择现代土壤是因为频繁的燃烧和众所周知的燃烧历史，而古代土壤是根据考古文物选择的，具有已知的燃烧历史。该项目的成果首次有助于利用土壤和沉积物中烧焦物质的脂质成分，重建自然和人为改造的生态系统中的火灾条件和植被。

Lipids are main components of fresh plant biomass and organic matter in soils and sediments. Individual plants and plant groups carry a specific lipid distribution pattern which allows for their application as biomarkers. Thermal degradation of plant biomass i.e. during anthropogenic or wildfires shifts the distribution patterns depending on burning conditions. Therefore, burning conditions may be reconstructed based on patterns of primary lipidic components like alcohols and acids as well as their degradation products including aliphatic and polycyclic aromatic hydrocarbons (PAHs). Charred biomass incorporated in situ in soils and sediments will be subjected to biomarker analyses. Within an experiment the influence of temperature, duration, and oxygen availability during thermal degradation on modification of lipid distribution patterns of several plant species will be investigated. Experimental results are compared to recent and fossil soils and sediments containing charred biomass. Recent soils are selected due to frequent burning and well known burning history, whereas ancient soils are selected with a known burning history based on archaeological artefacts. The results of the project facilitate for the first time the reconstruction of fire conditions and vegetation in natural and anthropogenically modified ecosystems by means of lipid composition of charred materials from soils and sediments.