苯多羧酸生物标记物对土壤中生物炭含量及特性的描述

生物炭进入环境后，在生物和非生物过程中会发生不同程度的降解，其质量和性质随时间而变化。遗憾的是，目前没有很好的方法将生物炭从土壤中分离出来，从而动态描述其性质和环境效应。生物标记物技术在理解有机碳来源和行为领域做出了重要的贡献，苯多羧酸（BPCAs）生物标记物方法的引入，可能为理解生物炭的生命周期及其性质变化提供重要的技术手段。本研究拟以不同生物质制备的生物炭为研究对象，通过模拟实验构建BPCAs分子组成及13C稳定同位素信息在生物炭制备和老化过程中的变化特征，并将其应用于环境样品中，描述生物炭施用后的相对含量和性质变化，对天然土壤中生物炭的来源、降解、稳定等过程，特别是通过对土壤洗矿前后BPCA含量、分布特征以及单分子13C丰度的信息比较，理解生物炭与土壤无机矿物之间的相互作用机制，探究有机-无机复合体在生物炭稳定中的功效。本研究将为客观、动态评价生物炭在环境中的行为和功效提供新的思路。

Once applied in the environment, biochars may be degraded biologically or chemically, and thus their quantities and properties altered accordingly. However, no techenique is currently available to separete and thus characterize biochars after they are applied in soils. Thus biochars are treated as a static component after their applications, which brougtht improper avaluation of biochar functions and turnover times over their life time in the environment. Extended work is needed to investigate biochar properties, especially their dynamics, in complex environmental matrix. Biomarkers have been widely used in carbon cycling, and played an important role in understanding carbon sources, turnover, and stabilization. Benzene polycarboxylic acids (BPCAs) are used as biomarkers for black carbons. Considering the similar chemical properties between black carbon and biochars, BPCAs could be used as biomarkers for biochars. Incorporating BPCA biomarker technique in biochar research will greatly improve our ability in describing biochar property change in the environment. This study includes both laboratory simulation and field study. BPCA molecular information in relation to biochar prodcution and properties will be firstly investigated. Different types of biomass as well as biomass model materials (such as lignin and cellulose) will be collected, and biochars will be produced under different temperatures. The obtained biochars will be chemically or biologically degraded in the simulation experiments. All the materials are subject to the analysis of BPCAs. Importantly, all the samples will be analyzed for 13C abundance, and the relationship between biochar pyrolysis temperature or feedstock properties and BPCA molecular specific 13C information will be established. All the results obtained above will be applied in the field study. Soil samples from intense human activity area will be collected and analyzed. These areas include agricultural and living/industry districts. Biochars in all these soil samples will be quantified using thermal oxidation method. The origination, degradation pathway, and stabilization of biochars will be analyzed and compared. BPCA information will also be compared before and after removing mineral compositions from soil particles. Consequently, the interactions between biochar and mineral particles can be revealed. This comparison will provide valuable information in clarifying the interaction mechanisms between biochars and mineral particles, as well as the role of mineral particles in biochar stabilization. This line of study will unfold a new research strategy in dynamically evaluate biochar properties and functions in complex matrix after being applied in the environment.