Processes of litter and soil organic matter transformation during extreme drying/wetting as assessed by compound-specific isotope approaches

通过化合物特异性同位素方法评估极端干燥/湿润期间凋落物和土壤有机质转化的过程

• 批准号: 68810257
• 负责人: Professor Dr. Bruno Glaser
• 金额: --
• 依托单位: Ökopedologie der gemäßigten Zonen
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/68810257?language=en
• 关键词: Processes; litter; soil; organic; matter

Recently, intensive droughts followed by heavy rainfall can already be observed in Europe as proposed by climate models. Shifts in amount, intensity and frequency of precipitation could change soil structure and soil organic matter quality and thus turnover in temperate forest ecosystems. Contradicting results have been reported from drying and wetting experiments in field and laboratory studies or from observations of natural drying and wetting periods. To verify different interpretations, a combination of stable and radio-isotopes and biomarker .analyses seems a promising tool. This can be achieved by establishing tracer experiments in the drying and wetting fields (13C and 15NJ and in controlled laboratory studies (14C, 13C, and 15N) and by analysing the 13C, 14C and 15N signatures not only in the bulk SOM but also in biomarkers characterizing chemically defined SOM pools, e.g. microbially and plant-derived sugars, phospholipid fatty acids (PLFA) and benzenepolycarboxylic acids (BPCA). The combination of biomarker and isotope (δ13C, 14C and δ 15N) analysis allows not only deducing SOM turnover after drying / wetting but also to identify the involved microbial community and the fate of chemically defined compounds during SOM decomposition and turnover under the experimental manipulations.

最近，根据气候模型，欧洲已经出现了严重干旱和强降雨，降水量、强度和频率的变化可能会改变土壤结构和土壤有机质质量，从而导致温带森林生态系统的更替。根据现场和实验室研究中的干燥和润湿实验或对自然干燥和润湿时期的观察报告，稳定同位素和放射性同位素以及生物标记物的结合似乎是一种很有前途的工具。在干燥和润湿（13C 和 15NJ 以及受控实验室现场研究（14C、13C 和 15N）中建立示踪剂实验，并通过分析大量 SOM 以及表征化学定义的 SOM 的生物标志物中的 13C、14C 和 15N 特征库，例如微生物和植物来源的糖、磷脂脂肪酸 (PLFA) 和生物标记物和同位素（δ13C、14C 和 δ15N）分析的结合不仅可以推断干燥/润湿后的 SOM 周转率，还可以识别所涉及的微生物群落以及化学定义的化合物在 SOM 分解和分解过程中的命运。实验操作下的营业额。