Importance of soil organic carbon and mineral particle size fractions for the fate of soil supplied organic chemicals and their microbial transformations

本项目中的生物地球化学界面(BGI)被定义为被微生物定植的土壤颗粒的有机矿物表面。在前面的项目中，不同的土壤颗粒组分分别与特定结构的微生物群落、土壤有机碳的特征量和对有机化学品苯酚和2，4-二氯苯酚的特定吸附能力有关。虽然微生物群落的多样性对施肥决定的较大颗粒组分中的额外有机碳有反应，但在粘土中不受影响。用~(13)C标记的苯酚和2，4-二氯苯酚进行的稳定同位素探测表明，BGI中的土壤有机碳也影响了参与这些化学物质降解的微生物的多样性。所有这些结果都只是基于对一种含有三种有机碳变量(Bad Lauchstädt)和只有两种有机化合物的土壤的研究。这一第二阶段项目的目标是应用第一阶段开发的创新技术，使用来自另一土壤(UlTuna，SPP 1315地点)的土壤有机碳变体，并使用手性苯胺类杀菌剂甲霜灵作为附加化合物来研究BGI过程。这个第二阶段的SPP 1315项目还将与另外两个SPP 1315合作伙伴合作，分别调查(1)BGIs对甲霜灵的非选择性降解的重要性和(2)土壤微生物在结合残留物形成中的作用。此外，该项目将利用稳定的同位素探测和新一代DNA测序，将负责有机化学品代谢的微生物群落的结构和功能多样性联系起来，这些微生物群落负责在不同的BGI中代谢有机化学品，这些微生物群落由颗粒大小和土壤有机碳变量确定。

The biogeochemical interface (BGI) in this project is defined as the organo-mineral surface of soil particles colonized by microorganisms. In the preceding project it was demonstrated that the different soil particle size fractions were associated with specifically structured microbial communities, a characteristic amount of soil organic carbon, and a specific capacity for adsorption of the organic chemicals phenol and 2,4-dichlorophenol, respectively. While the diversity of the microbial community was responsive to fertilization-determined additional organic soil carbon in the larger particle size fractions, it was unaffected in clay. Stable isotope probing with 13C-labelled phenol and 2,4-dichlorophenol revealed that the soil organic carbon in the BGIs also affected the diversity of microorganisms involved in the degradation of these chemicals. All these results are yet only based on studying one soil with three organic carbon variants (Bad Lauchstädt) and only two organic compounds. The objective of this 2nd phase project is to apply the innovative technology developed in the 1st phase for studying the BGI processes with soil organic carbon variants from another soil (Ultuna, SPP 1315 site) and with the chiralic anilide Fungicide metalaxyl as an additional compound. This 2nd phase SPP 1315 project will also, in a collaborative effort with two other SPP 1315 partners, investigate (1) the importance of BGIs for the entantio-selective degradation of metalaxyl and (2) the role of soil microorganisms in the formation of bound residues, respectively. Furthermore, the project will utilize stable isotope probing and next-generation DNA sequencing to link the structural and functional diversity of the microbial communities responsible for metabolism of organic chemicals in the different BGIs determined by particle size fractions and soil organic carbon variants.