Interactions of soil microbial communities and persistent organic pollutants at different biogeochemical interfaces in soil

由于不同的微生境共存，土壤中的微生物群落高度多样和复杂，并且在很小的尺度上变化。在项目的第一阶段，我们可以证明两种模式土壤(Scheyern Luvisol，UlTuna Cambiol)中的细菌群落对菲的反应截然不同。与路维索土相比，风化土的反应较慢，但在两个月后，两种土壤都可以检测到明显的群落变化。只在菲处理的土壤中检测到参与菲降解的酶(RHDα)的编码基因，并且在两种土壤中观察到了显著不同的RHDα基因的丰度和多样性。通过分子指纹图谱还可以看出，矿物组成和木炭的存在对8种人工土壤中细菌群落的组成有很大的影响。在第二阶段，我们将研究4种人工土壤中两年成熟后建立的土壤微生物群落对菲的响应。我们假设，根据矿物组成的不同，在成熟过程中将建立不同的微生物群落，通过产生细胞外聚合物和代谢物来塑造生物地球化学界面(BGI)的性质。BGI的性质和微生物群落组成，特别是它们的降解潜力将影响菲的命运。我们假设玉米的添加将通过水平基因转移促进土壤细菌群落的适应。我们的目标是通过批式和柱式实验确定参与生物转化的微生物种群，并调查土壤微生物群落对菲的响应如何受水供应的影响。

Microbial communities in soils are highly diverse and complex and vary at very small scales due to the coexistence of different microhabitats. In the first phase of the project we could show that the response of the bacterial communities in the two model soils (Scheyern Luvisol, Ultuna Cambisol) to phenanthrene was strikingly different. The Cambisol showed a slower response compared to Luvisol but distinct community changes were detectable for both soils after two months. Genes coding for enzymes involved in the degradation of phenanthrene (rhdα) were detected only in phenanthrene-treated soils, and a strikingly different abundance and diversity of rhdα genes was observed for the two soils. By means of molecular fingerprints we could also show that the mineral composition and the presence of charcoal strongly influenced the composition of the bacterial community established in eight artificial soils.In the second phase we will study the response of soil microbial communities established after two years of maturation in four artificial soils to phenanthrene. We hypothesize that depending on the mineral composition different microbial communities will be established during maturation that shape the properties of the biogeochemical interfaces (BGI) through the production of extracellular polymeric substances and metabolites. The properties of the BGI and the microbial community composition, in particular their degradative potential will influence the fate of phenanthrene.We hypothesize that maize addition will foster adaptation of soil bacterial communities by horizontal gene transfer. We aim to identify the microbial population involved in biotransformation in batch and column experiments and to investigate how the response of soil microbial communities to phenanthrene is influenced by water availability.