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

• Applicant: Professorin Dr. Kornelia Smalla
• Subject Area: Soil Sciences
• Term: from 2007 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 40956058

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.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1315: Biogeochemical Interfaces in Soil