Microbial colonization and its effects on mineral weathering (CCES-Big Link)

We study the biochemical interactions between microorganisms and mineral surfaces. Foto: Beat Frey (WSL)

Colonization and initial soil formation after glacier retrieval in alpine regions is surprisingly fast. A key factor of the relevant weathering processes most probably arises from microbial exudates. Systematic studies will show the potential abundance of weathering-active microorganisms and the role of their exudates on mineral dissolution and nutrient mobilization. We focus on the interactions between biota and mineral surfaces and the subsequent mineral dissolution.

Aims

• Characterization of the biochemical interactions between microorganisms and mineral surfaces and their influence on mineral dissolution rates.
• Elucidation of the roles of cyanobacteria, bacteria and fungi in the weathering processes at the beginning of soil formation.
  

Methods

1. Characterization of bacterial and fungal community structures at various weathering stages with molecular tools (T-RFLP, DGGE).
2. On site microbial colonization experiments on rock/mineral surfaces.
3. Isolation of relevant microorganisms (cultivation dependent methods, sequencing).
4. Setting up and performing siderophore- and cyanid-assays (real-time PCR).
5. Weathering studies using various minerals occurring at the glacier forefield (SEM-EDX).
   

Added value

The resulting insights are crucial for the entire BigLink project, where weathering of bare rock material is a critical step of initial soil formation and the subsequent establishment of a new ecosystem that is able to prevent rock material from continuous erosion. This information will be fundamental for the understanding of isotope fractionation (Subproject 4) and carbon turnover (Subproject 1).

Projectpartners

• Prof. Josef Zeyer, Inst. of Biogeochemistry and Pollutant Dynamics, Env. Microbiology, ETH Zürich.
• Prof. Gerhard Furrer, Inst. of Biogeochemistry and Pollutant Dynamics, Environmental Geochemistry Group, ETH Zürich.
• Dr. Michael Plötze, Inst. for Geotechnical Engineering, ETH Zürich.
• Dr. Ales Lapanje (from 1. 10. 2007) and Dr. Ivano Brunner (both WSL)