Preface; 1. Overview of geomicrobiology and the relative roles of bacteria and fungi H. Erlich; 2. Integrated nutrient cycles in forest ecosystems R. Finlay; 3. Fungal roles in transport processes in soil K. Ritz; 4. Regulation of ecosystem processes, including water transport M. Allen; 5. Carbon and nitrogen cycling in forest ecosystems: importance of mycorrhizal fungi E. Hobbie; 6. The role of arbuscular mycorrhizal fungi in carbon and nutrient cycling D. Johnson; 7. Mapping nutrient fluxes in mycelial networks S. Watkinson, M. Fricker and M. Tlalka; 8. Relative roles of bacteria and fungi in polycyclic aromatic hydrocarbon biodegradation and remediation of contaminated soils C. Cerniglia; 9. Colonisation and deterioration of polymeric materials G. Robson; 10. Fungal dissolution and transformation of minerals: significance for nutrition and metal mobility G. Gadd and M. Fomina; 11. Fungal activities in rock-inhabiting microbial communities A. Gorbushina; 12. Roles of bacteria and fungi in carbonate-oxalate biomineralization E. Verrechia; 13. Mineral tunnelling by fungi M. Smits; 14. Mineral dissolution by ectomycorrhizal fungi H. Wallander; 15. Lichen biogeochemistry W. Purvis and J. Haas; 16. Fungal roles as components of deep sub-surface microflora K. Pedersen, J. Retiner and G. Schumann; 17. Biogeochemical activities in freshwater environments K. Suberkropp and V. Gulis; 18. Biogeochemical roles of fungi in marine and estuarine habitats N. Clipson, M. Otte and E. Landy; Index.