Professor Geoffrey Gadd

Microorganisms are intimately involved in the biogeochemical processes underpinning metal and mineral transformations in the environment, as well as the cycling of related substances like organometals, metalloids and radionuclides. A variety of processes determine metal and radionuclide mobility and bioavailability and these influence transfer to other environmental components and other living organisms including plants and humans. These processes are also intimately associated with such global phenomena as bioweathering, soil formation, and the biodeterioration of rocks, minerals, metals and building materials. As well as being of environmental significance, microbial metal transformations are relevant to plant productivity and human health, with application to the treatment of pollution (bioremediation). For bioremediation, solubilization of metal contaminants provides a means of removal from soils, sediments, and solid industrial wastes. Alternatively, immobilization processes may enable metals or radionuclides to be transformed in situ and are applicable to removing metals from aqueous solution.

In the Geomicrobiology Group, we carry out research on the geoactive properties of microorganisms in order to understand their importance in key biosphere processes and their applied potential. The prime focus is on metal-mineral transformations with most research under the heading of geomycology, the roles of fungi as geoactive agents. We are particularly interested in understanding physiological and morphological responses to toxic metals and mineral substrates, mechanisms of mineral dissolution, and the formation of novel mycogenic biominerals, especially carbonates, phosphates, oxides and oxalates. Research of applied significance that builds on our fundamental research includes the application of metal-mineral-microbe transformations for bioremediation of metals, metalloids and radionuclides, nuclear decommissioning, biofertilizers (phosphate release), and the production of mineral-based biomaterials. We are also interested in the biodeterioration of rock and mineral-based structural materials including concrete and cultural artefacts, as well as biocorrosion of metals. Research on the functional consequences and mathematical modelling of fungal growth in heterogeneous environments is carried out in collaboration with Dr Fordyce Davidson, Division of Mathematics.