Biogeochemical Processes

The distribution, transport and fate of many contaminants in the geosphere is controlled significantly by the presence and metabolic activity of microorganisms within the subsurface environment. The fundamental biogeochemical processes which occur through the activity of microorganisms in the natural environment are well known. However, the interactions between microorganisms, reactive components in porous media and contaminants which can control the speciation, form and concentration of many organic and inorganic compounds in polluted settings remain poorly understood and difficult to predict. Such interactions can affect the mobility, toxicity and environmental hazard created by the contaminant. They must be researched at a fundamental level to deduce the relevant microbiological and environmental controls on contaminant behaviour. The results must also be interpreted in a practical sense which enables this knowledge to be used for environmental risk assessment and decision-making for the management of contaminated land and groundwater.

The research that GPRG undertakes in this area considers the micro- to macro-scale and integrates multidisciplinary analysis. The challenges, which embrace our research expertise, are to:

  • Understand at the cellular level the interactions between microorganisms and reactive surfaces in porous media and other materials, which may influence the activity and function of specific populations of bacteria through the development of biofilms
  • Understand the complex relationships between microorganisms in the subsurface environment at the molecular level and how these are controlled by spatial and temporal variations in growth factors which may influence microbial distribution, diversity, activity and function. This is particularly important at the interface between uncontaminated and contaminated media, where strong gradients in geochemical processes and chemicals in mixtures exist and exert an important influence on the biodegradation, transport and fate of contaminants.
  • Develop robust performance models from well-constrained process models, which allow the fate and transport of chemicals in porous media to be quantitatively predicted. This must consider how the detailed process understanding gained from laboratory and field studies can be conceptualised and integrated within appropriate mathematical constructs that can be applied across different scales.