Environmental Geochemistry and Geomicrobiology, focuses on the characterisation of mineral water organic matter reactions in surface and near surface environments. Since chemical reactions in these environments are often catalysed by microorganisms, we have developed a recent and expanding interest in geomicrobiology. Here by combining the techniques of microbiology and molecular biology with physical, chemical and modelling approaches, we focus on the role microorganisms play - or have played - in key geological processes. Fundamental work aims to identify the biogeochemical controls on mineral cycles in a range of environments, including the iron and sulphur cycle; as well as those of toxic metals, including arsenic, chromium, technetium and transuranics. Our excellent infrastructure facilitates the study of the biological, mineralogical and geochemical components of such cycles at a molecular scale.