Microbial communities in UK aquifers: current understanding and future research needs

The presence and activity of microorganisms in aquifers can affect, amongst other things, nutrient cycling, contaminant degradation and water flow. The introduction of a pollutant or other changes in water chemistry can alter the microbial community composition and affect aquifer functioning. To understand the microbial response to anthropogenically induced changes, a better knowledge of baseline microbial communities in uncontaminated aquifers is needed. Here, we review the information on microorganisms in UK aquifers together with examples of research from other countries on this topic, and discuss how these communities might respond to disturbance. Research into microbial communities in UK aquifers has mostly been limited to bacteria and often reveals a community dominated by Proteobacteria. The community composition is influenced by factors such as mineralogy and water chemistry, and the natural baseline community may be altered by aquifer contamination. A UK-wide survey of aquifer microbes, similar to one recently carried out in New Zealand, would provide valuable information about the current state of UK aquifer microbiology. This would lead to a greatly improved understanding of the ecosystem services provided by the microbial communities present in aquifers, allow future monitoring and assessment of the effects of pollution, and assist in groundwater resource management.