Aquifers are important freshwater reservoirs and thus drinking water source, yet only a little is known about the function and natural character of groundwater ecosystems. This project aims to improve our understanding of how groundwater microbial communities respond to and mitigate problematic anthropogenic pollutants, such as nitrate. A further important goal is to better understand the natural character of groundwater communities. To achieve these aims we are determining the genomic and metabolic capacity of a model alluvial groundwater system that transverses a nutrient contaminant gradient in Canterbury, NZ. Alongside this, we are also analyzing microbial community attributes in a larger selection of national aquifers.