Lithological control on soil chemistry and microbial diversity

The geological diversity of Northern Ireland provides a unique opportunity to investigate the effects of differing lithologies on the geochemistry of overlying soils. This will increase our understanding of how lithology influences the microbial populations within the soil and their role in biochemical cycling. Whilst several factors contribute to the properties of developing soils, source rock is one of the major controls in determining chemistry and formation rate. The array of geological ages and formations within Northern Ireland occurs over a relatively small area. When this is combined with the glacial history of the British-Irish ice sheet during the last glacial maximum, any soils present now will all be of the same age and have undergone the same climatic conditions. The Tellus project, an intense high resolution geochemical mapping study which analysed soil samples across Northern Ireland, has been utilised to select sites of potential interest where specific elements occur in high concentrations and evidence of anthropogenic activity is limited. There are several components to this interdisciplinary study; one of which is the chemical analysis, of inorganic and organic constituents throughout the depth profile. This has been undertaken upon soils from varying lithologies (Paleogene basalts, Devonian sandstones and Carboniferous limestones). The study also includes biological assessment in the form of various DNA profiling techniques and lab based microcosm experiments using soils obtained from the field. This will enable a thorough investigation of the microbial communities present which will identify microbial diversity arising from differences in lithology through the soil profile.