The goal of this research is to investigate the interplay between microorganisms and silicate minerals in subsurface aqueous environments. Microorganisms interact with minerals and dissolved species in solution, perturbing the geochemical environment. Though groundwater chemistry changes and minerals are dissolved and other phases precipitated, there are many unanswered questions about the role microorganisms play in these processes. Since this is a linked system the problem must be approached from several angles, involving microorganisms, minerals and aqueous solutions. Our research attempts to look at different aspects of this interaction to better understand the entire process. One aspect of the research investigates mineral weathering, comparing biotic and abiotic weathering kinetics. Another focuses on microbial nutrition as a mechanism controlling microbial colonization and consequently mineral weathering. The role metabolic byproducts and microbial chelating agents in silicate weathering and iron chemistry are also being investigated.