Bacteria plays a critical role in the geochemical cycling of manganese in aquatic environments. They are readily able to transform manganese through oxidative and reductive processes. In natural environments, it is well known that some bacteria are able to oxidise Mn(II) to Mn(IV) under aerobic conditions, while others reduce Mn(IV) to Mn(II) under anaerobic conditions. In the current project, manganese transforming bacteria were investigated on both a physiological and molecular basis to further understand bacterial transformation. Paralana hot springs (PHS), an aqueous environment rich in heavy metals, was used as a model environment in the study. The diversity of microorganisms in PHS was initially investigated using both culture dependent and independent techniques. Metagenomic 16S rRNA screening revealed bacteria belonging to 24 different phyla, 11 of which have been previously determined to contain manganese oxidisers. Mesophilic and thermophilic bacteria were detected and isolated, with many able to oxidise and/or reduce manganese as well as other metals (including iron, arsenic, cobalt, manganese, molybdenum, selenium, uranium and vanadium). Subsequent 16S rRNA analysis of obtained isolates revealed a number of novel bacteria, including the manganese transforming bacteria; Bacillus sp. DLH-1207, Bacillus sp. PMO and Paenibacillus sp. AEM-1106.