Sulfidic mine waste microorganisms in an ecological context

Sammanfattning: The focus of this thesis are the microorganisms found in sulfidic minewaste and their ecology. The microorganisms are investigated from the point of view of being an important, if not the most important, factor in the production of acid rock drainage (ARD). The thesis is a summary of several studies. One study was trying to find a good way of separating the organisms from its abiotic counterpart by different means of sterilization. The effectiveness of the methods as well as their effect on the minerals was investigated.The carbon metabolism in a soil covered impoundment was investigated with the aim of unraveling the composition of the microbial ecosystem. The results agreed with the two case studies, from soil and water covered impoundments that indicate a very uneven distribution of the bacteria. The presence of microbial hotspots where autotrophic bacteria acts as primary producers and creates conditions for a wide range of bacteria and a relatively high activity seems a reasonable conclusion from these studies.In yet another study the effect of low temperatures was investigated.The conclusion from this study was that there was considerable activity even at temperatures 4°C or perhaps even lower.In summary the picture of a highly active and dynamic ecosystem is emerging. An ecosystem with a very uneven distribution of organisms, which in part could explain difficulties in transferring laboratory results to the field situation.