New insights into the biogeochemistry of extremely acidic environments revealed by a combined cultivation-based and culture-independent study of two stratified pit lakes.

摘要: The indigenous microbial communities of two extremely acidic, metal-rich stratified pit lakes, located in the Iberian Pyrite Belt (Spain), were identified, and their roles mediating transformations carbon, iron, sulfur confirmed. A combined cultivation-based culture-independent approach was used to elucidate at different depths examine physiologies isolates, which included representatives least one novel genus several species acidophilic Bacteria. Phosphate availability correlated with redox this (rather than solar radiation) dictated where primary production concentrated. Carbon fixed released as organic compounds by phototrophs acted electron donors for heterotrophic prokaryotes, many catalyzed dissimilatory reduction ferric iron; ferrous iron generated re-oxidized chemolithotrophic acidophiles. Bacteria that catalyze also although these appeared be less abundant oxidizers/reducers. Primary numbers greatest, biogeochemical transformation sulfur, most intense, within a zone c. 8-10 m depth, close chemocline, both lakes. Archaea detected sediments Thaumarchaeota clones, indicating members recently described phylum can inhabit acidic environments.