Prokaryotic communities in the historic silver mine Reiche Zeche

The research and education mine Reiche Zeche in Freiberg (Saxony, Germany) represents one of the most famous mining facilities reminiscent to the century-long history of silver production in the Ore Mountains. The mine was set up at the end of the fourteenth century and became part of the Bergakademie Freiberg in 1919. Galena, pyrite, sphalerite, arsenopyrite, and chalcopyrite are the most common minerals found in the mine. As acid mine drainage is generated from the dissolution of sulfidic ores, the microbial habitats within the adits and galleries are characterized by low pH and high concentrations of metal(loid)s. The community composition was investigated at locations characterized by biofilm formation and iron-rich bottom pools. Amplicon libraries were sequenced on a MiSeq instrument. The taxonomic survey yielded an unexpected diversity of 25 bacterial phyla including ten genera of iron-oxidizing taxa. The community composition in the snottites and biofilms only slightly differed from the communities found in acidic bottom pools regarding the diversity of iron oxidizers, the key players in most investigated habitats. Sequences of the Candidate Phyla Radiation as, e.g., Dojkabacteria and Eremiobacterota were found in almost all samples. Archaea of the classes Thermoplasmata and Nitrososphaeria were detected in some biofilm communities.

Automated summary

The Reiche Zeche mine in Freiberg, Germany is known for its rich history of silver production and is now a famous research and education facility. The mine, established in the late 14th century, became part of the Bergakademie Freiberg in 1919. The mine contains various minerals such as galena, pyrite, sphalerite, arsenopyrite, and chalcopyrite. The acidic mine drainage in the mine has led to the development of microbial communities with low pH and high metal concentrations. The study investigated the community composition of these microbial habitats and found a diverse range of bacterial phyla, including iron-oxidizing bacteria. Overall, the presence of iron-oxidizing bacteria plays a crucial role in the investigated habitats.