Drivers of bacterial community structure in a gold bearing sub-Arctic soil ecosystem

Soil microbial communities drive geochemical cycles and recently it has been shown that the transport of even inert metals, such as gold, may be microbially driven. In this study the linkages between soil bacterial community structure and geochemical factors were investigated in a metallogenic sub-Arctic soil. Samples were obtained from gold and rare earth element (REE) enriched soils located in Mäkärä, Lapland, Northern Finland. Soil was sampled from the B horizon of nine sites around a gold-hematite quartz vein and one control site outside the mineralization. In addition, hematite samples were obtained from an excavated research trench. Bacterial community structure in the soil and hematite samples was characterized by 16S rRNA gene amplicon sequencing using Ion Torrent technology. Geochemical parameters of the soil samples were analyzed, and geochemical drivers of the bacterial community structure evaluated by multivariate methods. A particular interest was to identify linkages between gold and soil bacteria in an attempt to identify signature taxa associated with gold anomalies.