16S rRNA Gene Sequencing Data for Cement and Mineral Creeks, Silverton, Colorado

Streams impacted by historic mining activity are characterized by acidic pH, unique microbial communities, and abundant metal-oxide precipitation, all of which can influence groundwater-surface water exchange. This study investigated how metal-oxide precipitates and hyporheic mixing mediate the structure and composition of microbial communities in two streams receiving acid-rock and mine drainage within the Bonita Peak Mining District near Silverton, Colorado, USA. In one stream (Mineral Creek), a large, neutral pH hyporheic zone facilitated the precipitation of metal particles or colloids in hyporheic porewaters. In the second stream (Cement Creek), a small, acidic pH hyporheic zone, limited by the presence of a low-permeability, iron-oxyhydroxide layer known as ferricrete, led to the formation of steep geochemical gradients and high dissolved-metal concentrations. To determine how these two different hyporheic systems influence microbiome structure and composition, we installed well clusters in each stream at three depths to sample porewaters and sediments for 16S rRNA gene sequencing.