Water column microbiome of two Canadian boreal shield lakes

Bacterial 16S ribosomal RNA gene sequencing was performed on genomic DNA from two boreal shield lakes (Lakes 227 and 442) in the International Institute for Sustainable Development Experimental Lakes Area (IISD-ELA; near Kenora, Ontario, Canada). Water samples were collected for genomic DNA extraction from across the stratified water column of both lakes over multiple years. Both lakes had an anoxic zone during sample collection. The goal of this study was to probe the seasonal anoxic zones of both lakes for potential iron-cycling bacteria, to explore how iron biogeochemical cycles could affect modern lake ecosystems. It was also of interest to explore how iron cycling in boreal shield lakes could be extrapolated to early Earth ocean environments, which are thought to have had similar anoxic, ferruginous conditions.