seasonal stratification means that the deepest three-quarters of this
lake is anoxic, supporting fewer predators that can complicate
microbial distribution patterns and that the deeper parts of the
lake are relatively isolated from external inputs.
To characterize microbial diversity, we conducted ampliconbased
bacterial surveys (16S rRNA gene library from DNA
samples) along a vertical transect in the lake, collecting samples at
approximately each metre of depth. We grouped 16S rRNA gene
sequences into operational taxonomic units (OTUs) using the ecologically
informed distribution-based clustering algorithm, which
merges sequences from related organisms that have similar spatial