Depth-discrete profiles of bacterial communities reveal pronounced spatio-temporal dynamics related to lake stratification.

With this work we intend to stress the importance of considering discrete depth sampling for bacterial community analysis of stratified aquatic systems. Depth is a very important parameter to consider when sampling bacterial communities, as their abundance and composition can change within the distinct water layers. Stratified lakes are good model systems to study these connections since changes in environmental parameters can occur on a cm-scale at the thermo- and/or chemocline. Lake Grosse Fuchskuhle was sampled at discrete fine-scale depths at three time points covering a stage in which the lake was stratified and the beginning of winter mixing. In this paper we present the most abundant bacterial groups at the different depths sampled and also the most abundant operational taxonomic units (OTUs). Overall, oxygen was found to be an important factor shaping the microbial community composition.