Vertical organization of freshwater sediment microbial communities: implications for microbial activities and burial processes

Microbial activity in lake sediments is essential for cycling of organic matter that continuously sinks from the water column. Its ongoing accumulation and subsequent burial at the sediment surface has unknown implications for the structure and function of microbial communities. We performed a full biogeochemical and microbial community analysis of 4 replicate sediment cores in a clear lake. The 30 cm cores spanned ca. 170 years of accumulation according to Cs dating. Simultaneous DNA-metabarcoding of archaea, bacteria, and eukaryotes delineated three clusters corresponding to three discrete depths (0-5 cm, 5-14 cm, 14-30 cm). Taxa community structure was partitioned into replacement and richness components, and a fuzzy set analysis was used to determine correlates of each component. The two clusters of the upper sediment (covering the last 70 years) were determined by taxonomic replacement and microbial activity, and the replacement component was correlated with Preprint submitted to http://biorxiv.org/ June 4, 2016 . CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/057117 doi: bioRxiv preprint first posted online Jun. 4, 2016;