RT Journal Article
SR Electronic
T1 Vertical organization of freshwater sediment microbial communities: implications for microbial activities and burial processes
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 057117
DO 10.1101/057117
A1 Christian Wurzbacher
A1 Andrea Fuchs
A1 Katrin Attermeyer
A1 Katharina Frindte
A1 Hans-Peter Grossart
A1 Michael Hupfer
A1 Peter Casper
A1 Michael T. Monaghan
YR 2016
UL http://biorxiv.org/content/early/2016/06/04/057117.abstract
AB 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 137Cs 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 parameters indicative of ongoing biological processes (e.g., protein production). In contrast, the lower cluster was dominated by the richness component correlated with conservative, often historical parameters (e.g., metals). The upper two clusters form an upper horizon termed the “replacement zone” and includes a redox-stratified as well as a transition zone. The lower CO2 and CH4 rich horizon, termed the “depauperate zone”, was characterized by taxa impoverishment and a dominance of archaea, frequently found in marine systems. Our study uncovered a highly structured microbial community in yet unexplored freshwater sediments. Based on biogeochemical and microbial characteristics, we here propose a general model of freshwater sediment structure and function.