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/2016/06/06/057117.abstract
AB Microbial activity in lake sediments is responsible for the cycling of organic matter that continuously sinks from the water column. Accumulation and burial of carbon therefore depends on the indigenous sediment organism. This interaction of burial processes and microbial activity in the sediment, that should lead to a vertical succession of organism is largely unexplored in aquatic sediments. Our aim was to provide a basic model for the vertical community structure in sediments. We performed a full biogeochemical and microbial community analysis of 4 replicate sediment cores in a deep, clear lake. Each core was 30 cm, spanning ca. 170 yr of accumulation according to 137Cs dating, and sectioned into layers 1-4 cm thick. DNA-metabarcoding of archaea, bacteria, and eukaryotes delineated three clusters corresponding to distinct communities at <5 cm, 5-14 cm, and 14-30 cm. The two upper clusters (covering ca. 70 years) were dominated by taxonomic replacement, and the replacement component was correlated with parameters indicative of microbial activity (e.g., CO2, CH4, protein production). We term these two clusters the ‘’replacement horizon”. The lower cluster was characterized by the richness component that was correlated with conservative, often historical parameters (e.g., elemental C, N, P). We term the lower horizon the “depauperate horizon”, characterized by taxonomic impoverishment and a dominance of archaea. Our study uncovered a highly structured microbial community in these unexplored freshwater sediments. Based on biogeochemical and microbial characteristics, we here propose a general model of freshwater sediment structure and function.