Diversity and assembly: 16S rRNA sequences from a year-long incubation of microbial communities manipulated with a dilution gradient and inoculated into Australian pasture and forest soils

In an effort to explore whether the diversity of microbial communities affects the formation of mineral-associated organic matter in soils, we manipulated the diversity of the microbial community present in similar soils on two contrasting land-covers (an adjacent pasture and forest) and observed the transformations of plant detritus and soil organic matter (SOM) using stable isotope (13C) tracing coupled with a novel nuclear magnetic resonance (NMR) experiment. The diversity manipulation was achieved by inoculating (gamma-irradiated) sterile soils with a dilution series (4 one-thousand fold dilutions) of a soil-water mixture. Biomass of the communities was "rebuilt" during a 3-month pre-incubation, after which the year-long experiment began. Microbial communities (and other functional measurements) were assessed at Days 0, 13, 76, 188, and 370. (These days are after the 3-month pre-incubation.) We also assessed fungal communities, which are stored separately.