16S of wetland sediment sample
In the lab, subsections of each sediment core were taken from the surface and the subsurface horizons using sterile utensils. DNA was extracted from each subsection using a Qiagen DNeasy PowerSoil Kit (Qiagen, Germantown, MD) following the standard protocol with the addition of a 10-minute, 70C heating step prior to bead beating. PCR amplification of the V4 region of the 16S rRNA gene used the primers (515F/806R) and procedures recommended by the Earth Microbiome Project (Gilbert et al., 2014, https://earthmicrobiome.org/protocols-and-standards/16s/). Amplicons were cleaned using a Wizard SV Gel and PCR cleanup kit (Promega, Madison, WI) and quantified and qualified with NanoDrop. The amplicon library was normalized and prepared for sequencing following the protocol in Caporaso et al. (2011). Sequencing was performed on the Illumina MiSeq platform using a 300-cycle V2 Reagent Kit.