Hidden heterogeneity and co-occurrence networks of soil prokaryotic communities revealed at the scale of individual soil aggregates - experiment 1

Metagenomic DNA was extracted from samples decreasing in size from 250 mg to 1 mg taken from the same soil and subjected to Illumina MiSeq paired-end amplicon sequencing targeting the 16S rRNA gene. The soil was a loam topsoil from a Haplic Chernozem (FAO classification) from the Bad Lauchstädt experimental research station of the Helmholtz Centre for Environmental Research in Germany (51°24'N 11°53'E). It was collected in December 2017 from a plot under long term sugar beet – potato – winter wheat – barley rotation that had not received fertilization. Control samples were included that did not contain soil only the reagents used in the DNA extraction and PCR to test for the presence of contamination.