design: DNA was sequenced using the Illumina NextSeq PE300 platform with modified versions of primers 926f and 1392r (926f-modified: AAACTYAAAKGAATWGRCGG; 1392r-modified: ACGGGCGGTGWGTRC) which target the V6V8 variable region of the 16S rRNA gene from bacteria and archaea, as well as the 18S rRNA gene in eukarya.