Shotgun ceccum
Genomic DNA was quantified using the Invitrogen qubit and sheared using the Covaris Sonicator to the desired size range. Metagenomic shotgun libraries were then generated using Takaras Apollo324 automated library system and Illumina compatible PrepX DNA library kits (Takara) following the manufacturers instructions. Shotgun libraries were then sequenced on a 2x151bp lane of the Illumina HiSeq2500. A part from the LCM extraction controls, an empty blank was employed during each extraction to account for the possible contamination present in the extraction kits and downstream processing.