Period 2 DNA (Archaea)
Amplicon pyrosequencing of DNA biofilm extract was done using 454 GS-FLX Plus system by an external company (Macrogen Inc., Seoul, South Korea). Gene fragments of archaeal 16S rRNA were amplified using universal archaeal primers (340F-CCCTAYGGGGYGCASCAG and 958R-YCCGGCGTTGAMTCCAATT). Different barcodes were used to allow demultiplexing of sequences on a per sample basis.