Table 3 Summary of the 16S rRNA gene sequencing data and α-diversity values (Shannon index and Faith’s phylogenetic diversity)
|  | Read counts | Observed OTUs | Shannon index | Faith’s phylogenetic diversity |
|---|---|---|---|---|
BES-cathode | 201,720 | 55 | 2.67 | 5.0 |
BES-anode | 191,150 | 56 | 2.73 | 5.2 |
(BES→) FFR | 198,254 | 170 | 4.31 | 11.3 |
(BES→) FFR-C | 158,351 | 232 | 5.27 | 13.4 |
NBES-left | 171,495 | 52 | 2.94 | 5.0 |
NBES-right | 202,435 | 52 | 2.87 | 4.4 |
(NBES→) FFR | 189,784 | 117 | 2.14 | 10.1 |
(NBES→) FFR-C | 258,361 | 133 | 2.09 | 11.8 |