Table 5.

Quantification of nitrifying bacteria by FISH

SampleNo. (± SD) of cells (107· mm−3) detected by probe
NSO1225NSV443NSR826/NSR1156NSR447
A1
 Shella 5.55 ± 2.754.30 ± 0.7062.1 ± 17.91.71 ± 0.90
 Centerb 1.80 ± 0.621.35 ± 0.1312.3 ± 11.60.06 ± 0.02
A2
 Shell4.39 ± 2.224.80 ± 2.5678.5 ± 25.41.75 ± 0.90
 Center1.92 ± 0.591.87 ± 0.5431.3 ± 19.00.07 ± 0.02
A3
 Shell2.74 ± 0.382.24 ± 1.1793.4 ± 55.03.9 ± 0.71
 Center0.97 ± 0.571.14 ± 0.2142.1 ± 27.30.14 ± 0.12
  • a Number of cells within the active, nitrifying shell of the aggregates.

  • b Number of cells within the inactive central part of the aggregates.