TABLE 2.

Two-way ANOVA used to test for differences in BCC between the dam, middle, and river incubations throughout all experimental variants and different time intervalsa

ProbeBottom-up manipulationb (F value)Top-down manipulationc (F value)
24 h48 h72 h96 h24 h48 h72 h96 h
BET42a3.160.351.490.180.220.720.651.13
R-BT06515.3**80.5***6.12*0.4829.4***583***18.8**6.24*
GAM42a0.270.361.793.866.15*11.3*2.322.12
CF319a0.6627.1**8.45*0.963.070.090.020.01
HGC69a1.092.940.612.2810.5*43.3***6.4*6.2*
  • a We tested the differences in the relative contributions (as a percentage of total DAPI-stained bacteria) of five different phylogenetic groups of bacteria targeted by the probes BET42a, R-BT065, GAM42a, CF319a, and HGC69a induced by transplanting the samples from the dam area upstream to the middle and river areas and by manipulating top-down control via size fractionation of water samples. The significant differences are in boldface type. *, P < 0.05; **, P < 0.01; ***, P < 0.001.

  • b Dam samples transplanted to the middle and river parts.

  • c Effects of distinct grazing pressures when bacterivore-free treatments are compared to bacterivore-enhanced treatments.