TABLE 4.

Video microscopic determination of contact rate, capture rate, and ingestion rate of Ochromonas sp. DS with bacterial strainsa

ParameterValue for exptl condition(s)b
Low abundance of P. pu. MM1 + S. au. WQM4Low abundance of P. pu. MM1 + H. gr. WQT2High abundance of P. pu. MM1 + H. gr. WQT2P. pu. MM1 onlyH. gr. WQT2 only
No. of bacteria (106 ml−1)
    MM11.03 ± 0.040.85 ± 0.0417.48 ± 2.8544.66 ± 3.82
    WQM40.81 ± 0.02
    WQT21.00 ± 0.0621.61 ± 2.5641.38 ± 1.84
No. of flagellates (104 ml−1)4.595.528.978.978.97
Contact rate (no. of bacteria flagellate−1 h−1)
    MM149.9 ± 7.369.6 ± 14.3199.2 ± 98.6408.0 ± 175.9
    WQM450.9 ± 10.4
    WQT257.1 ± 6.9187.2 ± 31.6582.0 ± 47.4
    t testcNSNSNS
Capture rate (no. of bacteria flagellate−1 h−1)
    MM122.1 ± 5.528.3 ± 8.0117.6 ± 64.6236.4 ± 81.5
    WQM414.9 ± 9.5
    WQT224.5 ± 6.275.6 ± 30.2229.2 ± 51.1
    t testcNSNSNS
Ingestion rate (no. of bacteria flagellate−1 h−1)
    MM118.7 ± 5.226.4 ± 8.140.8 ± 20.167.2 ± 23.8
    WQM45.3 ± 2.0
    WQT25.8 ± 3.67.2 ± 6.645.6 ± 23.1
    t testc***
Contact SId0.56 ± 0.07 (NS)0.42 ± 0.06 (*)0.41 ± 0.07 (*)
Capture SId0.37 ± 0.16 (NS)0.51 ± 0.08 (NS)0.40 ± 0.07 (*)
Ingestion SId0.34 ± 0.12 (*)0.19 ± 0.07 (*)0.21 ± 0.09 (*)
Overall SId0.27 ± 0.11 (*)0.17 ± 0.12 (*)0.13 ± 0.13 (*)
  • a The contact rate includes the capture rate and the ingestion rate. The capture rate includes the ingestion rate. Mean lengths of S. aurantia WQM4 and H. gracilis WQT2 were 15.4 and 7.2 μm, with a range from 6.0 to 25.8 μm and 3.0 to 23 μm. P. pu, P. putida; S. au., S. aurantia; H. gr., H. gracilis.

  • b Values are given ± standard deviations.

  • c There was no significant difference between the value for P. putida MM1 only and that for H. gracilis WQT2 only.

  • d SI, selectivity index: Significance is given in parentheses: single asterisk, significant (P < 0.05); NS, not significant.