Ref ID : 7185
B.S. Griffiths; Enhanced Nitrification in the Presence of Bacteriophagous Protozoa. Soil Biol.Biochem. 21(8):1045-1051, 1989
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Experiments in liquid culture indicated that nitrification was increased in the presence of bacteriophagous protozoa. There were significant accumulations of NO3- and NO2- in media containing (NH4)2SO4 only in the presence of amoebae and ciliates. Increasing the concentration of (NH4+)-N from 1 to 10 µg ml-1 in the absence of protozoa did not increase nitrification, indicating that enhanced nitrification was due to the presence of protozoa rather than the excretion of NH4+ by protozoa. The interaction between protozoa and nitrification was also studied during 4 weeks in an amended clay-loam soil held at 15 degrees C. The addition of the biocides, cycloheximide and Triton X-100 reduced both protozoan populations and nitrification. Nitrification was significantly enhanced when protozoan numbers were increased by the addition of supplementary nutrients or extra bacteria.