The numbers and distribution of ammonia-oxidizing bacteria in some Northern Territory and South Australian soils

Abstract

Ammonia-oxidizing bacteria were detected in 75 soil samples from the Northern Territory and South Australia. Silica gel plates gave soil counts comparable with those obtained in liquid media. The counts varied from 20 to 8000 cells per gram of soil. Nitrosogloea merismoides was detected in 53 of the soils, Nitrosornonas europaea in 39 soils, and Nitrosococcus nitrosus in 14 soils. There was little difference between the numbers and types of nitrifying bacteria present in the desert soils compared with those from the more temperate areas, nor did the average annual rainfall have any appreciable effect.