Effect of Crude Oil and Petroleum-degrading Micro-organisms on the Growth of Freshwater and Soil Protozoa

SUMMARY: Growth responses of six species of freshwater and soil protozoa were determined for cells grown monoxenically on various petroleum-utilizing microflora. Protozoa were cultured either in the presence or absence of partially degraded crude oil. The regression coefficient characterizing the slope of the growth curve was used as a comparison index throughout. The nature of the prey species determined the magnitude of the protozoan growth response. The presence of crude oil did not consistently raise or lower an individual species' rate of division. Crude oil had no overall influence on protozoan size although there was a slight tendency towards larger cells in the presence of oil.