Abstract
Atmospheric precipitation samples (rainwater and dry deposits) were added to thiosulfate media to measure sulfur-oxidizing activities. The dry deposits collected outdoors showed sulfur-oxidizing activity, while those collected indoors showed little each activity. Although sulfur-oxidizing activity was observed in all atmospheric samples, it was greater in the neutral culture medium (pH 6) inoculated with rainwater than the acidic medium (pH 3.5). In addition, the sulfur-oxidizing activity found in those samples was markedly suppressed by various methods of sterilization. It was suggested that biological oxidation of sulfur occurred in these samples. Therefore, atmospheric biological sulfur oxidation should be considered in the global sulfur cycle.
