A Study of Volatile Sulfur Gases Produced from the Decomposition of Cysteine in Paddy Soil

摘要

Volatile sulfur gases emitted from terrestrial ecosystem may play an important role on the global sulfur cycle and have profound influence on climate change. It may produced from the reduction of sulfate and decomposition of sulfur-containing amino acid under the activity of microorganism in soil and other terrestrial ecosystems. In order to investigate the source of sulfur gases production and emission in paddy soil, the sulfur-containing amino acid was added into the incubated Chinese paddy soil, and the emission of sulfur gases was determined. Three sulfur gases were detected from waterlogged soihhydrogen sulfide(H_2S), carbonyl sulfide(COS) and dimethyl sulfide(DMS). When cys-teine was added, detected concentrations of COS and H_2S increased obviously, CS_2 and CH_3SH were also detected, while the concentration of DMS did not change obviously. These results show that the decomposition of cysteine may be the one of sources of emission of COS, H_2S, CS_2 and CH_3SH. Under aerobic condition (ambient atmosphere), the emissions of H_2S, COS, CS_2 and CH_3SH were lower than under anaerobic condition (nitrogen atmosphere), that of DMS higher than under anaerobic condition. It shows that, the production of H_2S, COS, CS_2 and CH_3SH from the decomposition of cysteine in paddy soil need strong reduction situation, the microorganisms that produced these four gases from cysteine need strict anaerobic condition. That produced DMS need higher oxygen content than former four microorganisms. The influences of soil pH, water content and illumination in incubation on the production of sulfur gases from the decomposition of cysteine were investigated.