Abstract
Interest in the atmospheric sulfur (S) budget has developed rapidly because anthropogenic activities are increasing the rates of emission of S gases into the atmosphere. These increase are important because S gases are oxidized in the atmosphere with formation of sulfate, the resulting contributes to environment problems associated with acid rain. There also is evidence that S gases may alter the optical properties of clouds and which could affect global climate. Large uncertainties remain concerning the chemical speciation and the magnitude of natural emission of S gases to the atmosphere. It has been well documented that dimethylsulfide (DMS) is most important in ocean, which have been estimated to contribute 40 Tg or 15 TgS to the atmosphere as S gases each year. The annual amounts of S evolved from soil have been estimated to be 7 to 77 TgS. Very little is known concerning emissions from paddy field, which are abundant in many parts of the world. The purpose of this report is to summarize the results of recent measurements of emissions of biogenic S gases from rice paddies in Japan. Emissions were measured in laboratory studies to learn more about the kinds and sources of S gases produced. Emissions were measured in paddy lysimeters and in paddy fields to gain better information about the amounts of DMS, carbonyl sulfide (COS), and carbon disulfide (CS2) emitted, the seasonal and diurnal patterns of emission, and the factors affecting emissions of these gases under field conditions.
