摘要
贵阳近郊水稻田释放甲烷显示出一个三阶段的日变化过程：早晨至正午前后，稻田甲烷的释放处于一个相对低落阶段；下午至晚上，释放过程逐渐加强，并可能出现一至两个释放高峰；此后甲烷的释放又进入逐渐减弱阶段。贵州水稻田甲烷的δ^（１３）Ｃ值在－６４．５‰──５４．１‰范围内变动，平均δ^（１３）Ｃ值为－６０．７‰，与美国和肯尼亚所报道的稻田甲烷的碳同位素组成相近似。
The systematic measurements of emission flux of methane from paddy fields in Guizhou were carried out by means of static chamber technique in 1991. Methane emission rates show that the highest diurnal variation is at midnight or before dawn and the lowest one at midday. During the whole rice cultivation period, methane emission flux ranges from 3.0mg . m￣(-2) · h￣(-1) to 34.4mg ·m￣(-2)· h￣(-1) with an average of 15.6mg . m￣(-2)· h￣(-1)· Three maxima of methane emission flux were observed, i.e.,the first maximum in late June, the second in mid July, and the third in late August. The total amount of methane released from paddy fields is estimated to be 0.33 × 10￣(12)g per year based on our results. Six δ￣(13)C values in trace methane released from paddy fields are initially determined in China by converting methane into CO_2 in self-made vacuum line. Methane from paddy fields has a mean δ￣(13)C value of -60.7‰±3.6‰, ranging from -64.5o‰ to -54.l‰, and can be considered as a light-carbon isotopic source for the atmospheric methane.
出处
《地球化学》
CAS
CSCD
北大核心
1995年第C00期98-104,共7页
Geochimica
关键词
贵州
水稻田
甲烷释放通量
碳同位素
日变化过程
methane
paddy field
emission flux
carbon isotope
trace gas
global changes
Guizhou Province
