盐度对长江河口芦苇湿地甲烷排放的影响

盐度对河口湿地甲烷气体的产生与排放影响重大。为揭示海水入侵对河口湿地CH₄排放的影响，利用静态密闭箱—气相色谱法在2016年4～10月期间对崇明东滩芦苇群落CH₄气体的排放通量进行测定。结果表明:CH₄排放总体表现出春夏季较高，秋冬季较低的季节变化规律；排放通量在0.19～7.68 mg/（m2·h）间波动，4～10月这半年内平均排放通量为3.41 mg/（m2·h）。在一定范围内，较高的盐度抑制CH₄的产生与排放，较低的盐度不足以对CH₄产生抑制作用，甚至会促进CH₄的产生；在高盐环境下，CH₄排放通量与盐度呈现出显著的对数负相关关系。在芦苇群落生长旺盛的初期（4～6月），CH₄排放通量与温度、光照呈现正相关关系；而在芦苇生长后期（7～10月）则呈现负相关关系。

Effects of salinity on methane emission at Yangtze Estuary Phragmites australis wetland

Salinity has a profound influence on methane(CH₄) production and emission in estuarine wetlands.In order to reveal the effects of seawater intrusion on CH₄ emission from estuarine wetlands, static closed chamber combined with a gas chromatograph technique was used to investigate the flux of CH₄ at a Phragmites australis wetland in Chongming Dongtan from april to october in 2016.The results showed that the flux of CH₄ was higher in spring and summer than in autumn and winter.The flux ranged from 0.19 to 7.68 mg/(m2·h) and the average flux was 3.41 mg/(m2·h) from april to october.High salinity level inhibits the production and emission of CH₄, while low salinity promotes CH₄ production within certain range.In high-salinity conditions, CH₄ emission flux has a significant logarithmic negative correlation with salinity.In the early stage of growth of Phragmites australis, the flux of CH₄ is positively correlated with temperature and light; however, in the later stage of growth, it is negatively correlated with temperature and light.