黄河三角洲滨海盐沼CO_2,CH_4通量特征及其影响因素

Fluxes Characteristics of CO_2,CH_4 and Their Correlating Factors in Coastal Salt Marsh of the Yellow River Delta

采用静态暗箱/气相色谱（GC）法,考察了2012年4月至12月黄河三角洲不同植被类型盐沼CO2和CH4通量的季节和日变化及其与主要环境因子的关系.研究发现：时间变化上,CO2通量范围为2.287~331.371mg·m-2·h-1,均值为77.107mg·m-2·h-1,该研究区域四季均表现为CO2排放源,CH4通量范围为-0.004~0.015mg·m-2·h-1,均值为0.003mg·m-2·h-1,黄河三角洲滨海盐碱地春夏季表现为CH4吸收汇,秋冬季表现为CH4弱排放源;空间变化上,不同类型盐沼CO2通量整体由小到大依次表现为,裸地,碱蓬（Suaeda glauca）,芦苇（Phragmites australis）,柽柳（Tamarix chinensis）,除裸地外,柽柳、碱蓬和芦苇群落均表现为CH4汇.影响因素的分析结果表明：温度和植被是影响CO2和CH4通量的重要因子.因此,在估算滨海盐沼温室气体排放清单时,应特别注重温度和植被的影响.

The characteristics of methane （EH4） and carbon dioxide （CO2） fluxes and the environmental factors from the coastal salt marsh of the Yellow RiveI Delta across 4 vegetation types （bare flat, Suaeda glauca, Phrag- mites australis and Tamarix chinensis） were observed in situ with static-chamber and gas chromatography（GC） meth- ods from April to December in 2012, and the seasonal variation and the key factors affecting CH4 and CO2 fluxes were discussed. The results were as follows. The CO2 emissions varied from 2. 287 to 331. 371 mg· m 2 . h-1 , and the CO2flux mean was 77. 107 mg ·m-2 · h-1 , indicating that the coastal salt marsh was the source of CO2all the years round. The order of CO2 fluxes of the vegetation types was bare flatUS, glauca〈P, australis〈T, chinensis The CH4 annual emissions varied from --0. 004~0. 015 mg- m-2 · h 1, and the mean was 0.003 rag. m 2 . h-2. The coastal salt marsh were the sink of CH4 in spring and summer, while the source in autumn and winter. Except the bare flat, the other vegetation types were all acted as the sink of CH4. Results also showed that temperature and veg- etation were the key factors that affected the CO2 and CH4 emissions. So the temperature and vegetation of salt marsh should be paid more attentions when the GHGS inventory of the salt marsh were estimated.