模拟潮汐和植被对湿地温室气体通量的影响研究

以福建省九龙江入海口的滩涂潮间带作为研究对象，通过原位采样和室内人工微宇宙实验，利用静态箱-气相色谱法，研究了潮汐植被对湿地CH₄、CO₂和N₂O 3种重要温室气体通量的影响.结果表明，3种温室气体通量在模拟潮汐和植被作用下表现出明显的差异.模拟潮汐对CH₄和N₂O通量的影响没有明显的规律，总量上都表现为排放；对CO₂通量具有显著影响，退潮时抑制，表现为吸收，涨潮时促进，表现为排放.植被促进CH₄的排放，对CO₂通量影响无明显规律，对N₂O通量表现为抑制作用.植被除了自身对温室气体直接作用外，还通过改变沉积物的理化性质影响微生物活动，进而影响温室气体通量.综合分析，植被对温室气体通量的影响要比模拟潮汐作用明显.

Impact of simulated tide and vegetation on the wetland greenhouse gases fluxes

To evaluate the effects of environmental factors on the greenhouse gases (GHGs) fluxes, sediment samples from the Mangrove Nature Reserve of Jiulong River estuary were collected and homogenized evenly before microcosm experiments. Tide and vegetation types were simulated in the microcosm. A static chamber technique was used to measure the fluxes of three important greenhouse gases, i.e. CH₄, CO₂ and N₂O. Three vegetation types were simulated in the microcosm according to the plant coverage patterns in the estuary, i.e. unvegetated, Spartina alterniflora and native mangrove plant Kandelia obovata, while tide was simulated by using peristaltic pump controlled by a timing device. Results showed that the fluxes of three GHGs responded differently to simulated tide and vegetation. The simulated tide seemed to have no impact on the emission of CH₄ and N₂O, and all the treatments showed positive values in total fluxes, indicating general possibility of release. CO₂ flux was inhibited during the falling tide and promoted during the rising tide, resulting in the negative and positive value during the falling and rising tide, respectively. Vegetation showed positive effect and negative effect on CH₄ and N₂O emission, respectively, and no significant difference was observed on CO₂ flux between different vegetation types. Except for the direct effect on gas flux, plants also influenced the sediment microorganisms by altering the sediment physicochemical properties. Through comprehensive analysis, the impact of vegetation was more significant compared with the simulated tide.