河口潮滩湿地CH4、CO2排放通量对氮硫负荷增强的响应

以闽江河口区高、中潮滩短叶茳芏湿地为研究对象,于2014年6—11月植物生长季进行氮硫负荷增强实验,利用静态箱-气象色谱法测定土壤CH_4、CO_2排放通量,并同步观测相关环境因子.结果表明,氮硫负荷增强对潮滩湿地CH_4、CO_2排放通量的影响不尽一致.与对照相比,NH_4~+-N输入使高、中潮滩CH4排放通量分别提高了(107.53%,7.19%),使高潮滩CO_2排放通量增加了3.39%,中潮滩减少了3.00%;NO_3~--N输入使高潮滩CH4、CO_2排放通量分别增加了(29.99%,16.99%),使中潮滩分别减少了(3.45%,4.77%);SO_4~(2-)-S输入使高、中潮滩CH4排放通量分别减少了(8.99%,7.67%),使高潮滩CO_2排放通量减少了3.87%,中潮滩增加了5.44%;N-S复合输入使高、中潮滩CH4排放通量分别提高了(72.48%,25.66%),CO_2排放通量提高了(13.32%,13.48%).氮硫负荷增强改变了短叶茳芏沼泽生长季CH_4、CO_2排放通量变化规律,但除了NH+4-N处理对高潮滩CH4通量的影响显著外,其他处理影响均未达到显著性水平.相关分析显示,高、中潮滩湿地CH_4、CO_2排放通量与土壤温度,含水率具有显著的正线性相关关系,与土壤电导率相关性不显著.在全球环境问题日益严重背景下,系统研究湿地生态系统温室气体排放的机制与规律,对于准确估算全球温室气体排放量具有重要而直接的意义.

Effects of enrichement of nitrogen and sulfate load on CH4 and CO2 fluxes from different tidal flat wetlands in the Min River estuary

Using enclosed static opaque chamber-GC techniques, the short-term effects of enrichement of nitrogen and sulfate load on the CH₄ and CO₂ fluxes from the high and middle tidal flat Cyperus malaccensis wetlands were measured during the growing season in 2014 in Min River estuary, and the key factors controlling the variation of CH₄ and CO₂ simultaneously were examined. The results show that the influences of nitrogen and sulfate load enrichment on the CH₄ and CO₂ fluxes were different in the high and middle tidal flat wetlands during the experiment. Compared to the control experimient, CH₄ fluxes under the ammonium addition from the high and middle tidal flat wetlands increased by 107.53% and 7.19%, respectively, the CO₂ flux in the high tidal flat increased by 3.39%, reduced by 3.00% in the middle tidal flat; the CH₄ and CO₂ fluxes under the nitrate addition in the high tidal flat increased by 29.99% and 16.99%, reduced by 3.45% and 4.77% in the middle tidal flat, respectively; the CH₄ fluxes under the sulfate addition from the high and middle tidal flat wetlands reduced by 8.99% and 7.67%, respectively, the CO₂ fluxes reduced by 3.87% in the high tidal flat and increased by 5.44% in the middle tidal flat; the CH₄ fluxes under the nitrogen and sulfate compounds input treatment from the high and middle tidal flat wetlands increased by 72.48% and 25.66%, the CO₂ fluxes reduced by 13.32% and 13.48%, respectively. The enrichement of nitrogen and sulfate load changed the variation of CH₄ and CO₂ emissions in growing season from C. malaccensis wetlands. While no significant differences were found at different tidal flat wetlands during the experiment, except the effect of NH₄⁺-N addition treatment on CH₄ flux in the high tidal flat wetlands. We found soil temperature and moisture were the dominant factors that controlled temporal variation of CH₄ and CO₂ emissions in tidal flat wetlands. However, no significant correlation between greenhouse emissions and soil conductivity were found in the two wetlands. In the context of increasingly serious global environmental problems, systematically studied on the mechanisms and rules of the wetland ecosystem greenhouse gas emissions was very important for the accurately estimation of global greenhouse gas emissions.