| 苏北潮滩温室气体排放的时空变化及影响因素 |
| 摘要点击 2133 全文点击 1139 投稿时间：2015-10-29 修订日期：2016-01-11 |
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| 中文关键词 互花米草滩 CO2 CH4 N2O 全球变暖潜能 |
| 英文关键词 Spartina alterniflora flat CO2 CH4 N2O Global warming potential |
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| 中文摘要 |
| 滨海湿地温室气体CO2、CH4和N2O的排放在全球碳氮循环中发挥着重要的作用,进一步影响着全球气候变化.为研究滨海湿地CO2、CH4和N2O排放的时空变化及影响因素,以苏北潮滩为例,采用静态暗箱-气相色谱法,于2013年4月至2014年3月,测定了不同时空尺度下CO2、CH4和N2O通量的变化规律,并分析了影响温室气体通量变化的环境因素.结果表明, CO2、CH4和N2O通量的季节变化的最大值出现在夏季,CO2和N2O通量的最小值出现在冬季,而CH4在春季表现为弱吸收;互花米草滩年均排放CO2量最大,为(766.3±496.9)mg·(m2·h)-1,芦苇滩年均排放CH4和N2O最大,分别是(0.420±0.900)mg·(m2·h)-1和(17.4±5.0) μg·(m2·h)-1.光滩表现为对CH4的吸收,为(-0.004±0.032)mg·(m2·h)-1,对CO2和N2O的排放,且排放通量最小,分别是(57.1±16.2)mg·(m2·h)-1和(6.1±2.1) μg·(m2·h)-1.全球变暖潜能的最大值出现在互花米草滩,为68841.280 kg·(hm2·a)-1,分别是芦苇滩和碱蓬滩的1.41倍和3.02倍,光滩的GWP最小,为5002.100 kg·(hm2·a)-1.通过Pearson相关分析发现,除光滩外,CO2通量与气温、土温呈显著的相关性(P<0.05),而CH4和N2O通量与温度则不存在显著的相关性.尽管如此,CO2、CH4和N2O通量的时间变化更多地是受温度以及植被生长状况的影响,而空间变化则主要由植被的状况所决定;外来种互花米草主要是通过增加CO2排放来影响滨海湿地的全球变暖潜能. |
| 英文摘要 |
| Although coastal wetlands play an important role in governing the atmospheric concentrations of CO2, CH4, and N2O, thus control the global warming, research of the greenhouse gas emissions conducted in the coastal wetlands were not well-documented because of the difficulty in fieldwork in these harsh environments, and the complicated controlling factors affecting the greenhouse gas emissions. The temporal and spatial variations of CO2, CH4, and N2O were investigated simultaneously in the coastal saline wetland in North Jiangsu during the period from April, 2014 to March, 2014, using the closed static dark chamber method. And the results showed that seasonal variations of CO2, CH4, and N2O were higher in summer, and lower CO2 and N2O fluxes were observed in winter, while for CH4 in spring, it presented the sink in the coastal wetland. The annual average CO2 emission derived from the Spartina alterniflora flat (SAF) was the highest, with the value of (766.3±496.9) mg·(m2·h)-1, and for CH4 and N2O, the highest values were found in Phragmites australis flat (PAF), with the values of (0.420±0.900) mg·(m2·h)-1 and (17.4±5.0) μg·(m2·h)-1, respectively. The bare mud flat (BF) presented the sink of CH4, and the source of CO2 and N2O, with the lowest emission rates across all the tidal flats. The global warming potential (GWP) from the coastal wetlands in north Jiangsu was observed higher in SAF[68841.280 kg·(hm2·a)-1], which was 1.41 and 3.02 times higher compared with those of PAF and SGF, the GWP of BF was the lowest, with the value of 5002.100 kg·(hm2·a)-1. Furthermore, significant correlations were found between CO2 fluxes and temperature, including air temperature (AT), soil temperature (ST), and temperature inside the chamber (CT), however, for CH4 and N2O, the correlations were not so obvious. Above all, the temporal variations of CO2, CH4, and N2O were mainly controlled by the temperature and characteristics of vegetation, the spatial variations of CO2, CH4, and N2O were determined by the characteristics of vegetation. Furthermore, we may safely draw the conclusion that the invasive S. alterniflora increased the global warming potential dominantly through increasing the CO2 emission rates, compared with the native plant. |
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