中国科学院海岸带环境过程与生态修复重点实验室知识库

中国科学院东北地理与农业生态研究所湿地生态与环境重点实验室;中国科学院研究生院;福建师范大学地理科学学院亚热带湿地研究中心;中国科学院烟台海岸带研究所海岸带环境过程重点实验室;

利用静态箱-气相色谱法;研究了氮输入对闽江河口短叶茳芏湿地CH4和N2O排放通量的短期影响.结果表明;高氮输入在不同采样时间均促进了湿地CH4排放;低氮输入在不同时间则具有不同的变化特征.与对照处理相比;低氮和高氮2种处理分别使湿地CH4排放通量增加了-44.35%～1 057.35%和7.15%～667.37%.外源氮输入在24 h内对湿地N2O排放通量具有明显的正激发效应;最高可增加171.60倍和177.79倍;但在8 d后;氮输入对湿地N2O排放的激发效应减弱甚至消失.氮输入在短时间内对湿地土壤Ec、pH和Eh均未产生显著影响.湿地CH4排放通量在对照处理下仅与5 cm Eh存在显著负相关;在低氮处理下仅与10 cm地温呈显著负相关;在高氮处理下则与5 cm Ec、0、5 cm pH以及0、5、10 cm土壤Eh均呈显著相关性;而N2O排放通量在不同处理下与湿地气温、地温、盐度、pH和Eh等环境因子均不存在显著相关性.研究表明;探讨氮输入对湿地温室气体排放的影响应考虑其时间变异性.

Using static chamber-GC techniques, the shorHerm effects of nitrogen input on the emission fluxes of CH4and N20 from a Cyperus malaccensis wetland were determined. The results showed that the emission of CH4 was increased by high nitrogen input at all sampling times, whereas the low nitrogen input exhibited different variation characteristics at different time points. Compared to the control treatment, the CH4emission flux in the two nitrogen input treatments （N1, N2） was increased by -44. 35%- 1 057.35% and 7. 15%-667.37% , respectively. The input of exogenous nitrogen had positive priming effect on N20 emission flux within 24 hours, increased by up to 171.60 folds and 177.79 folds, respectively. After 8 days, the priming effect by the nitrogen input weakened or disappeared. There was no significant effect of nitrogen input on the Ec, pH and Eh of soil at different depths in the salt marsh during the experiment. In the control treatment, the CH4 emission flux was negatively correlated solely with Eh of soil at 5 cm depth, whereas in the N1 treatment, it was negatively correlated solely with soil temperature at 10 cm depth. In the N2 treatment, there was negative correlation between the CH4emission flux and Ec of soil at 5cm depth, pH of soil at 0, 5 cm depths, and Eh of soil at 0, 5, 10 cm depths. However, no significant correlation between the N20 emission flux and the environmental variables in the wetland was found. This study indicated that the temporal variability should be taken into consideration when examining the effects of nitrogen input on the emission of greenhouse gases in the wetlands.