凤眼莲入侵对洪湖湿地CO_(2)、CH_(4)、N_(2)O通量的影响初探

A preliminary study on the effects of the invasion of Eichhornia crassipes on the fluxes of CO_(2),CH_(4)and N_(2)O in Honghu wetland

为揭示外来植物入侵对湖泊湿地温室气体排放的影响机制,选择入侵植物样地和本土植物样地,通过漂浮箱-气相色谱法原位研究了洪湖湿地温室气体排放规律及其控制因子,探讨了外来入侵植物对洪湖湿地温室气体排放的影响。结果表明,外来植物凤眼莲(Eichhornia crassipes)入侵洪湖湿地后,CO_(2)通量高于开阔水域,但低于挺水植物区莲+菰群落和浮水植物区欧菱群落;入侵植物区凤眼莲群落监测点CH_(4)通量高于浮水植物区欧菱群落监测点,但低于开阔水域和莲+菰群落监测点;凤眼莲群落监测点N_(2)O通量均低于莲+菰群落、欧菱群落和开阔水域监测点。相关分析表明,莲+菰群落和凤眼莲群落监测点CO_(2)通量与温度显著正相关,莲+菰群落监测点N_(2)O通量与温度显著正相关,而4个监测点CH_(4)通量与环境因子无显著相关性。洪湖湿地CH_(4)排放通量(1.11~534.40 mg·m^(-2)·h^(-1))比通常观测到的数值高1~2个数量级,可能是由于该湖泊湿地水体污染严重,湖泊呈富营养化。

To reveal the effects of invasive plants on greenhouse gas emissions in lake wetlands,the effects of alien invasive plants on greenhouse gas emissions of Honghu wetlands were studied.The invasive plant and native plant sites in the Honghu wetland area were established in China,and the variation of greenhouse gas emissions(CO_(2),CH_(4)and N_(2)O)on the autumn in the Honghu wetland area was observed by using the floating chamber and gas chromatography,and the relationships between the greenhouse gas fluxes and environmental factors were analyzed by Pearson correlation analysis.The results showed that the CO_(2)flux in the invasion site of exotic plant from the Eichhornia crassipes in the Honghu wetland was higher than that of open water site,but lower than that of emergent plant site from the Nelumbo nucifera and Zizania latifolia community,and lower than in the floating plant site from the Trapa bispinosa.The CH_(4)flux at the invasion site was higher than that at the floating plant site,but lower than that at the open water and the emergent plant sites.The N_(2)O flux at the invasion plant site was always lower than those of the emergent plant,floating plant and open water sites.In addition,the correlation analysis showed that CO_(2)flux was found to have a significantly positive correlation with temperature at the emergent plant and invasion plant sites,the N_(2)O flux was positive correlation with temperature at the emergent plant site,but the CH_(4)flux was not have a significant correlation with environmental factors in the four sites.It indicated that the CH_(4)emission fluxes(ranged:1.11~534.40 mg·m^(-2)·h^(-1))in the Honghu wetland were one to two orders of magnitude as for other observed wetlands in the past,which might be caused by the severely polluted lakes,and then the lake eutrophication.