Li Zhe, Bai Lei, Guo Jin-Song, Fang Fang, Jiang Tao
College of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, China.
Huan Jing Ke Xue. 2013 Mar;34(3):1008-16.
The Three Gorges Reservoir (TGR) is a huge reservoir under the subtropical climate condition. It shows great spatio-temporal heterogeneity on biogeochemical cycling of carbon in the TGR's aquatic ecosystem. 1 a field monitoring on water-air CO2 and CH4 fluxes was conducted from June, 2010 to May, 2011 in Longxi River and Pengxi River, the 2 typical tributaries in the Three Gorges Reservoir. Comparative study showed that annual CO2 diffusive fluxes in the Longxi River and Pengxi River were (7.30 +/- 1.89) mmol x (m2 x h)(-1) and (0.71 +/- 0.46) mmol x (m2 x h)(-1), respectively, and the CH4 diffusive fluxes were (0.11 +/- 0.095) mmol x (m2 x h)(-1) and (0.007 4 +/- 0.001 7) mmol x (m2 x h)(-1). Higher intensities and seasonal variance of CO2 and CH4 fluxes were observed in Longxi River compared to those in Pengxi River. Through a comparative analysis of the environmental and watershed parameters in both rivers, it was found that the unstable hydraulic conditions and habitat of Longxi River prohibited the growth of phytoplankton, reducing its capability of carbon assimilation. The higher pollution load in the basin and the higher organic matters and total nitrogen in the impounding soil of Longxi River also resulted in the higher level of greenhouse gas fluxes compared to those in the Pengxi River. More studies shall be conducted to elucidate the variance of CH4 flux and its controlling factors in both rivers.
三峡水库是亚热带气候条件下的大型水库。其水生生态系统的碳生物地球化学循环具有显著的时空异质性。2010年6月至2011年5月，对三峡水库两条典型支流——龙溪河和蓬溪河的水-气CO₂和CH₄通量进行了实地监测。对比研究表明，龙溪河和蓬溪河的年CO₂扩散通量分别为(7.30±1.89) mmol·(m²·h)⁻¹和(0.71±0.46) mmol·(m²·h)⁻¹，CH₄扩散通量分别为(0.11±0.095) mmol·(m²·h)⁻¹和(0.007 4±0.001 7) mmol·(m²·h)⁻¹。与蓬溪河相比，龙溪河的CO₂和CH₄通量强度更高，且具有明显的季节变化。通过对两条河流环境和流域参数的对比分析发现，龙溪河不稳定的水力条件和生境抑制了浮游植物的生长，降低了其碳同化能力。龙溪河流域较高的污染负荷以及蓄水土壤中较高的有机物和总氮含量，也导致其温室气体通量水平高于蓬溪河。需要开展更多研究以阐明两条河流CH₄通量的变化及其控制因素。
