Zhao Deng-Zhong, Tan De-Bao, Li Chong, Shen Shao-Hong
Changjiang River Scientific Research Institute(CRSRI), Changjiang Water Resources Commission, Wuhan 430010, China.
China Three Gorges Corporation, Beijing 100038, China.
Huan Jing Ke Xue. 2017 Mar 8;38(3):954-963. doi: 10.13227/j.hjkx.201607086.
Greenhouse gas emission from aquatic ecosystem will affect climate change on the regional and global scale. So large river interception project which affects the carbon cycle model and greenhouse gas emission from aquatic ecosystem has provoked more and more attentions in recent years. In order to understand and evaluate the effects of typical hydropower project construction on the aquatic ecosystem and carbon cycle, the Geheyan Reservoir, a typical river interception project, was selected as a typical case in this paper for measuring carbon dioxide fluxes from interface between water and atmosphere from March, 2015 to February, 2016. The integration of the online gas analyzer and floating box was used to obtain carbon dioxide fluxes from interface between water and atmosphere. Data was obtained over the before dam, upstream, tributary, drawdown area and bay area respectively for understanding the spatial Heterogeneity of carbon dioxide fluxes. Data analysis showed that yearly mean fluxes of carbon dioxide from the Geheyan Reservoir was (55.6918±66.3329) mg·(m·h) during measurement, which indicated that the temporal distribution was higher in winter and lower in other seasons and the spatial variation was higher in typical bay and lower before dam as well as drawdown zone over the reservoir. Moreover, the seasonal variation of carbon dioxide fluxes from the interface between water and atmosphere was very stable at Yuxiakou measurement points as a typical background area of the reservoir, which was unexpectedly higher than those before dam and drawdown zone in the most months during measurement. The results from data analysis also indicated that the spatial and temporal variation of carbon dioxide fluxes from the Geheyan Reservoir was affected by water quality parameters such as dissolved oxygen, chlorophyll, pH, water temperature and conductivity and carbon in water, but the relationship between carbon dioxide fluxes and other parameter was very different within each season and impound period. So the results above will provide more supports for understanding the import pathway and transfer of aquatic carbon cycle caused by large river interception project in China.
水生生态系统的温室气体排放会在区域和全球尺度上影响气候变化。因此，影响碳循环模型和水生生态系统温室气体排放的大型河流截流工程近年来受到越来越多的关注。为了理解和评估典型水电工程建设对水生生态系统和碳循环的影响，本文选取典型河流截流工程——隔河岩水库作为典型案例，于2015年3月至2016年2月测量水 - 气界面的二氧化碳通量。采用在线气体分析仪与浮箱相结合的方法获取水 - 气界面的二氧化碳通量。分别在坝前、上游、支流、消落区和湾区获取数据，以了解二氧化碳通量的空间异质性。数据分析表明，测量期间隔河岩水库二氧化碳年平均通量为(55.6918±66.3329)mg·(m·h)，这表明其时间分布为冬季较高，其他季节较低，空间变化为典型湾区较高，水库坝前和消落区较低。此外，作为水库典型背景区域的鱼峡口测量点，水 - 气界面二氧化碳通量的季节变化非常稳定，在测量的大部分月份中意外地高于坝前和消落区。数据分析结果还表明，隔河岩水库二氧化碳通量的时空变化受溶解氧、叶绿素、pH值、水温、电导率等水质参数以及水中碳的影响，但在每个季节和蓄水期内，二氧化碳通量与其他参数之间的关系差异很大。因此，上述结果将为理解中国大型河流截流工程导致的水生碳循环输入途径和转移提供更多支持。
