全球水库CO_(2)通量分布格局及影响因素分析

A Study on distribution pattern and influencing factors of CO_(2)flux in global reservoirs

根据全球234个水库的277组CO_(2)通量排放数据,探索全球视角下水库CO_(2)通量的分布格局与时空变化特征,分析各因素对水库CO_(2)通量的影响.结果表明:位于热带的水库CO_(2)通量显著高于其他气候带.法属圭亚那和巴西的水库CO_(2)通量显著高于其他国家.全球水库CO_(2)通量与库龄、纬度和初级净生产力(NPP0)呈极显著相关(P<0.001),且随着库龄和纬度的增加,水库CO_(2)通量最初呈指数级剧烈下降,之后下降速度趋于平缓.水温、Chl-a浓度、DOC浓度和TP浓度与全球水库CO_(2)通量的相关性均不显著.青年水库的CO_(2)通量是中年水库、老年水库的2.16、3.077倍;低纬度地区的CO_(2)通量是中、高纬度地区的2.042、3.91倍.各因素重要性顺序依次为纬度>库龄>NPP0>Chl-a浓度>DOC浓度,全球尺度下,地理位置、水库老化情况和流域NPP0等具有全球属性的指标重要性远高于单个水库的碳含量和富营养化水平.在未来的水电开发中,应尽可能地考虑如何选址才能将新水库的CO_(2)排放量降到最低,尤其是对于热带地区的水库建设.

This study explored the distribution pattern,spatial changes and influencing factors of CO_(2) flux in reservoirs from a global perspective,based on 277 sets of CO_(2) flux emission data from 234reservoirs around the world.The study showed that CO_(2) fluxes in tropical reservoirs were significantly higher than in other climates,and those in French Guiana and Brazil were significantly higher than in other countries.The CO_(2) fluxes of global reservoirs were significantly correlated with reservoir age,latitude and primary net productivity(NPP0)(P<0.001).With the increase of age and latitude,the CO_(2) flux dramatically decreased exponentially,and then the decline rate slowed down.No significant correlations were observed between water temperature,chlorophyll-a(Chl-a),dissolved organic carbon(DOC),total phosphorus and CO_(2) fluxes in global reservoirs.The CO_(2) fluxes in the young reservoir were 2.16 and 3.077 times of those in the middle and old reservoirs respectively,while in low latitudes was 2.042 and 3.91 times that in middle and high latitudes.The importance of factors on CO_(2) fluxes in global reservoirs was in the order of latitude>reservoir age>NPP0>Chl-a>DOC.On a global scale,the importance of global indicators such as geographical location,reservoir age and NPP0were much higher than that of carbon content and eutrophication in individual reservoirs.In future hydropower development,location of new reservoirs should be considered as much as possible to minimize carbon dioxide emissions,especially in tropical regions.