Sediment Trapping by Dams Creates Methane Emission Hot Spots
Sediment Trapping by Dams Creates Methane Emission Hot Spots
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DOI：
10.1021/es4003907
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发表时间：
2013-08-06
影响因子：
11.4
通讯作者：
Lorke, Andreas
中科院分区：
文献类型：
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作者：
Maeck, Andreas;DelSontro, Tonya;Lorke, Andreas
内陆沃茨运输和转化了大量的碳，占全球甲烷排放量的18%。面积甲烷释放率高于自然沃茨的大型水库对淡水排放有很大贡献。然而，全世界有数百万座小型水坝接收和捕获高负荷的有机碳，因此可能向大气排放大量甲烷。我们评估了筑坝对中欧一条蓄水河流甲烷排放的影响。直接比较河流和水库河段，由于水坝的截留，水库河段的沉积物增加，表明水库河段是甲烷排放的主要来源（类似于0.23 mmol CH 4 m（-2）d（-1）vs类似于19.7 mmol CH 4 m（-2）d（-1），区域排放率远远超过以前对温带水库或河流的估计。我们发现，沉积物积累与甲烷生产和随后的沸腾释放率，因此可能是一个很好的代理估计甲烷排放量从小型水库。我们的研究结果表明，沉积物驱动的甲烷排放从筑坝河流热点网站可能会增加全球淡水排放量高达7%。
Inland waters transport and transform substantial amounts of carbon and account for similar to 18% of global methane emissions. Large reservoirs with higher areal methane release rates than natural waters contribute significantly to freshwater emissions. However, there are millions of small dams worldwide that receive and trap high loads of organic carbon and can therefore potentially emit significant amounts of methane to the atmosphere. We evaluated the effect of damming on methane emissions in a central European impounded river. Direct comparison of riverine and reservoir reaches, where sedimentation in the latter is increased due to trapping by dams, revealed that the reservoir reaches are the major source of methane emissions (similar to 0.23 mmol CH4 m(-2) d(-1) vs similar to 19.7 mmol CH4 m(-2) d(-1), respectively) and that areal emission rates far exceed previous estimates for temperate reservoirs or rivers. We show that sediment accumulation correlates with methane production and subsequent ebullitive release rates and may therefore be an excellent proxy for estimating methane emissions from small reservoirs. Our results suggest that sedimentation-driven methane emissions from dammed river hot spot sites can potentially increase global freshwater emissions by up to 7%.