Globally significant greenhouse-gas emissions from African inland waters
Globally significant greenhouse-gas emissions from African inland waters
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DOI：
10.1038/ngeo2486
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发表时间：
2015-08-01
影响因子：
18.3
通讯作者：
Bouillon, Steven
中科院分区：
文献类型：
--
作者：
Borges, Alberto V.;Darchambeau, Francois;Bouillon, Steven
从内陆水域--溪流、河流、湖泊和湖泊--排放到大气中的二氧化碳几乎相当于全球海洋和陆地的沉降量。内陆沃茨也可能是甲烷和一氧化二氮排放的一个重要来源，但排放量很难量化，特别是在非洲。在这里，我们报告了撒哈拉以南非洲12条河流的溶解二氧化碳，甲烷和一氧化二氮浓度，包括2006年至2014年期间在39个地点采集的季节性采样。通量计算从公布的气体传输速度，并放大到所有撒哈拉以南非洲河流使用现有的空间数据集的面积。仅河流渠道的二氧化碳当量排放量每年约为0.4 Pg碳，相当于之前报告的非洲土地净碳汇总量的三分之二。如果将刚果河湿地的排放量计算在内，则二氧化碳当量温室气体排放总量将增加到每年约0.9 Pg碳，相当于全球海洋和陆地碳汇总量的四分之一。河流二氧化碳和甲烷排放量随着湿地面积和高地生物量的增加而增加。因此，我们认为，未来湿地和高地覆盖的变化可能会强烈影响非洲内陆沃茨的温室气体排放。
Carbon dioxide emissions to the atmosphere from inland waters-streams, rivers, lakes and reservoirs-are nearly equivalent to ocean and land sinks globally. Inland waters can be an important source of methane and nitrous oxide emissions as well, but emissions are poorly quantified, especially in Africa. Here we report dissolved carbon dioxide, methane and nitrous oxide concentrations from 12 rivers in sub-Saharan Africa, including seasonally resolved sampling at 39 sites, acquired between 2006 and 2014. Fluxes were calculated from published gas transfer velocities, and upscaled to the area of all sub-Saharan African rivers using available spatial data sets. Carbon dioxide-equivalent emissions from river channels alone were about 0.4 Pg carbon per year, equivalent to two-thirds of the overall net carbon land sink previously reported for Africa. Including emissions from wetlands of the Congo river increases the total carbon dioxide-equivalent greenhouse-gas emissions to about 0.9 Pg carbon per year, equivalent to about one quarter of the global ocean and terrestrial combined carbon sink. Riverine carbon dioxide and methane emissions increase with wetland extent and upland biomass. We therefore suggest that future changes in wetland and upland cover could strongly affect greenhouse-gas emissions from African inland waters.