Natural water input deposits little atmospheric carbon into groundwater in a desert
Natural water input deposits little atmospheric carbon into groundwater in a desert
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自然水输入将很少的大气碳沉积到沙漠的地下水中
DOI：
10.1016/j.catena.2020.105097
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发表时间：
2021
期刊：
影响因子：
6.2
通讯作者：
Wang Chaozi
中科院分区：
文献类型：
--
作者：
Fa Keyu;Xie En;Zhao Xiao;Wang Chaozi
全世界都有旱地土壤异常吸收CO2的报告。据报道，大气中的碳可以首先转化为土壤溶解的无机碳，然后通过灌溉（人工输入水）携带并迅速封存在地下水中。然而，沉积率可能不适用于没有人工水投入的旱地，大气碳的归宿也可能不同。本文以毛乌素沙漠为研究对象，通过对当地降雨量、自然入渗时间和长石风化碳消耗率的估算，分析了毛乌素沙漠土壤无机碳特征。结果表明，即使在极端降水条件下，输入的水也不能迅速将碳输送到第一隔水层，表明天然水输入不能将土壤吸收的大部分大气碳存款到地下水中。进一步的分析表明，长石风化可能会迅速消耗大部分大气中的碳。由于输入水的运移，消耗的碳将转化为成壤碳酸盐并保存在底土中。这些结果可为确定旱地土壤吸收的大气碳的去向提供依据。
Anomalous CO2absorption by soils in drylands has been reported worldwide. It has been reported that atmospheric carbon can first be converted into soil dissolved inorganic carbon, and then be carried and rapidly sequestered in groundwater through irrigation (artificial water input). Nevertheless, the deposition rate may be inapplicable in drylands without artificial water input, and the fate of the atmospheric carbon may also be different. Here, we assessed the amount of the local rainfall, evaluated the elapsed time of the natural water infiltration and the feldspar weathering-induced carbon consumption rate, and analysed the characteristics of soil inorganic carbon in the Mu Us Desert, northwest China, where we have previously studied abiotic atmospheric carbon absorption and the soil water input mainly derives from precipitation. The results showed that, even with extreme precipitation, the inputted water could not rapidly transport carbon to the first aquiclude, indicating that natural water input cannot deposit the majority of the atmospheric carbon absorbed by soil into groundwater. Further analysis indicated that feldspar weathering might be able to rapidly consume most of the atmospheric carbon. The consumed carbon would be converted into pedogenic carbonate and conserved in subsoil due to the transportation of inputted water. These results can provide a basis for determining the fate of atmospheric carbon absorbed by soils in drylands.