Arid and semi-arid ecosystems are increasingly recognized as important carbon storage sites. In these regions, extensive sequestration of dissolved inorganic carbon can occur in the terminal lakes of endorheic basins—basins that do not drain to external bodies of water. However, the global magnitude of this dissolved inorganic carbon sink is uncertain. Here we present isotopic, radiocarbon, and chemical analyses of groundwater, river water, and sediments from the terminal region of the endorheic Shiyang River drainage basin, in arid northwest China. We estimate that 0.13 Pg of dissolved inorganic carbon was stored in the basin during the mid-Holocene. Pollen-based reconstructions of basin-scale productivity suggest that the mid-Holocene dissolved inorganic carbon sink was two orders of magnitude smaller than terrestrial productivity in the basin. We use estimates of dissolved inorganic carbon storage based on sedimentary data from 11 terminal lakes of endorheic basins around the world as the basis for a global extrapolation of the sequestration of dissolved organic carbon in endorheic basins. We estimate that 0.152 Pg of dissolved inorganic carbon is buried per year today, compared to about 0.211 Pg C yr⁻¹ during the mid-Holocene. We conclude that endorheic basins represent an important carbon sink on the global scale, with a magnitude similar to deep ocean carbon burial.

中文翻译：

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全球封闭式流域中大量无机碳汇

干旱和半干旱的生态系统越来越被认为是重要的碳储存场所。在这些地区，溶解性无机碳的大量固存可能发生在endheheic盆地的末端湖泊中，这些盆地不会流到水的外部。但是，这种溶解的无机碳汇的总体规模尚不确定。在这里，我们介绍了来自干旱西北地区的石羊河内流域河床末端区域的地下水，河水和沉积物的同位素，放射性碳和化学分析。我们估计0.13 在全新世中期，Pg溶解的无机碳被储存在盆地中。基于花粉的盆地规模生产力重建表明，中全新世溶解的无机碳汇比盆地中的陆地生产力小两个数量级。我们使用基于来自全球endheheic盆地的11个末端湖泊的沉积数据的溶解无机碳储量的估算，作为对endorheic盆地中溶解有机碳的固存进行全球外推的基础。我们估计，0.152 溶解无机碳的PG是每年埋今天相比，约0.211 皮克 Ç 年^-1在全新世中期。我们得出的结论是，胶结盆地在全球范围内代表着重要的碳汇，其规模与深海碳埋藏相似。