干旱区生态环境知识资源中心

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.