Impact of soil temperature-difference on desert carbon-sink

The global carbon-cycle is crucial for climate change. Desert, which has long been neglected in the global carbon-cycle, may sequester enormous volumes of CO2 and play the role of a carbon-sink. As the world's second-largest shifting desert, the Taklimakan Desert (TD) contributes substantially to desert carbon-sinks. However, the contributions of the internal processes of the TD to its carbon-sink and the long-term trend of the carbon-sink under climate change are still unclear. This study will address this important knowledge gap. Through field observations, we found that the expansion/contraction of soil air containing CO2 caused by heat fluctuation in shifting sand, in combination with salts/alkali chemistry dominates the release/absorption processes of CO2 in shifting sand. The mutual counteraction of these processes means that the TD shifting sand acts as a stable carbon-sink that had a CO2 annual uptake of 1.60×106 t·a-1 during 2004–2017. It suggests that global shifting deserts m...