Assessment of CO2 fluxes in the hinterland of the Gurbantunggut Desert and its response to climate change.

Desert ecosystems, as an important part of terrestrial ecosystems, are considered potential hidden carbon sinks in the global carbon cycle. The Gurbantunggut Desert, as China's largest fixed/semi-fixed desert, has received little research on its role in the global carbon cycle and future trends. This study utilizes continuous observational data from the Gurbantunggut Desert from 2018 to 2022 and integrates CMIP6 global climate model scenario data to study the evolution of carbon balance in the desert ecosystem, carbon source/sink functions, and future trends. The result showed that: 1) The CO₂ flux in the Gurbantunggut Desert shows Carbon sink during the day and carbon source at night, with an annual cumulative carbon sink duration of over 240 days.2)From 2018 to 2020, the desert ecosystem of the Gurbantunggut Desert functioned as a net CO₂ sink.3) Desert ecosystems were subjected to concurrent influences from multiple environmental factors across varying time scales, with photosynthetically active radiation, air temperature, and soil temperature identified as the most influential factors affecting CO₂ flux in the Gurbantunggut Desert. 4) The climate of the Gurbantunggut Desert is projected to exhibit a trend of warming and increased humidity in the future. Against the backdrop of future warming and humidification, the Gurbantunggut desert ecosystem is anticipated to exhibit a pronounced carbon sink characteristic.