The surface of TD is mainly covered by a uniform layer of moving sand. The environmental conditions at the three monitoring points are consistent from north to south, especially in terms of soil temperature. The tower located in the heart of the desert is considered the most representative research area for TD. This study was conducted in Tazhong Flowing Sand (38 ° 58 ′ N, 83 ° 39 ′ E, altitude 1099 meters). The entire region belongs to a continental, warm temperate, and arid desert climate. The annual average precipitation is 25.9 millimeters, with extremely uneven distribution throughout the year, with precipitation concentrated from May to August. The annual potential evaporation is 3812.3 millimeters. The region has four different seasons and high diurnal temperature differences. The annual average temperature is 12.1 ° C, with a maximum temperature of 40.0-46.0 ° C and a minimum temperature of -20.0 to -32.6 ° C. The harsh environmental conditions have led to a severe shortage of animal and plant resources in the region. The total area of sand flow in TD is approximately 2.364 × 1011m2, covering about 70% of TD. Flowing sand is composed of silt and clay (1.5%), fine sand and very fine sand (88.8%) particles, and medium sand (9.7%) particles

    The topsoil (0-10 cm) was collected from the moving sand layer at the research site and divided into four parts. Sample 1 is a control and has not been processed. Sample 2 was subjected to high-pressure sterilization treatment to eliminate the influence of soil microorganisms on soil respiration. To ensure sufficient sterilization, repeat high-pressure sterilization three times, each time for half an hour. The sterilized fine sand is immediately placed in an oven and dried at 105 ° C. The displaced sand after drying should be sealed before being placed in a sterile UV room. Finally, after placing the sample in a sterile state for one day, add 17-18ml of distilled water to a watering can to match the soil moisture content measured in the field. While adding distilled water, mix the displaced sand sample evenly and seal it for two days to achieve equilibrium between carbon dioxide and water in the sample. Put sample 3 into a plastic box and add 30L of distilled water to the sample. After thorough mixing, let the sample stand for 1 hour, then pour out the upper layer of liquid. This process is repeated three times to remove soluble salts and bases from the sample. Then use the processing method of sample 2 (three rounds of sterilization, followed by drying, adding distilled water (15.9mL), and standing). The processing procedure for sample 4 is similar to that of sample 3, but distilled water (15.9mL) is used.

    Based on disassembly and temperature control experiments, the study quantified the exact magnitude and process of carbon dioxide flux of each component of quicksand in the transportation area. The study specifically considered the easily overlooked process of soil air expansion/contraction, as well as the exaggerated impact of soil moisture on carbon dioxide flux in desert environments. In addition, the absorption of carbon dioxide by saline alkali factors in the desert has also been confirmed. Finally, it was found that TD sediment transport is currently a stable carbon sink, with an annual carbon dioxide absorption rate of 7.11gm^-2· a^-1between 2004 and 2017. If we consider all the mobile deserts in the world, the role of desert ecosystems in the global carbon cycle cannot be ignored. These results help explain the missing carbon sinks in the global carbon cycle. However, CMIP5 simulations indicate that during the release of carbon dioxide, the contribution of TD to the movement of sand carbon sinks in the future will decrease due to the lack of attention paid to the temperature driven soil air expansion process.