Variation characteristics and influencing mechanism of CO2 flux from lakes in the Badain Jaran Desert: A case study of Yindeer Lake

The relationship between the variation of CO2 flux and the pH of inorganic factors. [Display omitted] •The difference of CO2 absorption and release is obvious during the day and night.•Yindeer Lake was a net sink of CO2 during the study period.•The lakes can absorb large amounts of CO2 every year to slow down global warming.•Meteorological factors controlling CO2 fluxes differed by time scale.•pH is the main influencing factor controlling CO2 absorption and release. Carbon sequestration levels in lakes are often underestimated despite being vital for the comprehensive analysis of CO2 budget and significantly influencing inland lakesin arid areas. In this study, the eddy covariance (EC) technique was used to measure CO2 flux for six consecutive years during 2012–2017 in a small salt-lake (Yindeer Lake) replenishedby groundwater in southeastern Badain Jaran Desert, China. The results indicate that: (1) Yindeer Lake was a net sink of CO2, which led to the estimate that the lakes in the Badain Jaran Desert can absorb approximately 1.91 × 103 t of CO2 per year andhelp slow down the rate of global warming. (2) The effects of meteorological factors on the CO2 flux of the lake vary with timescales. (3) Inorganic processes, in which pH is the main influence mechanism, control CO2 absorption and releases in Yindeer Lake. Thus, the study results provide a new guide for solving the “missing sink” problem.