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

Carbon sequestration levels in lakes are often underestimated despite being vital for the comprehensive analysis of CO2 budget and significantly influencing inland lakes in 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) replenished by 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 and help 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.