Bosten Lake, the largest inland freshwater lake in China’s arid northwest, located in the Tarim River Basin, Xinjiang. This study quantified CO 2 and CH 4 diffusion fluxes using multi-season observations (2023–2025) and examined how water temperature intervals and ion composition interact to regulate carbon fluxes in an arid-region lake. Mutual information analysis and multiple linear regression were applied to identify key drivers across cold (20 °C) water temperature regimes. Bosten Lake acted as a net carbon sink during ice-covered periods, with average CO 2 uptake of 141.02 mg·m⁻²·d⁻¹ , challenging the conventional warm-season-centric view of arid-region lakes as perennial carbon sources. The moderate water temperature (WT) range (9–20 °C) dominated flux regulation, where CH 4 fluxes were best explained by a synergistic “WT– SO 4 2 − –Mg 2 + ” pathway (adjusted R 2 =0.569). Annually, the lake’s emissions offset ∼22.6% of the basin’s carbon sink, underscoring its role as a dynamic carbon node in arid landscapes. These findings highlight temperature-interval-specific mechanisms and the importance of winter processes in arid-lake carbon budgets. • Bosten Lake acts as a winter CO 2 sink under ice. • Water temperature drives CH 4 flux. • Bosten Lake offsets ∼22.6% of basin carbon.
Fan et al. (2026) studied this question.