Study region Bosten Lake, the largest inland freshwater lake in China's arid northwest, located in the Tarim River Basin, Xinjiang. Study focus This study quantified CO2 and CH4 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 (<9 degrees C), moderate (9-20 degrees C), and warm (>20 degrees C) water temperature regimes. New hydrological insights for the region Bosten Lake acted as a net carbon sink during ice-covered periods, with average CO2 uptake of 141.02 mg & centerdot;m(-)& sup2;& centerdot;d(-)& sup1; , challenging the conventional warm-season-centric view of arid-region lakes as perennial carbon sources. The moderate water temperature (WT) range (9-20 degrees C) dominated flux regulation, where CH4 fluxes were best explained by a synergistic "WT-SO42--Mg-2(+) " pathway (adjusted R-2=0.569). Annually, the lake's emissions offset similar to 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.