Algal blooms significantly alter biogeochemical cycling and greenhouse gas (GHG) fluxes in reservoir ecosystems. To investigate the impact of algal blooms on the spatial-temporal dynamics and interfacial transport mechanisms of GHGs, high-resolution monitoring of dissolved CO2, CH4 and N2O concentrations and fluxes were conducted in the Gaobazhou Reservoir during a bloom event. . Dissolved concentrations ranged from 0.12 to 215.82 μmol/L for CO2 (saturation: 1.8% to 1332.9%), 0.01 to 0.41 μmol/L for CH4 (saturation: 1198.2% to 12789.5%), and 17.83 to 48.78 nmol/L for N2O (saturation: 221.8% to 538.5%). Except CO2 in the bloom zone, all monitored GHGs were highly supersaturated. Floating chamber measured CO2, CH4 and N2O fluxes in non-algal bloom areas were 204.39±170.93 mg/(m2·h), 0.36±0.42 mg/(m2·h), and 0.01±0.01 mg/(m2·h), respectively, in the algal bloom areas were -88.42±39.20 mg/(m2·h) for CO2, 0.55±0.51 mg/(m2·h) for CH4, and 0.07±0.05 mg/(m2·h) for N2O. Driven by intense photosynthetic activity in the algal bloom areas, the surface water shifted from a CO2 source to a net sink;, compared to non-bloom areas However, CH4 and N2O emissions increased by 54% and 342%, respectively. Significant methodological discrepancies were found between the flux results of floating chamber and thin boundary layer methods: floating chamber estimations were 3-10 times higher than those derived from the thin boundary layer method, with the maximum divergence (~10×) occurring in the algal bloom regions. Algal blooms altered dissolved gas compositions and induced total dissolved gas (TDG) supersaturation (111.6% to 136.4%). The TDG supersaturation triggered microbubble formation, shifting the dominant gas transfer pathway to a coupled process of molecular diffusion and microbubble-mediated emission, which significantly enhanced CH4 and N2O emissions. This study demonstrates that algal blooms stimulate GHGs emissions by fundamentally altering interfacial gas transfer pathways, providing a new insight for accurate reservoir carbon budgeting and eco-hydraulic management.