Subtropical estuarine carbon budget under various hydrologic extremes and implications on the lateral carbon exchange from tidal wetlands

•Estuarine carbon fluxes are highly dynamic from drought to hurricane-induced flood.•Lateral exchanges from tidal wetlands dominate the total carbon loading.•Annual CO2 emission from northwest Gulf of Mexico estuaries is double of the North American estuaries average.•Interpretation of an estuarine carbon budget requires greater spatiotemporal coverage than past studies, and to meet the future climate change challenge.