In a series of measurements of CO2 flux over the sea the mean flux was near zero, even though the surface water had substantially higher partial pressure of CO, than the air. Hourly variations in wind speed were well correlated with the flux, suggesting that a wind-driven process, such as wave breaking and downward mixing of bubbles, may drie additional CO2 into the water as the wind speed increases. The traditional model of air-sea gas flux as a function of sea-air partial pressure difference was modified to include downward pumping by wind. We conclude that the flux of nonatmospheric gases such as radon does not serve as a complete model for the two-way surface flux of atmospheric constituents such as CO2.