Air- water gas exchange and CO2 flux in a mangrove- dominated estuary

Mangrove forests are highly productive ecosystems, but the fate of mangrove-derived carbon remains uncertain. Part of that uncertainty stems from the fact that gas transfer velocities in mangrove-surrounded waters are not well determined, leading to uncertainty in air-water CO2 fluxes. Two SF6 tracer release experiments were conducted to determine gas transfer velocities (k(600)=8.30.4 and 8.10.6cmh(-1)), along with simultaneous measurements of pCO(2) to determine the air-water CO2 fluxes from Shark River, Florida (232.1123.69 and 171.1320.28mmol C m(-2) d(-1)), an estuary within the largest contiguous mangrove forest in North America. The gas transfer velocity results are consistent with turbulent kinetic energy dissipation measurements, indicating a higher rate of turbulence and gas exchange than predicted by commonly used wind speed/gas exchange parameterizations. The results have important implications for carbon fluxes in mangrove ecosystems.