Study of the transmission of the diurnal CO2 concentration changes observed above a Posidonia seagrass bed. A method to determine the turbulent diffusion coefficient in a 8 meters water column

A simple method is presented to calculate the CO2 vertical turbulent diffusion coefficient in the upper layer above a Posidonia sea grass bed. The method relies on the measurement of the attenuation and phase shift of the diurnal CO2 variation at different depths in the water column. The values of the turbulent diffusion coefficient fall in the upper range of values given in the literature for the mixed layer (⋍102m2s1), which is consistent with the high-energy environment studied.