Denitrification is a critical step in the global nitrogen cycle which converts bioavailable nitrogen into relatively non-bioavailable N2 gas. Eutrophication (caused by excessive nitrogen loads) is known to reduce the efficiency of denitrification. Despite the fact that a large fraction of Australia's estuaries have sand beds, there are no accurate measurements of carbon mineralisation rates and denitrification in these sediments. This project will use novel approaches to the quantification of denitrification (modelling and kinetic measurements) and carbon mineralisation (eddy correlation technique) in permeable sediments to better constrain denitrification rates and efficiency in coastal sands as a function of carbon mineralisation.