Infuence of benthic fauna on trimethylamine concentrations in coastal marine sediments

Abstract

Seasonal variation of trimethylamme (TMA) concentrations in sediment porewater was detected at 3 different sites in a Danlsh estuary. A significant increase, from a pool size of 0 to 0.5 pM in fall and winter to 5 to 10 FM during spring, was observed in 2 fauna-rich, sandy sediments. An organlc-nch silt ulth few animals showed low TMA concentrations throughout the season Depth profiles of TMA also correlated with the distribution of burrowing infauna. Only fauna-nch sedlments showed detectable efflux of TMA to the water phase. With few an~mals, the flux was negligible due to efficient TMA consumption at the oxic sedunent-water interface. Animals are proposed to influence production and emission of TMA by osmoregulatlon and physical activity in the sediment.