Spatial distribution of intertidal sandy beach polychaeta along an estuarine and morphodynamic gradient in an eutrophic tropical bay

► Sandy beach polychaeta from an organically polluted tropical bay was studied. ► The spatial distribution of polychaetes changed according feeding modes. ► Beaches composed by very coarse sands with sea water renewal had the richest fauna. ► Heavily disturbed beaches had the highest densities of opportunistic species. ► Polychaeta distribution changed with morphodynamic and eutrophication condition.