Uptake, accumulation, and biotransformation of metal oxide nanoparticles by a marine suspension-feeder

► Suspension-feeding by mussels can greatly alter mobility and fate of metal oxide nanoparticles. ► Bioprocessing of metal oxide nanoparticles by mussels removes large fraction from water column. ► Mussels repackage metal oxide nanoparticles in highly concentrated pseudofeces. ► Novel biological pathway between major compartments in marine systems. ► Very different outcome for ZnO and CeO2 nanoparticles based on their solubility.