Marine mussels are bivalve mollusks, just like oysters and clams. This means they have two hard shells to protect their soft bodies. Like other bivalves, mussels can improve water quality, and contribute to healthy marine habitats. Mussels like marine mammals can be used as bioindicator of their environment. Mussels are filter feeders. They draw in seawater and filter out phytoplankton and sediments, cleaning the water as they go.

On the video, you can observe filter and particulate organic matter filtration by a mussel!
Siphoned material is either transferred to the mouth for digestion or sloughs off the gills and exits via the ventral margin of the shell (pseudofeces). Digested material is either used as fuel for various life processes or excreted as feces. The amount and rate of particulate matter removed from the water column and subsequent deposition of waste is largely dependent on species, size, water temperature, particle concentration.This video shows the run of water (blue) and associated food (orange) in the mussel. Water goes trough the gills from the inhalant chamber at the level of the palleal cavity, reachs the suprabranchial chamber and leaves the mussel at the level of the exhalant siphon. The food is seized at the level of the gills and routed to the labial pals before entering in the mout.