The major non-algal plants that are usually entirely under water are seagrasses. These form extensive meadows in shallow, clear, sandy areas. They can be important habitat for some kinds of fish, and also function to stabilize sediments. Marsh grasses are found in tidal salt marshes in estuaries and other shallow regions. Marshes are important as habitat for birds and fish, and act as filters, removing silt and contaminants from the water flowing through them.
Mangroves are small trees found in the tropics that root in shallow marine sand and mud.
They have special adaptations for dealing with the high salt content of the water. Mangroves are important in shoreline stabilization. Feeding modes There is a diverse array of food for animals in the benthos, and an equally diverse array of ways to get it. Many worms, snails, sea cucumbers, and some other animals feed on sediments, much as earthworms do on land. They digest out the good stuff and leave mostly inorganic matter, plus organic matter that is indigestible.