As a nursery environment, seagrasses support small fish, shrimp, and crabs that hide among the blades and feast on decaying leaves. Seagrasses also help stabilize shifting sands on the bottom of the bay and improve water clarity by trapping fine sediments and particles. Damage from motor boats is severe in areas. As boats carve through shallow grass flats, their propellers cut sandy trenches that may stay barren for years. Turtle grass can live in many substrates, from mud to sand and broken shell, and tolerate a wide range of salinities, from 10 to 48 parts per thousand.
Turtle grass has long, leafy blades that usually occur in bundles of three to seven.
It is used by a variety of organisms, including more than 113 species of algae which attach to its leaves. For instance, the leaves of turtle grass are about of an inch wide, while those of shoal grass are less than a half-inch wide. And turtle grass may grow to 2 feet or more, while shoal grass tops out at about 15 inches. Although both types of grasses are often found together, shoal grass usually holds the distinction of being there first. For this reason, it is known as a pioneer species.