Named after their “grass-like” appearance seagrass are not grasses at all. Seagrasses are fully submerged flowering plants with leaves, roots and veins that produce tiny flowers and seeds. Over 55 species of seagrass are thought to occur worldwide with seven seagrass species found in Florida including more common ones such as shoal grass (Halodule wrightii), manatee grass (Syringodium filiforme) and turtle grass (Thalassia testudinum) while widgeon grass (Ruppia maritima), star grass (Halophila engelmannii) and paddle grass (Halophila decipiens) are less common.
In the Mississippi areas seagrass species include the dominant shoal grass (Halodule wrightii) as well as manatee grass (Syringodium filiforme), turtle grass (Thalassia testudinum), widgeon grass (Ruppia maritima), star grass (Halophila engelmannii) paddle grass (Halophila decipiens), clover grass (Halophila baillonis), and Johnson’s seagrass (Halophila johnsonii) (Phillips and Meñez 1988)). Seagrass species come in many different shapes and sizes. They grow both vertically and horizontally—their blades reach upwards into the water column and their roots down and sideways—to capture sunlight and nutrients from the water and sediment.
In oceans from the tropics to the Arctic Circle, seagrasses live in shallow marine and estuarine (brackish) waters because they depend on light for photosynthesis.
In Florida, seagrasses are found along the entire coast of Florida waters. In Mississippi, seagrasses are found in the Mississippi Sound around Cat, Petit Bois, Ship and Horn Islands as well as the Chandeleur Islands
Seagrasses are a food source: Seagrasses are eaten by animals such as parrotfish, surgeonfish, sea urchins, pin fish and endangered sea turtles and manatees. Other species benefit indirectly from seagrasses. Bottlenose dolphins feed on fish and other organisms that live in seagrass areas, dead seagrass provides food for worms, sea cucumbers, crabs, and filter feeders such as anemones and ascidians.
Seagrasses provide habitat: Organisms such as algae, sponges, crustaceans and barnacles grow on the blades of seagrass. Additionally, they are important habitat for seahorses and are nursery grounds for commercially important species such as spiny lobster, scallops, flounder and crab.
Seagrasses stabilize the ocean floor: The extensive root system of seagrass beds extends both vertically and horizontally and help diminish the force of current along the bottom.
Seagrasses help with water clarity: Seagrasses trap sediments and particles in their leaves and root system which aids in improving water clarity.
Pham, Linh T., et al. “Seagrasses in the Mississippi and Chandeleur Sounds and Problems Associated with Decadal-Scale Change Detection.” Gulf of Mexico Science, vol. 32, no. 1, 2014, doi:10.18785/goms.3201.03.
Phillips, R.C., & Menez, E.G., 1988. Seagrasses. Smithsonian Contributions to the Marine Sciences,no. 34.