Seagrass is an aquatic plant that grows and flowers under water. Worldwide, 52 species of seagrass exist in both temperate and tropical regions. Seagrass serves several important functions, both in the environment and as a natural resource. Today, many seagrass areas are disappearing due to development and pollution.
Seagrass grows at the bottom of bays, estuaries, lagoons and other shallow coastal waters. Seagrass is not a true grass, but a relative of the lily. The plant owes its name to its resemblance to grass, which grows on land. Most seagrasses have three to five green leaf blades attached to a straight stem. Thick roots and rhizomes attach seagrass to the marine bottom.
Seagrasses can cover wide areas. More than a half million acres of seagrasses grow in Florida waters alone. Seagrass spreads as the rhizomes extend outward and sprout new plants. Seagrasses flower and produce seeds. Strong currents and tides distribute the seeds.
Seagrass helps the marine environment. The leaves trap fine particles, which improves water clarity. Seagrass roots and rhizomes prevent erosion by stabilizing sediments at the aquatic floor. The plants also are an important part of the marine food chain. They provide habitat, shelter and food for fish and other aquatic life, as well as hunting grounds for larger predators. An acre of seagrass supports 40,000 fish and 50 million invertebrates, according to the Smithsonian Marine Station.
Commercial fisheries depend on seagrass habitats to support pink shrimp, lobster, red fish and stone crab species as they grow. The Florida Department of Environmental Protection (FDEP) estimates that more than 70 percent of the recreational and commercial fish in Florida's waters spend part of their lives in seagrass areas. Dried seagrass has human uses as well, including as a fiber for weaving rugs and baskets.
Seagrass areas are "disappearing at an alarming rate," the FDEP reports. Officials blame dredge and fill operations, poor water quality and other activities for the decline. At Ponce Inlet in Florida, the entire seagrass habitat was destroyed to allow developers to dredge and fill the waterway.