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Seagrass Facts

Seagrasses grow underwater and produce an abundance of blossoms. There are 58 marine seagrass varieties worldwide, according to the Gulf of Mexico Program, which is administered by the U.S. Environmental Protection Agency (EPA). These plants are found in shallow ocean waters, where an abundance of light can still reach them. Seagrasses obtain their nutrients from sediment and from the water around them.


Seagrasses are a natural resource. They help to produce water clarity by trapping sediments in their leaves; they provide an ideal habitat for aquatic life; they prevent sediment erosion with their root system; and they are a valuable source of food for aquatic lifeforms. Manatees and green sea turtles thrive on seagrasses. One acre of seagrass will easily produce 10 tons of leaves, which can sustain 40,000 fish and 50 million small invertebrates, according to the Smithsonian Marine Station at Fort Pierce, Florida.

Safe Haven

An abundance of seagrass offers a safe haven for small fish that fall prey to larger predatory fish species. The grasses also offer a nursery setting for many fish to spawn within. Juvenile fish species hatch within the protection of the seagrass and hide in its confines.


There are several threats that can endanger seagrass. Any change in the salinity of the water can easily kill the delicate seagrass. Seagrass depends on water clarity to thrive through photosynthesis. If the water becomes contaminated with sewage, urban storm water runoff, chemical runoff from agriculture operations or industrial operations, the waters clarity is reduced, and the seagrass dies.

Human Threats

Dredging and boating are serious threats to the well-being of seagrass. Boat propellers sometimes tear grass roots from the sediment. Docks often shade the grasses, causing their inevitable death.

Seagrass beds that sustain heavy scarring from commercial fishing operations can take up to 10 years to recover, according to the Gulf of Mexico Program, administered by the EPA. Dredging reduces the water clarity by causing an inbalance between fresh water and sea water. It also disturbs the sediment, producing excessive water clouding.


Seagrass roots give stability to the sediment structure of the ocean floor, helping to reduce wave activity. The strong root system of seagrass anchors it to the hard substratum of the ocean floor, which reduces sediment accumulation during storms. The loose and flowing grass blades offer buoyancy during storm activity, which lessens wave force. This is invaluable in areas of severe tropical storms or hurricanes. Without seagrasses, homes, beaches and businesses would sustain even more serious damage during any type of storm, according to the Florida Fish and Wildlife Commission.

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