Seagrass Ecosystems

The seagrass ecosystems are among the most productive communities found in the ocean. Through photosynthesis, seagrasses and associated plants, provide the plant matter that feeds the animals which live in seagrass beds. Sea- grasses thrive in clear, shallow water, typically less than ten feet deep. They require high levels of sunlight, in some case twenty five times more light than land based plants!! In Bocas del Toro, Panama seagrasses grow in the sandy, flat areas around the islands. Seagrass beds perform the following ecological functions: serve as nurseries for young fish, add oxygen to the water, stabilize the ocean bottom and, create habitat for animals such as the sea cucumber.

Types of Seagrass

Turtle grass (Thalassia testudinum) the most common of the Florida seagrasses, characteristically has deeper root structures than any of the other seagrasses.

Illustration of turtle-grass Illustration of manatee-grass Illustration of shoal-grass Illustration of paddle-grass

Manatee-grass (Syringodium filiforme) is easily recognizable because its leaves are cylindrical.

Shoal-grass (Halodule wrightii) is an early colonizer of disturbed areas and usually grows in water too shallow for other species.

paddle-grass (Halophila decipiens) requires less light than other species and can grow in deeper water or water with more sediment.

Seagrass Ecosystems: Global Crisis!

The collapse of seagrass ecosystems is linked to human caused pollution. From Belize to Thailand, Malyasia to the United States seagrass beds are dying.

Eroded soil sediment is carried by rivers into the sea. The erosion is often caused by deforestation and agriculture. The sediment clouds the water and buries the seagrass beds.

A seagrass bed that has been damaged by a motorboat propeller.

Boat propellers carve channels through the seagrass beds. These channels weaken the beds and make them less stable.

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Pipes like these carry nutrient rich water into the ocean. The

nutrients increase the plankton which causes the water clarity to decrease. Consequently, seagrass beds suffer from reduced light infiltration.

Scientists Study Seagrass

	A scientist surveys a seagrass bed. He measures the height and density of the plants. These measurements are compared to pervious
	year’s data. In the lab, the different parts of the turtle grass are sorted. The leaves, roots, and rhizomes are separated. The healthy leaves are separated from the
	unhealthy. All the parts are dried and then weighed. The dry weight of the plant parts is used to calculate the total biomass of the seagrass bed.