Due to their morphological similarities they are called Seagrass even though taxonomically they are not. They develop in sandy bottoms and muddy areas, where the depth is limited due to the lack of clarity of the water and the availability of light.

Amongst the ecological functions of this ecosystems are the production of food, sediment stabilization and the recirculation of nutrients and sediments. A lot of organisms seek refuge, food and a place to raise their offspring. Some of the marine organisms in this ecosystem are turtles, manatees, fish, sea urchins and others.

Ecological relations are very important amongst marine ecosystems because a lot of reef organisms seek these ecosystems, coral reefs, seagrass and mangroves, for their larval stages.