Seagrass Facts for Kids

A sea grass bed in Florida Bay

Young mangroves and carbonate mud in the internal part of the lagoon – Florida Bay

Diagram of plant evolution from the Precambrian to the sea grasses.

Sea grasses are flowering plants which live in the sea. They come from one of four plant families in the order Alismatales. They are monocotyledons which grow in marine, fully saline environments.

Sea grass is a key part of continental shelf ecosystems where phytoplankton produce carbonate sediment. This kind of ecosystem occurs in subtropical places like Florida Bay, and around Bermuda. Sea grass beds often contain many species from various phyla. Apparently, seagrass herbivory is a highly important link in the food chain. Many species feed on sea grasses, such as green turtles, dugongs, manatees, fish, geese, swans, sea urchins and crabs.

Taxonomy

Family	Image	Genera	Description
Zosteraceae	The family Zosteraceae, also known as the seagrass family, includes two genera containing 22 marine species. It is found in temperate and subtropical coastal waters, with the highest diversity around Korea and Japan. Species subtotal:
		Phyllospadix	6 species
		Zostera	16 species
Hydrocharitaceae	The family Hydrocharitaceae, also known as tape-grasses, include Canadian waterweed and frogbit. The family includes both fresh and marine aquatics, although of the seventeen species currently recognised only three are marine. They are found throughout the world in a wide variety of habitats, but are primarily tropical. Species subtotal:
		Enhalus	1 species
		Halophila	19 species
		Thalassia	2 species
Posidoniaceae	The fast of Australia. Species subtotal: 2 to 9
Posidoniaceae		Posidonia	2 to 9 species
Cymodoceaceae	The family Cymodoceaceae, also known as the manatee-grass family, includes only marine species. Some taxonomists do not recognize this family. Species subtotal:
		Amphibolis	2 species
		Cymodocea	4 species
		Halodule	6 species
		Syringodium	2 species
		Thalassodendron	3 species
Total species:

Evolution of seagrass Showing the progression onto land from marine origins, the diversification of land plants and the subsequent return to the sea by the seagrasses
Morphological and photoacclimatory responses of intertidal and subtidal Zostera marina eelgrass
Zostera marina seedling
Seagrass bed with several echinoids
Seagrass bed with dense turtle grass (Thalassia testudinum) and an immature queen conch (Eustrombus gigas)
Structures of sulfated galactans from marine organisms Sulfated polysaccharide structures from left to right: red algae: Botryocladia occidentalis, seagrass: Ruppia maritima, sea urchin: Echinometra lucunter, tunicate: Styela plicata
White-spotted puffers, often found in seagrass areas