What is seagrass and why is it important?

What is seagrass?

Seagrasses are a group of aquatic plants that live in salty or brackish water in coastal areas. (Brackish water means a mix of seawater and freshwater. Brackish water is less salty than seawater.) Seagrasses can live partially or entirely submerged by water.

Is seagrass a type of algae?

There are many types of algae in the ocean. Some are microscopic, like microalgae. Some are big. Kelp is an example of a macroalgae. Here are more examples of macroalgae:

Seagrass is not a type of algae.

Seagrass is a true flowering plant. Like grasses that grow on land, seagrasses have roots, stems, leaves and flowers. Seagrasses can absorb the nutrients they need through both their leaves and their roots!

Where do seagrasses grow?

Seagrasses grow in shallow coastal areas and estuaries around the world. Seagrasses can form large underwater meadows. In fact, the world’s largest plant may be a seagrass meadow off the coast of Western Australia.

Here is an aerial view of a seagrass meadow:

Aerial of seagrass meadow in Myeik Archipelago, Myanmar. Image: Ben Jones | Ocean Image Bank

Here is an underwater view of a seagrass meadow:

Eagle Rays in seagrass (Thalassia testudinum), Quintana Roo, Mexico. Image: Ben Jones | Ocean Image Bank

Watch this beautiful video of life in a seagrass meadow:

Courtesy of Aquawork Underwater Films

Why is seagrass important?

Here are some reasons why seagrass meadows are important:

Seagrasses prevent erosion. In other words, they help keep coastal sediment like sand from washing away.
Seagrasses absorb carbon and help in the fight against climate change.
Seagrasses are an important habitat for many species of animals and plants.
Seagrasses are a critical source of food for dugongs and turtles.
When the leaves of seagrass plants die and wash ashore, they become food for decomposers, organisms that eat dead plant matter.
Healthy seagrass meadows support our fishing and tourism industries.

See if you can find even more reasons why seagrass is important in this infographic from the Wildlife Conservation Society: