On The Ocean Floor: 5 Fascinating Facts About Seagrass



Every so often I am delighted to welcome guests to my blog, who share their expertise and fascinating facts with us all. Today I am handing the reins over to the Ocean Conservation Trust, who are focussing on all things seagrass:

Grass is something we may all be familiar with from walks in our local parks. What may be less familiar is grass growing underwater. Seagrass grows in dense meadows under the Ocean. It flourishes in our well-lit coastal waters, providing benefits many of us may not be aware of but which influence our daily lives. Loveday Trinick, the Ocean Conservation Trust’s Education Officer, explains below the top 5 things we should all know about seagrass:

1. It’s a flowering plant

Just like plants on land, seagrass has roots, makes seeds and needs light to grow. This makes seagrass different to seaweeds (algae) because they have no roots, relying instead on a holdfast, a hand-like gripping structure, to provide a strong anchor to the seafloor. This makes seagrass the only flowering plant to be found in the Ocean.

2. It grows around the world

Seagrass grows in both cool water and in the tropics. In the UK, we have four species of this super plant, two of which are found in the Ocean. Zostera marina and Zostera noltii are both species of Ocean-growing seagrass known as eelgrass. Worldwide, there are over 70 species of seagrass, found in a variety of coastal locations. Globally, they support an enormous array of life, including juvenile sharks and rays, as well as turtles and manatees, which survive by eating the seagrass.

A dugong (Dugong dugon) feeds on seagrass in shallow warm waters in the tropics.

3. It provides a sheltered habitat

Seagrass is a nursery for juvenile fish. It also supports an enormous amount of invertebrate life as well as harbouring rare species such as stalked jellyfish and seahorses. This is of enormous importance to the fishing industry because the fish which spend their juvenile years in this nursery will become the adult fish our fishermen catch and deliver to our tables. 

4. It is a natural coastal defence

Seagrass takes energy out of the waves approaching our shores, protecting coasts from erosion. When habitats like seagrass are removed, waves can become more destructive, washing away our coastlines. Without the seagrass roots, the sediment can also wash away under the sea, affecting the animals which live there.


Female spiny seahorse
A female spiny seahorse (Hippocampus guttulatus) shelters is a meadow of common eelgrass (Zostera marina). Photographed in summer (August) in Studland Bay, Dorset, England. British Isles. English Channel.

5. It stores carbon

This amazing plant stores carbon in the sediment which surrounds its roots. This ability has huge potential for helping the fight against climate change. In fact, the amount of carbon storage ability could rival that of the rainforests.

This really is a super plant – it supports the fishing industry by sheltering juvenile fish, it protects our coastlines, and it acts as an important carbon store.

We’re working to protect and restore seagrass as part of LIFE Recreation ReMEDIES, a four-year project to improve the condition of sensitive seabed habitats at five Special Areas of Conservation along England’s south coast. It is funded by the LIFE programme and led by Natural England.

Over the half term week, we will be taking a closer look at seagrass and find ways in which this amazing plant helps us. We will also be seeing how we might negatively impact it, and how we can help to protect it. 

For more information, please take a look at the LIFE programme on the link above, or visit the Ocean Conservation Trust’s website here.

Did you know?

Seagrass infographic

N.B. Thank you to my special guest today. This is a collaborative post, but I have not received anything in exchange for hosting it. For more details about how I work with others, please take a look at my disclosure page. Photos have been kindly supplied for this post, and must not be reproduced without permission.