Seagrass

We may all be familiar with grasslands in our fields, gardens and parks. Less well known are the underwater grasses, yet these are some of the most important seabed habitats in the ocean.

Seagrass is a flowering plant, the only one to grow in the sea, making it unique in the marine world. As a habitat, it delivers many benefits, not only to the ocean but to humans.

Seagrass has many features in common with the plants we know well, including roots and seeds. They also photosynthesise and therefore remove carbon from the environment, which helps to fight climate change.

As a sheltered, coastal environment, seagrass provides nursery habitat to animals which later move offshore, including pollock, plaice and herring. These later become food for other animals, including humans.

The same features which make it a good nursery mean that seagrass meadows are able to take energy out of incoming waves, protecting our coastal communities from damaging swells.

The importance of seabed habitats like seagrass is highlighted by being included as an Annex 1 habitat within the EU Habitat Directive. This means it is vital to understand and protect these underwater meadows for the future of the planet.

Seagrass. Photo credit Fiona Crouch
Seagrass. Photo credit Fiona Crouch

Maerl

Maerl grows in sheltered bays and coves, clustering on the seabed, forming hard, brittle, nodule shaped structures.

Fal and Helford Maerl beds

Maerl is an unusual type of algae. While some remains attached to the seabed, other fragments become detached, rolling, catching and forming a complex tangle. This complexity means that there are plenty of small nooks and caves for creatures to hide in.

This habitat is important because it provides spaces for small invertebrates like mussels, urchins, worms and crabs. These creatures provide food for juvenile fish like cod and pollock which are important to commercial fisheries.

Young Scallops also make their home amongst the carpets of Mearl, supporting these fisheries as well as ocean food chains. As well as being very fragile, Maerl grows very slowly, only gaining about 1mm a year. This makes them vulnerable to damage from boat anchors and from fishing equipment.

Due to its slow growth, Maerl cannot be regrown quickly. Once destroyed, a bed can take decades to return or may even be lost forever. Alongside its enormous benefits as a habitat, Maerl is also an important Blue Carbon store.

These amazing qualities make it a qualifying feature for Special Areas of Conservation, including Fal and Helford, which is one of the ReMEDIES project sites.