What is seagrass?
Seagrasses are marine plants which can sometimes be confused with algae but they are in fact very different. In contrast to seaweeds, Seagrasses are vascular marine plants with the same basic structure as many plants on land – they have roots, leaves, they produce flowers, fruit and seeds, but they live their entire life cycle underwater.
Where do you find it?
Seagrasses usually dominate shallow coastal waters around the globe where they form meadows under the water, and we are very lucky to have a substantial bed here off Looe within the VMCA. Sometimes, on a very low tide and in calm, clear water conditions you can snorkel off Looe and see the seagrass gently swaying in the current beneath you. There are several different types of seagrass, but the one that you find in Looe is the common seagrass, or Zostera marina, which seasonal grows between April and September and dies back in the late autumn and winter.
Why is it important?
Underwater seagrass meadows form incredibly important habitats. They are an important source of food and shelter for the young stages of many fish and crustacean species, some of which are themselves food for commercially-valuable fishery species such as seabass. They are also important feeding grounds for ducks and geese sought after by wildfowlers. The seagrass plants themselves play an important role in maintaining the stability of the shoreline. The dense network of roots bind the sea bed and reduces erosion in shallow waters. Bottom areas without seagrass are more often stirred up by wind and waves decreasing the water clarity and affecting marine animal behaviour and recreational quality of coastal areas. These network of roots and leaves in a meadow also provides ecological niches for a wide range of associated plants and animals such as pipe fish and seahorses, so are important in maintaining coastal biodiversity. Finally, seagrass has a high rate of primary production, increasing the oxygen content of the water. They help maintain water clarity by trapping fine sediments and particles.
Seasearch is a project for volunteer sports divers who have an interest in what they’re seeing under water, want to learn more and want to help protect the marine environment around the coasts of Britain and Ireland.
The main aim is to map out the various types of sea bed found in the near-shore zone around the whole of the Britain and Ireland. In addition we are recording what lives in each area, establishing the richest sites for marine life, the sites where there are problems and the sites which need protection.
Many Looe marine conservation group divers are trained up in Seasearch techniques so that they monitor the underwater environment to ensure its protection for the future. For more information about the Seasearch project, please check out the Seasearch Project and if you are diver wanting to get involved please get in touch with the Cornwall Wildlife Trust.