World Seagrass Day is coming up! Each year, on 1 March, the global community raises awareness of seagrasses and their value and promotes actions for their conservation.[1] Seagrasses are marine flowering plants that grow in shallow coastal waters. They have adapted to life underwater in the sea and they are able to tolerate salty water and withstand wave energy. They have roots to anchor in the sediment and green leaves, and they produce flowers and seeds. They are often confused with seaweed, but they are in fact very different ! [2]
Have you ever seen seagrasses at the coast? They grow in many parts of the world, from the tropics to the Arctic, in shallow waters where they can use the sunlight for photosynthesis. [1] Just like trees form a forest, many seagrasses covering an area form a meadow. Seagrass meadows are important habitats for marine wildlife and provide us with a range of ecosystem services. They serve as food for marine species like green sea turtles and dugongs and provide them with shelter from predators and wave energy. Just like mangroves, seagrass meadows buffer wave energy and protect coastal communities from impacts like storms and floods. [1] Their root systems form dense networks that trap and stabilise the sediment, preventing coastal erosion. Seagrasses improve water quality by taking up nutrients and pollutants and store 18% of blue carbon worldwide! [1]
Humans have relied on seagrasses for a variety of things throughout history and they may reclaim a place in our modern economy. Coastal communities have harvested certain seagrass species (e.g. Zostera marina) as a direct food resource. Seagrass has also been used as an indirect food resource. In their role as habitat providers, seagrasses have historically supported fishing in many coastal communities throughout the world. Seagrass has also been used in the food industry. For example, in the 1700s, Norwegian farmers collected and stored seagrass for cows in winter. Nowadays, seagrass habitats are reliable fishing grounds for coastal communities. In the past and today seagrass has been used for roofing material, packaging and preserving food, insulation, fertiliser and medical applications. [2] Industrial scale harvesting may come with a cost for seagrass habitats. Their slow recovery implies that industrial pursuits need to be gentle and coupled with restoration efforts of existing meadows. By acknowledging their societal value through history and today, we can prevent overexploitation and habitat losses. [2]
Human pressures have already resulted in an annual decline of 1-2% of seagrass ecosystems during the twentieth century. Luckily, many are on a path to recovery thanks to improving water quality and area-based protection and restoration.[4]
This week’s map focuses on the seagrass species Posidonia oceanica, which is endemic to the Mediterranean Sea. Beds of Posidonia oceanica face multiple pressures including marine fish and shellfish harvesting (professional, recreational) activities, development and maintenance of beach areas, mixed source marine water pollution (marine and coastal), shipping lanes, ferry lanes and anchorage infrastructure, marine aquaculture and modification of coastline, estuary and coastal conditions. Posidonia oceanica beds are protected under Annex 1 of the Habitat Directive. Eight European Union Member States designate Natura 2000 sites for this habitat. Natura 2000 is an ecological network of protected areas to protect species and habitats in Europe. Have a look at Natura 2000 Viewer to learn more. [5]
Many organisations are working to restore seagrass meadows. For example, the Archipelagos Institute of Marine Conservation works on the conservation of Posidonia oceanica meadows. Their aim is to restore patchy meadows by replanting naturally detached seagrass shoots in areas where coverage has declined. Check out their work!
Curious about seagrasses? Have a look at these resources!
- Browse through the Project Seagrass Educational Resources and Publications.
- Watch the video 5 reasons to protect and restore seagrass.
- Learn more about seagrass as a food source in the article “Sea rice”: From traditional culinary customs to sustainable crop for high-end gastronomy?
- Read the article Mapping Italy’s Blue Future about a large-scale mapping project that aims to identify where Posidonia oceanica is growing and where it is under stress.
- Discover Los Jardineros del Mar, Innoceana’s initiative to restore and protect the seagrass meadows of Tenerife.
- Explore the LIFE SeagrassRIAwild Project.
- Check out tips for sustainable boating and a cool app in the article An Ocean Lover’s Guide to Boating Sustainably that helps protect seagrass meadows.
The data in the map is provided by EMODnet.
The European Atlas of the Seas is powered by the European Marine Observation and Data Network (EMODnet).
[1] https://www.un.org/en/observances/seagrass-day
[2] https://link.springer.com/article/10.1007/s13280-025-02167-z
[3] https://www.nature.com/articles/s44358-025-00028-x