Yesterday, 28 November 2024, marked the Day of the Mediterranean, an annual celebration of unity, diversity and shared identity among the countries surrounding this historic sea. It honours the Mediterranean’s rich cultural heritage, unparalleled biodiversity and pivotal role in human society. In 2024, under the theme The Next Wave: Building a Shared Tomorrow, the day emphasised the urgency of collaboration as the world nears the milestones of the United Nations’ Agenda 2030 for Sustainable Development. Amid global challenges, it is a call to action for resilience, cooperation and sustainable progress. Through cultural events and initiatives, the day celebrates the bonds that unite the region and the vibrant Mediterranean life.
One of the unique features of the Mediterranean is Posidonia oceanica, commonly known as Neptune grass or Mediterranean tape weed. This week’s map highlights the distribution of this species, a seagrass species that is endemic to the Mediterranean Sea. Forming large underwater meadows, Posidonia oceanica is vital for marine ecosystems. Its free-floating fruit, called “the olive of the sea” (l’oliva di mare), and fibrous balls of foliage, known as egagropili, often wash ashore [1] . Explore the map to see Posidonia oceanica distribution across the Mediterranean and zoom in to see more details!
Since the 1930s, seagrass meadows have been declining globally at a rate of about 7% annually, threatened by pollution, coastal development and climate change [2]. However, these meadows are vital for marine ecosystems and coastal protection. They support biodiversity by providing food and shelter for species, including endangered seahorses and turtles. Seagrass meadows also improve ocean health by absorbing harmful nutrients and reducing marine pathogens. Acting as natural buffers, seagrasses mitigate ocean acidification, protecting fragile ecosystems like coral reefs. Additionally, it shields coastlines from erosion, storms and floods by absorbing wave impacts [3]. Crucially, Posidonia oceanica plays a significant role in climate change mitigation, absorbing carbon dioxide 15 times more effectively than an equivalent area of the Amazon rainforest [2].
The European Union (EU) is actively involved in restoring and conserving seagrass meadows in the Mediterranean through several initiatives. The recently adopted Nature Restoration Law sets targets to restore 20% of degraded ecosystems, including seagrasses, by 2030 and all by 2050. Moreover, projects such as ARTEMIS, supported by the Interreg Euro-MED program, focus on rehabilitating damaged seagrass ecosystems using innovative restoration techniques. These efforts enhance biodiversity, boost carbon sequestration, and protect coastlines while fostering collaboration among communities, researchers, and policymakers.
At the local level, you can help protect seagrass meadows by avoiding anchoring on them, reducing pollution, supporting sustainable practices and participating in restoration projects.
Wish to learn more?
- Read the United Nations Environment Programme report, ‘Out of the Blue: The Value of Seagrasses to the Environment and to People’;
- Listen to the ‘Parlons Peu, Parlons Bleu’ podcast by Éloïse Faure on Posidonia oceanica (in French);
- Learn about seagrass meadows restoration projects by the Archipelagos Institute of Marine Conservation, Innoceana and the MEDSEA Foundation;
- Are you a teacher looking to dive deeper into the world of Posidonia oceanica? Explore the marine biodiversity exercise available in the Atlas Teacher’s Corner and engage your students with fun, educational content;
- Wish to make learning more engaging? Register now for the Atlas’ online workshop for teachers ‘Bring the ocean into your classroom with the European Atlas of the Seas’, on 4 December 2024, from 18.00 to 19.30 (CET)!
The data in the map are provided by EMODnet.
[1] https://www.unep.org/topics/ocean-seas-and-coasts/blue-ecosystems/seagrass-meadows
[2] https://www.bbc.com/news/science-environment-56378397
[3] https://www.unep.org/news-and-stories/story/how-protecting-seagrasses-can-help-save-our-oceans