What is Posidonia oceanica?
What is Posidonia oceanica?

Posidonia oceanica is an endemic marine plant found exclusively in the Mediterranean Sea with an extraordinary environmental value. It forms extensive underwater meadows of great ecological importance: they protect the coast from erosion, stabilise the seabed,create a biodiversity hotspot, provide shelter and food for many marine species, capture carbon dioxide and produce oxygen through photosynthesis.

About 80% of coastal oxygen production comes from this plant.

Posidonia oceanica meadows are part of the so-called blue carbon ecosystems and playing an important role as natural carbon sinks, capturing and storing large amounts of CO2 from the atmosphere within the matte – rhizomes and roots of old plants trapped in the sediments.

It is estimated that 1 square meter of Posidonia oceanica can absorb about 130kg of CO2 per year.

What is Posidonia oceanica?
Carbon cycle in coastal marine ecosystems
NOAA Climate.gov graphic adapted from original by Sarah Battle, NOAA Pacific Marine Environmental Laboratory.

Italy hosts a large area of Posidonia oceanica meadows along its coasts. However, these ecosystems are heavily impacted by coastal anthropogenic activities such as fish trawling and anchoring, which, combined with the slow growth rate of the plant (1-2 cm/year), cause extensive damage not only to the meadow itself but to the entire marine ecosystem and the associated biodiversity.

Indeed, Posidonia oceanica meadows constitute a priority habitat that hosts many marine organisms, providing them with shelter, food, and an area to reproduce and grow. 

Over 350 different species are found within the meadows: marine invertebrates, juveniles of fish, mollusks, crustaceans, and small symbiont organisms.

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Discover more by watching our videos

The "lung" of the Mediterranean Sea
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What does it mean to restore a Posidonia oceanica meadow?
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Current status and conservation efforts
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The project
The Blue Forests project

In the international context of the UN 30x30 Agenda and the increasing importance of protecting blue carbon ecosystems, and in line with the Foundation's Mission to protect the ocean, One Ocean Foundation has chosen to invest in a project that aims to protect and restore the blue natural capital and in particular Posidonia oceanica meadows.


Promoting the restoration of biodiversity and blue natural capital in line with the UN 30x30 target


Supporting Ocean Literacy and scientific research on project-related topics


Identifying and promoting a common methodology for the evaluation and valorisation of blue natural capital


Raising awareness about the importance of this species to the marine ecosystem

Our Blue Forests
The documentary
The documentary

The documentary "Posidonia oceanica – Restoring Mediterranean Seagrass" provides a comprehensive exploration of the entire restoration process and highlights the significance of this species, investigating the ecological aspects, examining the impacts this plant faces, and offering potential solutions for its preservation and protection.

A dive with researchers and scuba operators through the reforestation process to discover what it really means to restore a marine habitat.

Produced by One Ocean Foundation and directed by Fabio Benelli, marine biologist and underwater filmmaker, the documentary will be available in 2024.

Watch the trailer

Blue natural capital

The international scenario

Ocean-based natural resources correspond to blue natural capital, therefore its protection, conservation, restoration and enhancement are critical actions to achieve a sustainable development that respects the planet.

The Blue Forest Project and the Foundation’s commitment perfectly align with the international context of protecting and enhancing the blue natural capital, emphasizing the importance of preserving seagrass meadows in the fight against climate change.

Coastal ecosystems, including Posidonia oceanica meadows, can sequester about 50% of atmospheric CO210 times more than terrestrial forests – in the marine sediments; this carbon is called blue carbon.

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On-field activities
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On-field activities
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