Project #3
What if the Mediterranean Sea isn’t what it seems?
Sometimes, the most devastating catastrophes make no noise.
The water is still blue. The beaches are still full. The Mediterranean Sea is still seen as paradise. But maybe not for much longer… because truth is: without posidonia it will fall apart. Since the 1960s, more than 20% of its posidonia meadows have vanished — a result not of one single cause, but many: illegal mooring, trawling, pollution, coastal development, extreme storms…
A vision of progress that never stopped to ask what was happening beneath the surface.
At HUMANSDID, we want to give visibility to the Blue Wave Alliance initiative — restoring posidonia meadows and raising awareness about their importance and benefits.
To make it happen, we need our community to take action:
HUMANSDID’s Project #3 consists of supporting and giving visibility to Blue Alliance’s initiative “The Great Posidonia Meadow in the Mediterranean.”
What you ignore today might become irreversible tomorrow. Register and join a community that acts.
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What is POSIDONIA oceanica — and why should you care?
Posidonia is neither algae nor an exotic species. It’s a living infrastructure — a marine plant endemic to the Mediterranean Sea that supports vast biodiversity. It covers more than 12,000 km² of the seafloor and can be found at depths of up to 40 meters. In its densest forms, it creates true underwater cities: a network of rhizomes and leaves that provides shelter, food, and breeding grounds for hundreds of species.
Each square meter of posidonia captures up to ten times more CO₂ than a square meter of the Amazon rainforest. It oxygenates the water, protects coastlines from erosion, and feeds and hosts marine life. Once damaged, it can take between 100 and 600 years to recover. It also has the ability to retain sediment over thousands of years, forming layers up to five meters thick that help stabilize the seafloor and safeguard the coast. Despite covering less than 1% of the seabed, it helps trap nearly half of all CO₂ stored long-term in marine sediments.
Without it, the Mediterranean Sea collapses from within.
What does this have to do with you?
More than you think. When posidonia disappears, we don’t just lose marine life — we lose quality of life.
If we don’t act now, the Mediterranean we know could vanish much sooner than expected. Bluewave Alliance puts it plainly: “The most urgent thing now is to protect the meadows that are still alive. Because this restoration shows just how easy it is to destroy posidonia… and how hard it is to bring it back.”
A Mediterranean Sea without posidonia would mean eroded, shrinking beaches that are increasingly expensive to maintain. Waters would turn murky and polluted. Harmful algae would spread. Local fisheries would collapse — with fewer species, rising prices, and less food sovereignty. Last but not least, centuries of stored carbon would be released, accelerating the climate crisis.
Bluewave Alliance is supporting a Posidonia reforestation project in collaboration with Asociación Vellmarí, founded and led by marine biologist Manu San Félix. The seeds are collected from beaches, germinated naturally, and replanted in the sea. A restoration process that takes time, care, and collective effort: scientists, volunteers, and young participants from the Vellmarí Dive Camp all play a part — under the supervision of IMEDEA (Spanish National Research Council).
97% of the community voted in favor of this initiative! To take part in upcoming projects, log in to your profile on the app if you’re already registered, or sign up if you haven’t yet.
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What does HUMANSDID have to do with this?
At HUMANSDID, we don’t just amplify causes — we build community around them.
And while this isn’t our own project, we believe it’s one that needs to be told— to raise awareness about our impact on the Mediterranean Sea and help us understand the reasons why we can still enjoy it today.
If you sign up on HUMANSDID today and share our project, you’ll help us give visibility to initiatives like this one.
Project by project, our community is shaping what HUMANSDID stands for.
We keep working on the development of several other projects like this one, which will require your participation through the HUMANSDID application. If you haven’t registered yet, sign up now.
