Underwater forests

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Just like terrestrial forests, there are vast expanses of life beneath the ocean's surface: submarine forests.

Armel Ruy / Fondation 1 OCEAN
Underwater forests, cradle of biodiversity

From the kelp forests of California to the mangrove swamps of the Indian Ocean and the sponge fields of Antarctica, underwater forests offer a diverse range of ecosystems in all the world's oceans. Veritable temples to life, these underwater jungles are lush biological cities, home to exceptional biodiversity. Like terrestrial forests, they are both the scene of territorial wars and the point of convergence for countless interdependent relationships. For thousands of species, underwater forests are a sure source of food and a healthy refuge.

Laminaria in the Iroise Sea © Pierre THIRIET PatriNat
underwater forests: biological pumps

Little-known to the general public, these forests are the guarantors of the balance of life: they play an essential role in the production of the oxygen we breathe, and absorb the excess carbon released into the atmosphere. They are thus part of what is known as the "soft biological pump" of carbon, whereby CO2 is transformed into O2 through the action of photosynthesis. Underwater forests also protect coastlines from waves and erosion, and provide a vital resource for coastal populations. Undoubtedly, their preservation is a decisive issue for the future of mankind and our planet.

Laminaria in the Iroise Sea © Pierre THIRIET PatriNat
endangered forests

There are many threats to these forests: water pollution (chemical, noise, plastic, etc.), overexploitation, changes in ecological status, but above all the proliferation of invasive species and the artificialization of habitats. These disturbances can have a negative impact not only on the density of forests, but also on their composition, diversity and structure.

Rebuilding our underwater forests not only means helping to preserve biodiversity, it also means making a commitment to the climate.

- Alexis Rosenfeld, 1 OCEAN Project Leader

1 OCEAN explores these underwater forests

Twenty or so expeditions are planned all around the planet, to the heart of the unknown worlds of the ocean's forests.

Underwater forest map

In addition to the usual content created (photo exhibitions, documentary film, book, capsules for social networks and the press), from 2023 1 OCEAN will be involved in several projects to restore these forests.


1 OCEAN has joined forces with an ambitious underwater reforestation program in the Loire estuary to restore underwater seaweed forests. This innovative initiative in France, carried out in collaboration with the ELV (Estuaires Loire Vilaine) association, targets an experimental site in an area where kelp(Laminaria hyperborea) has disappeared. These brown macro-algae are among the world's richest ecosystems, capturing the CO2 emitted by human activities and producing O2.
The experiment takes place over 500 m2, with regular monitoring over three years to assess the growth of these re-planted forests and the return of their indispensable role in the ecosystem. Our commitment: to restore the vitality of kelp in areas that are in decline or in poor condition.

It was with the desire to make concrete commitments in favor of ocean biodiversity that TBS decided to support us in this program, inspired by efforts to restore mangroves and terrestrial forests. Witnesseas is the project led by TBS & 1OCEAN to help bring life back to underwater forests.

Produced in partnership with