Marine vegetation

Silo of algae, seagrasses and underwater forests: living organisms essential to the ocean's balance.

🌊 0–35 m (known range of the family)

• 🌊Atlantic Ocean
• 🌊Pacific Ocean
• 🌊Mediterranean Sea
• 🪸High seas / open water
• 🪸Kelp forest / seaweed meadow

Low danger

Sargassum

Sargassum natans

Sargassum

This brown alga never puts down roots: it drifts at the ocean's surface its entire life, forming immense floating rafts that gave the Sargasso Sea its name.

🌊 0–5 m

• ⚡ Reproduces only through fragmentation, with no sexual reproduction ever observed
• ⚡ Gave its name to an entire sea, the Sargasso Sea, which has no coastline at all

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Harmless

Mediterranean seagrass

Posidonia oceanica

Mediterranean seagrass

Some Posidonia meadows form a single clonal organism over 100,000 years old, potentially making it one of the oldest living things on the planet.

🌊 1–35 m

• ⚡ A single clonal individual may be over 100,000 years old, one of the oldest known living things
• ⚡ Captures up to 15 times more CO2 per hectare than an equivalent area of Amazon rainforest

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Harmless

Giant kelp

Macrocystis pyrifera

Giant kelp

Perhaps the fastest-growing organism on Earth, giant kelp can gain over 60 centimeters a day and build an entire underwater forest within months.

🌊 0–30 m

• ⚡ Can grow more than 60 cm per day, one of the fastest growth rates in the living world
• ⚡ Forms underwater forests that host biodiversity comparable to a coral reef

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