Found only in the Mediterranean, neptune grass is a secret weapon in the battle against climate change.
This remarkable marine seagrass absorbs more carbon dioxide than an equivalent area of the Amazon rainforest.
Dense balls of dead neptune grass leaves are formed by ocean currents and can help trap plastics, removing them from the ocean when they wash up on the shore.
In 2006, a colony of neptune grass stretching over 8km and thought to be over 100,000 years old, was found off the coast of Ibiza. It is thought to be both the oldest and largest living organism on Earth.
Neptune grass forms larges undersea meadows in the sands of the Mediterranean Sea, from its shallow waters to around 40m deep. Specialised stems stretch into the sand and form a thick mat of roots that anchor the plant, while bright green ribbon-like leaves grow upwards to around 1.5m long and 10mm wide. Neptune grass produces small green flowers which develop into free-floating fruit commonly referred to as 'sea olives'.
Food and drink
Neptune grass meadows provide grazing grounds for a variety of ocean life, including fish, urchins and turtles.
Materials and fuels
The dead leaf balls are occasionally used as compost.
In the past, dead leaves were used for animal bedding and insulation for housing.
Did you know?
Both the common and scientific name for neptune grass (Posidonia oceanica) come from classical gods of the sea. Poseidon is the Greek god of the sea, and Neptune is his Roman counterpart.
Neptune grass meadows provide an important habitat for marine life. They provide shelter for fish and are used as a nursery for their offspring.
Whilst neptune grass is exclusively found in the Mediterranean, all other members of the genus Posidonia are found off the southern coast of Australia.
Where in the world?
Temperate sea water in the Mediterranean Sea