Neptune Grass (Posidonia oceanica) is a flowering sea grass in the Posidoniaceae family of saltwater plants. It is also known as Ocean Grass Wrack and Mediterranean Tapeweed.
It is endemic to the Mediterranean Sea.
It forms a large underwater meadow. Each meadow can be up to 8 kilometres (5 miles) across. About 55,000 hectares (140,000 acres) of the meadows around the Balearic Islands of Mallorca and Formentera are registered as an UNESCO World Heritage Site.
It has a very high carbon absorption capacity, soaking up to 15 times more carbon dioxide every year than the equivalent size of the Amazon rainforest.
The Neptune Grass has free-floating fruit known as ‘olives of the sea.’
Its ribbon-shaped leaves are bright green and measure up to 150 centimetres (57 inches) long. The leaves turn brown with age. Balls of fibrous material from the leaves and are often washed up on the shore – these are known as Neptune balls.
Photographed in the Aquarium de Paris-Cinéaqua, France, April 2022.
Photographer: Martina Nicolls
MARTINA NICOLLS – MartinaNicollsWebsite