The Posidonia plant - disturbing, but extremely important for our nature

You know how it is, you want to go to the beach on your holiday, arrive there full of expectation and instead of crystal-clear water and waves you find a net of water plants. Have you also always thought it was algae that washed ashore and lost the desire to swim? Today we explain to you what natural phenomenon you will find when the beach is full of it.

Posidonia oceanica, the Posidonia plant, forms widely branching roots and shoot axes and leaves up to one metre long. After flowering, the leaves die from the tip and detach from the shoot axis. They fray and wash ashore, where we find them annoying and disgusting. The rhizomes also wash up on the beach. These are the ginger-like structures. The felt-like balls also come from the Posidonia. Many fibre remnants accumulate on the seabed and are driven back and forth by the waves. Over time, they coalesce and become matted. They become a ball and wash up on the beach However, these balls have nothing to do with real sea balls, the popular aquarium plants.

Posidonia meadows are an important habitat for many fish and marine animals such as snails and mussels. What we find disgusting and disturbing when we come into contact with them on the beach are precisely these dead posidonia plant remains. These plants play an important role for the climate because they store far more carbon dioxide than forests of the same size. They ensure clear water because their leaves catch dirt particles. And they protect beaches from erosion because the long leaves act like a reef that slows down the waves. This is precisely why environmentalists demand that the neptune grass not be removed from the beach, because it ensures that the sand is not eroded during storms.

But water pollution, anchors and climate change are taking their toll on Posedonia. The water is cleaned of organic substances, but if the concentration is too high, it dies. This is especially the case in high summer, precisely when the overloaded sewage treatment plants can no longer clean the water sufficiently before discharging it into the sea. The Posidonia reacts particularly sensitively to ocean warming. For this reason, it is strictly protected and may not be removed from the beach. Sea balls, which are often taken as souvenirs, are also affected. Anchoring on Posidonia fields is also prohibited for this reason. The anchors that tear holes in the fields cause a lot of damage because the plant grows extremely slowly.

For years, the Aquarium Palma de Mallorca has been fighting for the preservation of the Posidonia plant and is actively working to keep this natural phenomenon alive in the environment.

So if you come into contact with the dead plant remains, appreciate the work that these plants do for our environment.