Posidonia Oceanica – The Secret of Menorca’s Crystalline Waters

Última actualización: 20/08/2024

MenorcaPosidonia oceanica is a very common marine plant in Menorca.
Although many call it seaweed, it is a plant.
Posidonia has its natural habitat between 0 and 40 meters deep, and with the change of leaves that it makes every year, it takes to the beaches the berms (posidonia leaves).
The berms of posidonia are dark brown or even black, and are deposited in the areas where the waves break on the shore of the beaches.
Thanks to them, the beaches maintain their sand, since the posidonia formations cushion the force of the waves on the sand of the shore, especially during storms.
In addition to the berms accumulated on the shore of the beaches, the wind often moves part of the posidonia towards the dune formations behind the bathing areas.
The accumulation of posidonia in the dunes is good for the ecosystem, as it provides organic matter and stabilizes the sand.

Posidonia“Cleans” the Sea Water

Posidonia keeps the sediments fixed with its roots and creates areas of oxygen production and breeding and refuge for a large number of marine species.
Posidonia meadows function as elements of seawater filtration, and help to keep the water clean and very transparent.

The good condition of posidonia contributes to cleaner and clearer water.
The destruction of posidonia by boats and pollution negatively affects water quality and can accelerate the loss of beach area.

Without Posidonia, Beaches Disappear

One of the most serious problems in Menorca during the last decade has been the progressive loss of sand on the beaches.
Tourists do not like to be surrounded by posidonia while bathing or sunbathing, as they consider the presence of this plant as a sign of dirt and neglect.
In reality, the presence of these marine plants means that we are in a protected ecosystem.

• Unfortunately, the authorities have been systematically removing posidonia on Menorca’s busiest beaches to keep the tourists happy.
  This removal of posidonia is done with heavy machinery and generates a loss of sand during the process.
• Although in Menorca the removal of posidonia is very efficient (the least harmful) according to studies by the University of the Balearic Islands, sand is still being lost during this process.

Will We Run Out of Sand to Protect the Tourism Sector?

I hope not, and to avoid this it is necessary to raise awareness and educate people who visit the beaches every year.
You are already informed, if you want beaches without posidonia the best thing to do is to go to urban beaches.

Map of Zones Prohibited for Boat Anchoring

Since 2020, the IDE viewer of the Consell Insultar de Menorca publishes a map with the prohibited map with the prohibited areas for anchoring boats..
It is very important to respect them, because damaging the posidonia has a very high ecological impact on marine ecosystems and beaches.
The layer of the viewer that allows to see the prohibited zones is in:

• Capas > Medi ambient agricultura i caça > Cartografia del medi marí mar > Zones de Fondeig prohibit de Menorca

Related articles

• The removal of posidonia in Menorca is the least harmful
• Oceana warns the Consell de Menorca that if it removes the posidonia the beaches of Menorca will disappear
• The removal of posidonia from virgin beaches in Menorca is a “political problem”.
• The tourism sector applauds the removal of algae, but the GOB and the PSM criticize it.
• The Consell will remove the algae “so that the coves are like the photos”.
• Proceedings of the VI Coastal Geomorphology Conference (Tarragona, 2011).