Turismo El Ejido > Punta Entinas Visitor Center > Posidonia meadows

Underwater meadows

Posidonia oceanica is historically known as “glaziers’ algae”. Despite its appearance it is not an alga, rather a plant known under the name of marine phanerogam. It is endemic to the Mediterranean and in Almeria we have 16,000 hectares of these meadows, often felt as the best preserved in Spain. Punta Entinas-Sabinar houses the largest area of Posidonia in Andalusia, with 2,275 hectares that fortunately were declared SCI (Site of Community Interest) in 2006 and ZEC (Special Area of Conservation of the Natura 2000 Network) in 2016.

Its presence indicates the good quality of the waters of Punta Entinas-Sabinar, since this plant needs sunlight to perform photosynthesis, meaning it usually grows in depths between 30 and 40 metres on preferably sandy beds.

An essential plant

Seagrass meadows play a major role in our coastline’s biology and dynamics as they perform the following fundamental functions for us:

  • Its network of roots and rhizomes stabilises and consolidates the sediments of the seabed. This fosters the waters’ transparency creating fine sandy beaches.
  • Its dry leaves accumulate on the beaches forming shoals, which reduce the erosive impact of the waves and help in the sendimentary balance of the sands.
  • As plants, they are responsible for widespread production of oxygen and organic matter. Furthermore, the capture a large amount of CO2, on the gases responsible for the greenhouse effect.

The inhabitants of underwater medows

Thanks to the oxygenation of its waters in the Posidonia meadows numerous species find shelter, feed and reproduce. Some of them protected, such as the noble pen shell and others with fishing interest such as cuttlefish, octopues or red mullet. All of them comprise one of the most biodiverse ecosystems on the planet.

Posidonia

Its leaves can reach one metre in length by one centimetre wide. Its greatest growth spurt occurs in the summer season. Ever so slowly, the leaves are covered with other organisms, which live on them, covering them and preventing photosynthesis’ taking place. This brings about their death (changing the intense green color for brown) and their expulsion to the beaches by storms. The accumulations of dead Posidonia leaves on the shores are know as shoals and protect our beaches from erosion and wind.

A thousand year old plant

Posidonia grows very slowly: 1 cm per year, 1 metre in a century and takes thousand years to form a meadow.

That is why it is so valuable meaning we must preserve it while avoiding the threats it faces.

SOS Posidonia

Our Posidonia meadows are threatened by several agents:

  • Trawling at less than 50 metres’ depth. The metal doors destroy everything in their paths as the trawl along the sea bed.
  • The anchoring of pleasure boats, which with their anchors tear the Posidonia from the ground.
  • Discharges of human origin that bring with them more suspended particles decreasing the transparency and purity of the waters. This prevents proper light penetration, seriously hindering the photosynthesis process.
  • This increase in turbidity can also occur due to the undertaking of coastal works, such as boating marinas, breakwaters, or dredging.