Hidden like a precious secret under the surface of the sea are the “blue forests” or “algae”, as fishermen and divers usually call them, the Poseidonia meadows. “They are found almost everywhere but they are not algae. They are normal plants. Marine, flowering plants, like those we have on land.

Essentially, they have moved to the sea, that is, they have returned from the land to the sea,” says APE-MBE, WWF biologist Mr. Vangelis Paravas. Where the vast blue darkens, and swimmers become wary, a small miracle begins to take place in the Poseidonia meadows, as it is one of the most important habitats of the Aegean.

“Poseidonia is a type of plant that exists only in the Mediterranean. We don’t find it anywhere else in the world. It is very common, but also very important to marine ecosystems“, explains Mr. Paravas. Firstly, because, when found on the coasts, these specific plants “maintain and allow the development of the beach, protecting it from erosion. They are fertilizer for all the plants that hold the sand” and therefore must not be removed from the beaches, especially with the use of machinery. In addition, however, in the sea, the Poseidonia meadows act as “blue carbon stores”, i.e. they remove and bind carbon dioxide from the atmosphere, through photosynthesis!

“We find posidonia from very shallow up to 45 meters deep, precisely because it is a plant that needs solar radiation to photosynthesize” so it does not survive where the sunlight does not reach, while “it is greatly affected by the purity of the waters, by turbidity and pollution. Fortunately, in our country we do not have significant pollution in most areas, only in closed bays or ports” points out Mr. Paravas.

Therefore, every time we come across the long leaves of the Poseidonia, we have every reason to dive fearlessly because the sea is clean and welcoming, not only for swimmers but also for hundreds of fish and species of the bottom. “We can imagine them as marine forests that protect different species of life, many of which are important for fisheries. Too many species of fish live, breed and feed in the Poseidonia meadows,” notes the WWF biologist. As for carbon dioxide, these plants form “blue carbon ecosystems because they store very large amounts of it, so they contribute to the fight against climate change, and they have a very large production of oxygen» he emphasizes. In particular, each square meter of a healthy grassland produces up to 20 liters of oxygen per day and grasslands are important “natural carbon sinks”, as they store around 10% of the carbon dioxide sequestered by the oceans each year.

Posidonia meadows in danger

As Mr. Paravas emphasizes, “human activities are the only threats that poseidonia faces and the most important one that exists in our country is uncontrolled mooring». Although posidonia meadows are considered by the European Union a priority protected habitat, and “many NATURA areas in Greece have been designated as such for the presence of posidonia, as well as its protection from fishing, especially from towed gear, i.e. trawlers and seines which are prohibited in certain areas where there are meadows, which affects it at the moment too the position of the poseidonia is the anchorage» explains the WWF biologist.

Why, however, does something so seemingly simple destroy the ‘blue forests’? “Anchors falling into the posidonia meadow don’t do a single point of damage where the anchor drops, but because they have their chain and the boat rotates around the anchor, it creates large clearings uprooting all the posidonia leaves that are around“, emphasizes Mr. Paravas, adding that “if there is a lot of boat traffic, the repeated threat eventually completely defoliates the posidonia and kills the meadow». The time it takes a haystack to recover is long and, of course, it assumes the cessation of the threat, i.e. control of the anchorage.

Otherwise, initially, “the ecosystem is greatly degraded in terms of biodiversity because there is no longer the stem and the leaves that provide cover for the various species that live there, so they can neither feed nor gather. In other words, they become like marine deserts“, says Mr. Paravas. Secondly, “carbon dioxide is slowly released, which has been stored in the leaves, the shoots but mainly in the rhizomes of the plant, which is the most important storage point”. “Destruction and degradation of blue grasslands will lead to the release of large amounts of carbon dioxide into the atmosphere” emphasizes Mr. Paravas.

The meadows of Poseidonia

WWF, ELKETHE and CycladesPreservationFund join forces to protect marine “lungs”

The total area of ​​posidonia meadows in our country is estimated at approximately 2,500 square meters. km., covering more than 70% of the coastline. With the aim of protecting them, WWF Greece, the Institute of Oceanography of the Hellenic Marine Research Center (ELKETHE) and the Cyclades PreservationFund (CPF) are joining forces with partners from France, Tunisia and Turkey in the framework of the “Blue Forests of Mediterranean” and under the coordination of WWF’s Mediterranean office. First, the size of the “blue carbon sinks”, as they are called, will be assessed, and then, the intensity of the threat of uncontrolled mooring and its effects will be assessed, “using satellite and other data”, as Mr. Paravas states, especially with the contribution of ELKETHE in the research part.

Specifically, the areas of intervention in Greece are the marine protected area of ​​Gyaros and the Natura 2000 area of ​​the Small Cyclades (Schinoussa, Heraklia, Koufonisia, Keros, Antikeria), which are “touristically important, in order to assess the pressure they are under”.

In addition, the three bodies will proceed with the development and submission of proposals for the institutional protection of the posidonia meadows, the simplification of the licensing of moorings friendly to them, but also their installation. “These are fixed anchors which are usually screwed to the bottom and do much less damage because we save the piece of chain, which would drag and destroy the haystacks. Friendly moorings are supported with a floating system on top, which does not allow the intermediate to drag on the bottom” explains Mr. Paravas. Finally, as the existence of posidonia is an indicator of the health of the marine environment, the CycladesPreservationFund will play an important role in the involvement of local communities both in the formulation of proposals and in the implementation of management measures. “The aim is to restore degraded ecosystems through nature-friendly solutions that have already been tested“, concludes Mr. Paravas.