Sea Forest
© SchirraGiraldi (Manuela Schirra and Fabrizio Giraldi)More than 1,000 leaf bundles per square meter, from 5 to 8 leaves per bundle, one centimeter wide and up to one meter long. At least 40 square meters of leaf surface per square meter. Posidonia Oceanica is an endemic plant of the Mediterranean Sea and is at great risk due to illegal trawling, recreational boating and discharges into the sea. Its prairies are ecosystems that play a fundamental role for the sea and the land. One square meter of Posidonia meadow can generate up to 20 liters of oxygen per day and for the same fixed surface area 50 times more CO2 than the Amazon Forest.
In addition to being a fundamental habitat for the oxygenation of the sea and therefore the life itself in, it also has a crucial role in terms of biodiversity and in terms of coastal erosion. Over 350 different species of marine organisms coexist in one hectare of Posidonia meadow finding food and protection among its leaves, and therefore it are fundamental for the sea natural repopulation, and the meadows itself reduce the force of the sea motion by 20%, while its dry leaves perched in 'banquette' on the beaches physically protect the coast from storm surges.
In Italy alone, of the 300 thousand hectares mapped by ISPRA in 2005, a loss of at least 50 thousand hectares of meadow is now estimated, of which 20 thousand in Sardinia. Every year in the summer season there are thousands of boats mooring which cause irreversible damage to the meadows of the Mediterranean, the most overexploited sea in the world also on a recreational level.
Posidonia Oceanica has a very slow growth, less than one linear centimeter per year, and this is the main condition for which it is becoming extinct. Its protection and restoration are today the main objectives of NGOs and institutions active in the issue, from teaching people to know and respect the sea ecosystem, to the creation of buoy fields to regulate moorings, up to reforestation to sew the irreversibly damaged meadows. While at the legislative level the aim is to recognize the CO2 credits (blue carbon) that the institutions could place on the market to recover the resources necessary to protect this precious and fragile habitat. It is estimated that one square meter of meadow that disappears is equivalent to a monetary loss of 39-89 thousand euros per year quantified in terms of oxygen production, CO2 fixation, repopulation of the seas (even purely in terms of fish) and erosion and coastal nourishment.
The images are taken in Sardinia, an iconic place for the Mediterranean thanks to the surface of existing and devastated prairies and thanks to its various geological conformations, and therefore thanks to the different conditions in which the prairies was developed and the related different degrees of CO2 absorption, and also thanks to its different coastlines which allow the question of coastal erosion to be studied in the most varied forms.
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