BioLOGy

let's gather information about the flora and fauna of the Baltic and the Mediterranean, relating the results to the geographic location and climate regions

Sardinian team... has made a research on marine system in Mediterranean and after that wrote this document and a short quiz on the information given..

Why  posidonia is vital to the marine ecosystem?

Posidonia is the foundation of marine ecosystems. It is a priority habitat and fundamental to the ecological balance of the seas.
The grass meadow is a "climax community" representing the highest level of development and complexity that a marine ecosystem can reach. Posidonia in coastal ecosystems plays a major role for several reasons:

1. Thanks to its leaf development, the environment frees up to 20 liters of oxygen per day and per m2 of meadow
2. It produces and exports biomass both to surrounding ecosystems and to greater depths
3. It provides shelter and breeding grounds for many fish, cephalopods, bivalves, gastropods, echinoderms and tunicates
4. It consolidates the seafloor to help offset costs and excessive sediment transport due to coastal currents
5. It acts as a barrier, attenuating the force of currents and waves and thus preventing coastal erosion
6. It dampens the waves through the layer of dead leaves deposited on the beaches, which protects against erosion, especially during winter storms

The disappearance of grasslands has negative effects not only on the micro-ecosystem itself but also on linked ecosystems; just think that the loss of a single meter of grassland can lead to the disappearance of several meters of beach due to erosion. Furthermore, regression of grasslands involves a loss of biodiversity and deterioration of water quality.

This species is found only in the Mediterranean Sea where it is in decline, occupying an area of only about 3% of the basin. This corresponds to a surface area of about 38,000 square kilometres (15,000 sq mi). Posidonia grows best in clean waters, and its presence is a marker for lack of pollution.

The presence of Posidonia can be detected by the masses of decomposing leaves on beaches.

            

The roots of Posidonia, spread from the stem, called a rhizome. The rhizome has the ability to reproduce both horizontally and vertically. The maximum length of the leaves is reached in the spring. at the end of August, just before their death take on a reddish color. The autumn storms off the leaves from the rhizome and gather along the coasts where, as a result of the waves take the form of a potato. The flowers appear in autumn, and early winter, the fruits are formed, called "sea olives".

And now .... Test yourself

Posidonia on PhotoPeach

 

Sardinian team .