The leaves sea is accumulation on the Littoral of natural scrap (Algue S, Deadwood, bone of dry, etc) and of waste of anthropic origin, which are brought there by the sea to high tide.
Among the latter, one can evoke oil wafers resulting from the oil slicks or degasification at sea, the waste thrown or lost at sea by the ships, the fishing machines lost by the fishermen or other types of waste brought at sea by the wind or the rivers before being rejected on the beach by the tides.
In many countries, basic sea leaves it or of open sea is used to chart the limit between the ground and the sea.
Ecological function
The leashes of sea, when they are not not polluted, have an important ecological role. Thanks to the Mucilage S and Mucus which they contain, the failed, alive or died algae, even in full sun, preserve under the leashes of sea a microclimate fresh and protected from the solar Ultra-Violets, sheltering there and nourishing many species which live in sand (micro-organisms and shellfish primarily).Once degraded and mineralized, they become one of the sources of nutrients of the terrestrial plants top of the Estran and the plants (Zostère S, Posidonie S) and marine algas. Thus the organizations which they nourish and shelter doubly contribute to fix the beaches, sands and sediments in bays or estuaries and the foot of the first dunes.
They are also the base of a completely particular Food chain where in particular the birds feed, but which also benefit the Alevin S, Crabe S, etc On the littoral, the swallows and of many other species of birds uses algae recovered on the leashes of sea to manufacture their nest.
On this écotone, one finds in addition to typically terrestrial Invertébré S (Insecte S primarily), completely marine species, and species typical of these mediums, with for example of the Talitridae, of which Talitrus saltator which is a very appreciated food of the Gravelot. The night, the Sanglier S do not scorn to come to excavate the leashes of sea at the times when they can find there corpse S of fish or birds. Perhaps they found formerly there a food interesting for its wealth of Iode, they are likely today to consume products there more Toxique S.
To clean or not?
There exists a strong pressure of the littoral communes to clean the leashes of sea mechanically in order to present to the tourists beaches " propres".
That seems useful where abnormal pullulations of green algas occur because of a Eutrophisation or Dystrophisation induced by the contributions with the sea of excesses of Nitrate S and Phosphate S agricultural or emitted by the purification plants. Another source of risk, locally can be made up of nitrates resulting from immersed ammunition, which can also lose toxic of combat of the type Ypérite, Chloropicrine, etc (yperite with consistency and the appearance of small oil wafers when she flees of shells bored by the Corrosion and that she is brought on the estran by the currents.
Detonators and sachets of Pesticide S were failed per thousands on the French coasts a few years ago following the loss at sea of Conteneur S by the Sherbro at the time of a storm. These objects are found in the leashes of sea which it is thus advisable to supervise. It is also necessary to clean the usual Déchet S anthropic (treated wood, nylon nets, which can still trap birds and various hazardous substances for the environment or those which attend the beaches.
From the point of view of the bearable development, it is however advisable to preserve the natural part of the leashes of sea, particularly with the feet of the Dune S which they contribute to fix.
See too
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