Fresh water

The fresh water is a Eau which, contrary to the earthy water or the Sea water, contains few salts dissolved. It contains generally less than one gram of dissolved solid matters (like nutritive salts, metals and elements) per liter. Turbidity indicates the opacification of the water caused by the presence of solid matters in suspension.

One also speaks about fresh water for a water little Calcaire (a earthy water is an extremely calcareous water).

The fresh water as a habitat S natural is the ecosystems mariconasos. In Europe they are covered by recent a Directive tallies on the water which aims at the return in an ecological good state of the water masses (soft, brackish and navy).

The fresh water ecosystems are victims many sources of Pollution, individual and collective, urban and industrial (accidental pollution, insufficiently purified effluents, scrubbing by the stormy showers), agricultural (nitrates, phosphates, erosion source of turbidity, pesticides). The ecological fragmentation by large the Stopping S insuperable, the warming or pollution contributes to prevent freedom of movement of the watery organizations, of which migrating fish. And locally, in the wetlands and on their basins slopes, leads of fishing and lost Hunting or shooting-trap are a source of Saturnisme in the animals, the water birds being touched more. They are also a durable source of pollution of the Sédiment S. Lastly, water streaming on sectors touched by the after-effects of war, or certain lakes, marshes, arms died, well, etc, in particular in old the Red zone can be seriously polluted by poisons when the Munition S which there were given up or lost put to flee.

The warm water tends to lose to them Oxygène which dissolves naturally better in cool water, the average, night warming in particular of the zones hot and moderate is an additional factor of degradation of the Biodiversité. Many fresh water fish belong to the species which regress in the majority of the developed countries and under development, just as the Amphibien S considered as indicating goods of water quality soft.

The original fresh water undoubtedly comes mainly from the meteorites and the rocks. After the appearance of the life, the cycle of water was modified by its use by the plants and the animals. On the emerged mediums, the fresh water is vital for the majority of the species. It comes from the Précipitation of atmospheric steam. Itself is resulting from the evaporation of marine and terrestrial water, but also of the cyclic recondensation of the evapotranspiration and breathing/perspiration of the plants and animals. It also comes from the meteoritic cycles of reevaporation of the dew and water which evaporated before joining the tablecloths or the rivers which feed the Lac S interiors, the Rivière S and Fleuve S, as well as deep underground sheets of water, either directly, or following the cast iron of snows or ices (see the Cycle of water). On Ground, 97% of surface water are salted; the 3% remainder constitute water reserves soft of planet. There is roughly the following distribution: 2/3d' fresh water in the form of Ice and 1/3 pennies forms Liquide.

The access to fresh water and clean is an increasingly critical problem for the survival of many species (“hydrous stress”), including the human being, in particular in the Désert S and other regions Aride S, polluted, or in the zones in the course of salinisation following the deforestation, with the irrigation or the drainage. The fresh water being very unequally distributed and accessible on the Earth, it is one of the great sources of inequalities and conflicts for the future according to UNO.

The year 2003 was proclaimed the international year of fresh water by the General meeting of the United Nations.

External bonds

File of CNRS on the fresh water
Web site of Canada Environment on the fresh water
Article of UNESCO on the war of water

Simple: Fresh toilets

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