Sunday, 31 October 2010

Waters of Portugal

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In the biosphere we find water in permanent circulation, and this makes it a renewable resource.Water on Earth moves continually through a cycle of evaporation or transpiration (evapotranspiration), precipitation, and runoff, usually reaching the sea. Over land, evaporation and transpiration contribute to the precipitation over land.
Water is fundamental solvent to photosynthesis and respiration of flora. For human life, water is vital both as a solvent in which many of the body's solutes dissolve and as an essential part of many metabolic processes within the body.Earth's surface waters are filled with life. The earliest life forms appeared in water; nearly all fish live exclusively in water, and there are many types of marine mammals, such as dolphins and whales. Some kinds of animals, such as amphibians, spend portions of their lives in water and portions on land. Plants such as kelp and algae grow in the water and are the basis for some underwater ecosystems. Plankton is generally the foundation of the ocean food chain.

Clean drinking water is essential to human and other lifeforms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world.
Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation.The UN World Water Development Report (WWDR, 2003) from the World Water Assessment Program indicates that, in the next 20 years, the quantity of water available to everyone is predicted to decrease by 30% -40% of the world's inhabitants currently have insufficient fresh water for minimal hygiene.
On year 2006, Portugal Post issued the stamp series of six pieces that featured the waters of Portugal for presenting are the importance of water in Portugal and generally for all lifeforms in the world.

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