Water Distribution
Water is a critical issue for the survival of all living organisms. Some can use salt water but many organisms including the great majority of higher plants and most mammals must have access to fresh water to live. Some terrestrial mammals, especially desert rodents appear to survive without drinking but they do generate water through the metabolism of cereal seeds and they also have mechanisms to conserve water to the maximum degree.
Out of all the water on Earth, salt water in oceans, seas and saline groundwater make up about 97% of it. Only 2.5-2.75% is fresh water, including 1.75-2% frozen in glaciers, ice and snow, 0.7-0.8% as fresh groundwater and soil moisture, and less than 0.01% of it as surface water in lakes, swamps and rivers. Freshwater lakes contain about 87% of this fresh surface water, including 29% in the African Great Lakes, 23% in Lake Baikal in Russia, 21% in the North American Great Lakes, and 14% in other lakes. Swamps have most of the balance with only a small amount in rivers, most notably the Amazon River. The atmosphere contains 0.04% water. In areas with no fresh water on the ground surface, fresh water derived from precipitation may, because of its lower density, overlie saline ground water in lenses or layers. Most of the world's fresh water is frozen in ice sheets. Many areas suffer from lack of distribution of fresh water, such as deserts.
Read more about this topic: Fresh Water
Famous quotes containing the words water and/or distribution:
“Our star was brighter perhaps when it had water in it.
Now there is no question even of that, but only
Of holding on to the hard earth so as not to get thrown off,
With an occasional dream, a vision ...”
—John Ashbery (b. 1927)
“There is the illusion of time, which is very deep; who has disposed of it? Mor come to the conviction that what seems the succession of thought is only the distribution of wholes into causal series.”
—Ralph Waldo Emerson (1803–1882)