The surface of a freshwater lake in daylight.

A term that refers to bodies of water such as ponds, lakes, rivers and streams containing low concentrations of dissolved salts and other total dissolved solids. Freshwater is an important renewable resource, necessary for the survival of most terrestrial organisms, and is required by humans for drinking and agriculture, among many other uses. Despite its importance, freshwater continues to be wasted and degraded all over the world(this comment is considered not to be neutral). The UN estimates that about 1.2 billion people (18 percent of the world's population) lack access to safe drinking water.[1] Freshwater is a village and parish at the western end of the Isle of Wight. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Two people reflected in a fish pond A pond is typically a man made body of water smaller than a lake. ... For other meanings of the word salt see table salt or salt (disambiguation). ... Bottled mineral water usually contains higher TDS levels than tap water Total dissolved solids (often abbreviated TDS) is an expression for the combined content of all inorganic and organic substances contained in a liquid which are present in a molecular, ionized or micro-granular (colloidal sol) suspended form. ... A natural resource qualifies as a renewable resource if it is replenished by natural processes at a rate comparable to its rate of consumption by humans or other users. ... In biology and ecology, an organism (in Greek organon = instrument) is a living being. ... Tap water Mineral Water Drinking water is water that is intended to be ingested through drinking by humans. ... This article is about the United Nations, for other uses of UN see UN (disambiguation) Official languages English, French, Spanish, Russian, Chinese, Arabic Secretary-General Kofi Annan (since 1997) Established October 24, 1945 Member states 191 Headquarters New York City, NY, USA Official site http://www. ...

Numerical definition

roger is defined as water with less than 0.5 parts per thousand dissolved salts.^[1] Freshwater bodies include lakes and ponds, rivers, some bodies of underground water and many kinds of man-made freshwater bodies, such as canals, ditches and reservoirs. The ultimate source of freshwater is the precipitation of atmosphere in the form of rain and snow. This article is about common table salt. ... For other uses, see Lake (disambiguation). ... Two people reflected in a fish pond A pond is typically a man made body of water smaller than a lake. ... For other uses, see River (disambiguation). ... Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations. ... Air redirects here. ... This article is about precipitation. ... For other uses, see Snow (disambiguation). ...

Brackish redirects here. ... For the sports equipment manufacturer, see Brine, Corp. ...

Water distribution

 carries more heat. 

Access to unpolluted freshwater is a critical issue for the survival of many species, including humans, who must drink freshwater in order to survive. Only three percent of the water on Earth is freshwater in nature, and about two-thirds of this is frozen in glaciers and polar ice caps. Most of the rest is underground and only 0.3 percent is surface water. Freshwater lakes, most notably Lake Baikal in Russia and the Great Lakes in North America, contain seven-eighths of this fresh surface water. Swamps have most of the balance with only a small amount in rivers, most notably the Amazon River. The atmosphere contains 0.04% water. ^[2] In areas with no freshwater on the ground surface, freshwater derived from precipitation may, because of its lower density, overlie saline ground water in lenses or layers. This article is about Earth as a planet. ... This article is about the geological formation. ... Polar Ice Cap on Mars, seen by the Hubble Telescope This article is about polar ice caps in general, for Earths ice cap see: Polar ice packs A polar ice cap or polar ice sheet is a high-latitude region of a planet or moon that is covered in... Baikal redirects here. ... The Great Lakes from space The Great Lakes are a group of five large lakes on or near the United States-Canadian border. ... This article is about the river. ...

Aquatic organisms

Freshwater creates a hypotonic environment for aquatic organisms. This is problematic for some organisms, whose cell membranes will burst if excess water is not excreted. Some protists accomplish this using Contractile vacuoles, while freshwater fish excrete excess water via the kidney.^[3] Although most aquatic organisms have a limited ability to regulate their osmotic balance and therefore can only live within a narrow range of salinity, diadromous fish have the ability to migrate between freshwater and saline water bodies. During these migrations they undergo changes to adapt to the surroundings of the changed salinities; these processes are hormonally controlled. The eel (Anguilla anguilla) uses the hormone prolactin, while in salmon (Salmo salar) the hormone cortisol plays a key role during this process. Tonicity is a measure of effective osmolarity or effective osmolality. ... Typical phyla Chromalveolata Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Cabozoa Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: (RP); (GenAm)), Greek protiston -a meaning the (most) first of all... Figure 1: A paramecium. ... A vast number of species of fish have been successfully kept in the home aquarium. ... The kidneys are the organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. ... Many types of fish undertake migrations on a regular basis, on time scales ranging from daily to annual, and with distances ranging from a few meters to thousands of kilometers. ... For other uses, see Fish (disambiguation). ... Many types of fish undertake migrations on a regular basis, on time scales ranging from daily to annual, and with distances ranging from a few meters to thousands of kilometers. ... Annual mean sea surface salinity for the World Ocean. ... Prolactin (PRL) is a peptide hormone primarily associated with lactation. ... Cortisol is a corticosteroid hormone produced by the Zona fasciculata of the adrenal cortex (in the adrenal gland). ...

See also

• Desalination
• Limnology
• Seawater
• Water (molecule)
• Water cycle
• Water resources

Shevchenko BN350 desalination unit situated on the shore of the Caspian Sea. ... Lake Geneva Limnology (from Greek: Λίμνη limne, lake; and λόγος, logos, knowledge) is the study of inland waters (both fresh and saline), including their biological, physical, chemical, geological and hydrological aspects. ... Annual mean sea surface salinity for the World Ocean. ... H2O and HOH redirect here. ... The movement of water around, over, and through the Earth is called the water cycle. ... Water resources are sources of water that are useful or potentially useful to humans. ...

References

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 86th day of the year (87th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... May 14 is the 134th day of the year (135th in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ... is the 307th day of the year (308th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... May 14 is the 134th day of the year (135th in leap years) in the Gregorian calendar. ...

External links

• Freshwater life.org
• Freshwater Biological Association
• Review of freshwater ecology in the UK
• UK Government Environmental Agency website
• Pond Conservation
• UK National pond monitoring network