Hydrosphere<br /> A hydrosphere (from Greekὕδωρ - hydor, "water" and σφαῖρα - sphaira, "sphere") in physical geography describes the combined mass of water found on, under, and over the surface of a planet.<br />The total mass of the Earth's hydrosphere is about 1.4 × 1018tonnes, which is about 0.023% of the Earth's total mass. <br />
<ul><li>About 20 × 1012tonnes of this is in the Earth's atmosphere (the volume of one tonne of water is approximately 1 cubic metre). Approximately 75% of the Earth's surface, an area of some 361 million square kilometres (139.5 million square miles), is covered by ocean. The average salinity of the Earth's oceans is about 35 grams of salt per kilogram of sea water (35 ‰).</li></li></ul><li>
Other hydrospheres<br />A thick hydrosphere is thought to exist around the Jovian moon Europa. The outer layer of this hydrosphere is almost entirely ice, but current models predict that there is an ocean up to 100 km in depth underneath the ice. This ocean remains in a liquid form because of tidal flexing of the moon in its orbit around Jupiter. The volume of Europa's hydrosphere is 3 × 1018 m3, 2.3 times that of Earth.<br />
<ul><li>It has been suggested that the Jovian moon Ganymede and the Saturnian moon Enceladus may also possess sub-surface oceans. However the ice covering is expected to be thicker on Jupiter's Ganymede than on Europa</li></li></ul><li>Hydrological cycle<br />Insolation, or energy (in the form of heat and light) from the sun, provides the energy necessary to cause evaporation from all wet surfaces including oceans, rivers, lakes, soil and the leaves of plants. Water vapor is further released as transpiration from vegetation and from humans and other animals.<br />
<ul><li>Aquifer drawdown or overdrafting and the pumping of fossil water increases the total amount of water in the hydrosphere that is subject to transpiration and evaporation thereby causing accretion in water vapour and cloud cover which are the primary absorbers of infrared radiation in the earth's atmosphere. Adding water to the system has a forcing effect on the whole earth system, an accurate estimate of which hydrogeological fact is yet to be quantified</li></li></ul><li>Water pollution<br />
Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans and groundwater). Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds.<br />
Water pollution is a major global problem. It has been suggested that it is the leading worldwide cause of deaths and diseases,and that it accounts for the deaths of more than 14,000 people daily. <br />
An estimated 700 million Indians have no access to a proper toilet, and 1,000 Indian children die of diarrheal sickness every day.Some 90% of China's cities suffer from some degree of water pollution, and nearly 500 million people lack access to safe drinking water<br />
The causes of water pollution may be due to direct and indirect contaminant sources. The former are effluent outputs from refineries, factories, waste treatment plants.<br />
The latter are the water supply from soils/groundwater systems that have fertilizers, pesticides and industrial wastes. Also those through the atmosphere like bakeries, factories emission and automobile discharge. Contaminants can also be divided into inorganic, organic, acid/base and radioactive.<br />
Organic water pollutants are:<br />1.Food processing waste, including pathogens<br />2.Insecticides and herbicides, a huge range of organohalide and other chemicals<br /> 3.Tree and brush debris from logging operations<br />4.Bacteria from sewage or livestock operations<br />5.Petroleum hydrocarbons like diesel, gasoline, jet fuels, fuel oils, motor oils<br />6.Volatile organic compounds like industrial solvents<br />
Inorganic water pollutants are:<br />1.pre-production industrial raw resin pellets<br />2.heavy metals including acid mine drainage<br />3.chemical waste as industrial by-products<br />4.acidity due to industrial discharges like sulphur dioxide<br />5.silt in surface runoff due to logging, slash and burn practices, construction sites or land clearing sites<br />6.fertilizers in runoff from agriculture including nitrates and phosphates<br />
The effects of water pollution are varied and depend on what chemicals are dumped and in what locations.<br />
<ul><li>Boston Harbor is a strong example of how badly pollution can damage bodies of water. The water is filled with toxic waste and sewage, and routinely receives more waste when rainfall pushes it into the harbor.
Many bodies of water near urban areas are highly polluted. This is the result of both garbage dumped by individuals and dangerous chemicals legally or illegally dumped by industries.</li></li></ul><li>Many bodies of water near urban areas are highly polluted. This is the result of both garbage dumped by individuals and dangerous chemicals legally or illegally dumped by industries.<br />
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