Importance of waterOrganisms are composed of much water––70%-95% Supportive external environment for aquatic organisms Cellular medium within which biochemical reactions can occur Transport medium for food, oxygen, and other things needed by cells Means of support-Turgid plant cells /Hydrostatic animal support systems
Two main processes: precipitation and evaporation Powered by energy from the sun Hydrologic cycle purifies water
Three Forms of Water. Solids: When water becomes very cold and freezes it will change from a liquid to a solid. It has a definite form and shape. Liquids: When water takes the shape of its container it is in a liquid form. Gases: When water is seen in a vapor form and has no definite size or shape it is in a gas form.
World Water Supply97.200% salt water in the oceans02.014% ice caps and glaciers00.600% groundwater00.009% surface water00.005% soil moisture00.001% atmospheric moisture
Earth as water planet Earth is often referred to as `the water planet. Earth is unique amongst planets of our solar system because of its abundant water - in oceans, in the atmosphere, in glaciers and as fresh water on land. Without water, life could not exist.
The earths freshwater supply Only about 3% of Earths water is fresh. Two percent of the Earths water (about 66% of all fresh water) is in solid form, found in ice caps and glaciers. One percent of all the Earths water in a form useable to humans and land animals. This fresh water is found in lakes, rivers, streams, ponds, and in the ground. (A small amount of water is found as vapor in the atmosphere.)
Distribution of water Ocean Water: The vast majority of water on the planet is the salt water in the oceans and seas. Fresh Surface Water: This is the fresh water in rivers, streams, lakes, ponds and similar bodies of water. Groundwater: The majority of the planets liquid freshwater is stored in underground aquifers. Water that enters an aquifer remains there for an average of 1,400 years!
Water : A precious Natural Resource We use water for drinking, irrigation, industrial purposes and energy production. Water use agriculture and energy production - 80% industry and public use - 20%
Water is used in many ways as a nourisher of plant and animal life, a bearer of food, a prime element of industrial processes, and a medium for transportation