GEF

Unit 4   |  The Global Ecosystem 93 3. Water that seeps beneath the ground is called ground- water. It flows to underground reservoirs called aquifers , affecting the lithosphere by breaking down rock and dis- solving minerals. 4. From there, water is taken up by plants to become a part of the biosphere. Water is essential for plant growth and therefore life on Earth. 5. Humans harvest fresh water for use in agriculture, industry, or as drinking water. The water cycle illustrates how water moves through the various states on earth. Fresh potable (drinkable) water is in short supply, making up less than 1 % of all water on Earth. Humans threaten this critical resource through inefficient use and pollution. Water shortages are a growing problem in many areas around the world. AQUIFERS Underground layers of porous rock that allow the movement of water between layers of non-porous rock; they are important and critical sources of water for agriculture in many parts of the world. POTABLE Drinkable.