GEF

147 Glossary DICHLORODIPHENYLTRICHLOROETHANE (DDT)  A pesticide that was widely used until 1972 when the U.S. banned it after discovering its detrimental effects on human health and the environment. DISSOLVED OXYGEN  Microscopic bubbles of gas- eous oxygen mixed in water and available to aquatic organisms for respiration. DRIP IRRIGATION  A form of irrigation that saves water and fertilizer by allowing water to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone, through a network of valves, pipes, tubing, and emitters. ECOLOGICAL SYSTEMS  Large-scale components of the Earth, such as the oceans, the atmosphere, and the biosphere. ECOSYSTEM SERVICES  Services such as crop pollination and flood control which are provided by natural ecosystems. ECOSYSTEMS  Biological communities of plants, animals, bacteria, fungi, and other organisms in combination with their environment. EMBODIED WATER  The amount of fresh water used to produce a product or service. Also called virtual water. ENDOCRINE DISRUPTORS  Chemicals that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological, and immune effects in both humans and wildlife. ENVIRONMENTAL PROTECTION AGENCY (EPA)  An agency of the United States federal government whose mission is to protect human and environmen- tal health. EROSION  The process by which soil or rock is removed by water or wind. ESTUARINE  The area where the sea meets a river and the salt water is diluted by the fresh water from the river. EUTROPHICATION  T he process in which a body of water becomes excessively enriched with nutrients resulting in growth of aquatic life and depleting the oxygen availability for other organisms. EVAPORATION  The change of matter from a liquid to a gas. EXTERNALITIES  Consequence of an industrial or commercial activity that is not reflected in the cost of the goods or services involved. FAUCET AERATOR  A device installed on a faucet head to introduce air into running water. FEEDBACK LOOP  In biology, a process in which the level of one substance influences the level of another substance. FISH LADDER  A mechanical device that allows fish to pass by or through dams. FOSSIL FUELS  Nonrenewable carbon-based fuels, such as oil, coal, and natural gas, formed from the decomposition, geological compression, and heat- ing of organic material. FOSSIL WATER  Water that has remained in under- ground aquifers for long periods of time. GAS  One of four main states of matter composed of molecules in constant random motion. GENETICALLY MODIFIED CROPS  Crops such as corn or soybeans in which genes from one species are placed into another entirely unrelated species, for example to increase yield or to provide resistance to pests. GLACIER  A large body of ice that persists for a long period of time. GOVERNANCE  The act or manner of governing.