GEF

146 Glossary AQUATIC ECOSYSTEM  Biological communities of plants, animals, bacteria, fungi, and other organ- isms in a body of water. AQUIFERS  Underground layers of porous rock that allow the movement of water between layers of non- porous rock. ATRAZINE  A synthetic compound typically used in agriculture to kill plants, such as, weeds. BARRIER ISLANDS  Long, narrow islands close to the mainland, which protect land areas and cities from flooding and provide a range of ecological services. BIOMASS ENERGY  Renewable energy produced from organic materials. BIOSPHERE  The zone of life on Earth. BLACKWATER  Water used to flush away human waste. BLOCK PRICING  A pricing structure in which users pay higher rates with higher levels of use. BOREHOLE  A narrow shaft drilled into the ground for water extraction. CAPILLARY ACTION  The ability of liquids to flow through narrow spaces, such as blood vessels or plant tissues, against gravity. CARBON DIOXIDE (CO 2 )  A gas that is the most common form of atmospheric carbon, used by plants in photosynthesis, and emitted during the combustion of carbon based fuels such as petroleum. CHANNELIZATION  To make, form, or cut channels. CIVIL SOCIETY  A community of citizens with no direct involvement with the government, linked by common interests and collective activity. CLEAN WATER ACT  A U.S. federal law that regu- lates the discharge of pollutants into the nation’s surface waters. CLIMATE  Regional weather patterns over an extended period of time. CLIMATE CHANGE  A long-term change in the Earth’s weather patterns and temperature, caused primarily by human emissions of greenhouse gases. COHESION  A measure of how well molecules stick to each other, caused by the attractive force between like molecules. CONDENSATION  The change of matter from a gas to a liquid. CONSTRUCTED WETLANDS  Artificial wetlands created for filtering wastewater and improving wildlife habitat. CONSUMPTIVE  Activity that consumes or depletes the water source. CRYOSPHERE  The portion of the Earth where water is maintained as snow or ice. DAM  A barrier constructed to hold back water and raise its level, the resulting reservoir being used in the generation of electricity or as a water supply. DEAD ZONES  Marine areas with low levels of oxy- gen caused by the decomposition of algae blooms or other phytoplankton. DEFORESTING  The action of cutting down trees to create clear land. DENSITY  A measure of mass per unit of volume. DESALINATION  The removal of salts and minerals from a target substance, such as from salt water in order to create fresh water.