Key Terms

• What is ablation?

  The loss of ice and snow, especially from a glacier, through melting, evaporation, and sublimation.
• What is abstraction?

  The extraction of water from rivers and boreholes for public water supply, agriculture etc.
• What is acidification?

  A process in which the pH drops as the conditions become more acidic.
• What is the active layer?

  The near surface layer in a periglacial environment which seasonally freezes and thaws.
• What is afforestation?

  Planting trees to increase the area of forest.
• What is albedo?

  A measure of the reflectivity of a surface. More reflective surfaces have high albedos. A surface that reflects all light has an albedo of 100%, while one that absorbs all light has an albedo of 0%. The albedo of an area can affect the local climate.
• What are anaerobic processes?

  A process that takes place in the absence of oxygen.
• What are aerobic processes?

  A process that takes place in the presence of oxygen.
• What does anthropogenic mean?

  Adjective describing outcomes caused by human activities.
• What is the aphotic zone?

  Deeper layers of water that receive no sunlight because they are absorbed by shallower layers.
• What is an aquifer?

  A rock which contains water that is abstracted by humans.
• What is the atmosphere?

  The gases surrounding the Earth. Different layers are characterised by their temperature, density, turbulence and composition.
• What is the biogeochemical cycle?

  A series of linked processes which use and re-use elements such as carbon, nitrogen, phosphorus, iron and sulphur, as they move between biotic and abiotic reservoirs.
• What is bioleaching?

  A method of using bacteria to dissolve metals from low grade ores.
• What is biological weathering?

  The breakdown of rocks through the chemical and physical action of living organisms, e.g., burrowing, tree roots etc.
• What is biomass?

  The total mass of living, or recently living material in an area.
• What is the biosphere?

  The space at the earth’s surface and within the atmosphere occupied by living organisms.
• What is the canopy?

  The uppermost layer of treetops and branches in a forest or woodland ecosystem.
• What is carbon capture and storage?

  A method to reduce carbon dioxide emissions, by removing the gases and storing them in underground geological structures.
• What are carbon credits?

  Allowances that permit given levels of CO2 emissions by businesses. Excess emissions must by covered by trading carbon credits.
• What is carbon fertilisation?

  Rising CO2 levels in the atmosphere which increase photosynthesis and stimulate plant growth.
• What is carbon footprint?

  An estimate of the total releases of greenhouse gases caused by the actions of an individual, group of people, an organisation or activity. The amounts of all greenhouse gases are expressed as the equivalent amount of carbon dioxide.
• What are carbon offsets?

  Market-based approach to limiting carbon emissions. Businesses receive annual carbon quotas (credits). These can be sold/bought on international carbon markets.
• What is carbon sequestration?

  Any process which removes carbon dioxide from the atmosphere, such as afforestation or underground storage (carbon capture).
• What is a carbon sink?

  A long-term store of carbon in ocean sediments, carbonate rocks, forests etc.
• What is a catchment area?

  The area drained by a river and its tributaries i.e., a drainage basin.
• What are CFCs?

  Chlorofluorocarbons; ozone-depleting gases emitted from aerosols, fire extinguishers and refrigerators.
• What is chemical analysis?

  Laboratory tests confirm the chemical composition and purity of minerals in the rock samples.
• What are cirrus clouds?

  Thin, wispy clouds, usually found at altitudes above 6000m. Cirrus clouds can reflect infrared energy emitted by the Earth’s surface and emit infrared produced from absorbed sunlight.
• What is combustion?

  The process of burning.
• What is condensation?

  The phase change of water vapour (gas) to water (liquid).
• What is contour cropping?

  A soil erosion control measure where land is cultivated by ploughing horizontal furrows along the contours of the land.
• What is convection?

  The motion of a gas or liquid which when warmed rises until eventually it cools and sinks in a continuous circulation.
• What is the cryosphere?

  All the frozen water on Earth.
• What is C2C?

  Cradle to cradle (C2C); the concept of designing items such that all the materials used can be reused or disposed of without leaving toxic or harmful wastes. The concept is based on the natural systems that recycle elements without depleting resources or causing harmful wastes to build up.
• What is dead organic matter?

  The fresh residues, or “dead” organic matter, consist of recently deceased microorganisms, insects, earthworms, old plant roots, crop residues, and recently added manures.
• What are decomposers?

  Organisms that break down dead organic matter, releasing nutrients in the process. Many bacteria and fungi are decomposers. They secrete enzymes onto the dead organic matter and absorb the products of digestion.
• What is dendrochronology?

  The method of determining the age of a piece of wood using the characteristic sequence of sizes of growth rings in the wood.
• What are detritivores?

  These are heterotrophic animals that ingest and digest dead organic matter. Examples include: earthworms, millipedes, woodlice, dung beetles and slugs. They often break up the dead organic matter into smaller pieces, providing access to decomposers.
• What is downwelling?

  The sinking of dense, salty (or cold) water in the oceans.